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Little green truck hit the rollers last weekend

BigBlueChevy

BigBlueChevy

Compression Ignition Addict
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It was a great time and everybody had alot of fun. Even had a little bit of a scare at the end of the dyno day as the truck wouldn't start. Thanks Tim (Turbine Doc) for giving a few pointers on where to start as far as diagnosing what caused this. Somehow it ended up being an ECM fuse... and hasn't reoccurred since.

17 trucks showed up in total. 14 Cummins of various generations, 2 powerstrokes, and some joker with a 6.5L :rofl: Highest HP / Torque was a 6.7L Cummins hitting 500+hp and just shy of 1200ft/lbs of torque with a dying CP3 and spraying nitrous. The dyno however is was really only designed for cars, as it could only simulate a 3800lb load, so there where troubles with turbochargers lighting too late. So if anything the numbers on the Torque side could be a little off. I HAD a video of the truck on the dyno, but the @$$hat I asked to take the video felt like adding his own commentary during the whole thing and it becomes EXTREMELY irritating.

As far as spec's go for my truck its slightly modified 95' GMC K/1500 with an "S" vin EGR 6.5L and a 4L80E Automatic. Factory claims 180hp from the engine, not factoring in parasitic loss from the drivetrain. Mod's include a full exhaust (SS 2.25" crossover, 3" DP, 4" for the rest, and a 4" MBRP muffler fitted with the louvers away from the engine (backwards)), fluidamper HB, DMAX 21" fan, Marine nozzles, and my own blend of the "feed the beast" mod.

I did 5 pulls total. With the the first one being used as a test run to dial things in. The lowest pull was 164hp and 265ft/lbs. The best was 205hp and 525ft/lbs. The average between them all came out to around 195hp at 4200rpm and 385ft/lbs at 1650rpm Some of the spikes on the DYNOJET showed that those higher numbers came due to shift spikes from the truck wanting to drop into 2nd gear and take off. However, after some practice, I was able to roll into it a few times without downshifting and got the above numbers. Overall, I'm very pleased. The truck did way better than I expected it too, especially without an ECM tuning and the GM4 turbo choking the engine off. I feel there would be an amazing amount of potential unlocked from this engine with an HX40 / ATT and the proper ECM tuning.



Dyno_1.jpg

Dyno_2.jpg

Dyno_Day_6-23-12_2.jpg

Dyno_Day_6-23-12_3.jpg
 
those runs look like about 175rwhp/340rwtq

Hard to get anything accurate when the trans shifts though... should of had them lock it out.
 
BigBlueChevy said:
I HAD a video of the truck on the dyno, but the @$$hat I asked to take the video felt like adding his own commentary during the whole thing and it becomes EXTREMELY irritating.
Click to expand...

Not to tough to un ass hat the video. You Tube has tools to put a new audio track over the commentary, if you dont have editing software to do it locally.

Mark
 
Primarily building low end torque with the DS4 and GM4. That matches more like the factory rating, but hard to tell without locking it in 3rd gear with TCC locked. With a couple switches on the right lines you could force the tranny to stay in 3rd and TCC locked. And not loading it enough is an issue, not so much with the GM4, but larger turbos.
 
Anybody here (probably Buddy), have the DYNOJET interactive program (.drf files) that lets you read your results? I have one on my laptop at home but the computer here at the school doesn't like stuff being downloaded on it, otherwise I'd put up the last 3 screen shots. I think the last 3 pulls I was able to roll into it enough that the truck wouldn't downshift. All the pulls where done with the selector in "3" rather than "D".

I can put the video up if you really really want to see it lol. And this was on Saturday at AZ dyno chip in Chandler, AZ (I'm not in PA right now I'm out in AZ taking classes for Power Generation.)
 
I looked at the dyno sheet and saw "lancaster PA", that's why I asked! I live on the edge of lancaster. If there was a dyno gathering, I for sure woulda been there!
 
I think if tranny is only selected to 3rd lock up won't engage. You have to had it in D for lock up to work I'm pretty sure at least from my experiences
 
It definately locks even just selecting 3rd, but the TCC over ride is to have it locked from the get go right at its stall rpm and not unlock from high pedal percentage. And you want tranny locked in 3rd gear at the lowest possible speed, which would technically cause a 2nd gear downshift, but the 3rd gear switch override prevents it. This way you get 1 to 1 with locked converter from engine flywheel to wheels. Basically if you coast on the dyno at like 20mph in 3rd gear, then get into the pedal, that would provide good dyno results from 1500rpm up.

1500rpm being where the TCC will stall, minimum you can get without lower stall converter. You could basically be rolling 20mph or 40mph and be at 1500rpm, but if starting out at 40mph your engine will already be loaded more, with the turbo already spooled. That would cause a difference in low end torque results.
 
This is to add on to what buddy just echoed...

you can dyno in whatever gear you want. My truck makes more power in 5th than it does in 4th. The main thing with an auto is that you have it locked out in whatever gear you're in. You want to be able to floor it from 1500rpm or whatever you start at, without it shifting and causing a torque spike during shifts. If you have a locking converter... lock it as well to give you the most "accurate" results.
 
Well shoot I wish I had known all this before I ran on the dyno. Either way this is great info for the next time I ever do a dyno run with an auto. Plenty easier on a manual if you don't slip the clutch. I wonder if using one of those laptop controlled standalone trans controllers would allow you to lock the trans in "X" gear without needing to add more switches?

And the dyno sheet says Lancaster, PA as its where I will be moving into(or the general area) once I finish up out here. Good to know I might have a TTS member living nearby!
 
I have the dyno software and recall seeing the INOP bug next to me. I guess I was left off the guest list... :sadwavey:

Anyway it does have trouble getting turbo's to light...
 
BigBlueChevy said:
And the dyno sheet says Lancaster, PA as its where I will be moving into(or the general area) once I finish up out here. Good to know I might have a TTS member living nearby!
Click to expand...

Give me a shout when you hit the area, there are other members close by too! 6.2turbo is only an hour away :) We can go have us a high horsepower gathering!
 
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