Thanks to John Kennedy for the open house this weekend. Late Saturday, after all of the Duramax fireworks, we put my Suburban on the dynamometer. Here's the bottom line:

Power at the wheels: 223 HP
Torque at the wheels: 428 lb-ft

This is raw data, not corrected to a standard day. Corrected values follow:

Corrected power at wheels: 228 HP
Corrected torque at wheels: 436 lb-ft

Definitely doesn't rival John's 590+ Hp and 980+ lb-ft from his Duramax, but exciting to me none the less.

We pulled Moondoggie's stock chip (since I didn't think to bring mine) and then ran some comparison tests. Keep in mind also, that the "stock" data here isn't really stock. I have a Kennedy intercooler, K&N filter, Banks 3" exhaust and Kennedy high-pop injectors installed on the truck. I ended up adding a Kennedy boost control to the BARO sensor and John set my timing to -1.94 deg.

The stock chip produced (all raw at the wheels):

188 HP, 373 lb-ft

Installing Kennedy's top TD Max chip produced:

209 HP, 409 lb-ft (This is how I arrived for the weekend)

Adding the boost controller produced:

220 HP, 419 lb-ft

Changing the timing from -.7 deg to -1.94 deg produced:

223 HP, 428 lb-ft

These tests were run to show the cummulative effect of each change. The boost controller keeps the boost from rolling off so much at higher rpm and made a big difference in top end power.

Towing performance with the controller added and the timing set was noticeably better. I have been running Kennedy's top chip for almost a year now and reported significant improvements previously. As seen from the data, the boost controller added about 10 HP at the peak (about 3250 rpm). However, lower down at 2920 rpm, I went from 207 HP to 220 HP with the controller added plus another 2 HP from the timing change.


Kennedy's products have changed my Suburban from being a towing "dog" to a towing "machine". It is truly fun to drive now.

By the way, on the trip home towing my travel trailer, I saw sustained boost of 17 psi on grades. The engine liked it, since the egt ran a lot lower than before. I can now shift down into 3rd (direct) at about 60 mph mat the accelerator and sustain boost at 14-15 psi until about 65 mph where it begins to roll off slightly. EGT stays below 1200 F. Previously, the boost would roll off to about 8-9 psi and my egt could hit 1450 F by the time I reached 70 mph.

We didn't record boost pressure during the dynamometer tests, but I watched the gage. The test was run in 3rd (direct) with the converter clutch locked. The test ran from about 38 mph to about 70 mph under maximum effort acceleration. Boost started at about 9 psi under full throttle at 35 mph and quickly built to 15 psi as the speed came up. When speed reached about 65 mph, the boost began to roll off, dropping to about 12 psi at the end of the test (with all mods in place).

Many folks say that the GM 4 turbo won't make any more power above 12 psi boost, but the dynamometer tests show otherwise. This is coupled with the added benefit of lower egt.


Here are two data plots. The first compares the four different configurations described above. The second compares the data with all mods but the timing in place to a stock 2004 Duramax LB7. Take a look:


http://www.schoolcraftpowertrain.com/Pictures_&_Data/Comparison.jpg


http://www.schoolcraftpowertrain.com/Pictures_&_Data/Schoolcraft_vs_stock_Dmax.jpg

Ron,


There you go speaking jet stuff again http://www.dieselplace.com/forum/smileys/Big Smile.gif, STD day conditions next you will be wanting to talk enthalpy.


I've estimated my Hp to be in this ballpark good to see you have numbers to back it up, my dyno was a dissappointment. see below






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<TD class=smText noWrap>Posted: 29 October 2003 at 8:57pm | IP Logged </TD></TR></T></TABLE></TD></TR>
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Diesel Addict
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Group: Diesel Addict
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Thanks for putting the event together it was fun I learned a lot, met some new friends, put some faces to names I knew. Got a serious case of power envy, somebody needs to make a box or program bypass to let the 6.5 do it's thing, factory program needs help. I felt like the "little engine that could, I think I can" PCM or TCC lock up cut boost just as I was starting to build power. Dmax truly is a drug as some sigs state, just can't afford it.


