need some help on a gmmg+ory+a4+ cme tip= rasp at certain rpm's?????
08-02-2008, 07:29 PM
#1
need some help on a gmmg+ory+a4+ cme tip= rasp at certain rpm's????? ok anybody that has the above a4+gmmg+ory+ cme tip, how did you get rid of the rasp at the certain rpm's , if you have the above then you know what im talking about......it happens at like 1,700-1,800 rpms 1st thru like 3 if you get on the gas alittle .....was wondering how to solver it was thinking of putting 2 magnaflow #59929 metallic spun cats on the y and maybe it would solve the rasp but i dont wanna loose the throaty exhaust or would it sound better? anybod yknow for sure, was planning on puting a cam maybe heads on it later on but was curious on how to solve this problem anybody have a heads up on this problem ....cause rasp sucks
.......Lol almost sunds like im j-braking my camaro lol.
.......Lol almost sunds like im j-braking my camaro lol. 
08-04-2008, 10:12 PM
#6
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If you Y pipe is not merging really well it will make it worse. As said before a good flowmaster y merge will kill most of it and make it flow better, best of both worlds. I have LT to a corsa that should rasp like crazy but it isn't bad at all. Plus it'll be cheaper then cats.
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08-05-2008, 11:42 PM
#10
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thanks for the compliments guys. i haven't come across very many people with headers and GMMG that weren't completely happy. when your not in a garage pulling on a dyno and instead on the street cutting loose on the thing is screams and sounds incredible and NO RASP (with catted Y)
08-06-2008, 03:25 PM
#11
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I got the same rasp after I installed my headers. Now with my CME setup and torque converter the rasp is gone for some reason. It may be from the looseness of the converter since it take more rpm's to get moving.
08-07-2008, 10:43 AM
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On a car with longtubes, no cats in the y pipe into a GMMG the only way to not get the rasp is to have a good merge collector at the end of the longtubes such as the HVMC ( high velicioty merge collector) on the American racing headers and kooks along with a flowmaster y merge. If you cant do that then just buy yourself 1 or 2 magnaflow highflow cats i believe they are $50 each and with the cats you will get rid of the rasp. As long as you have high flow cats you will still get that amazing sound you want.
08-07-2008, 09:34 PM
#13
im goin to toss around the merge idea for alittle while but im leaning more towards the metallic spun hi-flow magnaflow cats by the way, i like the pic with slp sign, cool man! 
On a car with longtubes, no cats in the y pipe into a GMMG the only way to not get the rasp is to have a good merge collector at the end of the longtubes such as the HVMC ( high velicioty merge collector) on the American racing headers and kooks along with a flowmaster y merge. If you cant do that then just buy yourself 1 or 2 magnaflow highflow cats i believe they are $50 each and with the cats you will get rid of the rasp. As long as you have high flow cats you will still get that amazing sound you want.
09-10-2008, 10:10 AM
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I have QTP's with custom Y into a Borla XR1 into my GMMG. This took care of the rasp for me. Sounds very nice at idle and OMG! mean as hell at full throttle. Just a suggestion.
09-20-2008, 03:39 PM
#16
Well............lol
i was going to put 2 metallic cats on my y-pipe like i had recently said above but i was looking at how close my y & Lt's meet to the floorpan and im pretty sure it would have ran into clearance issue with them before i bought them....so now i tried a sweet thunder muffler put into the i-ipe but it didnt work still got some of the rasp) im curious about the borla-xr1 in the i-pipe like the guy wrote about above that might be my next option ......as long as it sounds good still lol
Last edited by CULATR; 09-21-2008 at 07:36 PM.
09-20-2008, 05:41 PM
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On a car with longtubes, no cats in the y pipe into a GMMG the only way to not get the rasp is to have a good merge collector at the end of the longtubes such as the HVMC ( high velicioty merge collector) on the American racing headers and kooks along with a flowmaster y merge. If you cant do that then just buy yourself 1 or 2 magnaflow highflow cats i believe they are $50 each and with the cats you will get rid of the rasp. As long as you have high flow cats you will still get that amazing sound you want.
And yes, that will help alot with the rasp, but the only way to get rid of it would be the Flowmaster merge as said above.