Next in this 3 part series, continued from STACK SEALING (http://dieselplace.com/forum/showthread.php?t=40080), there presently are a total 5 nose configurations in the Duramax evolution. Each one requires a different nose shroud design. These pics are from recent installs I have done. Some of the pics are of 05 chevy, and some are LLY GMC. Just FYI, this mod is applicable to non-TD vehicles as well. The 8.1 perhaps would benefit.

Commonly (and affectionately) referred to as the POS flap.

Pic shot from below, this darn AC flap is so flimsy, the least bit of pressurization on the nose, sends it flopping to the street, spilling anything that is captured by the grill. This one showed up at my place looking like this. The first thing we removed. It is so full of holes, it's a wonder it helps at all.


http://dieselplace.com/forum/attachment.php?attachmentid=8035&d=1125236985

Shows the replacement, cut to correct size.

http://dieselplace.com/forum/attachment.php?attachmentid=8036&d=1125236985

Getting this in can be a bit of a workout, the material is stout. Use gloves, JJ can tell you. When in place, there is no where for ambient to go. This pic shows the tranny line detail, as the form is put in place under the CAC.

http://dieselplace.com/forum/attachment.php?attachmentid=8037&d=1125236985

Side pieces are next. They should be able to fit the body, with no additional support. These are made to also block recirculated air from the motor bay, no more hot air coming around to the front. Note the tabs at the top that sit on top of the CAC, under the rad support.

http://dieselplace.com/forum/attachment.php?attachmentid=8038&d=1125236985

Installed, will not move. Nothing but the design itself holding it in place, the lower part of it is buried in the bumper, blocking escape airflow paths.

This is an 05 kit, a fairly demanding fabrication process. The originals took about 10 hours to get right. Use a rigid material, note the 2 fabric layers in the sheet.

http://dieselplace.com/forum/attachment.php?attachmentid=8039&d=1125236985

The cutouts shown, to allow the piece to flex enough to keep from deforming back at the CAC. The seal against the CAC is the most important aspect.

http://dieselplace.com/forum/attachment.php?attachmentid=8040&d=1125237092

This shows a GMC grill removed, to see the importance of the grill in the design. The grill structure (Chevy also) holds the side piece back, so that none of the grill openings are lost to arflow. In addition, the integration insures air pressurizes the nose (which it does) and keeps ambient flow maximized. Fit here, must be correct or the grill will keep popping off, or if cut too short, the leading edge of the shroud will flail in the wind.
http://dieselplace.com/forum/attachment.php?attachmentid=8041&d=1125237092

All the posts other then the first one are red x's.

Is anyone else able to see the pics, I see them fine.

All the posts other then the first one are red x's.

Same as Max .... first is good, all the rest are red x's

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I can see the photos. For those who cannot, they are the same photos as in KB's first post, but bigger with the textual descriptions.

Joseph

I see the photos fine.(not bragging).

I see the photos fine.(not bragging).

Look familiar, Stallion?

I also see all the photo's just fine..........

Must be your browsers or your settings............
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.
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The one on my 2002 GMC is made of hard plastic and doesn't droop like that.......... Now I understand why you call it the POS A/C flap-:t
Commonly (and affectionately) referred to as the POS flap.

Pic shot from below, this darn AC flap is so flimsy, the least bit of pressurization on the nose, sends it flopping to the street, spilling anything that is captured by the grill. This one showed up at my place looking like this. The first thing we removed. It is so full of holes, it's a wonder it helps at all.


http://dieselplace.com/forum/attachment.php?attachmentid=8035&d=1125236985

Installed, will not move. Nothing but the design itself holding it in place, the lower part of it is buried in the bumper, blocking escape airflow paths.

This is an 05 kit, a fairly demanding fabrication process. The originals took about 10 hours to get right. Use a rigid material, note the 2 fabric layers in the sheet.

http://dieselplace.com/forum/attachment.php?attachmentid=8039&d=1125236985

KB: All the pics came in fine on my end. Your product does look factory and saying that the 05 is a demanding process is an understatement, particularly after messing with mine yesterday trying to get a decent looking template. As per your e-mail I will forward you some photos of my grill design. Thanks for your help.

Next in this 3 part series, continued from STACK SEALING (http://dieselplace.com/forum/showthread.php?t=40080), there presently are a total 5 nose configurations in the Duramax evolution. Each one requires a different nose shroud design. These pics are from recent installs I have done. Some of the pics are of 05 chevy, and some are LLY GMC. Just FYI, this mod is applicable to non-TD vehicles as well. The 8.1 perhaps would benefit.

Is one of those 5 nose configurations specifically for a 2002 GMC? I'm concerned with the fitment of the side upright pieces with the grill as it is totally different from the GMC's I've seen in your posts. Given your statment that the grill fit is critical to holding the uprights in place, achieving proper pressurazation, and keeping the uprights from flailing in the wind.. Also when looking at my buddy's 05, I swear that my CAC is thicker than the 05 LLY CAC,(but have not actually measured it) I also know that the bumper sticks out further on the newer models.

Bottom line is that I'm ready to send the paypal pmt if the kit will fit my 2002 GMC without requiring me to modify it to fit my truck. I know I would probably screw up trying to custom cut it to fit. :badidea:

Thanks again, again, again for all the work you guys have put into this effort.

Yes, the earlier GMC is one of the 5. I still need to polish those. I need someone with an 01-03 GMC who is local. Any AZ volunteers? Email me.

I have seen only one CAC in all the vehicles I have looked at. I would like to know for sure if you have seen another "factory" one. I have done 2 banks CAC's, they mount to the same flushness.

I could see all the pictures fine also. Looks like a great design. Are you going to make templates or kits available. I have a 2004 LLY Chevy.
Steve

I can see the pics now.

I see the pix OK.
My question is what is the material and where did you get it?

The material is a multi-ply, nylon fiber, rubber composite used as an industrial belt material, 13/32 thick. I purchase in large quantities from a rubber factory. If you try this, you will need something like a bandsaw to cut it. It will outlast the dinosaurs.

Steve, E-mail me for more details on kits.

are you going to make some and have them available for sale? or at least some paper templates?

Are there only three pieces needed? Two sides and one bottom?
Steve

Yes.

I'm gonna try some on my 02 8.1, no cooling probs yet but would like to keep tranny a bit cooler, it runs about 190-210 now. If this doesn't do well then it's time for a Mike L cooler.
Will definitely cut up something for boss's 05 GMC Dmax, also some others. have had no temp complaints but I'm sure they're coming to our shop soon.

Are there only three pieces needed? Two sides and one bottom?
Steve

Let me restate. I am working on a top piece, but it mostly serves as a tranny cooler assist. There is a considerable amount of vertical flow, once inside the grill, from bottom to top. The shrouds reduce much of that, but what is left can be converted to lateral flow, over the cooler. I hope this will be a significant improvement in tranny cooling. I will be done with that today.

KB, no rest for the weary around here. You've been going at this full throttle for several weeks. Very much appreciated. :exactly:

I installed a set of KB's nose shrouds yesterday. I was trying to get several mods completed before hitting the road to Tennessee. Hurricane Katrina has changed our road plans for now. Hopefully we will be able to get on the road Wednesday or Thursday. ;)

Shroud install was pretty easy, KB sent good instructions, just wear a pair of soft cotton gloves or you will look like you have been in a cat fight when its all over with. ):h

I'm still using aluminum foil to seal the sides of the CAC near the headlights. We'll need better materials for that job. Still waiting on the silicone foam to seal between the CAC and radiator, I'm using metal tape for now. I also installed the modified 5.3 airbox, used a C-clamp to hold the corner together where the screw is missing. On my airbox there was quite a gap that had to be closed. Most appear OK, but best to check em all to ensure a good seal.

