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Losing POWER!!!

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on 9/8/04, 1st dyno run: 329.6 whp with ct intake box, air side induction, taitec exhaust, CTSC 6#, no headers! :biggrin:

I then asked comptech what difference would headers make and they showed me another car similiar setup with headers, it was doing 350 whp. :eek:

Today 5/23/05 dyno run, i now have CT headers, pulled 326.8 whp! :mad:

SO, comptech adjusted the fuel pressure regulator to give it more fuel. Then adjusted the ESM, then it pulled 325.9 :mad: I was told they can't seem to figure it out and to wait till Shad gets back! I'm hoping he can do it! but in meantime, does anybody know what is wrong???!!! Comptech tech,Brian, states everything seems to be fine and he's baffled as well!
 
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do you have the AFR's from the runs?
 
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I'm running everything the same! Same dyno, same wheels. 18/19 hre wheels. only thing that has changed are the headers. AFR before was 11.3, after this last dyno run, they've increased to a steady mid 12's. :frown:
 
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Its a good idea to look at the whole curve too. I would take a 2.8peak HP decrease if it gave me more in the powerband anyday. How long are you at 7999 rpm anyways?

As for something being wrong, maybe the only thing wrong is their idea of hp gains with their equipment? Were you really expecting 25 hp from the headers? I dont know the details of your system, but at your current numbers, you are running stonger than alot of other similarly equipped ctsc cars out there.

EDIT: I have gone to SAME dyno with SAME exact set up on my car and have had variances of over 12 hp.
 
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I saw similar behavior when I was dynoing my car. In my case it was attributed to heat soak and leaking boost.

Did you by chance check the boost output to see if it was the same as before?
 
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What year is your car? If its a 3.2, the most you would have increased, already having the Taitec, is 4, maybe 5 hp. If your last dyno was afew months ago when the weather was in the 60's, and now it is pushing the 90's, all seems normal to me. Temp correction on the dyno is an aproximation at best.

If its a 3.0 then the most you should have gained is maybe 10, so again, with the ambient temp diff and the normal dyno delta, I don't think you are missing more than a few ponies. CT promising a 25 hp gain was a bit, well- optimistic, IMO.

MB
 
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The car is a 2000 3.2. Now the AFR is running mid 12's. My concern is that i didn't increase in HP with the headers, in fact i lost! :mad: I'll look to see if i'm loosing boost and the heat soak.

Once again, i had asked them what a comparable nsx of similar set up and year would gain with their headers, and they showed me that it was pulling 350 whp. Now that i got the headers i end up losing hp.

I appreciate those who've responded with positive feedback. I'll recommend it to Shad @ comptech.
 
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NSXTech said:
What year is your car? If its a 3.2, the most you would have increased, already having the Taitec, is 4, maybe 5 hp. If your last dyno was afew months ago when the weather was in the 60's, and now it is pushing the 90's, all seems normal to me. Temp correction on the dyno is an aproximation at best.

If its a 3.0 then the most you should have gained is maybe 10, so again, with the ambient temp diff and the normal dyno delta, I don't think you are missing more than a few ponies. CT promising a 25 hp gain was a bit, well- optimistic, IMO.

MB

I was about to get a comptech cat back exhaust, but decided not to after I reviewed the dyno chart on their site. It losses hp and torque up until 5600 rpm.. I suspect it would be worse than their chart in real life. :frown:
 
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NSXTech said:
What year is your car? If its a 3.2, the most you would have increased, already having the Taitec, is 4, maybe 5 hp. If your last dyno was afew months ago when the weather was in the 60's, and now it is pushing the 90's, all seems normal to me. Temp correction on the dyno is an aproximation at best.

If its a 3.0 then the most you should have gained is maybe 10, so again, with the ambient temp diff and the normal dyno delta, I don't think you are missing more than a few ponies. CT promising a 25 hp gain was a bit, well- optimistic, IMO.

MB

MB,

Do you think the same results would occur on a bbsc/paxton car? At 10psi (with original CR), ems, fuel system, old school taitec gt parallel cat back exhaust, cat replacement pipes, and stock headers, i dyno'd at around 350 (corrected, at around 64 Deg F. with ~150-160 Deg F. air temps in the manifold). With my current setup I was looking for a solid 400 (when tuning was completed). Ofcourse I was running way rich, around 10:1 over 6k rpm, but I was attributing about half the loss to the stock headers and the other half to the AFR at the time.

-mike
 
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