FP3, Decatted Head Pipe, "Cross Talk"
Tourer
Joined: Jan 2016
Posts: 338
Likes: 23
From: Wisconsin
Without doing a dyno pull with a stock header, a decat and an "X" pipe at the same time the dyno sheet doesn't mean much. Nice numbers though.
Grand HDF Member
Joined: Nov 2004
Posts: 3,917
Likes: 184
From:
The tuner is a good friend of mine and he said they compared dynos they have done and the decatted head pipe on a stage 1 or 2 build makes 10-12 more Tq. below 3200 rpm's than a X pipe does. I actually re-read the text to make sure I was telling you correct. This was with the 103's and 255 cams.
Now if you want to see some of the thing's your asking for, go to Fuel Motos web site or FB page and you will find it.
Now if you want to see some of the thing's your asking for, go to Fuel Motos web site or FB page and you will find it.
Last edited by Tn.Heritage; Apr 8, 2016 at 11:22 AM.
Cruiser
Joined: Mar 2011
Posts: 176
Likes: 14
From: Terrell, TX
I've heard all the stories about cross talk, so much that I actually replaced my decatted pipe with a x-pipe several years ago. Fast forward to a week ago and my x-pipe developed two vibration cracks in it and I had a long weekend trip coming up without enough time to secure a replacement x-pipe. I installed my decatted pipe back on to make the ride, and my butt Dyno tells me there is no difference in the performance of the bike. A Dyno might show something, but I don't ride a Dyno. Time will tell if I replace my x-pipe or just leave it as is.
Grand HDF Member
Joined: Nov 2004
Posts: 3,917
Likes: 184
From:
Also from what I gather the stock decatted pipe is a little more restrictive than the x pipes which keeps a bit more back pressure, this is in theory mind you, I've never actually seen flow numbers to prove that but you can see in my chart the big difference in the bottom end than my 1st combo. Overall the x pipe made a little more Tq. but where the Tq. starts was night and day difference in the feel of the bike.
Road Warrior
Joined: Jun 2014
Posts: 1,297
Likes: 57
From: N. IL
jt, I have posted this before but I can show the difference in a bolt in 57 cam and fuel moto's x pipe and rc 4" mufflers with 2.5" baffles compared to a Rush Wrath, same bike just a different pipe and retune.
Also from what I gather the stock decatted pipe is a little more restrictive than the x pipes which keeps a bit more back pressure, this is in theory mind you, I've never actually seen flow numbers to prove that but you can see in my chart the big difference in the bottom end than my 1st combo. Overall the x pipe made a little more Tq. but where the Tq. starts was night and day difference in the feel of the bike.
Also from what I gather the stock decatted pipe is a little more restrictive than the x pipes which keeps a bit more back pressure, this is in theory mind you, I've never actually seen flow numbers to prove that but you can see in my chart the big difference in the bottom end than my 1st combo. Overall the x pipe made a little more Tq. but where the Tq. starts was night and day difference in the feel of the bike.
HD Forum Stories
The Best of Harley-Davidson for Lifelong Riders
7 Surprising Harley-Davidson Products that Are Not Motorcycles
Verdad Gallardo
8 Best Harley-Davidson Motorcycles Ever
Pouria Savadkouei
10 Worst Harley-Davidson Motorcycles Ever
Pouria Savadkouei
Killer Custom's Jail Break Is The Breakout That Refused to Blend In
Verdad Gallardo
Crazy Bunderbike Build Looks Amazing, But Is It Impossible to Ride?
Verdad Gallardo
Harley-Davidson Reveals Super Cool Cafe Racer Concept
Verdad Gallardo
Engraved Rebellion: Inside Bundnerbike's Glam Rock II
Verdad Gallardo
10 Motorcycles You Should Never Buy
Joe Kucinski
10 Things Harley-Davidson Needs to Fix in 2026
Verdad Gallardo
Grand HDF Member
Joined: Nov 2004
Posts: 3,917
Likes: 184
From:
Yes Sir it is but the key is in the combo of the exhaust as well. Jamie and I had a discussion back in the dyno section about this when I posted that sheet. Look at it like this, If 1 2.5" baffled muffler will carry that much Tq and Hp down low then the question is how, back pressure and flow, thats also why the wrath is a stepped design as well. Now take that same amount of flow from say a x pipe design and install mufflers with 2.5" or bigger baffles and what happens, no back pressure, bottom end suffers. The top end Hp. may pick up or even a few numbers higher on Tq. but where you ride most of the time will not.