I will post more in 6.5 forum, even if I didn't make big numbers I had hoped for I looked good on the dyno. Thanks again all, Steve special thanks for standing by and getting this pic.


http://dieselplace.com/forum/uploads/K1500_Dallas_dyno_run.jpg


http://dieselplace.com/forum/uploads/Turbine_Doc_K1500-1.JPG

Edited by Turbine Doc on 29 October 2003 at 9:35pm

__________________
TDP# 4442(tbogemirep)
98GM K1500,6.5TD IC,L65PCM,3.73 gear,4L80,3.5" exh,BST Ctrl,Amz air &amp; byp oil flts,JK fan clutch,mandrel crossover,pilar gage BST/EGT/TRN,remote elec fan tran cool,alum trn pan </TD></TR></T></TABLE>


JK says part of it was dyno set up, looks like I need to plan a road trip to get mine fine tuned and see what I'm actually laying down, since last years Dallas run I've found a bad MAP sensor, installed JK Hi-Pops, and running Heath 2.0 PCM.


On the offset I'm running -1.5 I don't know that going to -1.94 from there is that much different. GMCTD &amp; I have a theory that for towing power -1.5 is a better #, &amp; -1.94 gives good dyno # as you are hitting it hard &amp; fast

TD,
Your numbers were alot different form the first post.

kinda makes the case for jacking the boost sensor with another resistor(for the opposite effect from what you had.)
Now I'm really interested to see what numbers I'll make.Edited by: quantum mechanic

Tim,





Doing it again Labor Day weekend...


Be sure to bring a stock PCM also...


My 96 could only hit like 210's when tested inertially. The dyno wasn't operational before it left for TX. I don't think that the inertial type dyno will load the 6.5 enough. I also had a high velocity squirrel cage fan on the IC and a 48" barn fan for general air.





The test run on Ron's truck was a 12 second sweep from start to finish with the truck "matted" and normalized prior to releasing. The Hold TQ was up with timing up which would indicate thet it liked the timing for towing etc...

I always have stock PCM on hand, just in case I breakdown and need to convert back to L56 so my visible mods other than my IC don't void my warranty, one of the things I wanted to do in Dallas was run different stock vs hybrid combos just to see what net effect was; what vs what adds gains like Ron did, but we did not have time for that. I'll keep the Labor day date in mind, but the homefront boss has me committed elsewhere I think. Maybe your reflash will be up then and we can try it as well, then there was that big turbo, and ....., and ...........http://www.dieselplace.com/forum/smileys/Big Smile.gif maybe more than a weekend trip, since I have the GN hitch maybe we can pull one of those big trailers loaded up for a road test once we get optimal set up on the dyno.

QM,


One of the things happening during that dyno with factory program was boost would peak to 12-13psi then fall off to 5-6, going home with tail between my legs I dialed in JKs control for peaks up to 15, still had cutback but only to 7-8.


Driving on open road vs dyno I just seemed to have more power SOP than what dyno showed. I've pulled 12K of trailer since then up to 75mph still had more power left; I doubt if the 150 HP was real, I could have done that.


When I installed the 2.0 reflash I was peaking to 13 psi boost, but between 3rd & 4th gear shift boost would clip to 0, running TM vs JK boost control it did not do that, but with 2.0 tune & TM I would also occasionally get a SES code for boost/WG that I had never seen before.


Checking with my scanner I was also showing boost of 35psi from MAP output, I changed the MAP sensor, gauge & MAP now have the same readings, & the clip to 0 has stopped. So in addition to dyno not loading up right, no TCC lock up command, I think MAP was starting to go then as well, & the boost fooler helped hide it, I did not put it all together, to know the PCM was possibly retarding boost/fuel to control a false overboost condition.


2.0 does not cut back boost at same place as factory program, but evidently does still have some self preservation logic if boost goes too far out of range of what it anticipates it should be.

I agree with Kennedy. The way the test was run, I'd say the truck likes the -1.94. It also had more seat of the pants power when towing my travel trailer home. Of course, I also had the boost controller installed.

TD,

So what would you do to fool the PCM if your running an aftermarket
turbo that makes 45 psi?

