V-Twin Forum banner

My New Prototype 2inch Thunderheader!!!

8K views 43 replies 19 participants last post by  TheNowhereman 
#1 ·
OK, I finally finished the 2 inch (SHOT GUN) Thunderheader. I have a 117ci in my FXDX. I have run the stock Thunderheader, and the Vance & Hines Pro pipe with competition baffle on the same dyno, and tuned both for max performance. Now Im going to run my Prototype pipe, hopefully this weekend. I will post all results soon!




 
See less See more
5
#7 ·
Hell, your build quality looks a tad better than Thunderheader's.
Hope it works out for ya.:clap:
 
#8 ·
They look nice ...but don't they get in the way of the rear brake pedal?? Maybe it is just the angle of the pictures, but it looks to me as if they are aweful close,also how is the heat on your feet?
 
#9 ·
looks great good job!!!
 
#23 · (Edited)
SBfighter, very good. A friend of mine made a stepped, equal length headpipe and TH collector for a bagger. It's on a RevPerf 114" and makes good power, 125hp/tq. I've not taken a good look at his graph, so can't comment on if it has a dip or not. Myself I have never felt the dip on mine (stock TH on a 113"). Although I did bend 2 of the edges on the baffle and it improved the graph a bit. Are those 103+ heads on your 117"? Whats the build details? Awesome looking ride.

To modify the baffle:
Use the end of a broom handle and bend the edges of the square baffle out towards the inside wall of the muffler, but not all the way. leave an 1/8" or so. Start with 2, (need some dyno time), and do no more than 3 so you still can get a AF probe up into the pipe.
 
#25 ·
The pipe looks GREAT. I cant wait for a dyno comparison!
 
#27 ·
So I dyno tuned the bike yesterday, and the results sucked balls!!
We played with the bending of the baffles and it didnt respond well.
Back to the drawing board! I think i might have to step it further down the tube. Im going to throw in torque cones, if that increases the torque then I will step it further down. If not????

-The Blue info represents the new 2 inch stepped Thunderheader pipe.

-The Black represents the Vance & Hines Pro pipe with competition.
baffle.

-The Green represents the stock Thunderheader.
 
#36 ·
So I dyno tuned the bike yesterday, and the results sucked balls!!
We played with the bending of the baffles and it didnt respond well.
Back to the drawing board! I think i might have to step it further down the tube. Im going to throw in torque cones, if that increases the torque then I will step it further down. If not????
Oh man, that really bites SBfighter. All that work, I mean it really came out nice, and results not what you expected. I really frickin hate exhaust systems, no matter how much you research to find what is best for your particular engine, it's still a big unknown.
I had downloaded Engine Analyzer Pro demo for fun (it's fully functional for 10 days), and I put your engine specs (as close as I could) and ran 2 tests, comparing 1.75" primaries with 2" primaries.
Now, the exhaust modeling is pretty limited with the program, but it pretty much mimicked what you dyno chart shows, a torque loss below 5K, and a HP increase above 5K. That's a classic "primary diameter too big" result. WTF, 2" primaries on a 117" too big? That is the sucky part, because there is too much conflicting info out there. You have RB racing saying that any engine over 100" should have 2" primaries, D&D's boarzilla is iffy at a minimum of 117", and then you have real world experienced people like KOCubes saying that they have seen better numbers and curves on 117-124 engines with smaller pipes like the fatcat. This is why I hate exhausts, because whatever I'm running, I'll always be thinking "is there something better"?
BTW, torque cones never work.
 
#29 ·
Great work making your own pipe-I can appreciate the hard work it takes to re-design something that is good and trying to make it even better.
Another option for your bike would be the Guppy III. Your motor is just big enough to appreciate the power this pipe can provide. There is no reason your motor with that build, the right pipe and a good tune shouldn't be making 135 HP.

http://www.jbvracing.com/exhaust.html
 
#31 ·
Thanks! I have always liked the TH, but I want more performance out of it. I ordered a RB racing ( it took 6 weeks! )but the quality looked like crap! I didnt even run it! I understand they produce power, but I could of put together a better pipe!! As for the Guppy III, Wow thats a nasty pipe! R u running one? It sucks there are so few Large ci pipes out there.
 
#37 ·
Did you talk to the TH guys?

<<Have you spoken to the TH guys? Bob L. (FLTRI) is the tuner for RC Cycles in Hayward, CA and he says TH is getting ready to release a new version for big inch bikes. Actually he said that a while back.>>

<<No, but good idea i'll call TH tomorrow! I hope they do release one for the big ci motors.>>
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top