I'm 99.9% certain this is not a header leak, but I just wanted to ask to be certain (just got my headers and hfc's installed) - in 1st gear from 4k to 7k RPM it sounds like my engine has a blow-off valve - under WOT it makes a REALLY loud TSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS sound - I first thought this was a header leak, but it's only in 1st, only at that RPM range, and oddly enough, previously (from the spacer) in that range I was a whistling sound, so I guess headers + hfc + spacer = TSSSSSSSSSSSSSSSSSSSSSSSSSSSSSSS instead of a whistling noise?

I have no sudden loss of power anywhere in the curve, no hissing sound at idle, and like i said, only udner WOT in 1st gear from 4-7k

.....in any case, the TSSSSSSSSSSSSSSSSSSSSSSSSSS is pretty cool ^_^ (As long as it isn't a leak ^_^ )

your description makes it sound pretty cool..........i want a blow off valve.......a header leak would be a hell of a night mare

I know; 5hrs to install them and then to pay another 5hrs labor to get them fixed and whatnot - ouch :/

But yea, i'm almost positiv eit isn't a leak because my mechanic would most certanly have pointed it out, and i have no power loss anywhere in the curve, and it only happens in 1st

But yea, if I had to declare it I would say that it sounds exactly like a loud-*** blow off valve ...... that goes for 3000RPM ^_^

Check in the morning. Is it still cool in the mornings? You should be able to see the vapors if it is a leak. Lift the hood and watch and from underneath also. If it's kind of a tinny sound could be just the noise of the headers. Good luck

You can also use a make shift stethoscope that will greatly help localization of any exhaust leaks.

To make one, find 3 feet of clear vinyl 1/4" ID tubing and 1 foot of 1/4" OD copper tubing.

Plug about 1" of the copper tubing into the vinyl and you have a way of quickly finding exhaust leaks under your car or in your engine compartment.

While holding the open end of the clear vinyl tubing at your ear, move the open end of the copper tubing all around the circumference of the header flanges. If needed, you can bend the copper tubing in a right angle to get into the tight parts of the system.

It greatly amplifies the sound and location of exhaust leaks.

it was checked out when it was -10degrees Celcius (below freezing) outside, so I'd think that 3 skilled mechanics would see a leak......

is the check engine on?

nope

I have the same mods but it doesnt make a pssssssssssssssssssssssssss sound. i can hear air sucking in while I accelerate and then it stops once I let off the pedal.

but if u dont have any check lite or any lost of pw than maybe its normal with those headers.

That's what i'm hoping ^_^

No leaks this morning, so I'm pretty sure it's the headers - plus I found somebody on my350z who has topspeed headers and said his do the same thing (making a TSsssssssssssssss in 1st).

Oh well, it's a good thing I don't find that noise annoying, haha ^_^

did you find what what was the problem?

wasn't a problem; just the increased air volume/flow

Cool, thanks. It's nice to know

Good one, Magyver! I'll remember that.

indeed

a month+ later and i still <3 my new headers; they basically turned it into a bradnd new car