I've experienced the simulated overboost(computer thinks your overboosting)

I would think this could be programmed in to a reflash, but havn't heard anyone
talking about it.

The other thing is more(additional) resistance in the map signal to trick the MAP into not seeing over 12 psi boost.
With a scantool and a boost guage you should be able to find a happy medium.


I would like to set my TDC offset to -1.75 to -1.95, but wonder where you run actual timing after this change?
Edited by: quantum mechanic

My truck is still down, so don't have time to think right now, but would be interesting to see same vehicle with less restrictive turbine running same events, limiting Boost to 15 ~ 17psi.


Those torque plots are significantly interesting, including -1.94deg adjustment.


Excellent post, guys......

Too bad the sequence wasn't:


1) stock Chip


2) -1.94 Timing adjustment


3) Boost Controller


4) Chip


I would like to see what 1,2 and 3 do for a stock L65.

45 psi boost??? you think the 6.5 will hold up to that is pretty high from what I read for these engines.


What you would have to do I guess is dial in the fooler to get minimal output from MAP sensor, one more piece to this puzzle that just hit me is that the 2.0 reflash is as a L56 PCM, I had been running a stock L65 PCM so maybe part of the faulting was the huge difference between baro sensor on fire wall and Map sensor on manifold, with a F PCM there isn't a baro it just quick reads baro at start through the MAP.


Also the L56 has a MAF sensor that the L65 does not have, guess I'll give Bill a call to see what he thinks on the subject. The more I learn the less it seems I know.

Darren payne has the 45 psi turbo and a built 6.5 block.





My '94 has the baro on the firewall but the didn't see it on the '96, both "f" engine.

I was so moved by how low your numbers were, that I've taken to the idea of more resistance on
the boost control and I've sodered(between torrential downpours) an additional 10 ohm inline resistor into the curcuit.

Now I would like to "see" the boost output, but alas, I still havn't purchased a boostguage.


Edited by: quantum mechanic

Every "F" engine I've seen has a BARO sensor on the firewall. The port is just open to atmosphere.

That's it, it looks like the map exactly.

I dont know why everyone here seems to be saying they need to change the base timing of their injection pump, the advance is completely computer controlled, as long as base timing is within specs the pump will work fine whether you set it at the high end or low end.


But if you want quick power from your 6.5 Electronic, swap in a low number resistor into your PMD (1,2...maybe 3 if your brave) and open the top cover of your injection pump, loosen the T40 bolt holding the optic sensor in place and give it a little bump to the passenger side of the truck. this is the ONLY way to achieve true advanced timing (outside of a PROM/ECU upgrade) and it ups fuel delivery simultaneously. The optic sensor sends signals to the ECM for start/end of injection, moving to the passenger side will trick the pump into starting injection earlier than it was calibrated, giving your rollers inside more ramp time, and you trim off the end of injection so you can still make it idle right (go too far or dont put in a lower resistor and it will surge at idle). After you do this, then set your Base Offset timing wherever you like and give her a run. I haven't put mine on a dyno yet, but I assure you, its a very noticeable gain.Edited by: Texas Diesel Guy

OBD-II reads Baro from MAP (Boost sensor) during wait-to-start period.


OBD-I L56 used firewall mounted sensor for EGR vacuum feedback via short tube tied into the EGR solenoid pair.


OBD-I L-65 used module with different calibration for BARO.

Setting base timing does nothing but get the "window" centered so the stepper can do it's job. TDC learn gives it more advance throughout the curve. Messing with the encoder DOES dump fuel, BUT it shifts the amount of APP required excessively and it is tough to drive w/o smoke and very early shifts.





"S" engines had 2 sensors in all years. Vac hose attached to the one on the firewall.





"F" engines had two in 94-5 like Ronniejoe describes, and went to a single in 96 up .

40 pounds of boost for 250-300 hp?????????????????????? How bout a turbo designed to move enough air for that much power

I know of no 6.5 running 40 psi.


If we add atmosphere (14ish) to boost, we'll get close.





My '96 runs 25-26 psi with the big turbo.

I think you could get a 6.5 to run 45 lbs boost....once.

The turbo he described was an ATS aftermarket turbo for a cummins rated for 45 psi coupled to custom ceramic coated headers.

