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View Full Version : Dyno numbers and "The Area Under The Curve"



SoCalDMAX
09-29-2002, 18:06
I spent most of the morning on Sat. the 28th with Joe at Pacific Performance, what a great guy! He ran my truck on the dyno and I learned volumes about the truck, dyno testing and hp/torque numbers. Not to say I'm any expert now, but the wealth of info he and others shared with me was incredible. I'll post the scanned dyno sheets Mon or Tues. for all to look at.

The truck ran 247hp and 430ft-lbs stock, or I should say with Amsoil filter and Gibson Exhaust. This is right smack in the middle of results from a number of other Dmaxes. Keep in mind, there are differences between 01s and 02s, example: the 02s have a "throttle plate" of sorts which allows low pressure EGR to mix with high pressure intake, 02s have slightly higher rev limit (3300 vice 3100) and probably other issues we didn't discuss. Those of you concerned about whether Juice V3.xx is putting out advertised numbers, relax... on level 4 it generated 332hp and 653ft-lbs, fully 85hp and 225ft-lbs more. The Powershot 2000 propane generated 345hp and 601ft-lbs, a 98hp and 171ft-lb gain. The combination of Juice level 4 and propane was good for 401hp and 724ft-lbs, a 154hp and 294ft-lb gain. As you can see, each mod gives the advertised gains, but at higher levels it becomes more difficult to make more power, no matter how much we'd just like to add up 90 + 100 and get 190hp. I do believe that diesels respond better than gassers in that regard.

What I'd like everyone to keep in mind is the area under the curve and at what rpm we really drive at. The stock Dmax produces 250ft-lbs of torque as low as 1450rpm, probably 300ft-lbs at 1800rpm and crosses 400ft-lbs at 2300rpm. Juice level 4 (which was not designed for towing) produces 300ft-lbs at 1700, 400 at 2100, 500 at 2300, and 600 at 2450. We'd rather not be towing at 2200 rpm and up, either we're in 4th which is killing mileage or 5th, in which case we're racing minivans. ;)

As much as I'd lke to think everyone with a cool dmax is reading TDP, I saw a very cool truck there with $18,000 in audio, video and engine upgrades. I haven't seen anyone here brag about owning it. It also had dual remote reservoir Bilsteins up front, 37" tires, lift, dual Autometer gauges in the overhead console (for airbags) and triple Autometer gauges in a pillar pod which was faired in and painted. There were also trick electric powered steps which swung down from under the truck for each of the 4 doors. I saw dyno sheets on this engine and it blew me away! How about a tow program that provides a flat min. 600ft-lbs of torque from 1700rpm to redline!

My point in mentioning this is not to discuss any one product, but to keep in mind what you really are doing with the truck. Stomping out poorly executed Rice is fun and all, but I think it would be wise to see dyno charts as well as a photo of smoke levels of a product to ensure that it's suitable for the intended use. For those (I think most of us) who bought the truck for towing, an honest look at torque as well as hp curves would ensure that you're getting something suitable for the task, without covering your trailer in soot. Look at how much torque is available at what rpm, be honest about how much time you spend at what rpm.

I know John Kennedy and others have said it before, but it bears repeating - "Look at the area under the curve!" I'm very happy with my truck and the mods I've bought. For those looking at this new crop of power programmers, etc, just keep in mind the curve as you drool at all of the new features.

I'm really excited about all of it! :eek:

Regards, Steve

NutNbutGMC
09-29-2002, 18:45
Steve, .. well spoken and excellent points of consideration. Thank you for sharing the information. After all of the above ciphoring and calculating, all I want is 115 mph. :cool:

[ 09-29-2002: Message edited by: NutNbutGMC ]</p>

mackin
09-29-2002, 18:48
Steve

As always top shelf info...Thanks
Can't wait for the day I'll get my fat a$$ on the dyno rollers...Not me my truck...... tongue.gif
Very impressive......
All I can say is we got a winner in our DURAMAXES......Long time Chevy fan, finally we can mix it up with the competition.......