Took the 5ver for a drive after doing the mods. Fan engages at higher temps now than before (roughly 214* versus 198* average-inconsistent engagement). Highest ECT's were 225* (Attitude monitor) on a 0-60 hard throttle run. OEM gauge just above 210*, totally inaccurate. ECT's dropped like a rock upon deceleration from 70mph to full stop off interstate exit ramp (187*). Stack definitely appears to be shedding heat more effectively. Still some fan engagement upon initial acceleration, not too long though. :confused:

CAI effect is all SOTP's since I don't have sensors or Predator to monitor temps, so nothing definitive there. EGT's are definitely cooler when not towing. Here's a link with mod pictures, air box, and 5ver. Sorry for bad quality on a couple of these.

www.msnusers.com/mamajjsdumax/shoebox.msnw (http://www.msnusers.com/mamajjsdumax/shoebox.msnw)

Oh, that's Mama JJ partying on her 50th in case any of you are wondering. Dang drunk!

I posted 9 mpg's through 170 miles of testing. Not too impressive unless you consider that is a 40' 5ver strapped to my truck at about 24-25k lbs GCW. I ran the truck at 75mph to create a lot of drag to work the stack good and hard. OAT's between 92*-95*, light wind (negligible). We have a fairly high bridge (8%+) that gives my gas vehicles a hard time. I took this bridge 3 different times at differing speeds: 60;65;70mph. Very high RPM's on these climbs, wasn't able to hold speed, may have waited too long to put my foot into it. Then again I was about 2k lbs over GCWR, it is a light duty truck. ;)

ECT's cranked up to 220*-224* at crest, fan engaged and ECT's dropped quickly. This was a mixture of city/highway, 30%/70% respectively. No doubt in my mind that at 60-65mph straight interstate driving I would have been in the 11mpg+ range. With this much air drag and weight I'll take that any day! :D

Really wish the weather had cooperated for our run to the mountains, we'll regroup later in the week. Those of you that have installed nose shroud mods and tow heavy we need your input. BTW, I was reading my data incorrectly thinking that ECT's getting to 225* was a negative when in actuality it was a good sign that the fan didn't engage until then and pulled ECT's down. This is likely the way the stack was designed to work. Not likely I will ever hear the fan when not towing. Just need more test beds for validation purposes. ;)

Truck appears to have more zip to. :cool: All in all a good day! Later. JJ :)

I talked to JJ today. The seal and shrouds appear to move so much air, that the clutch onset is delayed, maybe 5 to 10 degrees ECT, due to cooler air arriving over the clutch. ECT's, and fan clutch activation are not linked electronically. The clutch relies on hot air flow over it to engage.

I feel that this is a major improvement, as I can't stand early fan engagement, it cost me 20 HP every time it comes on. Now when it comes on, it should wait longer, be for less time, and work twice as well.

Note, JJ remarked that 225 on the edge (fan engagement) was barely obver the 210 mark on the oem gauge.
JJ's economy improvement is due mainly to 2 things, cold air intake, and CAC improvment from the extra flow (denser combustion air). And of course, less fan engagement.

Just FYI for the questions I know are coming.

I forgot to mention E/J module temps. While towing underhood temps averaged about 175* with ECT's fluctuating between 198* and 212* with spikes higher at 225*. :confused:

I should also clarify that on the 75mph runs the fan would engage anywhere from 214*-225*, in each instance ECT's would draw down to 198*-200* before fan disengagement. Amazing to me just how fast ECT's drop when you let off the go-pedal. This furnace puts out some BTU's! :eek:

Are we satisfied that underhood temps are within reason? I recall some discussion about getting things too cold in the winter months. Evidently quite a balancing act. The truck is shedding a considerable amount of BTU's under the hood. My hood was very hot today, especially the front fender areas. Would be nice to get some temp readings on a mod'd truck.

KB, I don't know how you are keeping up this pace. This stuff can monopolize ones time, I know it has mine. Take a break and play with the kiddies, they're the real deal. ;) Later. JJ :)

KB, I don't know how you are keeping up this pace. This stuff can monopolize ones time, I know it has mine. Take a break and play with the kiddies, they're the real deal. ;) Later. JJ :)

true. so true.

If you are reading this, remember that while the Eagles can bring back memories for us oldies, there are wall-to-wall children trying to get into the superdome, New Orleans, just to survive. People may die tomorrow.

Tune in and help them if you can.

true. so true.

If you are reading this, remember that while the Eagles can bring back memories for us oldies, there are wall-to-wall children trying to get into the superdome, New Orleans, just to survive. People may die tomorrow.

Tune in and help them if you can.

People will die tonight/tomorrow morning from this storm. :(

New Orleans area is below sea level, and the populace isn't well off overall to begin with. We are all fortunate that we have the "problems" that we think we have, that modifying our $45k or so trucks for fun is a pressing issue in our lives. So many out there aren't so lucky.

Have a good night everyone, stay safe and pray for those in the path of danger!

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Tomorrow is shaping up to be a grim day. Just so hard to imagine an entire city underwater. They will need all of our prayers. See you guys tomorrow. JJ

I forgot to mention E/J module temps. While towing underhood temps averaged about 175* with ECT's fluctuating between 198* and 212* with spikes higher at 225*. :confused:

I should also clarify that on the 75mph runs the fan would engage anywhere from 214*-225*, in each instance ECT's would draw down to 198*-200* before fan disengagement. Amazing to me just how fast ECT's drop when you let off the go-pedal. This furnace puts out some BTU's! :eek:

Are we satisfied that underhood temps are within reason? I recall some discussion about getting things too cold in the winter months. Evidently quite a balancing act. The truck is shedding a considerable amount of BTU's under the hood. My hood was very hot today, especially the front fender areas. Would be nice to get some temp readings on a mod'd truck.

KB, I don't know how you are keeping up this pace. This stuff can monopolize ones time, I know it has mine. Take a break and play with the kiddies, they're the real deal. ;) Later. JJ :)


JJ, I thought last year you said you were letting out when it hit 230* anyway. So last year were we talking 230* edge or gauge? :confused:

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Is anyone else able to see the pics, I see them fine.

All that I see are red Xs.

All that I see are red Xs.

I see All the Pic's.

Fox

TxC,

Those were OEM gauge readings when I saw 230* ECT, 210* on the ally. I let off the go pedal once I saw temps rising. Yesterday when the attitude showed 225* the OEM ECT gauge was just above 210*. I believe it is so slow to react to such drastic/quick changes in ECT's to make it very unreliable. :o:

It really amazes me just how fast this engine can spike ECT's. On a 0-60mph heavy throttle run the ECT's went from 192* to 225* at OAT 95*. That's fast considering it takes just about a minute to get to that speed towing 15k-16k pound 5ver. It just may be these spikes that cause the very high ECT readings folks are seeing when climbing steep grades, especially on any aftermarket gauges. :confused: The OEM gauge would give one the impression they are not budging ECT's even though they are up around 220*+. Might explain why some are saying they never budge their gauges. Ignorance is bliss! ):h

On the bridge climb the fan didn't seem to engage until I was either cresting the hill or just over it and coasting. I had full power while climbing, just not enough hp/tq to maintain my speed at that weight and configuration. Until I see data to the contrary, I'm going to seal up the tow hook holes in the lower valance, just appears to be too much high pressure air pouring under the engine compartment IMHO. SOTP's of course. Later. JJ :)

I've been on four different computers. Red x's on 3 out of 4. Have no clue as to why.