I'm just interested in the theoretical possibities of using an EFI conrtolled
system. It certainly looks like the mechanical would be the simpler of the two sysytems but
I have the intent to gleen all I can in order to better understand what I might do next to any of my trucks.

PCM varies injection at idle based on inertia variance, input from hi res optical - does this to ensure quality idle under various loadings, such as ac comp on, steering input, shifting trans in and out of gear. Etc.


'Bumping' the optical pickup will cause surging, as indicated.


Best to adjust injectiion timing by rotating pump.


OBD-I trucks will learn new timing within 50 starts.


OBD-II trucks can re-learn immediately, based on routine suggested by factory.


Timing adjust can be predicted by simple dimensions - 1mm = ~2deg.


Rotate pump to driver-side = advance, passenger-side = retard.


Scribe a reference line, and proceed from there.


Problem is, unless you're the original owner, only a Tech-type reader can indicate whether the timing has been previously adjusted.


Factory should be 3.5deg desired, -0.5deg TDC Offset


8.5deg desired = -1.5deg TDC Offset.


3.5deg to 8.5deg = 5deg, or 2.5mm adj.


Lock'em and load'em....

Suffice to say, the dyno chart shows what setting TDC learn can accomplish...

Actually, what was demonstrated is that a gain was made from TDC offset
with your programming in place.

I also would like to see the boostjacker, TDC offset, and then your chip dynoed in that progression.

My understanding is that TDC offset is either right or its wrong setting it advanced or retarded will only cause the stepper motor to compensate and put the advance where the computer wants it.


I'm also in agreement with Stanadyne and General Motors that the factory pump mounted position of the PMD is the best way to keep it cool, and you can aid it by swapping in a lower number vent wire (i.e. 2 instead of most having 4 or 5 to put return fuel flow at the top of spec and help supply your injection pump with cooler fuel and help increase the life of your sensitive electronics onboard by doing so.


I also stand by my optic sensor adjustment and I can vouch that (assuming it is done properly) it will increases power, not cause smoke or surge, It will cause slightly more firm shifts, and it will make better fuel economy. I'm going to see if I can't get mine to a dyno this weekend and post my results, and as soon as I run a couple tanks of fuel through her I'll post mileage improvements too.Edited by: Texas Diesel Guy

That may be GM's & Stanadynes preferred location they are also in business of selling replacment parts, it's also darn tough to access it there when they can & do fail, nothing like trying to fix it roadside on a hot summer day or in pouring rain, GM acknowledges they have some problem in this area with their extended warranty.


I like capability of 5 minute or less changes, for that reason alone IMO remote is only way to go, I have 50K on mine since remote mounting 1 shutdown/fail that was corrected by cleaning &amp; retorquing transistor mount nuts/studs.


GM does not always get it right, see OPS/lift pump fail, crimped leaky oil lines, no IC from factory, 130gpm water pumps & dual therms to control overheat and try to change a 4wd engine oil filt that has not been remote located. PMD might be the designed location, but remote & turning into a FSD is better functionally.


QM, I went to Darren's post & did not see where he said he was running 45 psi boost but said he had a 45 psi capable turbo, did I miss something, I don't think 45 psi is none too healthy for the 6.5, if so probably someone before us would have done it.Edited by: Turbine Doc

OK, so what's not to believe about 2-3 horsepower gain across the spectrum from TDC offset learn to -1.94 deg? As I've always said, the proof's in the pudding... the numbers are there for all to view. Texas, I look forward to your dyno numbers. Let's see if they match the ones provided above. I can definitely say that the truck is also much "spunkier" than before with better off idle throttle response. By the way, I'm running a #9 resistor, and could see the difference.


You can argue all you want to. That won't change cold, hard facts.


Also, there's no need to go getting insulted and all belligerant. Everybody is wrong now and then. It's a lot easier to recover if you don't throw a fit first.http://www.dieselplace.com/forum/smileys/Ermm.gif. Trust me, I've learned that the hard way!http://www.dieselplace.com/forum/smileys/Confused.gif


Nobody that I've dealt with here thinks they know everything, but you've got some convincing to do because of my personal experiences with my truck and with the folks involved in getting it to the performance level it is currently at. If it was a dog now, I might be more inclined to listen to you when you say that I and others don't know what we're talking about. Clearly, it isn't a dog now, so I'm not too inclined to listen.


