I've been using the cobb TBE (with AP stg.2 map) for around 1500 miles now, and it seems to be much quieter than before. I am well aware of the aftermarket-exhaust syndrome - exhaust seems progressively quieter and quieter, but I think it might not just be me because the turbo hissing seems to have gotten louder in proportion. Obviously the car doesn't feel as fast as it first did, but I don't think I have a boost leak because it still spools up relatively quickly. Of course I could be wrong. So here's what I want to know, if you (Cobb TBE user) are cruising in 3rd gear at 3k (like 45mph?) with the windows down and music off, can you hear the turbo as loudly as the exhaust and road noise? It's very odd because I would assume that if I had a leak then the exhaust would sound much louder too? The up-pipe is stock, and has never been messed with, same goes for exhaust manifold. As for possible post-turbo boost leaks, I have a samco silicone y-pipe with t-bolt clamps on every single interface from the turbo to the TB - so it's unlikely, but I'll double check.

Anyway, I am really just looking for some point of comparison so I can determine if I'm loosing it or the car is. Also, I don't usually go to any meets, but if someone on here has this same set up and goes to the MVKK or UCKK please speak up, I would like to hear it if possible.

 

i think its just you. i run an APS tbe and same thing happened to me. in fact i can hear the spool louder and louder with less exhaust drone.

 

i running the same set up as you. my exhaust got a little louder and the turbo spool is loud too.

 

You are less likely to hear the actual exhaust noise at those speeds as it is projecting out behind the car and not really howling yet.

That said.... you could always install a cut-out

 

*ducks* Dont kill me for the thread necromancy!


I was having nearly this same issue and was searching iclub for any info to relate.

I've had the downpipe for about 2-3 weeks and never heard the turbo spool. Monday night on the way to the ocha meet I had the windows up and heard the loud hissing from 2.5k and up. Im still hitting 17~ boost, and it still feels fast.

Freaked me out that I drove it for 2 weeks and didnt notice any intake sound or hissing, then out of the blue hearing this. Im thinking "how did i NOT hear this before? something must be leaking!"

Its very similar to the cobb SF sound, but no recirc sound and not quite as loud/harsh.

I guess its normal to hear the intake this loud at stage 2, with stock intake? I wonder why it gets louder over time...

 

When I added the catless downpipe to my HKS catback, and went stage two, I had a similar experience. Didn't really notice the spool sound for a week or so but it's plenty noticeable now.

 

I have a 99 RS with a 02 WRX 2.0L

When I had the stock DP, and EBay Catback (Cobb copy) it was all exhaust, of a pretty deep note, and not much turbo noise.

When I put my catless divorced wastegate Crucial DP on the note was not as deep, and in some ways really raspy and crackly. However, the turbo spool noise was way, way louder.

After my tune on the cobb AP and on e85 the raspyness is nearly gone. Much smoother note, and sounds quite good to me. The spool up and down is still pretty damn apparent though.

I had a friend rev the engine a little up and down while I listened near the tailpipe and what I found was that I'm pretty sure I'm hearing the turbo it self, not even the waste gate cause it has not real reason to be opening and closing with such little boost and no real load.

Regardless, I love the sound. I think it's great to hear the turbo.

Now, back to your issue, it freaks me out that you didn't hear it for 2 weeks. I would think such a common sound for catless cars would be apparently immediately.

 

When I first met my fiance, I could tell her exactly what she said to me the week before. Fast forward to now and I can't even recall what she said to me 10 seconds ago.

I think your ears are selectively ignoring the exhaust now and noticing the sweet turbo whistle.

 

Not sure if it matters but its a catted DP. Perhaps its just "settling in" and the components are broken in. Q300 CBE with Invidia divorced DP and stock intake. OTS Cobb ACN91 Stage 2

I had read on some other forums about the elbow pipe going into the IC becoming lose, and some of the 2008+ models removing a rubber gasket and fixing the seal.

It doesnt sound harsh or painful, and Im not seeing a performance loss... just scares me that It didnt sound this way 2 weeks ago. Going to keep an eye on the AP.

If I had an intake leak, would the AF guage show it?

 

Yaar... That's a different issue

 

If you can hit full boost and hold it fine I don't think you have a leak. My car got worked on and tuned with that sound and it's all normal.

Maybe the divorced DPs do it more than the Bellmouth DPs?

I'm hitting 22psi in 5th gear on the FWY. I can't imagine that happening if I had a leak.

 

Ok. Im in the same boat with all of you. Im going insane.

So it started when I installed my helix catted bellmouth with remflex gasket.

Didnt notice it until 3 weeks after installing then thought hey the gasket probably blew out.
I ended up buying a perrin divorced afterwards and reused the oem gasket to seal things up (which didnt work)

Ran it with major exhaust leaks for a month until I decided to buy the pimptastic grimmspeed divorced limited catted downpipe.
Replaced all gaskets with gs gaskets and it sealed up amazing. Fitment was perfect.

Still makes the spooling noise and now im getting a very loud rattle/hissing when I get anywhere near the throttle.

I dont mind the turbo whistle even tho it kinda came out of nowhere when I was WOT on 280N and continues to be loud.

Replacing turbo inlet as soon as it shows up in the mail and new intercooler with grimmspeed y pipe kit to eliminate intake leaks. Will work on pre turbo gaskets after as post turbo gaskets are solid.

I have an itch tho if im going to be removing the manifold and up pipe im going to get that p&p manifold jobby done from gs too.

If its nothing with the intake it will be a couple months before I can afford any of the stuff to take care of the leak as well as benefitting my mod itch lol.

 

Just noticed... under the intercooler there is that metal ring/arm thing (crap i have no idea what it is). It used to be lower, but after the DP and heatshield it is now crammed up against the Intercooler.

I mean its literally smashed up against the bottom of the intercooler. Going to take a picture and upload...

 

That is the wastegate actuator. Make sure it is free moving, it opens the waste gate flap inside the turbo. If it is held closed or anything, bad things can and will happen.

 

Fiddled with the arm to free it up, here it is pressed against the IC. Not sure which was to turn it so leaving it alone