Originally Posted by
velociabstract
I've had my car on a dyno with open headers and later in the same day connected to the stock exhaust from the resonator back. The difference was 7 hp. My tune has about the same advance with 19 lbs. of boost. (25 to 26º) I use 93 octane on the street and a mixture of 100 and 93 at the track.
I'm toying with the idea of changing my exhaust but for weight savings, not power. Burns stainless is one I'm looking at.
Les
Les, that's an expensive way to lose weight. I would not do it. Each 100lbs. is supposed to yield .1 change in et. Will the burns system save 100lbs.? You showed what Boostmonkey saw. Little to be gained with open exhaust when compared to a good exhaust system. I believe he saw a .08 difference in et and 7HP would work out to .07et wise. More encouragement that a good exhaust system will yield some power, better than 15whp. My tune is not that far off then as at 20.6psi it had 25* of timing and that was my more aggressive tune.
Les, have you tried an 18" extension on the open headers, should increase torque but you may have to try different lengths on the dyno to find the best. I'd try that first considering what those headers cost. Mark