Switching to 2 into 1 exhaust

Discussion in 'Dyna Models' started by ccmdawg, Mar 28, 2008.

  1. ccmdawg

    ccmdawg New Member

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    After two years of ear shattering rinehart 2 into 2 flush cut use I am looking at the 2 into 1 pipes. I have the HD fuel map flash and air cleaner and the bike runs perfect if not slightly lean. As a rule of thumb does a 2 into 1 have more or less back pressure than drag pipes? I am running the stock baffles and was hoping to not be forced into remapping and paying for dyno time. The bike could use a small amount more of back pressure I believe without a remap. Thanks, Dawg
     
  2. bikermonkey

    bikermonkey Active Member

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    I'm not arguing with the Hobit, he's wise for a hobit, but I went the other way on my fatty, 2 into 1 to twins and there was significant fuel mapping differences across the band,,(both V&H) I'd deffinatly say Dyno... I don't know if your reverse case would be so great seeing how the 2 into 1 is more efficient,, but if it we me,, dyno to know for sure.
     
  3. glider

    glider Veteran Member

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    I think the 2 into 1 would have less back pressure from the scavenging action of the design unless you are running drags with no baffles, then all bets are off. There's a lot of variables here like baffles etc.from one system to the other so it's hard to compare both systems without knowing.

    When you are looking for the max power out of an engine the 2 into 1 always wins out.
     
  4. glider

    glider Veteran Member

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    Good link. I think the last paragraph says it all. The final decision is how you ride.

    In conclusion the slip-fit mufflers are often the most economical choice, while longer pipes and 2-1 collectors are the best overall performers in a Harley exhaust system. Drag pipes and large open pipes look and sound "cool" but are definitely tuned for larger engines, thus giving up a lot of lower end torque where most daily riders need the power. While the old-school method of punching a hole in your mufflers will produce enough noise from your exhaust to wake the neighbors, this can never compare to a well tuned exhaust system.