Red x's on my laptop mobile and on the home pc. I can't figure out why, I have all the latest updates etc etc.

Anyone with ideas on that please toss 'em out.

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Anyone who can't see the pics, they are all the same as the original post 1 pics, in order.

Look familiar, Stallion?




Nice grill...I like it.;).......Note the name change...above left...Thanks for the info.

Just wanna vouch for KB and his shrouds. He recently installed the nose shroud and a gasser air box and sealed the stack on my truck in his driveway. Quality materials and a quality product. He's a straight-shooter and a has an impressive knowledge of the air flow these trucks experience. Good guy.

I don't tow all that heavy with my truck, but I do tow regularly, 6000-7000 lbs. 5 days a week in hot Phoenix city traffic. So far, I've noticed a difference in the frequency and duration of the fan roar with these mods. But since my truck is stock (other than KB's cooling mods) I don't have the ability to monitor the ECTs and EGTs like those with Edge modules and whatnot (since the factory gauge appears to be so unresponsive).

KB you are great! Thank you for creating a tunnel to the stack idea (we thought of that last year) and the cold air intake (last year too) then the current "nose shrouds" brought forth by Mike this year (from last years work) as well as the material being used (suggested by Mike). Oh and I forgot the air dam stumbled upon by JJ removing the splash guard and Fingers picking up on comments about the crossmember acting as a dam, then RDL noticing dams on trucks at the stealer. Good job! What was that about litigation and a self serving worm?????

I love how these are now KB's cooling mods. Beauty. RDL views it best I believe.

Credit where credit is due, the stack seal thing is impressive, for that one I extend thanks to KB since he did come up with that one it seems.

Whats one of these KB kits going for anyway?

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You're welcome.

...and I thank you. I need a good accountant.

No problem. Top notch effort overall, despite GM.

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Guys:

Here is an easy way to provide that 4th attachment point on the 5.3 airbox lid. I attached a one-inch L-bracket to the outside of the bottom portion of this airbox with a 1/4 inch bolt and nylon locknut (head to inside). Make sure it lines up with the attachment screw on the lid. Believe it or not, the one-inch L-bracket's hole spacing is just perfect to get the alignment right. I got a small metric sized (around 6mm) u-nut from a body shop (be sure and take one of the metric screws from the airbox lid to get the right size and thread count). Slipped the u-nut over the L-bracket and secured the bolt from the lid. Works great and gives some piece of mind that there will be no air leaks from that corner.

NICE JOB, Hooky! That's even easier that what I was thinking of. JJ will be happy.

5.3 airbox lid attachment

I'm slow, but I'm catchin' on! Looks like the shroud is taking on a new life (tranny cooler...cooler, good idea). After looking at the options for an additional intake port to the 5.3 box, I'm going to guess it will vent from the bottom through the metal box attachment plate. ???????

After looking at the options for an additional intake port to the 5.3 box, I'm going to guess it will vent from the bottom through the metal box attachment plate. ???????

That's what I am working on right now. A 3" additional source hole, elbowed just below the surface.

Without the hard suction on the fenders, the filter minder, SES etc should be just fine even in wet conditions. The element, after all, does get wet. Cold morning startups in dew condtions for example. It is the snorkel restriction plus the dirty filter that added up to enough resistance to set of codes in the 01 days.

I have a question about mods on the front of a 05 GMC. Looking at the front end (See pic highlight in green) If I remove this black plastic it looks like the air flow would go into the engine compartment and help evac the hot air. Would this work? Or help? I dont really have the money to buy the stack sealing kit. Also any word on what the dealer ships have to say about stack sealing and cold air getting to the intake?

Thanks
Attached Thumbnailshttp://dieselplace.com/forum/attachment.php?attachmentid=8107&stc=1&thumb=1&d=1125452497 (http://dieselplace.com/forum/attachment.php?attachmentid=8107&d=1125452497)

Make one.

It's a DIY project, that's why it's laid out in the open here.

If you direct the flow, over the top of the splash guard you may have something.

After you are done with your tests, let us know how it works. I have no crystal ball.

Same answer Paleale.

I never got an answer, I was wondering if you guys ever looked at that?

PART 3-Aux Tranny Cooling-AC improvement (http://dieselplace.com/forum/showthread.php?t=42883)

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I never got an answer, I was wondering if you guys ever looked at that?

Where is the original picture? I don't have a GMC but I will try to help you if I can......

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PART 3-Aux Tranny Cooling-AC improvement (http://dieselplace.com/forum/showthread.php?t=42883)
Email sent :)

Copied from the overheating thread.

Sorry for the delay in posting. Mama JJ and I are staying at a campground at Fort Arnold, TN that is way out in the boonees. No cell phone, no TV, nothing! We do have electric and water. Beautiful campground on a lake. http://www.dieselplace.com/forum/images/smilies/biggrin.gif

We climbed Monteagle yesterday, the rig weighed in at 24,600lbs on this run. I wasn't able to get up to 70mph before we started the climb to see how long I could hold 5th before having to downshift. Turns out the truck downshifted fairly quickly once we began to climb anyway. E/J level 1, stock intake, KB shroud mods.

We logged readings every minute or so. With O/D disengaged we ran 55mph at 2400rpm's the first 3 miles of the 6 mile, 6%-8% climb. All temps except Ally are E/J Attitude readings. I don't trust the OEM coolant gauge. Ironically it does seem to catch up with the Attitude readings at about 230*. Go figure.

ECTs started out at 216*, OAT 88*, Ally 170*, EGT's around 1220*-1300*. 2 minutes into climb ECT's were at 219*, OAT 88*, Ally 170*, EGT's hanging around 1250*-1300*, 55mph. When ECT's reached 221* the fan engaged fully.

Into the toughest part of the climb(8%) I decided to accelerate, truck seemed to have plenty of power left, what the heck! Accelerated up to 60mph, ECT's went up to 230*, Ally 180*, EGT's 1317*, 2500 RPMs. ECT's were at 234* when we crested the hill. When the truck downshifted and RPM's leveled off I noticed the fan wasn't engaged, no roaring. Sometime during the climb I lost track of when it disengaged. ECT's began to fall quickly just before we started the downhill slope, WEEEEEEEEEEEHHHHHHHHHHH!!! Grade braking worked just fine! http://www.dieselplace.com/forum/images/smilies/wink.gif

So what did I learn on this run. ECT's vary too much IMHO to use them as reliable predictors. I can go from 192* to 225* easily on hard acceleration on flat surfaces. At 24k lbs+ I put the hammer down and spiked ECT's at 234*, not bad, especially if the fan wasn't engaged. We'll monitor that more closely on the return trip. http://www.dieselplace.com/forum/images/smilies/confused.gif

All in all a good run IMHO. At no point did the truck seem to be lacking for power or losing any temp battles. The weather here in TN is mild, highs in the upper 80's and lows in the upper 50's-low 60's. Nice. More to come. JJ

Quick update. This was without the modified 5.3 airbox for CAI. I also had reinstalled the plastic shield underneath the stack which we suspect provides or improves lower pressures under the hood. JJ

I'm updating as I go. One other thing I noticed was the foam insulation strip that I put under the front lip of the hood was blown forward when I checked under the hood this morning.

Also, the top radiator hose was collapsed, thought I fixed that with a new pressure cap. Could this be an indicator of a sticking tstat or other issue? JJ

...
Also, the top radiator hose was collapsed, thought I fixed that with a new pressure cap. Could this be an indicator of a sticking tstat or other issue? JJ

don't think so. I see many top rad hoses collapsed, it is not really a problem and only happens when shut down in the cooling process. Is does indicate a gas in the system, if that makes sense to anyone. I guess it's impossible to not have some air.

JJ, I have had 6 new caps on my 04.5. It still collapses the hose. I don't know that there is a fix other than a spring inside.

So JJ,

before you don the cold air, can you say that with the mods in place, the fan controlled/stemmed ECT rise?

Remember folks, this is a triple axle, 10 ft tall, 25K,(slightly) illegal hi-drag load, on juice we are testing here. Keeping it in perspective.

Do you feel that having the fan come in late (giving you 25 extra free HP) was an assett, or a detriment?

Also, the top radiator hose was collapsed, thought I fixed that with a new pressure cap.

Sorry JJ,

I do believe your Cap wasn't doing it's job, however, KB's "Gas" in the coolant, is more valid. Gas in the coolant is bad, cavitation, OH.

Fox

JJ, I have had 6 new caps on my 04.5. It still collapses the hose. I don't know that there is a fix other than a spring inside.

Rick, 6 caps? Shouldn't do that. IIRC, 2 of yours oheat, one doesn't? This one may have an air pocket in it. If you are back on your feet, try running it with the cap off and heat on, see if coolant level in the tank drops, refill. It may puke out some before it gets hot. May help

Mike

Sorry for the delay in responding, been busy with biz'ness! lol Looks like many of you are enjoying a nice long weekend away. I haven't seen the news for about 5 days so I'm out of the loop on what's been happening. Heard lots of rumors about gas/diesel price gouging, $4-$6 per gallon in Atlanta one day. The highest price I paid for diesel was $2.99 per gallon, most is between $2.72 and $2.79 that I have found.

I reinstalled the CAI and took the time to seal off the airbox from the fan flow. Actually wasn't that hard with the materials on hand, can anyone guess what I used? lol I sealed off the section where the fan blows directly at the airbox, used duct tape to seal off the upper section. Ghetto? You bet!

Mama JJ took notes during the climb, dang if I can find them and she is out/about. Here's what I remember. Coming southbound on I24 the Monteagle climb is quite as long or high as the northbound run (makes sense). They give no warning on this climb so again I was only at 60-65mph when the climb began. I disengaged OD and cruised at 50-55mph. RPM's were in the 2400-2500 range. ECT's were a little lower, mostly due to OAT's only being in the mid to upper 80's, low humidity though. ECT's starting the climb were around 214* IIRC, Ally stook at 165*-170*, EGT's around 1300*. I'll have to wait on Mama JJ's notes for fan engagement ECT readings, though I'm of the opinion they are useless. Why?

This engine can spike ECT's faster than the thermal viscous fan clutch can react IMHO. I stated earlier that within 60 seconds I can go from 192* to 235* if I nail the go pedal. The fan clutch just suffers bad timing for lack of a better term. When it engages ECT's usually drop rapidly. The only exception is when the truck is being worked extremely hard on a long climb at high RPM's, they can hold at 230*-235* during sustained runs. Highest boost on the Attitude was 22psi.

KB, as for whether I feel the shrouds have helped that is a definite yes. I rarely hear the fan on small climbs like I used to, on longer hills it engages later which I'm sure is helping me to hold speed. Sweet spot for my 5ver seems to be 62mph, that is best mpg's, lowest ECT's, and minimal downshifting during climbs. Every rig is going to have a sweet spot depending upon load dynamics, wind, etc. Best to find it and stick with it IMHO.

One interesting thing was during the descent yesterday when RPM's were up around 4500 the ECT's actually rose a couple of degrees, didn't expect that. Also the air filter meter is halfway again, dang hose is collapsed as well. MPG's were right at 10, for mountainous climbing at this weight very respectable IMHO. So far it appears a 2-3mpg improvement with these mods. We need more folks to post their data for comparison.

That's about it for now. If I think of anything else I'll post it. Internet connectivity is hit or miss out here in the boonees. Mama JJ has us on some lake just outside of Augusta, GA, beautiful scenery. Later. JJ

... ECT's starting the climb were around 214* IIRC, Ally stook at 165*-170*, EGT's around 1300*. I'll have to wait on Mama JJ's notes for fan engagement ECT readings, though I'm of the opinion they are useless. Why?

...The only exception is when the truck is being worked extremely hard on a long climb at high RPM's, they can hold at 230*-235* during sustained runs. Highest boost on the Attitude was 22psi.

KB, as for whether I feel the shrouds have helped that is a definite yes. I rarely hear the fan on small climbs like I used to, on longer hills it engages later which I'm sure is helping me to hold speed. ...

One interesting thing was during the descent yesterday when RPM's were up around 4500 the ECT's actually rose a couple of degrees, didn't expect that. ... So far it appears a 2-3mpg improvement with these mods.

If you get this response before you leave the hills, please remove the seal between CAC and rad, along the top, as we have discussed, and compare. I think that may/will be a benefit to ECT rise, though I suspect you may see a bit higher EGT's as CAC function is reduced a bit in favor of Rad function.

4500 rpm a misprint? Your observation here is very important. Do you think high rpm may be, thru some phenom like pump cavitation, be reducing coolant flow? We do know the fan pulley is smaller (faster) than LB7. Wonder about the pump.

all in all, not bad for a "non-comp-liant" 25K total pull, on juice.

One interesting thing was during the descent yesterday when RPM's were up around 4500 the ECT's actually rose a couple of degrees, didn't expect that.
When we are using "Grade Braking", the engine becomes a Brake. It must disapate Heat like any other Brake. Normal response, IMO.
Also the air filter meter is halfway again,...

..... dang hose is collapsed as well.
Ref. GM14's observation; gas in cooling system.


Gas in the cooling system Will contribute to OH'ing.

FWIW.

Fox

I really hate not having a radiator cap.

That's what I am working on right now. A 3" additional source hole, elbowed just below the surface.

Without the hard suction on the fenders, the filter minder, SES etc should be just fine even in wet conditions. The element, after all, does get wet. Cold morning startups in dew condtions for example. It is the snorkel restriction plus the dirty filter that added up to enough resistance to set of codes in the 01 days.

KB:

There is a recent post on DP that uses a bottom intake with hose for RAM air. Any progress on your intake??? Are you considering an intake from the bottom of the airbox that dead ends facing the grill??? I'm a bit concerned about any intake that is directly exposed to outside air.

Also, after reading latest JJ post, is the stack seal possibly too efficient causing a delay in fan engagement??

KB:

There is a recent post on DP that uses a bottom intake with hose for RAM air. Any progress on your intake??? Are you considering an intake from the bottom of the airbox that dead ends facing the grill??? I'm a bit concerned about any intake that is directly exposed to outside air.

Also, after reading latest JJ post, is the stack seal possibly too efficient causing a delay in fan engagement??

I don't think anyone is paying as close attention to this as you are Hooky. I have all but eliminated the seal along the top, CAC to RAD. My last several installs were without it. It is possible that integrating the Rad and CAC created too much resistance. Having a place for unheated ambient to infiltrate, over the top of the CAC, is the added cooling. The extra Rad flow seems to be just what the doctor ordered. I talked to 2 people who installed that way, and the tranny is much better off also, by 10-15 degrees. That is what I want JJ to try next.

As for the intake I have finished testing for the best site for aux air, to modify the gas oem box. I chose to monitor 4 sites, surrounding the box, to see which area had the best cold air. Note there are practical constraints. It can't be where air is full of garbage, or too close to the ground (water crossings). "ram" air is pretty much worthless, the turbo really needs no help. The best you can hope to find is 1 inch of water pressure. That won't augment a turbo producing 550-700 inches of water pressure. What is important is the temp and contaminant free quality of the air.