I'm sure you have a lot to offer to the knowledge base, but others here do too.


Just my two cents.Edited by: ronniejoe

I'm sure they do, and I'm not trying to step on anyone's toes or belittle anyone, I just thought I'd throw a quick tip out there for someone who doesnt want to throw down any real money and it got shot down pretty quick. I've been rebuilding these pumps since they were introduced in 94, literally hundreds and I've had quite a few opportunities to tinker with them to try and sqeeze out some ponies during rebuild/calibration, and this is one that I came up with that worked well for my truck, maybe someone elses too, just trying to pass on information I've picked up from experience over the years.


By the way 2-3Hp gain, can hardly be called a gain, that falls well within the inevitable margin of error of the dyno and we all know results will vary slightly from run to run... just my opinion, I dont rebuild dyno's or anything ;)


By the way, Now that I've seen some of yall's dyno results, I have any idea what I'm trying to shoot for, 230Hp mark is what I'm aiming at now, even if I have to swap out cam rings to do it (by the way, a little fact most of you wouldnt be privy to, there's 3 different cam rings with different profiles that will work in a DS pump) And I'll be happy to share my results, success or failure and pass along whatever I discover in case you find a fuel shop out there willing to put together one of these High Output Injection Pumps for yourselves.Edited by: Texas Diesel Guy

Texas,


That sounds really good. I, for one, have been starting to dig into these pumps a little to try to learn some of this kind of information. I'm eager to hear anything more that you might be willing to share.


By the way, the plots that were displayed above were averages. Each line on the chart was an average of at least three runs. I haven't calculated standard deviations yet, but I personally witnessed each of the plots that went into the average. They were very close to each other, so the standard deviation will be small. This means that the data is pretty good.


Without this information, your assessment of the 2-3 horsepower being within the error would be reasonable. However, knowing what went into the data, I believe it is real. In the end, I picked up over 20 horsepower with the combination of boost controller and timing. I'll take that!


If you haven't already, you should take the time to get to know John Kennedy. He's a valuable resource.

I dont know why everyone here seems to be saying they need to change the base timing of their injection pump, the advance is completely computer controlled, as long as base timing is within specs the pump will work fine whether you set it at the high end or low end.


But if you want quick power from your 6.5 Electronic, swap in a low number resistor into your PMD (1,2...maybe 3 if your brave) and open the top cover of your injection pump, loosen the T40 bolt holding the optic sensor in place and give it a little bump to the passenger side of the truck. this is the ONLY way to achieve true advanced timing (outside of a PROM/ECU upgrade) and it ups fuel delivery simultaneously. The optic sensor sends signals to the ECM for start/end of injection, moving to the passenger side will trick the pump into starting injection earlier than it was calibrated, giving your rollers inside more ramp time, and you trim off the end of injection so you can still make it idle right (go too far or dont put in a lower resistor and it will surge). After you do this, then set your Base Offset timing and give her a run. I haven't put mine on a dyno yet, but I assure you, its a very noticeable gain.





When would the surging occur? Is it possible for it to get moved during shipping?

if the optic sensor is moved too far, or the resistor in the PMD is not lowered enough to compensate partially for the movement, the computer may not be able to find a pulse width that make the truck idle properly, but tap the throttle and it will run like normal...but with more fuel/advance/power than before. Note, this is ONLY if you move it too far, or fail to change the resistor in the PMD appropriately (it MAY work with the one you have in). There's a lot more to it, but that the jist. And no it can't move during shipment, its adjusted during calibration and locked in place with a torx head bolt.Edited by: Texas Diesel Guy

Driveability, one of the reasons for improving engine output, is not reduced in any manner when rotating inj pump housing to achieve increased timing.


Well.....fuel mileage has a tendency to drop drastically for a while, but mo' power is heady stuff. Not to mention, addictive.


While an optical procedure is workable, most folks should not be advised to attempt it due to the possibility of catastrophic damage. Rotating the pump is a recoverable error scenario.


