If you intend to do any serious towing, go with the intercooler. The thread http://dieselplace.com/forum/forum_posts.asp?TID=10883&PN=1 documents my Suburban's current level of performance.


I participated in the Diesel Page Pull-Off last weekend and made 42 mph in 1:22 minutes pulling a utility trailer loaded to 11,920 lb. The hill is a 6% grade. The contest starts at a dead stop at one mile marker and ends at the next mile marker. If I'd run again and lifted a little to let it shift into third, I think I could have done better. I had actually achieved 46 mph but dropped speed at the very top of the RPM band. A 2004 Dodge Cummins 600 with exhaust and air filter made 49 mph on the same hill with the same trailer.Edited by: ronniejoe

 

Gee,


Why not ask an easy question like "Whats the best religon?" or "Does proper chili have beans?"

There are pluses and minuses for each method, and each has its rabid supporters, and equally rabid detractors. To me, it all comes down to bux. If you can come up with $1000 without even breaking a sweat go with an intercooler. Otherwise, you can get 75% of the benefits for 40% of the cash with the Water Mist. (factoring out the need to keep the tank full)


Tim

 

get a pair of breathers, plug the PCV recirc inlet and you'll never look back, except to see who you just passed.

 

need to know more texas diesel guy

 

Hey TDG


Got pic and part numbers by chance??


I am very interested in this mod.

 

What do you mean?

get a pair of breathers, plug the PCV recirc inlet and you'll never look back, except to see who you just passed.

Won't pluggin the PVC build internal engine pressure? Or do you mean remove the PVC and put in a valve cover breather on it? Does the other breather go on the oil filler neck or other valve cover?

 

Texas Diesel Guy,


Why is it that you always have a "no expense, better than anything else" mod that you throw out? None of the mods that you've mentioned can come close to matching the performance that I've achieved with my Suburban. Since you have a Blazer, it's clear that you don't tow anything very heavy, so maybe what you're doing works for you, but it wouldn't do well the way I work my truck.


When you post stuff like that, it reads as though you're the only person on the planet who knows anything and all the stuff done and developed by others is a waste. That's really pretty ridiculous.


Physics says that intercooling is needed to substantially increase boost pressure (which I've done) and that high boost pressure makes diesel engines produce more power. Essentially, the modifications I've made are duplicating what over the road trucks and late model pickups do. It works. Aside from the fact that your Blazer would be dangerous hooked up to a 12,000 lb. trailer, there is no way you could pull it the way I have demonstrated with my Suburban.


While it is clear that you have significant experience with DS-4 pumps, it is also clear that you are lacking in experience towing heavy loads with 6.5 diesels. The little gimicks you mention cannot hold a candle to the performance that I have achieved with my Suburban. Others have achieved similar results with a similar approach. It is documented and it works.Edited by: ronniejoe

 

I accept your challenge Ronnie, intercooler, chip, wastegate controller, bring them and I'll put weights in mine to match your suburban, I've been dealing with not only these pumps, but these engines and these trucks for a decade, more if you count the 6.2s. Intercoolers are nice for dropping intake temps, but if just bypass the PCV so you dont suck that crap in the intake in the first place you wouldnt have a temp problem and you wouldn't need so much boost. If my truck ain't at the 240Hp mark, its darn close.


And by the way, they sell those breathers and just about any Autozone or Advance Auto parts, Edelbrock ones look real nice and fit perfect, make sure you get ones that fit a 1¼" hole and atleast one of them with a grommet to plug in where the oil filler cap goes, the other where the PCV valve is and whatever you can find to plug the PCV inlet on the intake tube. I guaruntee you will see gains in 5 minutes of driving.


I'll post pics ASAP. Edited by: Texas Diesel Guy

 

Any time. Be sure to have a 6% grade and 12,000 lb. trailer.

Nobody questions the length of time that you've worked on these engines. It's just clear that you don't tow heavy. It's also clear, from your comment on the PCV (really, it's called a CDR) that you don't understand where the heat in the intake really comes from. It's that physics thing again.


240 hp? I doubt it.


Again, I'd rather not be so belligerant, but I can't let this stuff go by unchallenged. I'm not trying to pick a fight, I'm just trying to keep rationality involved in the discussion.


