Originally Posted by MU71L4710N

incorrect. kenne bells website says not to have longtubes because the canned tune they mail out does not correct for longtubes and causes blown engines. if longtubes had zero effect on the car over stock headers, kenne bell would not have to have this disclaimer. there are people on this forum who have blown their motors with kenne bell's tune because they did not listen to the "no longtube headers without custom tune" part.

longtubes vs. shorties is good for HP at the top of the RPM band. so the way i see his car, his typhoon is likely causing a power loss, and having shorties vs. longtubes is not helping his peak horsepower numbers. if he were to switch to longtubes, he would loose roughly 20HP in the middle of his RPM band, but would pick up HP at the peak of his power band (which is where the peak HP number everyone makes such a big deal comes into play). so switching to longtubes and putting a real intake on his car, and possibly a few small supporting mods (since cliffy said his maf and injectors are way too big), he should be into the 300s. people with just cams and no stage 2 heads are putting down 285-295 range.

i can show you a dyno graph too. they did stock, shorty, and longtube headers compared on the same car.

the stock was baseline. forgetting the peak power numbers for a minute (and these numbers are not exactly accurate im going off memory but you see my point).

with equal length shorty headers, at 3,000rpm the car gained roughly 25rwhp more than stock headers at 3,000rpm. at 3500rpm, the car had roughly 20 more rwhp than stock headers at 3500rpm. at 4,000rpm the car had rougly 15 more hp than stock headers at 4,000rpm. the point where the car hit maximum power, equal length shorties had only 2-3rwhp over stock. this is where the PEAK horsepower number was taken from, so if thats ALL you go by, you think you only gained 2 horsepower...when in actuallity that is not correct because you had significant impact on other parts of your RPM band, but the peak horsepower numbers do not show this.

with longtubes, the car actually had a little less horsepower than stock in the low part of the rpm band. however, at 3,000rpm it had 2-3 more rwhp over stock headers at 3,000rpm. at 3500 it had 5rwhp more than stock headers at the same rpm. at 4,000rpm it had 10 more rwhp over stock headers at 4,000rpm. so on and so forth until the point where peak horsepower was made, the longtubes made roughly 20-25 more rwhp, so this 20rwhp was that over stock. so say with stock headers the car put 250rwhp PEAK. with equal length shorties, it was roughly 252rwhp at PEAK. with longtubes, it was roughly 270rwhp at PEAK.

Originally Posted by tbirdscwd

I was always told stock CR on PI engines was 9.7:1??

Originally Posted by b96gtman

Stock compression for a pi motor is 9>6 to 1 as told by the Mod Father himself: John T. from Modular Performance.

Originally Posted by MU71L4710N

didnt even read that, the typhoon needs to go. u should throw a stocker back on