SuperTrapp Open vrs Closed Trapp Caps
Tourer
Joined: Mar 2007
Posts: 385
Likes: 3
From: Mcdonough, Georgia
I run 18 disc's with closed end cap, and thats on dresser duals with 255's. It's pretty quiet. I was thinking of removing some disc's and using the open end cap to see what it would sound like..............
Outstanding HDF Member
Joined: Jun 2007
Posts: 2,542
Likes: 2
From: Cocoa Beach, Florida
ETA: Oops - sorry, somewhat OT for this thread.
Outstanding HDF Member
Joined: May 2007
Posts: 2,673
Likes: 16
From: Norfolk, VA
Did you want a video of just how the open end cap sounds or do you want it specifically with 255's? I can post video's comparing the open end cap sound to the closed end cap sound if you like. I have the closed in cap vid already, I would have to wait an hour or two to get the open end cap vid, I do not want to bother my neighbors early on a holiday revving the bike in the garage
Outstanding HDF Member
Joined: Jun 2007
Posts: 2,542
Likes: 2
From: Cocoa Beach, Florida
Did you want a video of just how the open end cap sounds or do you want it specifically with 255's? I can post video's comparing the open end cap sound to the closed end cap sound if you like. I have the closed in cap vid already, I would have to wait an hour or two to get the open end cap vid, I do not want to bother my neighbors early on a holiday revving the bike in the garage
What I'm trying to decide is whether or not to plan on being able to keep SuperTrapp w/open that I already have (with 2/1) when I goto 255s.
I'm an oldphart on a fixed budget and, if I can't keep Supertrapp, then my preference would be to upgrade for better sounding exhaust before 255s. Why?
I must finally get a tuner either way and I think (upper case on the THINK part) that, if I won't like the sound I would have using SuperTrap(s), then it would probably be easier to tune with a new exhaust first and then add 255s later.
Thanks mucho for thinking about how to git'er'done for me and BTW, no need for speed - idle would be fine. Again, sorry OP, I should have started my own thread on this.
Last edited by RangeRat; Sep 6, 2010 at 10:50 AM.
Outstanding HDF Member
Joined: Jun 2007
Posts: 2,542
Likes: 2
From: Cocoa Beach, Florida
Aw rats... you're one of the folks who try to help others out. Oh well. I'll start my own thread on that issue so now, "Back to the regularly scheduled program", hard data on open versus closed end caps.
Again, my personal opinion is that there's probably very little difference other than maybe the sound magnitude - no real advantage either way WRT actual performance. Both ways can be tuned to cover that issue when using SuperTrapp muff(s).
Again, my personal opinion is that there's probably very little difference other than maybe the sound magnitude - no real advantage either way WRT actual performance. Both ways can be tuned to cover that issue when using SuperTrapp muff(s).
Last edited by RangeRat; Sep 6, 2010 at 11:07 AM.
Road Captain
Joined: Jul 2009
Posts: 586
Likes: 1
From: Falcon, CO
Just the right back pressure leads to the best performance, the most open exhaust can perform worse then stock. It gets the exhaust gas out the engine the most efficiently. One of the Sportster guys saw a 7 hp gain from going from 24 disc to 20. If you want to go to a open end you should of bought a Kerker that is louder then the Supermeg.
Tourer
Joined: Mar 2007
Posts: 385
Likes: 3
From: Mcdonough, Georgia
Yea I'll try to do a sound clip tomorrow if i got time............
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Advanced
Joined: Sep 2009
Posts: 80
Likes: 0
From: Atlanta, GA
I ran 9 disc's with an open end cap on my 98 RK EFI with a Powecomander USB III and even with dyno tune I had a flat spot at 4500 an gas mileage was terrible. I switched to 18 disc's and closed end cap with a canned map and now the bike gets 48 MPG, no flat spot at 4500 or anywhere else in the RPM range. This was my experience with a Supertrapp Supermeg.
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