Engine/Transmission (1994 - 1998) Boost vs. Power

[JGheen]

Hey guys,

I am getting my truck dynoed this Saturday and wanted to get some opinions on how much boost to run before I run it.

My bombing is in the sig and since I have the HX-35, should I tighten the wastegate up some so that I can only make 35-36 pounds of boost since that is about the turbos maximum efficency pressure? Right now, with it pinned onto the freeway, I make 38-40psi max on the gauge in 3rd-5th gears with my mods and EGTs are never really a problem until 2800rpm in 4th where they tend to suddenly jump past 1300*+ pretty good.

I haven't touched the wastegate at all, it is still set to what Banks set it at before it was shipped out, which should be 43 psi according to the sticker on the actuator. So, should I turn that down or will that high boost past the 35's efficency range kill my top end HP due to the compressed air getting too hot beyond 35-36psi? My plate is about 3/4 forward and I was going to move it full forward for my second run. Probably even get a third run in there with it full forward to confirm the numbers.

So what do you guys think? Any advice on what else to possibly adjust for the dyno please fill me in. This will be my first dyno with this rig, hopefully it won't disappoint me.....



Thanks, Joe

 

[SEmerson]

I should be there in the early afternoon. When are you planning on being there?

 

[JGheen]

7:50AM. I want to be one of the first in line so that I can guarantee me a dyno. Apparently a lot of people.



Any advice from my above questions?

 

[Rams-n-Hogs]

If the truck is running good, I would leave it alone. It will only be run up that high for a few seconds, which won't make a noticeable difference in your numbers.



Jim

 

[JGheen]

Yeah, the truck runs great and pulls pretty good in the top end. I just don't want the boost to kill my power if it is past the efficiency range and just pumping hot air @ like 2800rpm+. I'll go ahead and leave it and if the power does drop off dramatically at the higher revs, depending on the numbers I might make a wastegate adjustment to lower the boost down.

So what do you guys think I will make? I've got a pool going at my work and they all are thinking less than I am thinking. My prediction is around 330+HP and 710+lb/ft. Anyone have any other guesses?



Joe

 

[pwerwagn]

Based on what I've seen around here, I wouldnt be surprised if you are correct. I also wouldnt be surprised if you are low. Kinda weird, as some trucks take to BOMBing better than others. If memeory serves corect, I believe it is TPCdrafting's truck that made like 369hp/900ftlb with a #11 plate and not much else? Please post when you get the #'s, you have pretty much the same setup I am fixin to do!

I watched a truck here in NM dyno the other day. It had an ATS "230hp" plate, ATS aurora turbo, unknown injectors, ats trans/convertor, and exhaust/BHAF and it dynod at 405hp corrected, and I think 355 uncorrected. It was a 96 auto. Torque was unknown, didnt have a RPM signal.

 

[JGheen]

I will definately get the numbers posted as soon as I get back to the house on Saturday.

I think if the high boost past my HX-35s primo range is not going to kill my power, then the big 37" Super Swamper tires probably will. But that correction factor will probably put a grin on my face rather than the raw power, but only the dyno will tell.

 

[pwerwagn]

you dont have any stock size tires to use just for the dyno run? Also, what if you remove one of the duals? would that help any?

 

[JGheen]

you dont have any stock size tires to use just for the dyno run? Also, what if you remove one of the duals? would that help any?

I don't have any smaller tires around and I could remove one of the duals but since they are on the truck all the time, I am just gonna dyno it with what it has to get a true power number. I don't care if it is low, but at least the corrected power will give me a good smile. I just want some numbers to give me another reason to continue to bomb.

 

[pwerwagn]

thats true, at least you'll see what you are actually getting to the ground considerering your setup. Man I love your truck . Sorry, maybe I went a little to far there!

 

[JGheen]

Do you or anyone know how much power is typically lost through the drivetrain and tires? I hope their dyno has the capability to estimate flywheel power if so.....

 

[pwerwagn]

Well, the corrected power I was refering too was corrected for altitude, not drivetrain losses. Im a Mech. Eng student now and one of my prof's tells me it is really hard to turn power 90* (such as the diff) and not loose less than 15%. But I dont think your RWHP #'s will be more than 15% lower than your flywheel power. If I remember right, Im my stealth Twin Turbo, All wheel drive the power loss was like 18%. Im thinking you can safely add 10-15% to your RWHP#'s and not be to far off. Im sure someone here has some hard data on this subject though. It also all depends on the axle you have (different designs/ring gear diameters/etc transfer more/less power), the condition of your trans, x-case, U-joints, etc. those effects are probably minimal, but still present nonetheless.