Knocking out the Cats on 4" mufflers
#11
02-12-2008, 04:40 PM
RE: Knocking out the Cats on 4" mufflers
NEGATIVE !
YES the V&H pipes, etc do FLOW better and are less restrictive but they are designed with a special baffle so the exhaust flows at a desired rate. Punched out stock pipes no longer flow like their designed to do. Also....how are ya going to get a map for that ?? You'd have to guess or dyno it. Your performance would be much better with a designed baffle system.
YES the V&H pipes, etc do FLOW better and are less restrictive but they are designed with a special baffle so the exhaust flows at a desired rate. Punched out stock pipes no longer flow like their designed to do. Also....how are ya going to get a map for that ?? You'd have to guess or dyno it. Your performance would be much better with a designed baffle system.
#13
02-12-2008, 04:56 PM
RE: Knocking out the Cats on 4" mufflers
ORIGINAL: CREEPSHOW
I agree. HD pipes are over restricted from the factory. That's one reason why they are so quite.
I gutted my stockmuffler and then welded pipe straight threw the center, "like a drag pipe". Performance was increased after converting my stock pipe into a 2-1 pipe. One would think the open pipe would only create power on the "top end" much like a drag pipe but, no. I think the difference is when making my header into a 2-1 there was restriction created where the two pipes meet making backpreasure. What I am saying is you never know till you try it....
ORIGINAL: Pumba11
Most aftermarket slip-ons reduce the crazy amount of restrictionthe the stock HD muffler has on our bikes. That is why most people get rid of stock mufflers to improve flow and increase tq and hp. I completely understand what backpressure does and that it is needed.
However, on this particular muffler that had an nicely baffled muffler that provides some back pressure, PLUS a flow choaking cat in each muffler was overkill. Removal of the cat eliminated "some" of the backpressure. It is by no means a drag pipe. It would in my opinion still provide more backpressure than most every V&H, Python, Wild Pig, Reinhart yada yada yada slip on muffler out there.
Just my $0.02
Most aftermarket slip-ons reduce the crazy amount of restrictionthe the stock HD muffler has on our bikes. That is why most people get rid of stock mufflers to improve flow and increase tq and hp. I completely understand what backpressure does and that it is needed.
However, on this particular muffler that had an nicely baffled muffler that provides some back pressure, PLUS a flow choaking cat in each muffler was overkill. Removal of the cat eliminated "some" of the backpressure. It is by no means a drag pipe. It would in my opinion still provide more backpressure than most every V&H, Python, Wild Pig, Reinhart yada yada yada slip on muffler out there.
Just my $0.02
I gutted my stockmuffler and then welded pipe straight threw the center, "like a drag pipe". Performance was increased after converting my stock pipe into a 2-1 pipe. One would think the open pipe would only create power on the "top end" much like a drag pipe but, no. I think the difference is when making my header into a 2-1 there was restriction created where the two pipes meet making backpreasure. What I am saying is you never know till you try it....
#14
02-12-2008, 09:04 PM
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#15
02-13-2008, 09:24 AM
RE: Knocking out the Cats on 4" mufflers
My discussion of removing the cats has nothing to do with gutting the baffle system that is already in place. After removing the cats you still have a fully designed baffled muffler in place, just minus the cats.
Well I have tried, and the perfromace, low and high end did impove in this situation.
Well I have tried, and the perfromace, low and high end did impove in this situation.
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