I dynoed my LT4, ~stock (160 degree stat, K&N and open lid), two months ago and it did 292 max hp, 307 max torque. Last week I sent the the PROM to Ed Wright for custom programming, in preparation for the exhaust system that I'm having installed soon. It did 307 max hp, 323 max torque. +15 hp and torque was the benefit of this $350 mod. The run was on a dynojet, the very same one, both times. I don't know if my results are typical, but if they are, I have a quick answer to 'What is the best first power mod for a stock LT4'. This is an awesome dollar/hp ratio, considering that a lot of guys spend $10,000 over all and pick up less than 100 rwhp.

[Modified by Charles Klein, 2:24 PM 10/27/2001]


[Modified by Charles Klein, 3:45 PM 10/27/2001]

 

also, I'm willing to bet people that have done the 10,000 in mods have already done the chip.

Also, there aren't very many things that can change the hp output like a chip can.

 

Of course.

A lot of guys say the opposite, at least for LT1/LT4 cars, that reprogramming is worthwhile only after heads and cam -- that it has very little value for a stock car. I find that the most common advice for a first mod is the exhaust.



[Modified by Charles Klein, 3:42 PM 10/27/2001]

 

duh, forgot about heads and crap.

Anyway, for what normal people are willing to do I think that a chip is a decent bolt on to do. After all, in my opinion 15 hp aint to bad.

 

I'd spend $350. for 1 rwhp. As for tuning the stock tunoing on a stock motor is very good. ED Wrigth and even A Hypertech will give you about 15 rwhp with a stick shift car, Autos LT1 will get less.
Sometime we put way to much importance in dyno numbers, the real comparison is at the track.

 

Pretty cool.

:)

 

In week or so, I'm going to install full length headers and the Power Effects cat-back system. I'll do another dyno run after that.

If anyone wants to see it, I can send a copy of the dyno graph (however it's a 6.57 MB file). It has the before and after curves. I am having trouble accessing my CorvetteForum website, which is the only web space that I have.

John,

A lot of people here bash the Hypertech for performance programming, saying its only good for setting fan temps, speedo recalibration, and rev limit. I went with Ed mainly because of his reputation on the forum and because I wanted custom tuning for my new exhaust. I wish some guy with a stock car would use the HPP performance programming (and no other mods) and do before and after dyno runs. That would really help settle this dispute.




[Modified by Charles Klein, 2:55 PM 10/28/2001]

 

Just a question and a comment.

Did you mention to him that you were going to have the full-lengths and freeflows on when he burned the calibration?

If having a chip done is the first mod to do, that calibration won't always be beneficial to further mods. One main case in point.

Say you install a camshaft one grind hotter than stock. The volumetric efficiency will be greater at the top end and worse at the bottom end than with the old cam. Volumetric efficiency is fiddled with in the calibration (generally). If you pay a bunch of money (well, I consider it a bunch :eek: ) to have a calibration done before a something like this (anything that changes your VE in fact), how many times is he going to recalibrate it if you keep adding more stuff? This necessarily doesn't just apply to cam swaps, but a K&N, air foil, throttle body, etc can all change the airflow.

I am just trying to point out both sides of the story and am not trying to step on any toes. -Matt-

 

Yes.

My mods will be in the three stages. Exhaust, gears, heads/cam. So I'll have to do two more recalibrations. My headers will lack EGR and AIR hook-ups, and I'll have no cats. But if I were using headers that had the hookups, I could use O2 sensors for the no-cats setup, and not do reprogramming just for exhaust. I think it is more common not to need reprogramming for one's exhaust set up. So if someone is doing mechanical mods like me -- exhaust, then gears, then heads/cam, I would recommend reprogramming first (based on my +15 hp/torque gain) because of its immediate high pay-off. Ed Wright charges $175 for additional reprogramming, so I'll spend $700 overall on programming, which will be a small part of the total cost of mods.

I am far from an expert as to what mods requires recalibration, but I am confident that switching to a K&N, adding a throttle body airfoil, going up a size in throttle body do not require reprogramming. They may be relevant factors in designing a custom chip. But, if so, these can be taken care of when necessary reprogramming is done (like for heads/cam).

Again, my experience may not be typical, but there is no mod that comes close to producing 15 hp for 350. Even if you it call it 700, 15hp/$700 is very cheap horsepower.





[Modified by Charles Klein, 6:49 PM 10/28/2001]

 

Adding mods will allow you to enhance you ability to tune your motor. Mods themselves have little affect on performance but when done as a package you can tune for greater HP. The only true way to tune is to programe your ecm/pcm/pcu on a dyno.