I would enjoy meeting you some day. If you're ever in central Indiana, look me up! Please, have a good evening.Edited by: ronniejoe

 

Ronnie, if you want to see what that suburban of yours is really capable of, then go to Autozone, get 2 breathers, and turn your boost down from 17 to about 7. Do you know what you create when you run that much boost in one of these engines? You double the amount of blow-by created, then you dump double the volume into the intake, then you have to make more boost because all that dirty air won't burn the fuel you've got goin to her, and then you have to run an intercooler to keep you IATs down, its a self defeating system.

 

TDG,


I'm curious to crap in the intake comment, how does oil vapor via CDR into turbo (I think that is what you mean, no PCV I'm aware of on the 6.5) detract from performance & increase IAT.


I'm not wanting to run a debate with you, but am interested in serious discussion of the mechanics of why you have come to the conclusion it is so successful; do you think it is result of reduced crankcase back pressure or another function giving the power gain, I'll grant you elimination of EGR & Cat is a plus


I'm jtrying to get a better understanding with how CDR circuit elimination improves things, also if I read description in GM's manual of CDR being essential to regulate proper venting of oil vapor within the crank case; what impact if any, have you seen on oil consumption, I have read elsewhere that an improper working CDR causes excess rear main seal leakage in some models, have you seen any evidence of that.


Again not wanting to debate if it's working for you great just trying to get a better understanding of why it's so successful.

 

Chevydave -


To specifically answer your question go to Kennedy Diesel website for a Spearco charge air cooler system designed for these trucks - it works.


And, go to Heath Diesel website for a water mist injection system designed for these trucks by Bill Heath - it also works, conserving water by injection as load demands.


Idea of each is to increase amount of oxygen per unit volume by cooling the compressed air out of the turbo back to ambient, from a high of ~300deg.


More oxygen, more fuel, more power, right?


Water mist can add even more cool oxygen by rapid evaporation, so maybe a cooler and mister would be the way to go, particularly in the desert, or way up high, as in New Mexico, Colorado, etc.


Here on the Gulf Coast, we got too much water anyway- we get buckets of water anytime we cool this air.

 

Well, the numbers I've posted, and the performance I've demonstrated show that what I've done works. Facts is facts.


The turbocharger increases intake temperature when it does it's job. Again, that's physics. Higher boost pressure overcomes restrictions in the inlet tract to improve overall efficiency. It also packs more air mass in the combustion chamber to allow a hotter, cleaner burn. More air mass also allows more fuel to be introduced...more power can be created. Higher boost pressure can cause more blow by, but it doesn't necessarily have to if the rings are in good shape. I've noticed no increase in oil consumption or blow by. My exhaust temperatures are now lower than they have ever been and get lower with increased boost pressure. That's largely due to better evacuation of the spent gasses during the exhaust stroke from the improved pressure differential across the engine.


I write this, not to argue, but to post the real reasons this stuff works so that others can understand and draw their own conclusions. It's kind of hard to argue with hard data.

 

Ronnie my truck would be better to put up to your burb.
10.5 in. 4.10 ring gear 4wd if I need it. but hell, if I'm racing up a hill I'd want a 2wd 4l80E, built, and a gear splitter to turn 4 into 8.
I'd probably want my supercooler and twin turbos too.

TDG, I have to agree that air density is better than air volume and intercooling makes it happen.
I bought a second breather today but I have to deal with my stalling/limp mode problem before I can say what I think.
Edited by: quantum mechanic

 

I think we were all responding at the same time I'll wait for TDG to digest some of what is being asked before replying again. I'm really interested in the mix dilution from oil theory. at 7 psi my truck won't pull my 12K tractor & trailer load, IC and more boost was required to make that happen.

 

OK, it seems I have several items to adress here....


first, boost, yes, pressure over comes restriction on the intake side of the engine and crams more air in the cylinder so you can burn more fuel faster, I agree completely. But, when you jump to 17psi your asking the turbo to do more than it was designed to do (I didnt say capable, it will do it for a while) you also put more vacuum on the crankcase and every bit of air you suck out of there is already combusted so it doesnt aid in power putting it back in the engine, its already hot and you make it even hotter by raising boost which is why you need an intercooler for this system, and raising boost increases backpressure which also increases engine temps and slows the flow of air out of the engine. Again, this system is self defeating.


