Hi guys,
I recently put on the Vibrant header and downpipe. I used the stock LSJ header exhaust gasket, with the Vibrant 3 bolt exhaust gasket and 2 bolt exhaust gasket (exactly how the manufacturer recommends it should be set up).

I had a small exhaust leak before I tightened the triangle joint, after I tightened it up the car sounded exactly like stock on fire up and revving the engine to 7K RPM. However, when I get into second gear (first gear at WOT does not do this), hit the sweet spot of 3.5k RPM and then floored it I notice a MUCH more pronounced sucking noise coming from what I think is my CAI area. Is this normal going from stock exhaust on a mid-highly modded car (see mods in sig)?

I checked all piping for exhaust leaks, as I naturally thought it was a leak. I couldn't see nor smell any leaking exhaust. Placing my hands around each joint I couldn't feel any leaks. I even used a flashlight at night beaming it on the joints to see if I could catch wisps of smoke leaking, but still nothing.

Please share your experience with the change in sound from going stock to mid-length headers. Thanks!

TL;DR Did installing an aftermarket header on your LSJ make it sound like it was sucking more air from the CAI?

 

Yes, you opened up the restriction the stock exhaust gave you with the new header.

You are flowing a little more air now, and the engine is breathing easier.

Perfectly normal to hear more induction noise.

 

Thanks so much, after all the leaks I dealt with I'm gun shy. I drove it and it if it's an exhaust leak it only happens above 80 kpa boost... Which seems impossible, so i believe it must be increased flow noise. You found the same?

Thanks again

 

Back when I removed the stock downpipe, the difference in induction noise was noticeable for sure.

If I blipped the throttle with the stock downpipe, you could barely hear anything. Now, all I have to do is tap the gas and the blower gives some whine and induction noise.

I also have a ported head, cams, full exhaust and prototype blower.

 

Nice, thanks, I can now stop taking it apart over and over! 4 times so far.

 

Yep!

Also, high flow manifolds and downpipes will almost sound like an exhaust leak at times due to the change in flow harmonics and different pipe wall thicknesses from stock. You can literally hear the air flowing through my catless downpipe through the floor. A true exhaust leak is a tick tick tick noise that follows through the entire rpm band, and residual soot around or near the leaking connection will be present.

 

Great, thanks! I am starting to really love the noise, sounds exactly like a turbo car pulling air through the charge pipes.