I've been troubled with a very high and annoying exhaust leak (sound) from under the car, it's sounded like it was coming from the downpipe somewhere. The sound is not that bad when looking into the engine, and you can't hear it when you're standing behind (you hear the normal exhaust noise).

So I've been trouble and been trying to find the source. The first time, I opened up the intakes and screwed the 4th and missing bolt on the downpipe (I was unable to fit it first time I took it all together). That didn't help, noise was still there.

Our experience (me and my wife) is that there is exhaust/gas smells as well from the car that is beyond normal...

So today I digged deeper to find the source, but unable to do so... the only thing I found was a possible leak between the mid- and downpipe, on the top of the joint. My question is: do you possibly think that this leak could create a very noisy tone?



(You can see the black spots on the top behind the seal)


Another question, how important is the two metallic protections around the turbo housing/downpipe? I found out it was 10-times easier to unscrew the downpipe after I removed them, and it's much easier to see if there is any problems (loose screws) to the whole turbo-rig. Think it's OK to run without them?

I think possibly the problem lies with the secondary turbo, it looks pretty dark (almost like exhaust waste) between the turbo and manifoil. It's not easy to see in the photos, but here is at least some of my mobile photos from todays sessions.

Please give me some advices on how I move forward, should I remove the oil tubes and further investigate and potentially remove the manifoil, or is there a simpler way of figuring out all of this?

My potential problem area:







Into the manifoil:







Various photos:

 

I hit the 10 photo limit, so here is the last one:

 

That flange leak might be enough to make the noise you're hearing. It's hard to tell from pics how wide the gap is when assembled.

I suggest you try a more forgiving gasket: you can use an embossed copper gasket such as the ones made by SCE gasket, or a thicker and more crushable graphite gasket like Remflex. Two OEM gaskets can also work much better. Unfortunately I don't know what's easily available to you in Norway. Beware of cut-it-yourself gasket materials - I've done much research and tried several and none of them could handle the incredible temps found in this part of the car.

The heat shields are not necessary to running the car, but I think they are a good idea. I would put them back on once you sort out this leak issue.

Dave

 

Friend of mine says I have a huge leak here at the mid/downpipe, he's probably right ... I'll get some exhaust paste and try to make everything tightened and hope that it fixes the problem, I'd like to avoid digging deeper into the manifoil and turbos.

 

If the exhaust paste holds up for more than 1k please share which product you used.

Dave

 

The heat-shield was ... well, not handled well when I took it off, so it's probably gone forever. It was just the one that covered all the bolts you see in my last photo and an "attacher" that connected that one, with the one that's beside block and manifoil.

I'll try and see if it improves with some gasket material, thanks!

 

Actually, the midpipe is a custom-made with original 2.5" flange, which is probably a big source for the leak, so actually I'm gonna throw that away and buy a better 3" midpipe, like this one: http://www.rx7store.net/product_p/midpipefd3s.htm

Suggestions for better alternatives?

 

i had a massive leak between downpipe and the center section, i wasnt getting any noise, just louder exhaust sound and lots of backfiring

 

These are my symptoms exactly but with the leak sound also. I had a mechanic look at it (allegedly) and he says there was no leak there! Guess I will just get the required gaskets and replace to be sure!!

Would an exhaust leak make the car less responsive and maybe spool to a lower psi??ie does it effect performance??

 

first: never trust a joe mechanic, they dont understand jack about our cars most of the time haha

second: an exhaust leak by itself will not affect performance to a noticeable amount, but there are 2 exceptions that i can think of.

1. if the leak is before the turbos, and is gigantic, it could cause your turbos to spool to a lower psi

2. an exhaust leak pre-O2 sensor will cause a lean reading, and the ecu will try to compensate by adding more fuel causing you to run rich, which can cause a performance loss.

 

i have the same problem but wont be able to take everything apart and install new gaskets on the block to manifold, turbo to manifold, etc... and hopefully fix it.. i'll keep you updated on where mine was.

 

In this picture, check these 10 mm bolts (see the white arrows) that hold the turbo hot side to the cold side. Mine had come up so many times giving the exhaust leaks that I ended up safety wiring the 10 mm bolts.

 

have you checked your flange gasket?

 

speaking of those bolts, i just pulled my turbos to track down where my exhaust leak was coming from and noticed that one of those bolts was missing................... weird, luckily i had some extras the same size and thread count. i ground down one to the same length and tichtened it down, weird ****.