So I put resonated test pipes on my g35 and then added a M2 HR designed y pipe with stock catback, I wanted the stock sound but louder and more exotic. I love the high pitch tone and gurgle. So it sounded great but over 1/4 throttle the rasp was insane!! So I took the y pipe off and put the stock y pipe back on, rasp was cut 75%, but still there, sound is less exotic.

So...

I got to thinking, rasp is normally due to exhaust turbulences and piping diameter differences. The test pipes are meeting a smaller diameter y pipe, previously the test pipes where meeting a proper 2.5" y pipe but it merged to a 3" that hit the stock piping 2.5" and was rasp city.

I have decided to hack up my M2 y pipe and leave the HR design but reduce the 3" merge gradually to a 2.5" and flange to meet the stock exhaust. I hope this helps and I am wrapping everything in header wrap just to be safe. If this doesn't work I will install ART pipes.

So do you think I am on the right path? I dont like any other exhaust but the stock, just want it louder and more exotic.

 

I couldn't agree more. That's exactly what I want to. I love the stock sound and hate the rasp that comes with all aftermarket exhausts

If you find a solution let me know

 

Never thought about doing something like that. It may work, it may not. I would probably bet on it not working though.

If you add ART pipes you will most likely still have the rasp. I would say your best bet here if you want a "louder, more exotic stock sound" is to put your stock cats back on and get a Nismo exhaust or weld a Flowmaster 80 series in place of the stock muffler.

 

Rasp is a product of every internal combustion exhaust in existence.

Having the smoothest exhaust flow possible will help, but naturally our engines are quite raspy. The S54 in the E46 M3 is super raspy.

My brother has the M54 in his 330ci. With long tubes, no cats, and a dual exhaust he has rasp all over the place.

More resonators will kill the rasp, it simply gives somewhere for the sound waves to dissipate.

Having the same diameter all the way through should reduce your rasp to the higher RPMs. I have dual 2.25in piping all the way back from the cats.

 

Any vids of your exhaust Massios?

 

The pipe is being welded this week. I will wrap the y pipe in header wrap and make some videos. If I am not happy I will try the ART V2, and then finally replace oem resonator with a longer one.

 

It's on the list. I'm at school now so its tough to find time between ROTC and class.

 

This is what I plan on using as a reducer, just weld a 3" flange, maybe a small section of 3" Stainless, and then this reducer on the front of the midpipe.


In the past I have always noticed rasp coming from exhausts that weren't 100percent mandrel bent, also keep an eye on flange entries and overlaps. I have filed and used a die grinder to smooth out some minor to major obstructions in flow even in high quality exhausts. I've seen some 3" exhaust flanges taper down to 2.75" to accomodate factory gaskets for catalytic converters, etc,. that crap has to go.

I'm not sure if wrap will help with rasp, possibly the twang sound in aftermarket exhaust, metal is alot of times thinner.