All I'm saying is you plug the CDR inlet, and simply vent crankcase pressure into the atmosphere, then all the air going into the engine is now cooler, and more oxygenated so you don't need to increase boost, you get lower IATs, you get more oxygen in the cylinder with less volume of air, which decreases power lost to compress the higher volume, which is very considerable in such a high compression engine, and the air can get out of the cyls faster because you don't have the wastegate closed so much building more backpressure. The breathers will not cause any pressure in the crankcase so leaking rear shaft seals and smoking out of the dipstick is not a problem.


If we were talking about a 6BT engine, this would be a totally different conversation, and I would say yeah, cram all the air you can get at her, but its not 6.5s are a very different animal than the other diesels on the market.


My truck will spike to 13psi and level off around 6-8, fuel delivery has been upped considerably but black smoke is actually less at take-offs now than it was stock and there's no smoke after the first second of acceleration. And I'm telling you, it makes guys with mustangs and even Duramax's take a double take when they see the 6.5 sticker I put on the tailgate.


I'm here to help everyone, Ronnie, if you try what I suggested and put that burb back on the dyno, I'll eat...I dont know think of something...if you don't make considerable gains.

 

 

Air goes into the compressor inlet at ~15psi, barometric pressure.


Crank vapors go into the compressor inlet at 6"wc max. And some of it is oil vapor, of which a Diesel burns to make power. ??


~27"wc = 1psi


~405"wc = 15psi


What is the ratio of 6"wc crank\oil vapor to 405"wc air?


What is the ratio of 6"wc vapor to 15psi Baro + 15psi Boost?


Functioning CDR limits crankcase vacuum to 6"wc, no matter what the Boost level.


That's why it is called a Crankcase Depression REGULATOR, and not Positive Crankcase VENTILATION.


Would insignificant be understated?

 

I agree on 17 boost too much from what I see on my gauge that I have mounted on where my EGR is supposed to sit, at 17 psi (actually anything above 13 psi) is counterproductive, as back pressure in exhaust/turbo is up to 40 psi and basically trying to slow the turbo at both compressor and turbine end plus jacking up temps somewhat, I will say that with reflash and IC EGT overall is lower than with stock program. (Doing some tranny TS this week and I saw that; I will have to run some tests & record the data stock vs reflash program)


I cruise while towing at about 7 psi, hill climb at 12-13, run empty cruise at about 5 @ 75 mph. Now intercooled 7 psi vs non IC 7 psi, more air is stuffed in the chamber with IC as it's more dense, so you can add more fuel/more power, but go too far with any fuel or air and it's counterproductive, it has to be a balance. GM set this engine/turbo combo for best overall driveability with moderate power, to get real gains they had to got to the direct injection 6.6 IC.


GM whatever turbos don't do much good above 13PSI sustained IMO from what I've seen on my truck, now go to a bigger less restrictive turbo on back end different story, but then you gotta add more fuel via bigger injectors or dial in more from or bigger IP or it's wasted effort.


For ultimate you need to lower compression to around 18:1 which allows you to go to 20+ psi boost, more HP; but then you can start impinging on ability to cold weather start, solved by extended glow cycle plugs, or moving to MS/TX/FL where cold days are few


TDG do you think dialing in the IP was most of your net gain and breathers were a side benefit or both are necessary for the gain, have you ever tested IAT with & without normal CDR venting just for comparison

 

TD, It was a combined effort I would honestly have to say, I didnt want to override the stock wastegate setup, but I upped the fuel from the pump so I needed what boost the computer would allow to do more for me, and this add-on and exhaust upgrade compensated for the extra fuel quite nicely.


GMCTD, It doesn't matter what amount of vacuum the CDR is limited to, its not drawing from an atmospheric pressure area, its drawing from a pressurized crankcase. The engine will make more blow-by at higher boost and pressurize the crankcase and blow it into the inlet.


steiner, The breathers are just tiny filters that dump the pressure and clean the air as it flows out, no air goes in.