I'll try to get that (Cooling mods-part 4-cold air) thread going, ASAP. I found that air 6" under the box to be suitable, and practical. The air right in front of the box, is hot in comparison.

How have you faired Hooky?

KB:

I will be making my first tow (app.9,000 lbs TT) through the Ozark Mtns. week after next for a little squirrrel hunting trip. There are a couple of key grades that always gave my 6.5 heat problems. Going to try those with the 5.3 airbox (unmodified) and hope my restriction indicator doesn't go red. I'll try to monitor engine and trans temps, along with fan engagement temps (maybe not as thorough KK) on these grades. Afterwards, I plan to go back on the same route in October with your cooling/airbox mods installed for comparison. The only variation may be outside temps between trips. Can't do much about that.

Thanks.

Here's what I remember.

I was ... at 60-65mph when the climb began. I disengaged OD and cruised at 50-55mph. RPM's were in the 2400-2500 range. ECT's were a little lower, mostly due to OAT's only being in the mid to upper 80's,

ECT's starting the climb were around 214* IIRC, Ally stook at 165*-170*, EGT's around 1300*.
Stats Just fully Open, Ally lov'in the Nose Shroud, EGT's real good.
I'll have to wait on Mama JJ's notes for fan engagement ECT readings, though I'm of the opinion they are useless. Why?
We know the fan is always engaged, is "fan engagement" the Roar?
This engine can spike ECT's faster than the thermal viscous fan clutch can react IMHO. I stated earlier that within 60 seconds I can go from 192* to 235* if I nail the go pedal. The fan clutch just suffers bad timing for lack of a better term.
192°, neither stat is fully open.

The fan clutch is thermally coupled, (as we know), But it is coupled through Four (4) different media; coolant>rad, rad>air, air>fan clutch, fan clutch>viscous control. When the temp guage(s) shows Change, the fan doesn't have a Clue.
When it engages ECT's usually drop rapidly. The only exception is when the truck is being worked extremely hard on a long climb at high RPM's, they can hold at 230*-235* during sustained runs.
Operating within system capacity(s).

230° - 235° is not OH.



Even with all the mods, it's still a diesel. ):h

Enjoyed the report JJ, good job.

Question, what would these numbers be without (before) any mods ?

Have funnnnnn.

Fox

I was assembling a reply to JJ along these lines.

We have become accustomed to associating fan engagement to ECT temps. As Fox points out, the lines of communication between ECT and fan clutch are comparable to the reaction time of a .25 B.A.C. DUI. The water has to get hot, then a stat has to open, then proceed to rad, and hope that the bimetal stips in the fan clutch respond quickly (they don't). The lag is probably around 20-40 secs.

We can live with it. And in a way, the lag is a good thing if it keeps the fan off longer. I am all for that.

Truth is, the CAC/condenser heat can engage the clutch before ECT's head over 200, in some conditions.

I support sealing the rad and CAC as a unit, real tight.

CAC: Air/Air; Ingestion/compression/consumption of media (air). This media, nor it’s product (O²) is stored (Ya, the Plenum). No heat sink, Changes are very quick, high peaks.

rad: Coolant/Air: Media in not consumed, media product (heat) is stored (engine) and dissapated over time. Changes are Slow, (relative).

CAC/rad as a unit: CAC peaks are modified and it's product (O²) is more dense over time.

Fan engagement ?, shorter lag ?

IMO, FWIW.

Fox

I left Mama JJ, truck and 5ver in Augusta, GA before seeing the e-mails about removing the strip between the CAC and radiator. I'll get this done once the truck is back here. ;)

I released the pressure on the coolant tank and drove the truck with the 5ver in tow for about 10 miles with the heat on per GM's suggestion. Didn't lose any coolant. It is hard to get both temps on these trucks to open fully unless you are in very hot weather or pulling something. Just thought that was a good time to get er' done. Will advise if hose is still collapsing. ;)

If I didn't have the Attitude monitor I would be happy as a pig in slop since the OEM ECT gauge hardly moves until ECT's are over 225*-230*. Those that aren't overheating may just not have the best intel at their fingerprints. :confused:

I am very comfortable that the truck can handle most jobs I put before it, just within reason. My EGT's never went much above 1300* in either of the mountain pulls.

Fox, good explanation, thanks! JJ :)

JJ,
We pulled the grade at Monteagle on Friday, the OAT's were 92 (my mirror). My fan was on most of the time that afternoon.My jeep and trailer probably weigh around 8k, so our numbers wont' compare. But, I was able to pull the entire grade at 70 with room left on the power. My temps ( on my OEM gauge were just a tick over the 210 mark, so I am guessing 230-240.
I'm going to the dealer to make complaint #2 (documentation reasons) so they can get this thing acknowledged.
I'm keeping my truck....
This thing kicked ass the whole trip.................
Ricky...seeya...

I support sealing the rad and CAC as a unit, real tight.


Fox

I do also, for maximum overheat resistance, fan engaged. Some want to reduce fan ops empty. Flow from the fan in full slip, is just about capable of keeping the fan from engaging, when shroud and rad are sealed.

If we seal the CAC to that, we add resistance, and consequently lower flow over the rad, until the fan kicks in.

It's a tough call without a controlled test. I'll probably leave it as an optional item till experience tells us.

It does appear as though the tranny cooler benefits a bit more, from reports I am getting.

RickyR, the last post I saw from you indicated you wouldn't have time to do the stack sealing, true? If you did what was accomplished? My fan engaged during the intial climb but was MIA at the crest of the hill with ECT's at 235*. Ironically temps weren't climbing even though I was at high RPM's and accelerating up to 65mph at the time. Key when towing on a climb seems to be keeping RPM's up in the 2200-2400 "minimum" range for EGT's and ECT's. If RPM's get too low you lose the HP/TQ battle versus the weight/resistance of the load being pulled. Lighter loads likely could be handled with lower RPM's. SOTP impression.

KB, yes 4500 RPM's, possibly even higher during the descent. BTW, EGT's were down to like 300* to. Granted I was flying by the seat of my pants, I had an 18 wheeler swirve into my lane and I had to swirve into the fast lane. Fortunately no cars were beside me at the time. Just reinforces how dangerous these rigs can be. Guys be careful when out doing these runs. ;) JJ :)

Here is MY lowdown...


Left Friday afternoon (4:00) about 110 I think. 1st hill to Flag was backed up and couldn't get a run at it from the bottom. 40 mph from bottom to half way. All of a sudden traffic cleared and I was able to get it pulling hard. 55 was about it as egts were still getting above 1400* . The water injection did nothing and I was mad (only to find out in Camp Verde that a wire I had spliced came loose) Fixed that and noticed that @ 20 lbs boost and 2400 rpm in 4th I did see 200* lower egts. I was on 30% meth mix, and had a few moments that seemed to "flood" the motor under full throttle. I turned it off and kept the Juice set at level 2.

Fan engagement was far less then ever before. I did see 246* ect under the hardest cond pulling up that 1st long hill (black canyon). Fan came on at about 237 and temps still rose slowly and came down fast (195) after I crested the hill.

Trans temps NEVER got past 185 +/- and once I got to Camp Verde trans temps were 1 line over the half notch all the way to Flag no matter what load I was under. OAT was 66 by this time and helped keep ECTs under 210 the rest of the time also.