Neither procedure should be attempted without first getting an instrumented timing reference - Tech-XX, SnapOn, etc.


If you don't know where you're starting from, it's difficult to know if you've arrived, as it were.


Also, since 'Forum' is some kinda foriegn word meaning 'opinions, ideas, and information', alternate views are usually not meant to discourage posting, so keep the ideas coming, dudes.......

I'm your ginnea pig texas guy,


I opened the pump, loosened the t40 bolt (had to use 1/4 driver/extension w/ t40 bit to turn it)
http://www.dieselplace.com/forum/uploads/F71_ipscrew.jpg
and moved the entire assembly to the passenger side 1mm.
Then retorqued it as tight as it would go.

I'm showing 8.5 deg actual and 4.5 desired at idle.
The idle didn't change any so I left the resistor alone.
Fuel delivery went from 8mm to 12mm at idle.
it seems to run 10 deg. cooler at about 180 deg but it was a cool day.

I'm running with the new 25 ohm boost jacker and if I give it 25 ohms resistance at idle it gives the code for too little volt signal from the map, but accelerating up hill it only knocks alittle off the volt signal.
i think that resisting while the curcuit is peaking volts is a good way to keep the compressor in.

I run a #7 resistor and 42" of fsd extension and connectors for a total of #9 or more (guessing)
I have an APP that has higher than normal volt signal on the #1 and #2 resistors. The optic change reduced the APP surge.
I find I have made some gains.
Thanks TDG!Edited by: quantum mechanic

Also, since 'Forum' is some kinda foriegn word meaning 'opinions, ideas, and information', alternate views are usually not meant to discourage posting, so keep the ideas coming, dudes.......





http://www.m-w.com/cgi-bin/dictionary?book=Dictionary&amp;va=forums

Thanks to you too quantum, let me know if you get a chance to dyno that baby for us to see your results.


I guess since it worked for you others might be tempted to try it too so I should post the torque spec for the Torx40 Bolt holding it down: 190-210 in/lbs. And also be sure you just loosen the lock bolt, and slide the actual sensor to the passenger side, under the lock plate (a screwdriver on each side will do the trick). The 1mm adjustment quantum used is a good place to start, and scribing a starting point on the sensor will help you keep track of your adjustments. But dont think its like the old DB2s and you can just crank more fuel out by moving it further.


Also, be aware that just because you move it and there seems to be no immediate problems (idle surge) you really have to get the truck to full operating temperature, espectially on the light dutys which try to idle lower than the HDs. if it surges put it back, or change the resistor.Edited by: Texas Diesel Guy

TDG,
When I first bumped the actual sensor I saw a line scribed on the sensor itself
and I put it back inline and moved the lock plate and sensor to the left together.
It seems you're saying I should have moved the sensor only.
Since it only took about 20 min start to finish, I have no problem redoing it.

I opened it back up and moved the locking plate back.
results: terrible idle, 8.5 deg. desired 6.5 measured

I removed the resistor from the FSD (took five minutes, try that pump mounted)

I changed it again, this time bringing them back in line and back toward center.
result: rough idle, desired 4.5 deg actual 5.7deg.

I changed it again, a hair advanced of the centered lock plate.
result: idles fine, desired 5.5 actual 8.0

since the idle is back, I'm leaving it alone for now.
Edited by: quantum mechanic

its a very fine adjustment...normally, when you first open one up, you will notice the lock plate is just smaller than the body of the sensor just in front of it and its very close to centered. you want to put it about 1mm or less closer to the drivers side, thus moving the optic sensor the same distance closer to the pass side.


how does it run though? and what did you change the resistor to? It wouldnt have something to do with the 7 foot extension on the wiring would it ;)Edited by: Texas Diesel Guy

1/2mm to the passenger side, don't move the lockplate just the sensor. Edited by: quantum mechanic

yes, it's a fine adjustment that shouldn't be done with out a timing readout.
I'm not running any resistor right now, just the seven feet of 18awg extension.
I'm about to test run it.

It won't do any good to change the resistor unless you can reset the tdc. (requires a tech 2 scanner)


My brother has been running without one for months.