I apologize to anyone if I seem bullheaded about all this, I'm only on this site to share what I've learned, and I can guarantee you this simple mod, does make a difference.Edited by: Texas Diesel Guy

 

i am very interested in your idea TDG, but the question i have is all of that air that is going into the crankcase good for the oil? i guess there isnt that much more air since the turbo isnt feeding air into the cdr because you have plugged it, but how good do those breather filters really filter?Edited by: steiner43511

 

Just look at the graph. It's really pretty simple.


Would I make more power at 17 psi with a bigger turbo? Yes. Does the engine like 17 psi with the current turbo? Yes. Numbers don't lie.


Traveling out to Montana and back, I cruised (in North Dakota, South Dakota, parts of Wyoming and parts of Montana at 75 mph towing my 32' trailer that weighs close to 9000 lb. loaded. EGT on flat ground held steady around 900-1000 F with boost pressure around 13 psi steady. Prior to the modifications, I could barely maintain 60 mph in the same areas and ran EGT of 1350 F plus at about 6 psi boost. Hmmm... Must be my imagination. Oh, darn! I just woke up and realized that I've been dreaming.


Notice the bulge at 2550 rpm between the stock programming (this was with intercooler, high pop injectors, K&N filter and Banks exhaust, so it's not stock mechanically) and top curve? 93 lb-ft and 45 hp gain at that point. That's a 28% increase from 335 lb-ft to 428 lb-ft and 163 hp to 208 hp.


Looking at max torque at 2190 RPM, it went from 373 lb-ft to 428 lb-ft... a 15% increase.


Looking at max power at 3285 RPM, it went from 188 hp to 223 hp... a 19% increase.


Notice how the green line (chip + boost control without timing change) diverges from the purple line (chip only) at 2920 RPM? That is the difference in boost, pure and simple. That is noticeable when towing.


You know, the data is squarely behind my comments. Take it or leave it.


Notice in the following plot how favorably my 6.5 Suburban compares to a stock 2004 LB7 Duramax.

This isn't even the best run, because the timing change is not included in this plot. Larger images of these plots are available at my website www.schoolcraftpowertrain.com if you're interested.


What more can I say?


Chevy Dave,


I apologize for how this thread has diverged from your original question. I hope that the data that I've posted here will help you to make a good decision. I've put on close to 10,000 miles towing this year so far (3900 last weekend alone) and over 20,000 last year. My Suburban has over 213,000 miles on it now. It is now running better than ever and tows very well. You should consider the towing experience of all who respond if you intend to tow with your truck. Running around empty is one thing, towing a heavy trailer is another... towing a heavy trailer west of the Mississipi is still another. There is an old saying that everyone should keep in mind... "There is no free lunch." It takes some effort and investment to make the 6.5 tow at an acceptable level. There is simply no way around it.


Good luck.


P.S. There is another forum site that has a large community of members with a wealth of knowledge. I encourage you to check it out. It's not hard to find with a search on 6.5 diesels.Edited by: ronniejoe

 

Ronnie,


Not debatating your graph/dyno results, do you tow at 17 this is what I'm talking about from my own dyno experience it's hit it hard, hit it fast lock up TCC to keep boost up, there 17 boost is a plus as it's short duration, but from my towing experience 12600# GN trailer & tractor that much boost on a tow is counter productive, maybe I'm doing something wrong but I'm not seeing much gain above 12-13 psi, except higher EGT, that is both with a TM and Kennedy control dialed all the way in to keep WG shut.


I'll call you tomorrow to compare notes. I'll be putting it to the test again this weekend I need to move my backhoe about 200 mi which with GN trailer should be around 18K total load I'm guessing I never pulled it before.

 

The dyno test never saw 17 psi... about 15 psi max in third. Towing I see up to 18 psi.

 

TDG


As you had addressed vacuum drawing hot vapors out of the crankcase, I intended to show the very small level available.


As the 6" max is at 2000rpm and above, it would indicate that GM felt blowby could be insignificant at those rpms - in a functional engine.


Meaning, one without excessive wear.


As you had already indicated that venting the crankcase caused some reaction from she who must be obeyed, it could indicate that excess blowby is causing some problems in your truck.


Or, simply, excess vapors from motor oil not formulated for Diesel service.


In any case, if crankcase vapors thru that small inlet tube are of sufficient volume to choke off the fresh air from the air intake filter, to the point where the truck runs better without the CDR, it would seem rather unsafe to vent that out over the hot turbo and exhaust manifold.