Exhaust rasp solution?
Exhaust rasp solution? dealing with a very annoying exhaust rasp in my 69 Camaro around ~2200-3500rpm. It sounds like a Honda Civic and not a muscle car. Sounds great at idle though.
Setup is:
ls1 stock bottom end, ai226 cnc cylinder heads, tsp 233/239 cam, Victor jr intake with Holley 4bbl throttle body.
holley stainless long tubes, 3” dual exhaust with x pipe and borla pro xs mufflers.
the borla pro xs mufflers did tone it down a bit but it’s still sounds terrible.
am I better off going to true duals or h-pipe or adding cats? Do tuning parameters have any affect on sound? Running holley terminator x. I hear other xpipe cars don’t sound like this so maybe the location of the xpipe makes a difference?
Setup is:
ls1 stock bottom end, ai226 cnc cylinder heads, tsp 233/239 cam, Victor jr intake with Holley 4bbl throttle body.
holley stainless long tubes, 3” dual exhaust with x pipe and borla pro xs mufflers.
the borla pro xs mufflers did tone it down a bit but it’s still sounds terrible.
am I better off going to true duals or h-pipe or adding cats? Do tuning parameters have any affect on sound? Running holley terminator x. I hear other xpipe cars don’t sound like this so maybe the location of the xpipe makes a difference?
Joined: Nov 2001
Posts: 34,629
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From: Schiller Park, ILL Member: #317
What is traditionally referred to as "rasp" in the LS1 world (the Kazoo on crack sound) is typically the product of a catless Y-pipe system (especially noticeable with certain mufflers or any mufflerless setup), but shouldn't be a serious problem with a catless true dual system that's using really any sort of mufflers at all. X-pipe does produce a different pitch and different overall sound than H or straight, but I'm surprised you'd be fighting with a Kazoo/Civic sound with that arrangement.
What I can tell you from personal experience is that cats are not required to effectively eliminate rasp, even with a Y-pipe, though they are certainly one available option and do become the ONLY option for Y-pipe folks who don't want any sort of muffler or resonator combos (personally, I wouldn't use cats in an application that didn't require them for strict emissions testing...putting them on a 1969 model would be totally out of the question for me). With that said, I'm not directly familiar with your mufflers but I, too, have heard many catless X-pipe setups that don't have any noticeable rasp (though, IMO, they never sound as good as an H or straight). Not sure how much impact moving the "X" would have, as my experience is more with Y, H and straight, but muffler selection is obviously going to play the biggest role in terms of sound. Tuning can certainly have some effect as well; a good A/F will have a "crisper" sound overall. And if fuel dump into the exhaust is very excessive, then afterfires will obviously be a problem too (though that doesn't sound like your issue here).
Have you been able to hear any other similar setups using the same mufflers in an X arrangement to compare?
What I can tell you from personal experience is that cats are not required to effectively eliminate rasp, even with a Y-pipe, though they are certainly one available option and do become the ONLY option for Y-pipe folks who don't want any sort of muffler or resonator combos (personally, I wouldn't use cats in an application that didn't require them for strict emissions testing...putting them on a 1969 model would be totally out of the question for me). With that said, I'm not directly familiar with your mufflers but I, too, have heard many catless X-pipe setups that don't have any noticeable rasp (though, IMO, they never sound as good as an H or straight). Not sure how much impact moving the "X" would have, as my experience is more with Y, H and straight, but muffler selection is obviously going to play the biggest role in terms of sound. Tuning can certainly have some effect as well; a good A/F will have a "crisper" sound overall. And if fuel dump into the exhaust is very excessive, then afterfires will obviously be a problem too (though that doesn't sound like your issue here).
Have you been able to hear any other similar setups using the same mufflers in an X arrangement to compare?
RPMWS6-
first I tried the holley blackheart mufflers then switched to the borla xs pro based on YouTube sounds. both are straight through 3”. It is slightly improved. I have seen similar setups that sound great but they seem to be 400cid or larger. Didn’t think displacement would cause that much difference in sound.
it does sound exactly like y pipe fbodys on YouTube, a really annoying rasp.
first I tried the holley blackheart mufflers then switched to the borla xs pro based on YouTube sounds. both are straight through 3”. It is slightly improved. I have seen similar setups that sound great but they seem to be 400cid or larger. Didn’t think displacement would cause that much difference in sound.
it does sound exactly like y pipe fbodys on YouTube, a really annoying rasp.
