What causes exhaust rasp?

**~Firehawk~** · 10-15-2005, 03:31 PM

In general, if you take off your cats in a car or truck, what is the actual mechanics of what causes the rasp? Also what is the best way to eliminate rasp on a vehicle with no cats?

**SlammedBlueZ02** · 10-18-2005, 08:56 AM

i had a lot of rasp with my headers and no cats....I had factory exhaust tips...then 3.5 inch magnaflows(better)... and then some tips from Magnaflow that split into two ovals(very similar to BB Triflow or Corsa tips).....that did the trick for me

**Frosty** · 10-19-2005, 08:09 PM

I believe it's the sound waves from the exhaust hitting each other at a certain RPM. I'm probably wrong but that's what I read somewhere lol

As far as getting rid of it? Well I have a SLP dual/dual muffler with mac midlengths and an ORY pipe..there is a tiny bit of rasp at like 2300rpms or so.

A lot of guys run those borla race mufflers or whatever they are in the I-pipe before the muffler and it gets rid of most of it.