In order to quantify the results, one needs a baseline AND repeatability. If a guy REALLY wanted to know what the encoder move was doing to timing, he'd have to do Time Set to lock out the stepper, BUT there is so much variance in the gearset and the electronic signals that it's about impossible to read. My point is that the desired timing numbers are changing due to the computer's changing needs. Desired timing will vary quite widely by ECT as will curb idle.





We don't arrive at our HP numbers by guessing, or by chance. This TDC learn spec is something that I've been doing for a long time now...

I've got a friend with a pristine 6.5L Chevy, and he wants to boost up the power. What's the biggest "chip" out there, what's the hp/tq gain, and who makes it?

Depending on the year a "chip" will produce a max of 40hp & 90lbs tq.


Later model years require a reprogramed computer.

The 6.5 really needs gauges, and air flow improvements first. I use 3.5" mandrel bent pipes as 3" is a bit small.





As for chip performance ratings, that will vary. I haven't had anybody beat my chip as used on Ronniejoe's Sub. There's a large variance however in mechanical condition on the 6.5's and it may not achieve the same results.





I'll also add that cooling upgrades are also often required whether stock or modified...

GMCTD,


I just re-read your post from 24 June. The most significant gains come right at the RPM range where I spend a lot of time while towing. It really made a difference in towing performance and pleasure.


I, too, would like to see results from a larger turbo charger limited to the same boost levels. More power would likely result from reduced back pressure and lower intake air temperatures. The only reason that I commented the way I did, was to point out that even with a GM-4 turbo, the engine responded well to 17 psi boost and the GM-4 can deliver it... just not as efficiently has a larger turbo charger.


Interestingly, the total combination helped significantly at 2550 RPM. Remember that the stock baseline on those plots was describing the electronic configuration. The mechanical configuration includes an intercooler, JK high pop injectors, K & N air filter and Banks 3" exhaust. So, the stock numbers are quite a bit better than what a truly stock 6.5 would put down. At 2550 RPM, I picked up 93 lb-ft with 9 lb-ft due to timing change and 45 hp. Notice how the green line (TDMax chip and boost control) at 2920 RPM diverges from the purple line (TDMax chip alone). The boost control added 23 lb-ft at that point and the timing added another 4 lb-ft for a total of 27 lb-ft and 44 hp. That, too, was noticeable while towing.


That bulge at around 2500 RPM was really significant from a real world, seat of the pants perspective.

While I DID nudge the pump to get there, the TDC offset value is what made the difference...

Ok JK


Where would you start on my 90 6.5 w 90,000 miles.


Cost does matter, If your chip gives me 40 hp and 90 lb/ft then what else should I do along with that. Cause thats about what I'm looking for from my truck. Right now my truck runs like I'm sure GM wanted them to. but I know I have to be proactive to keep it that way. My truck pulls my car and trailer ( 6500 lbs) great and never drops of 80 mph doing it. Cooling system mods are top of list because does run warm with A/C on during hot day.

Ronniejoe -


If you're seeing 17psi Boost in the intake plenum, it's closer to 20psi at the compressor, pre-cooler.


Experiments back in 2000, and again during Winter ought three\ought four with Tech-II, proved EBP to go to ungodly levels at that Boost.


I'm wondering at the negative differentials EBP/IBP you're seeing in your truck.


I had not installed a charge-air cooler at that time, so I ran the tests in Winter to keep the IAT's below ~120deg, usually 80-100deg.


Dense, cool charge-air, lots of oxygen per unit volume at 20psi.


I was running the GM chip with 63mm3 fuel - raw Boost would hit 20psi, but no sustained power. 20psi would indicate sufficient fuel to achieve better acceleration levels than PCM-limited 7psi at same fuel rates.


My powertrain consists of T400 trans with manually-shifted 5831 3-speed auxiliary od trans - meaning it can be in overdrive in Park, Reverse, Neutral, or any gear range.


Torque converter has Cummins\Dodge internals, for ultra low stall - hydraulic hook-up above 'stall' is similar to TCC converters.


DRW with 4.10 finals, 0.73 od gives effective final of ~2.99. 235-16 tires, 31"od.