If it wasn't 110*, I know I would not have seen 246* earlier. ( that is the same hill I saw 244* with my old trailer and no stack sealing) I am now towing 6,000 lbs more than last time. I have to be approx 25,000 lbs

DIC fuel mileage 6.8 to Flag
DIC fuel mileage 9.9 downhill to Phx

Fuel mileage went up overall from previous trips to Flag due to less Fan engagement!!!

last DIC #'s were more like 5.9 and 8.4 (IIRC) with a lighter load.

On the way down, trans 160-185*
Egt's can still get to 1400+ if I wanted

For the record I was towing with my buddy with approx the same weight as me with my old '02 LB7

He passed me.... 5 mph faster up the camp verde hill going back to PHX. We were walkie/talkie each other. His egts max were 1350* passing/out pulling me (35" tires) I was 1400*+....even with the W/I at 30% mixture. His ECT was 219* I was 237* (he has no stack mods at all) His trans was 200+/- ,I was 180* At this point, I wish I had an LB7 dually even If I had to trade it in...oh well

I 100% believe your mods helped. I had no foam melting issues although I will recheck tomorrow at work. I heard the fan engagement a lot like JJ claims. I have the 4" dryer hose CAI and the box foam sealed to the fender holes. When I got to Flag, I looked at the foam...ok noticed the filter meter at like 40%. Filter is clean. I see JJ has similar issue...I even have the 4" duct and get a restriction according to the filter minder.


If I towed in Texas, I'd say you could not get an LLY hot. Arizona on the otherhand, just too much. I hope they got it figured out in '06. I may have to make a trade (late '06 pending the '07 body style).

Still need to play with the W/I and see. Had these weird "bursts" at times. I thought I flooded it and was about to hydro, then a big puff off smoke came out the pipe and almost sounded like a "backfire" like 3 times in 1 min. Almost sounded like warming up the afterburners on those dragsters with the jet motors before they race....(scared me) Thought I had a nozzle problem. Checked that in Flag...ok. I used filtered water and meth from atv shop.


MODS SO FAR FOR OVERHEATING ISSUES ARE:

FULL STACK SEAL

NO SHROUDS
NO AIR DAM

4" CAI GOING DOWN TO TOW HOOK AND SEALED OFF AIR BOX TO FENDER HOLES...STILL NEED MORE AIR IMO..WORKING ON THAT

POS FLAP SECURED

MIKE L TRANS COOLER

WATER/METH INJECTION

4" BANKS EXHAUST/ NO CAT

JJ,
The only mod is the air dam. So, I am basically stock. I was out of OD and was running approx 2500 +/- rpms. Funny, but I don't remember hearing my fan during the climb, but it was running once the OAt was 91* and higher. The grade itself was kinda cool 86* or so..
Going down the grade, I was out of OD also and the tranny was holding me at 65, I did tap the brakes a few times to keep my rpms down.

BTW. Fuel was VERY reasonable (considering the present state of prices) in Augusta. $ 2.79 Friday vs $2.64 / gal on Monday. The GA Gov lifted the tax on fuel. I carried a 50 gallon fuel tank in the bed, so I only had to buy fuel 2x one going and one coming. Both times were in Augusta :) :) :)
Ricky...seeya...

RickyR, sounds about right for 8k lbs with air dam only. Sealing up the stack with that light a load and you won't hear the fan nearly as often. ;)

KTDuramax, still digesting your intel, GREAT! IMHO Edge level 2 is a bit high without a tranny upgrade at the weight you are towing. Might also explain the 1400*+ EGT's. You might PM MikeL and get his opinion on what the tranny can handle under extreme towing conditions. Then again I'm usually a bit conservative. ;)

Having to slow down to 40mph then accelerate is a huge BTU producer! Also, IIRC at low speeds we have very little flow across the stack and through the engine compartment. This is normally where I see the spikes in ECT's. Sounds like our fans were made the same day! ):h Tends to show up just a tad late for the dance if you know what I mean. ;) Sure wish you had weighed the rig though. :o: Was the plastic splash guard installed? 3" air dam?

I'm anxious to see a CAI fix that flows plenty of cool air with less restriction. These engines push a lot of air, needs to move faster IMHO. JJ :)

I did weigh the rig before I loaded it....14,240 before:


250 gal water, 850 lb golf cart (2) 300 lb kids quads, 30 gal gas in trailer + tools /jack/air compressor/ etc

Level 2 seemed ok, If the tranny lets go, I won't be to upset. Need an excuse to get a suncoast trans...:ro)

That gets us closer to a number, a rather large one apparently, but doesn't account for fully loaded rig with you, Mama KTDURAMAX and the little kiddies in the truck. ):h With the items you provided I have your rig right about 17,900lbs. Your GVWR for the trailer is 18k lbs, very close on those weights. You drive a dually so the truck likely comes in around 8500lbs for a combined 26,400 lbs+- a few hundred pounds.

On edit, Juice stacked with Predator! Yowza! Given that at 112* OAT's on a long climb 247* ECT's are still respectable. By chance were you heading into a headwind? I took on 20-30mph winds yesterday and could only maintain 60mph without downshifting. Remember folks, these are light duty trucks, this weight is in the medium duty range, normally with higher final drive ratios to get the power to the wheels more effectively.

We need to keep this overheating thing in perspective. Those like KTDuramax, Rick, myself, Fingers, ... that are towing at/above GCWR should expect to see some additional heat pouring out of the LLY's when we're working them well above spec. So what is a reasonable number? Given the data KT provided it sounds like he had a pretty good run.

Try making the run on E/J level 1, defuel between locked shifts, Predator off and see what happens to the EGT's. Then run it to level 5, stack it and get yourself a new tranny! ;) Later. JJ :)

I figured I had over 25,000 lbs. I didn't want MAMA KTDURAMAX nervous....;) I tryed level 0,1,2, only... level 0,1,2,3 with Water Injection. My buddy 02 LB7 had to be 24,000 lbs then and never saw over 225 ECT and 1350 egt level 2 juice (2500 cc lifted w/ 35's)

AT 26,000 lbs, the handling/stopping was still better than pulling a 26 ft TT @ 17,000 gvw

Predator program removed for towing can't turn on/off while towing like attitude...only use that for playing:ro) :ro) :ro)

Thinking out loud: The clutch is definately the slow link in the thermal chain. Bimetal strips, buried in a finned metal mass, that is the lag I think. Since the sealed airflow better cools the clutch now, during slip ops, the engagement is delayed, then works better when it does. Wonder now if we should try drilling out the bypass holes on the stats, for just a little more flow.

But winter...

Not complaining at all. I am happy actually. As long as I don't puke coolant or blow up, i'm good. At that weight I expect to get hot. I just miffed that my old LB7 handles the load better.

Hear's another thing noticed...going downhill coasting my egt's were 360 +/- and the LB7 was 190*

Didn't see the rise in temps to the tranny going downhill with engine braking like someone else mentioned earlier..nor did engine temps go up.

KT,

Was the LB7 a dually as well? :confused: Was he pulling a 40' "home on wheels" like you? There is a considerable amount of wind drag on these long units. I can snatch a 30' travel trailer up and not even know it is back there. ):h But this beast is a different story altogether. BTW, you were likely even heavier than I estimated since I didn't add you and the family to those weights. :o:

All things considered it sounds like you had a good run. Once again the Ally shows just how sensitive it is to OAT's. Did you seal the holes under the stack that KB keeps mentioning? Splash shield installed? JJ :)

But winter...

KB, makes me nervous when you think too much! lol

Kevin, have you ever changed the stats? Easy?

I can hear you thinking!!!

I don't think the clutches are serviceable...

how about using an LB7 clutch....didn't Kennedy figure this out before?