MAC

hoot
09-29-2002, 18:50
Steve,

Thank you so much for the detailed info. I like seeing the 345 RWHP with just the PS2K but 400 RWHP is kickin!

You are right in the usefullness of it all. Drag racing ...yes, but real world towing?? Unless they can bring the torque down to more useable rpms and keep temps under control along with tranny durability, the big numbers are only for short burst fun.

pullinpower
09-29-2002, 19:54
SoCalDMAX,joe wouldnt let you try the tricked out PCM on the dyno?stack the PCM with the juice and propane? Man I bet that would be some serious power.

SoCalDMAX
09-29-2002, 20:32
Thanks guys! Just sharing the info. I was there for 3 hrs, Joe and the others were a wealth of info about the Tech II, Mustang Dyno, Duramax programming, the combustion process differences between gassers and diesels, fueling constraints, you name it. I only hope I can remember most of it!

I didn't ask to try the PCM, we were running out of time, they took a lot of time out of their busy schedule and I didn't want to impose any more than I already had.

pullinpower, I'm sure you're very happy with the PCM and maximizer. When you see the dyno results posted on their website (soon, hopefully), you'll be able to see graphically why you like it so much. ;) When I decided to buy a diesel, it was on the basis of power, longevity and fuel economy. Kinda figured there must be a good reason all of the big rigs are diesels. I never even considered how much more potential they held. It's only going to get better and better!

Regards, Steve

Dave
09-29-2002, 21:06
Great information. Thanks.

SoCalDMAX did you do any dyno runs with the juice set on level 2? I ask because I'm curious as that is what most of us use to tow. I would like to know the level 2 curve for torque and Hp. Thanks again.

SoCalDMAX
09-30-2002, 00:01
Unfortunately, we only had time for a few runs. We ran it with level 4 and stock before realizing that a parasitic drag run had not been done, so the numbers were off. We did that, then the stock, propane, level 4 and level 4 with propane runs. Basically my dyno sheets look very similar to those posted on the Edge site, give or take a few. I think you could pretty much take those as being what you're getting out of your truck.

Regards, Steve

Dmax son
09-30-2002, 03:10
Wouldn't stacking the juice and the pcm be bad, I mean the juice advances timing and the so does the pcm. So if the pcm advances timing, would the juice also advance the timing by what it is program to do, and then when the engine sensors report back to the pcm retard the time so it doesn't do damage??

Bryan

sdaver
09-30-2002, 08:52
HEY STEVE GREAT NUMBERS.....POST THE TABLES ALONG WITH THE GRAPHS.......SOUNDS LIKE YOU MEET UP WITH SOME NICE KNOWLEDGABLE GUYS.....DAVE :rolleyes: :D

SoCalDieselNewbie
09-30-2002, 15:24
Hey SoCalDMAX,

I was in there on Fri afternoon... when they dyno'd that truck.

That beast sure was loud on the rollers (those 37" tires were howling). Did you notice that it was a 2-wheel drive?

Anyway, the was the 1st truck that I have sit in with a triple guage pillar pod... I didn't like it. The 2 gauge pods seem to be alot less obstructive.

Btw, did you see the sleeper that they are building?

[ 09-30-2002: Message edited by: SoCalDieselNewbie ]</p>

SoCalDMAX
09-30-2002, 22:56
Yup, that truck on the dyno had everything and the kitchen sink!

The sleeper looks like it's gonna surprise a lot of people, they don't expect a quick truck.

Regards, Steve

c5dura
10-01-2002, 07:07
dmax son, I have asked the same question a couple of times in other threads, but nobody seems to know the answer...

I agree with you that it seems like a bad idea. I know that on LS1 engines with custom tuning, you would never dream of doing something like this. You would totally screw up your long term average fuel trims, get pinging, and generally just destroy the custom tuning of one vendor by laying someone elses tuning parameters on top of it. Of course you can't really do this since all custom tuning on LS1 engines is via the PCM and not by some box you insert inline. (there are exceptions like MAF translaters and such, but thats different).