I've got a 2001 Z06 with 385 hp factory stock. The seller had installed the Halltech carbon fiber intake, a Halltech throttle body, and DRM headers. He had advertised 435 hp, which seemed a bit high to me with these mods, but I'm no expert. Any educated guesses out there on approx hp? Thanks a million.

TT :cheers:

 

My educated guess is that it's closer to 415 hp.

385 - factory
10 - intake
20 headers
0 - throttle body

 

Depending on how the car has been driven and how you have been driving it, OBD2 adaption and limits of the fuel injector sizing, and assuming that no software mods have been accomplished... best power is likely in the 400-410 HP range. Further, at full throttle above 6100rpm, the car is likely running a little bit on the lean side, which is going to flatten peak potential horsepower to some degree. Best bet is to get a scanner and look at what the Fuel Trim numbers look like. If the STFT and LTFT numbers are both positive, installing a set of 30#/hr injectors may produce a noticable gain in power (If the trim numbers are negative, injectors are not going to make any difference.) Further, a software upgrade may also help take advantage of the increased airflow of the intake and headers, and the increased fuel delivery of the injectors (if installed.) All together, the car should be able to get into the 430hp range, corrected for altitude and atmospheric conditions. However, if you don't drive it hard enough to actually use the additional potential capacity, no real gains will be realized and its all a waste of money.

To get an idea just how much adaption effects power, see the dyno sheet at:

http://www.corvetteforum.cc/performa....php?RegID=177

Note that from the first test to the fourth, each run produced more power, from 333hp (382 flywheel) to 368 (423 flywheel). This specific car had long tube headers, Donaldson intake, and aftermarket cats, so is close to your configuration. How much power is this car actually producing? Probably 382 as it is driven daily, with the capacity to make as much as 425 when driven hard, and adaption has increased fuel trim to match the increased demand. Your car is probably a little down from this overall, because it does not have the cats in it (the biggest restriction in the system.)

To further illustrate the adaption impact, check out this dyno chart:

http://www.dtmpower.net/project%20ca...k/air_fuel.jpg

Note that on the second pass, the fuel curve (lower line) is richer overall, and the power is higher by a small amount. This will continue to happen on each consecutive pass at full throttle, untill the Fuel Trim adaption has reached its maximum within the software's constraints, or the engine begins to go rich. As soon as the car is driven back on the streets, adaption is going to begin to notch down the gain made. Bring the car back in a week, and it will be back at the lowere numbers again...

So the question isn't really "How Much Power" anymore, as this is a floating variable, responding to how you drive the car. The real question might be "What is the potential"...However, if it's not pressed into service, it might as well not exist at all. In other words, if you drive around all day at part throttle crusing, and line up on an identical car that has just come off a series of drag race passes, the other car is going to out-power you at that moment, even if both cars are exactly the same.

Make sense? :cheers:

 

I can only go by what i have experienced...My 01 was dynoed at 356 rwhp which would be around 420 flywheel....My guess would be about the same, maybe another 5 but i doubt 435,,,a dyno will solve the question.. :yesnod:

 

Fellas,

Thanks for the replies, especially the impressive, in-depth discussion from kwillmorth. I just got the car several weeks ago, and took it to Thunderhill Raceway weekend before last, so that'll give you an answer on how she'll be driven. I'll do 4-5 open tracks a year, along with an autocross or two. Thanks again for all of the feedback!

Tom T. :yesnod: :cheers: :yesnod:

 

My 01 with the same kind of mods dynoed at 337 rwhp (SAE) on one dyno and 345 on another. Higher numbers are very common but I'm skeptical.

 

Just want to make one point that in the pulls shown above...the 1st pull was with the car in STOCK configuration. :) It was NOT with the headers, intake, cat mod, etc. Only the last 3 pulls are with all these mods.

So it didn't pick up 35rwhp from pull 1 to pull 4 as a function of computer learning/adaptation.

I'm not denying that PCM adaptation exists. I think it does to some extent.

 

:cool: Didn't notice the big time difference (doh!) But now we must ask... what was the temperature and atmospheric change between September (stock test) and February (modified tests) in Texas?...

In any case, adaption will vary from driver/car to driver/car, I've also seen a few go down in power with each additional pull, which may be heat soak related.

Here's another that appears to be adaption related, this time a stock C5 Coupe with modified intake:



Fun stuff.

:cheers: