because...?

If you do have an exhaust leak, you'd be able to hear it (as long as your exhausts aren't too loud.

 

yeah, i can def. hear it

 

Are you sure? What kind of sound does it make?

Also, if it is leaking, you can probably go under you car and find the source by smelling and hearing to get the general area and you can probably feel the leak.

 

It sounds almost like a wistle, but not quite. I always thought this was wierd, but ever since i bought my exhaust, when the engine/exhaust is cold, it sounds loud and racey, but after it heats up, it sounds deeper and .....I wanna say mellow, but thats not the word for it. I can get some sound clips, but it might be acouple days...

Anyway, I dont know why it does that. The only thing I can really think of is that there is a leak and when the exhaust warms up, the leak seals up(heat expansion). It just seems as if its gotten worse over time.

 

you were running on a limp mode ecu IMO. Race the car really hard through the gears immediately prior to the dyno test (on the street). Cool the engine while the engine is running for a few minutes and then dyno in 5th gear with the A/C off. Bet you pick up 20 RWHP.

 

Sounds like you do have a leak in your exhaust system. Try to find out the source of the whistle and replace the gaskets too.

 

I'm pretty sure the leak is either before or after the X pipe. Im gonna go ahead and replace all the gaskets from the cats back just to make sure.

 

If there is a leak, you can usually find out exactly where by just having your hand around where you think it is. You can usually feel the gas seeping through the leak. Just don't touch the exhaust itself or you'll get burnt.