I would think the hot CAC air would trigger the fan clutch before the ECT did?

never touched the stats, but interested.

JJ,

my buddy has identicle trailer load and family weight. He is 35' me 40' he only has 120 gal water same 5th wheel profile (smame trailer, just shorter) tow rig...3/4 ton SRW c/c

All holes sealed...splash shield off, no air dam yet

I would think the hot CAC air would trigger the fan clutch before the ECT did?

Combination of all things. I have guys tell me now, that with sealing and shrouds, they will never have a fan if the AC is off (empty). That condenser (about 15,000 BTU exchange) really damages the rest of the heat exchange in hot wx (works even harder).

The clutch is serviceable but I don't think I can change it's reaction time, unless it can be more ventilated. I have seen guys, change the onset temp setting by doing a little modifying. Not real interested in that.

Kevin, I know if you experiment with (moderate) mist pre-CAC you will make a real dent in cooling.

I can't help but think that the engine, tranny, stack.... are all spec'd for max GCWR and below. You and I were 3k-5k lbs over this weight. The additional heat load should be expected and harder for the stack to shed. Curious to see what a load within ratings does. JJ :)

kinda scared too...




here is my source for O.E stats/ratings. LB7

12T100D Record not on file. 0.00 0.00 1 Special Order - Please Call 1 01-04
[OE Type Thermostat]

OE Recommended Temp - 180 degree ; Includes Seal ; Rear Thermostat

12T99D Record not on file. 0.00 0.00 1 Special Order - Please Call 1 01-04
[OE Type Thermostat]

OE Recommended Temp - 185 degree ; Includes Seal ; Front Thermostat

Same for '05 LLY

If the factory ones are higher temps, I will change them out.

Kevin, I remember you saying you thought the shrouds you made were no help. I wonder how much help they would be if you pulled your overlay off. It just occurred to me. Once upon a time we discussed your grill, if you went to a recessed version, with fewer bars, you would likely increase "free" flow.

Those numbers are GM spec,

Kevin, if you order them, get me a set to play with.

JJ

MY old LB7 had to be 24,000 and had ZERO issues....and out pulled me. I used to get out pulled with my 17,000 GVW vs His 24,000 GVW

IF ALL Duramax's did this, I would be satisfied...GM can't claim the LLY has more power than Lb7's and then get outpulled with 7,000 less LBS. AND run hotter!!!!

I did say trailer loads were the same....he had 2 extra quads, firewood, carried all the beer!!!! (beer had to be 600 lbs) LOL:ro)

actually he didn't haul ALL the beer!

KT, I'm not concerned so much with the LB7 numbers, moreso just nailing your weights a little closer. Though a 3/4 ton anywhere close to that weight scares the wajeebees out of me. JJ

Comparison to LB7 is beating your head against a brick wall. LB7's did not have to meet the new government emissions standards implemented January 04. That in itself is some of the problems we face here.

Kevin, I remember you saying you thought the shrouds you made were no help. I wonder how much help they would be if you pulled your overlay off. It just occurred to me. Once upon a time we discussed your grill, if you went to a recessed version, with fewer bars, you would likely increase "free" flow.


NO overlay...is recessed.

no shrouds towing....

empty saw no diff in any temps EGT/ECT/trans

If I get a set of t-stats, I will get you a set. I want to know FOR SURE the LLY has hotter stats though. If I get time ( which at this time I don't) I will pull mine out to examine.

Comparison to LB7 is beating your head against a brick wall. LB7's did not have to meet the new government emissions standards implemented January 04. That in itself is some of the problems we face here.

That's why my head hurts!!!:lol:

I know, but Dodge and Ford get by the new standards without getting as hot....

And I know my buddy's LB7 has zero problems this trip along side of me, but he has gotten ECT's up to 240 a couple times last year.

As far as the thermostats go, I was told that the stats were the same as the 01's. Dodge and Ford are having problems adjusting also. Their owners just don't post here as much.

I can tell you for a fact how dodge is doing it. 26" fan. Yup 50% more area than our 21.

I didn't mean overlay, sorry. But yours is flush mounted, correct? vs recessed back.

I think the stats are the same.

What would be fun is to compare full open area dimensions, for volumetric flow limitations.

it is flush at the top and recessed as it get to the bottom. Don't really want to mess with the mounting tabs, maybe spacers...

As far as the thermostats go, I was told that the stats were the same as the 01's. Dodge and Ford are having problems adjusting also. Their owners just don't post here as much.

Rick,

you are right,seems like Ford has their own high towing temp/overheat/puking issues...

http://forums.thedieselstop.com/ubbthreads/showflat.php?Cat=&Board=2003Drivetrain1&Number=2511187&Forum=,f48,&Words=overheating&Searchpage=0&Limit=25&Main=2511187&Search=true&where=bodysub&Name=&daterange=0&newerval=&newertype=&olderval=&oldertype=&bodyprev=#Post2511187

I had a chance to look at my buddies 04 2500hd with the 6.0 in it today. It has a factory oem nose shroud and all the rubber flaps around the radiator to plug up any intruding air source. It looks like they totally forgot to put it in the Duramax. All of the mods we made are there from the factory. WHAT'S UP WITH THAT? DID GM DROP THE BALL ON THE DURAMAX?

Dodge also has shrouds around the sides of their stack, really did a nice job to. Add to that the grille area is larger and tapered towards the stack for airflow and wallah! :o: GM apparently just didn't "connect the dots" with the LLY and its cooling requirements. The mods for the 06 model year are a ringing indictment of this IMHO. :exactly: JJ :)

I can tell you for a fact how dodge is doing it. 26" fan. Yup 50% more area than our 21.

I didn't mean overlay, sorry. But yours is flush mounted, correct? vs recessed back.

Don't forget that the Dodge also holds 1 gallon more of coolant than the GM trucks.

Dodge....28 quarts

GM.........23.5 quarts

That has to help some.

I'll be going back to Augusta on Friday and will pull the 5ver on Monday. Tstats appear very easy to change out, yes even I can do them! :eek: Identify the proper tstats to buy and if I can get my hands on them I'll change em out before the pull and see what happens. JJ :)

Just don't change anything else JJ, keeping you honest.

Don't worry KB, I only plan to take the seal off between the CAC and radiator as advised. Any decision on changing out the tstats? I likely have a better chance of finding them in J'ville before I leave tomorrow morning than in Augusta, GA. Wazzup? JJ :)

I personally think that there might be a good result from drilling the bypass hole(s). It may not not be that good for winter ops, but at leat they are easy to experiment with.

J-M or Greasemonkey had some guidance on that, maybe they will chime in.

It is also something I may want to try on Italian Stallion's truck. He did a fairly heavy pull in 110 heat, and was mot happy his fan didn't turn off. He didn't overheat or even get close, so the kit worked IMO. I think the expectation was for less fan. If I can get a truck like his datalogged I think I could make a good decision on where to seek extra improvement, maybe even a quieter fan.

I have been reviewing my post on tstat operations, I now believe "I’m all Wet".

New information by Several members from physical testing of replacement stats (Gates, ACDelco and OEM’s) and road testing, post replacement, make my previous postulation of "Stat Ops" impossible.

My post on "Stat Ops" was predicated on a post from a GM tech that recited from his school material. I either interpreted it Wrong, or it was not factual.

The Front stat does control the Bypass Orifice, but performs it’s function LAST (higher temp) not first. This means to me, the bypass orifice is closed After the Rear stat completes it’s transition (close/open). There is rad flow long before the bypass orifice is closed, maybe 35 - 40 % of full flow. This changes My interpretation of KB’s and Fingers T graphs. It also totally changes the OH’ing issue as I now view it.

