What actually causes RASP?

[silvachris1]

Simple question really. What causes rasp in the upper rpms? I've seen on here several times that it's the unequal lengths on the Y-Pipe. Can somebody give me a better explanation? If it is the Y-Pipe, why isn't there a solution? Wouldn't it be as simple as a new Y-Pipe with equal length coming from the manifolds that meet together, and then go to the cat? Like this (Warning: Bad illustration ahead, ignore the dots):
\\....//
.\\..//
..\\//
..| |
..\ \__
...\__ \
.......| |
Would a Y-Pipe designed like that solve the rasp? Really, this is all out of curiousity. Any opinions welcome, thanks.

[ July 19, 2004, 05:49 PM: Message edited by: silvachris1 ]

[FireFighter]

interesting, now we need somebody to try it.

[silvachris1]

I would be willing to try it. I'm hoping to get headers really soon, so If the pacesetters have any problems (from the bad batch), I wouldn't mind having my shop make it. I finally found a place that knows what they are doing.

[ReodDai]

You looked at the Y-pipe before? or even looked under your car at how your exhaust is set up?

It wouldn't be very easy to make a equal length symetrical Y-pipe. Actually I think the symetrical part is impossible.

[OneQuickV6]

When designing an equal length Y-pipe, think to yourself why you would not go ahead and put an X in there and keep it dual. If you have the ability to work with the space constraints (which has been the main reasdon Y's are not more equal length as well as needing to mate up to the stock exhaust), why not go ahead and do a true dual setup?

[Ju5t_B3at_Me2005]

i've heard recently that most of the rasp can be solved with a custom y-pipe...or the one pacesetter provides.

by custom i mean this : when you look inside your y-pipe you can notice a larger hole for the exhaust gases, as well as a smaller one inside the pipe as well. pacesetter's y-pipe eliminates the smaller circle thus improving the flow and the sound of our cars. i'm contemplating having my exhaust shop go ahead an fab one up like this for me when i install my Rumbler in a few days. this way i can save up for new pacesetter headers rather than the used ones i was originally going with, which i may or may not end up with.

please let me know whether im talking out of my *** or if im right in executing my evil plan...

[silvachris1]

So, anybody know the answer? Is it the cause of the rasp? Would a custom YPipe solve the rasp. I know of the clearance issues under the car. I've been under there, and though it looks extremely tight, I still think it's doable. However, I'm not planning on it. Just curious. I wouldn't X-Pipe and true duals cause it's just not cost effective for me, and not really worth the hassle. If it's possible, my shop could fab one up in pretty quick. They've done several custom exhausts. Anywho, would the Y-Pipe I described fix the noise? I'm not too concearned with ground clearance (anybody ever see the LS1 Y-Pipes, not very high off the ground). Anywho, rasp or not?

[OneQuickV6]

I would say it's still not just the sizing of the pipes. I have 3" all the way on my car, and it'll still get raspy up top. Also LS1's with a 3" ORY have a ton of rasp.

[BirdMan8507]

yea hes right, even ls1's have rasp up top, but obviously, they dont sound ricey when they hit 3500 or 4000 rpm like our cars.....so anyways, what im saying is there really might not be any solution to rasp

[silvachris1]

Thank you, that's what I wanted to know. I know every little bit could help, but I'm not looking to do this, just if the oppertunity presented itself. Anywho, thanks again everybody.

[Ju5t_B3at_Me2005]

either way, headers will improve the sound. im going to try my y-pipe idea if i have the money for it....pay check on friday, even though the exhaust will be going on tomorrow...might have to pay myself back. but i'll try to report results in this thread. btw Chris, nice camaro! thats my second favortie color other than SOM [img]smile.gif[/img]

['94firebirdv6]

im convinced theres no way to completely get rid of rasp but you can reduce it a good bit.
headers help alot, a y-pipe, high-flow cat or even better a resonator. will keep the rasp to a minimum

[silvachris1]

Well, I've got a high flow cat right now, and I'm lookin to get headers very soon. I dunno which catback to go with though. I thought about gettin the American Thunder system, but I wan't 3" so I dunno what to do. Sugguestions.
Ju5t_B3at_Me2005, thanks for the compliments man. I really like the Sunset Orange Metallic too, but couldn't find one. Sad thing is, I looked everywhere for SOM, not even knowing that Hugger Orange was available. Then I saw the car on AutoTrader. Never looked back. Anywho, keep me updated on your exhaust man, cause I'm prolly gonna buy the headers real soon.

[AZ3.8Camaro]

I would say run a true dual setup, with an x pipe. I should equalize the pressure in both tubes and help reduce rasp.