Rasp issue, need help on fix?

[slyder]

So I have a Takeda catback with skunk2 headers now. After the headers I hear a rasp and it sounds directly from underneath me at 2k-4.5k rpm then I just hear full deep exhaust. I'm trying to get rid of the rasp but other then that the header and exhaust sound great together until that rasp comes and goes. I have a stock front pipe and over pipe. Does anyone have this combo or something similar to with an El header and exhaust combo and has tried to use a front pipe to get rid of the rasp. Would it be better to get a resonated front pipe not many choices but invidia or going with a catless front pipe such as mxp, invidia, stm etc. Thanks for your help in advance.

[Tenament05]

helmholtz resonator bro

[dem00n]

C-c-c-cherry bomb!

Seriously though. Resonator or cat's. Preferably long haired.

Edit: I re-read your post, the noise is coming from underneath you? I don't think exhaust leaks could be raspy, I'm stumped.
Rasp tends to get worse in higher RPM's. Interesting.

[Fizz]

I'm having similar issues....

See here: http://www.ft86club.com/forums/showp...postcount=5949

Funny thing is that I've heard another guy's car (still NA) with a full aftermarket exhaust system (catted header, overpipe, catless front pipe, and resonated catback) and there was no rasp at all. I wouldn't say his was quiet, but his definitely had a deeper tone.

I'm almost certain it's got something to do with the factory rear muffler.....perhaps it's not able to cope with the increased airflow especially being supercharged now, and the internal baffles are creating some weird resonance/rasp?? Or at least that's my theory....

[wparsons]

Is it vibrating/rubbing on a heat shield?

If you're currently running the stock front pipe, that's the most likely to get rid of rasp. it has a restrictive cat and helmholtz resonator.

[slyder]

Originally Posted by wparsons

Is it vibrating/rubbing on a heat shield?

If you're currently running the stock front pipe, that's the most likely to get rid of rasp. it has a restrictive cat and helmholtz resonator.

I do have a vibrating rubbing issue with the bottom sheild but I think that's due to the fact of my car being low and I have bottomed out that sheild so much it's bent up. There's no room for me to even stick my finger under the header when it meets the sheild. So are you saying that's my rasp issue as well? Or I need a front pipe to get rid of the rasp. As far as the sheild goes I jut need to bend it down a little to give the gap from the header touching it. I'm getting a good deal on a resonated invidia front pipe. Should I get the pipe?

[FirestormFRS]

I have a similar set up. Check your OP/frame clearance. Mine was barely touching but OMG the noise it made at low rpm's...

[wparsons]

Originally Posted by slyder

I do have a vibrating rubbing issue with the bottom sheild but I think that's due to the fact of my car being low and I have bottomed out that sheild so much it's bent up. There's no room for me to even stick my finger under the header when it meets the sheild. So are you saying that's my rasp issue as well? Or I need a front pipe to get rid of the rasp. As far as the sheild goes I jut need to bend it down a little to give the gap from the header touching it. I'm getting a good deal on a resonated invidia front pipe. Should I get the pipe?

What front pipe are you currently running?

The stock one is going to be the most rasp free, getting an aftermarket one will just make it worse.

Fix the heat shield clearance first, check to see if you're rubbing anywhere else, and then look at replacing parts.

[Hyper4mance2k]

The rasp is from the high compression engine, and huge amounts of overlap at part throttle, midrange applications. The only way to get rid of the rasp is with a second muffler, or with a well built resonator. I have the Skunk2 header as well. The higher compression the engine, the raspier it will sound. Just watch some vidoes of late 60's, early 70s, era sports cars that ran 12:1ish compression. 2000GTs raced by Shelby were raspy 12:1 screamers.

Also, larger wall thickness exhaust systems will help to an extent, but they reduce drone more than rasp.

[Hyper4mance2k]

Update: I replaced my burnt out glasspack with a Magnaflow 10436 muffler/resonator and every little last bit of rasp is gone. Last night I finally trashed my stock over-pipe for a berk 2.5", and the car was much louder and raspier from the obvious increase in flow rates, but after fixing the burnt-out glasspack my car has never sounded better.