Sorry, I posted "Bum Dope", based on "Bum Dope".

The pics are from ACDelco’s web site.


Fox

Fox,

I want to understand. The bottom plate on the first stat. From the looks of the spring, it failsafes to "bypass", or "rad flow"? Is that pic of a cold stat?

When in the extended position, is it plugging a port?

Is the wax pellet that cylinder visible inside the front stat.?

So long as the Bypass Orifice is Open, we are recalculating engine BTU's and Adding to ECT's without shedding this additional heat load @ the rad.

FWIW.

Fox

In the pic, I assume this is a cold stat. Are the springs in compression or tension?

Found this:

"The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at perhaps 180 degrees F (different thermostats open at different temperatures, but 180 F/82 C is a common temperature). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly and pushes the rod out of the cylinder, opening the valve. If you have read How Thermometers Work and done the experiment with the bottle and the straw, you have seen the same process in action. The wax happens to expand a good bit more because it is changing from a solid to a liquid in addition to expanding from the heat."


From this, I deduce that the springs are in tension, and under more tension (elongated) when heated up

Fox,

I want to understand. The bottom plate on the first stat. From the looks of the spring, it failsafes to "bypass", or "rad flow"? Is that pic of a cold stat?
Failsafes to rad bypass.

Cold stat.

My opinion, the smaller spring (lower), compounds the force of the open stat to seal the Bypass Orifice.
When in the extended position, is it plugging a port?
My opinion, Yes.
Is the wax pellet that cylinder visible inside the front stat.?
Wax pellet would be inside the stat engine (cylinder), not visable.


Fox

If my post above is correct, a weak stat can hurt the system if the bottom plate never fully seats into the "orifice" (am I on the same page?)

then rad flow would be reduced.

I need to just go get one and play with it.

Why would we want a device that failsafes to bypass, that would cause an overheat if it failed, correct? I think it fails to full rad flow. No?

Found this:

"The secret of the thermostat lies in the small cylinder located on the engine-side of the device. This cylinder is filled with a wax that begins to melt at perhaps 180 degrees F (different thermostats open at different temperatures, but 180 F/82 C is a common temperature). A rod connected to the valve presses into this wax. When the wax melts, it expands significantly and pushes the rod out of the cylinder, opening the valve. If you have read How Thermometers Work and done the experiment with the bottle and the straw, you have seen the same process in action. The wax happens to expand a good bit more because it is changing from a solid to a liquid in addition to expanding from the heat."


From this, I deduce that the springs are in tension, and under more tension (elongated) when heated up

Front stat: Compound function; provide flow to rad @ T and block bypass flow to engine (recerc.). Large spring under tension to hold stat closed @ low T, increases tension as stat opens. Small spring is compressed as stat opens and adds force to seal rad bypass

Rear stat: Single function; provide flow to rad @ T. Large spring functions as in front stat.

IMO.

Fox

Why would we want a device that failsafes to bypass, that would cause an overheat if it failed, correct? I think it fails to full rad flow. No?

Tstats low T state is Closed; failed state/no rad flow = OH, Yes.

Fox

If my post above is correct, a weak stat can hurt the system if the bottom plate never fully seats into the "orifice" (am I on the same page?)

then rad flow would be reduced.

Absolutely. Poor stat performance = poor cooling.

Fox

anyone know which stats GM is using at the factory, delco?

I guess where I am going with this, is with the front stat, if there is even a hint of recirculation when stat is fully expanded, there is potential for a large loss of rad flow.

If there is any hydraulic pressure exerted on the bottom of the "plug", and it is forced out of position, that could be harmful also, in the same way.

I guess where I am going with this, is with the front stat, if there is even a hint of recirculation when stat is fully expanded, there is potential for a large loss of rad flow.

If there is any hydraulic pressure exerted on the bottom of the "plug", and it is forced out of position, that could be harmful also, in the same way.

Without a doubt.

Fox

I tested one of these on the stovetop. There is a single piston, that connects the top hat, and the bottom plug. ,a single fixed distance. The whole thing moves down with heat. Both sets of springs are in compression at all times. The upper (main) spring serves to assist close the stat with cooling. The lower (lighter) spring serves one purpose I can see: To unseat the plug in reaction to excess pressure. That could be a gas forming, excess hydraulic pressure (think pump at high RPM),debri in the way of seating, etc

What I gather from this, is if the lower spring is not stiff enough, or if debris keeps the plug from seating, coolant recirculation could occur in hot conditions.

http://dieselplace.com/forum/attachment.php?attachmentid=8349&d=1126185794

I tested one of these on the stovetop. There is a single piston, that connects the top hat, and the bottom plug. ,a single fixed distance. The whole thing moves down with heat. Both sets of springs are in compression at all times. The upper (main) spring serves to assist close the stat with cooling. The lower (lighter) spring serves one purpose I can see: To unseat the plug in reaction to excess pressure. That could be a gas forming, excess hydraulic pressure (think pump at high RPM),debri in the way of seating, etc

What I gather from this, is if the lower spring is not stiff enough, or if debris keeps the plug from seating, coolant recirculation could occur in hot conditions.

http://dieselplace.com/forum/attachment.php?attachmentid=8349&d=1126185794

The bottom of the upper spring seats on the stat frame, does the top of the bottom spring also seat on the stat frame?

With a Single cylinder engine, presumeing the above, both springs would change compression in unison. If the bypass plug opens/closes, the stat must close/open an equal amount. IMO.

Fox

The bottom of the upper spring seats on the stat frame, does the top of the bottom spring also seat on the stat frame?

YES

With a Single cylinder engine, presumeing the above, both springs would change compression in unison. If the bypass plug opens/closes, the stat must close/open an equal amount. IMO.

Correct, what is not obvious, is the bypass plug is not connected to the end of the shaft, therfore the plug can raise and lower independent of the piston, on it's own spring. The piston only serves as a downward travel stop. The upper stop is full spring compression.

Fox


make better sense?

Roger. Thanks.

Fox

I am finally caught up with Nose Shroud/sealing Kit orders. Thanks for everyone's patience and understanding.

If you do not have your order today, please EMAIL (beekiller@cox.net) me.

Thought I would post this email I received today.

Hi Michael,

Could you send me the color photos of the install for the shrouds as I was a little unsure if the left and right shrouds are seated exactly right with respect to the grill (there were small plastic tabs next to the metal clips and I positioned the shrouds in between these ...) I want to make sure everything is positioned correctly.

Your mods worked wonders on our trip down I81 to I77 to North Carolina (and the return through WVA and I64 through the mountains.) We average (hand calculated) 12.5 MPG over our whole trip (915 miles). Normally we would have averaged 10.5 mpg if lucky. I climbed Fancy Gap at 65mph with the OEM guage only going to 222 degrees (2 small tick marks past 210 degrees) and returning very quickly as the fan kicked in. The fan would only run when under heave load and only for short periods of time. ...I suspect that the tranny cooler shrouds cut about 15 or 20 degees off of what I would normally see.

I could tell the fan sounded a bit different when coupled. I could see more of an effect (on crappy OEM temp guage) when it was running. It actually would make the temp drop a little below 210 degrees. Also, under normal (not climbing mountains at 65 mph) the tranny was 150 degrees and the engine a hear under 210. Since the thermostat does not fully open untill 230 degrees I would suspect that the slight rise on the OEM guage would be normal (I never hit 230 like before.)...

The CAI was a snap to install and I am sure it was mostly responsible for the 2mpg increase (which is about $60 saving this trip alone).

Thanks,
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