Exhaust system knowledge please

S

strokerlmt

Moderator
My experience with exhaust systems is mostly trial and error. I would appreciate thoughts from Jeff, dude, Steve or anyone. When I dynoed the 91 / 68 I had 2 to 1 1.75 alu headers and a supertrapp muff. Then I put a dominator muff on and got a little more feeling of pull. Then I put salvaged stock scram headers on with the dominator and it was ok. Then a salvaged D & D 2 to 1 and I couldn't push enough air through. So to the 2 to 1 supertrapp or dominator. I guess what I want to know is the long D & D system and the scram headers simply restricted the flow....correct ???
Thx
LMT
 
benjamindickens

benjamindickens

Street Tracker
strokerlmt said:
My experience with exhaust systems is mostly trial and error. I would appreciate thoughts from Jeff, dude, Steve or anyone. When I dynoed the 91 / 68 I had 2 to 1 1.75 alu headers and a supertrapp muff. Then I put a dominator muff on and got a little more feeling of pull. Then I put salvaged stock scram headers on with the dominator and it was ok. Then a salvaged D & D 2 to 1 and I couldn't push enough air through. So to the 2 to 1 supertrapp or dominator. I guess what I want to know is the long D & D system and the scram headers simply restricted the flow....correct ???
Thx
LMT
Click to expand...

With regard to exhausts its a simple in and out equation if you increase your output (exhausts) to make them run best you should increase your intake airflow to generate best performance. With an EFI you should get a re-map done at your dealer or carby version is modded with different jet sizes allowing more fuel. I have dominator touring exhausts and they sound fantastic and give my bike a bit more go but nothing drastic. Aftermarket exhausts in general allow the gases of combustion to flow better as they are far less restricted than stock. The best man to ask is carlos from triumphperformanceusa.com he recommended my pipes and they are awsome. Hope this helps mate best of luck Ben Dickens
 
S

strokerlmt

Moderator
Thx BD.....Matt and Carlos did my engine. Lots going in....it is getting the out just right. It seems the alu 1.75 headers and the supertrapp are the best but the trapp is very load.
LMT
 
Texas94fs

Texas94fs

Hooligan
You might look into the full 2-2 d&d system, the one with stepped headers that are shortened reverse megaphones. flows very well and is moderate at idle and low revs, but wails when opens up.
 
C

Chris in NC

Street Tracker
strokerlmt said:
Hey Chris.....no I have not tried Arrow. I am guessing you have and you like, why???
LMT
Click to expand...

I had one on my street tracker.. it made a helluva difference over the Thunderbike 2-into-1 header that I originally put on the bike.

The diameter of the header pipes is larger, the collector where the two header pipes come together is larger, and the slip-on is tuned to flow a helluva lot better than the pipe I'd been using. I tried to run the bike with the baffle in, then I took it out, and the motor simply came alive.

It's expensive, especially so if you're 'testing' to see which pipe works best. I've read lots of posts over the years where guys are getting good (sometimes real good) numbers from stock header pipes and Predators.
 
S

strokerlmt

Moderator
Chris in NC said:
I had one on my street tracker.. it made a helluva difference over the Thunderbike 2-into-1 header that I originally put on the bike.

The diameter of the header pipes is larger, the collector where the two header pipes come together is larger, and the slip-on is tuned to flow a helluva lot better than the pipe I'd been using. I tried to run the bike with the baffle in, then I took it out, and the motor simply came alive.

It's expensive, especially so if you're 'testing' to see which pipe works best. I've read lots of posts over the years where guys are getting good (sometimes real good) numbers from stock header pipes and Predators.
Click to expand...

Thx Chris......with my engine stock headers and preds or doms don't cut it. My un educated opinion is I need at least 1.75 inch headers and a short 2 inch run to one muff, dom, pred or supertrapp. Personally I like the sound of the dom best. Anyway bottom line is I am back to 2 into 1 1.75 headers and the trapp. As soon as I get the dom muff's mount bracket welded in the right spot it goes back on.
best
LMT
 
mikenva

mikenva

Rocker
awwh you say the 2into1 d&d didnt work for you? that has been the fastest system out there on our testing .Did you dyno it ?You sure you had the bike tuned right for it.We got 107 to 115 hp on the rear wheel with them on the 1087 motors
 
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