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CEG\'er
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What casues the RASP in our exhaust systems??
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Joined: Jun 2002
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Hard-core CEG'er
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Hard-core CEG'er
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Not enough muffling. Lose the resonator, ditch the cat or take out the mufflers and you'll get it.
1998 T-Red SVT #957
Born 5/14/1997
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Joined: May 2000
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Hard-core CEG\'er
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I have often wondered the same thing. What makes this engine rasp and not others. This is the first engine I've had that sounds like crap with open manifolds (a must when changing an exhaust  )
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Joined: Sep 2001
Posts: 311
CEG\'er
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CEG\'er
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Well, I have a very open exhaust... and it is completely smooth until the secondaries open. I think that the secondary butterflies maybe make turbulence in the airflow through the engine... which is very possible. Further proof is a GS-R. It has a dual-stage manifold like ours. Type R's do not. A type R opened up, although it doesn't sound good... is really not "rasp". A GS-R on the otherhand has the exact same sound as ours when the secondaries kick in at 5700 (on the GSR) ... which is "rasp". Granted, our exhaust sounds much better than a GS-R's IMHO and many others, but, we too have rasp just like them. The only way I can think to cure it is either have enough muffling to get rid of it, or to remove the butterflies like DemonSVT has done. I wonder if he has no rasp?! Anyone else notice this?
99 T-Red SVT
***Intrax, Bilsteins, Azenis, Offroad Y, CAI, Tint, Magnaflow Exhaust, Custom Grilles, Poly Mounts, Silverstar Bulbs, 100W Ion Fogs, Focus SVT Wheels, SHO UDP, Ford Racing Wires ***
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I removed my butterflies at one time and it made no difference
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Joined: Sep 2001
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CEG\'er
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CEG\'er
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.... weird... I wonder if it has to do with the dual manifold for some reason?
Also... other raspy vehicles I've heard all have very high HP/liter.
IE
New M3
Ferrari 360
Most Honda's
Our Car
Lotus Twin Turbo (small v8 high hp/liter)
etc...
99 T-Red SVT
***Intrax, Bilsteins, Azenis, Offroad Y, CAI, Tint, Magnaflow Exhaust, Custom Grilles, Poly Mounts, Silverstar Bulbs, 100W Ion Fogs, Focus SVT Wheels, SHO UDP, Ford Racing Wires ***
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Joined: May 2000
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Veteran CEG\'er
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high exhaust velocity mainly, when the wave front of an exhaust pulse exceeds the speed of sound due to insufficient muffling and strikes the metal walls of the exhaust system.
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I have 1 muffer (dynomax Ultra flow)where the stock res would go on a dual setup and I have NO rasp at all. Clicky Clicky
2003 Subaru WRX some mods
Even if you don't have the answer, you certainly have to admire the problem.
aka ZetecRacing
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I dont think the zetec has a problem with rasp AFAIK. They seem to sound good no matter what muffler you put on, or with no muffler at all.
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Joined: Sep 2001
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CEG\'er
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CEG\'er
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Originally posted by ZetecRacing:
I have 1 muffer (dynomax Ultra flow)where the stock res would go on a dual setup and I have NO rasp at all.
Clicky Clicky
That is a good setup (ala Cardoc) however... you have a zetec... the rasp really is from the duratec
99 T-Red SVT
***Intrax, Bilsteins, Azenis, Offroad Y, CAI, Tint, Magnaflow Exhaust, Custom Grilles, Poly Mounts, Silverstar Bulbs, 100W Ion Fogs, Focus SVT Wheels, SHO UDP, Ford Racing Wires ***
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