GM-8, smooth-transitioned plenum inlet, 3" downpipe, 3.5" exhaust from there. Soot trap not required, none installed.


'95 L-65, oem 3500 PCM/chip.


Dry vehicle weight - 8500lbs.


Parameters monitored via Isspro, verified, except EGT\EBP, with Tech-II.


I can nail it at 30mph in 3rd gear od, and 'lug' it just like a manual trans in 3rd\od.


Boot hits 20psi (~35-37 on Tech-II, fuel rate 63mm), it starts accelerating (no downshift to lower gear), then runs out of 'umph' about 50mph\2000rpm.


Tech-II Boost still @35psi, fuel 63mm, no pull-back.


Accel good below 2000rpm, falling off as exhaust volume from increased heat and flow rate at higher rpm overcomes turbine flow rate.


EBP levels way over 40psi - really big negative differential, with only 20psi Boost.


Runs limited to 15 seconds to avoid DTC73, where PCM will pull fuel if overBoost condition exists for 20secs or more.


No chance of PCM pulling fuel with IAT below 130deg.


(I added Max-E-Torq chip in late April, broke flex plate at crank hub after a few of those 30mph-up PCM-limited 15psi\78mm3 fuel-rate pulls. Sounded like a really bad lifter on decel only, no noise on accel.


Have not EVEN had the courage to attempt it again - new flex-plate, rebuilt trans - particularly after installing the charge-air cooler, DSG, and new 5521 IP @ -1.94deg earlier this month.)


From this, you can see my interest in your runs over 15psi with GM-4, though I assume some of that towing is at higher altitudes. Gage-pressure instruments are calibrated for sea-level, require some factoring at higher altitudes.


Note - Tech-II won't lie to you, with it's Baro comparo.http://www.dieselplace.com/forum/smileys/Cool.gif


Your dyno torque figures are notably interesting, as my truck runs\tows from 1800rpm city to 2000-2300rpm hiway in 3rd\od.


(You can easily count on one hand the number of times it has been over 2500rpm since I built it late'99 early '00).


Are you any closer to installing your EBP gage? Iirc, B-D offers one for use with their Tork-Loc\Exhaust Brake setup - Tanker has one on his truck.

Yes, but I've been looking at putting together a system using a remote pressure transducer and electric gage to avoid plumbing the exhaust gas into the passenger compartment. I'm in the process of researching DOT rules on that issue.


I can assure you that the engine is making more power at 18 psi boost than it does at 12 psi boost in my configuration...and my egt stays lower.


You're right about pressures at the compressor outlet, although I havn't measured them there yet.


Most of the high boost pressure readings I've had are between sea level and 2500 ft. Around the midwest (between 600 and 1200 ft ASL) is where I've done most of my towing since adding the boost controller. I've made one trip to Boston and Cape Cod and one trip to Montana for the Pull-Off. In western North Dakota, the waste gate bushing partially siezed, limiting my boost and performance. I was still able to make about 11 psi, but the truck was significantly down on power and the egt was significantly (300+ F) higher than when it was working properly.


After replacing the turbo at the Pull-Off, I came home through Wyoming and South Dakota on I-90. On Sunday running in about 95F outside temps, I could only make about 15 psi max boost. I suspect two things...


1) Coolant temps were running a little high and the PCM was probably pulling fuel.


2) Even with the charge air cooler, the high ambient conditions were limiting the power potential of the engine and reducing the energy available to drive the turbine. Later that night, after things cooled, boost pressures came back up to 18 psi.


I'm a little confused on your gage calibration comment. Gages like these are reading pressure relative to ambient. To get absolute pressure, barometric pressure must be added to the gage reading. Therefore, the gage pressure should be read as that...pressure above ambient.


I am running Kennedy's top chip with a #9 resistor, so I'm probably at or above 80 mm^3 fuel delivery. Maybe that makes a difference between what I'm seeing and what you saw in your tests. I'm planning to get a Tech II, just need to scrape together the pennies (dollars, actually) to do so.


Thanks for the info.Edited by: ronniejoe

BTT This post should be read with the improvements post, along with the Wild Rides postEdited by: gmctd

http://www.dieselplace.com/forum/showthread.php?t=23677 latest run info