Too Much Back Pressure question

Discussion in 'Engine, Fuel and Exhaust' started by BOBFLHTC, Mar 17, 2010.

  1. BOBFLHTC

    BOBFLHTC Active Member

    273
    0
    0
    The vast majority of discussions about exhaust modifications seem to address the problem of losing too much Back Pressure and Low end torque. It’s usually obvious since you have punched out the baffles and increased the exhaust flow. On the other end of the spectrum how do you know if you have created too much back pressure for your engine?

    I recently installed a set of Cycle Shack staggered turn downs on my 85 EVO. I picked up some low end torque and reduced the sound some. I wouldn’t mind making it quieter and picking up some more torque on the low end but I don’t want to overdo it. What would be the best indication that this has occurred? Spark plug color? Runs hotter ? Seat of your pants Dyno ? I apologize if this is a dumb question
    Thanks - Bob
     
  2. ultrat

    ultrat Senior Member Contributor

    1,315
    0
    1
    Id say seat of pants, not dumb ? baffles inside not much smaller than head pipe 1 3/4..1 1/2 in.....
     
  3. BOBFLHTC

    BOBFLHTC Active Member

    273
    0
    0
    I currently have some baffles in the end of the mufflers. I tried some exhaust wrap on them but it was blown apart pretty easily. I have about 50 miles on it so I'll pull the plugs to see what they look like before I start. I already have holes for baffles at the end of the head pipes and I have a set of 4" drag baffles so I thought I would try them and see how it feels. Its not bad the way it is. I'm just curious to see if I can make it better.
    As a side note I noticed that the inspection was up. Actually I haven't had it done for 10 years. I was stopped recently with an expired sticked on my truck and it cost me $130 so I thought I better have my bike checked out. They didn't even start the bike so the sound level wasn't an issue.
    Thanks for the feedback - Bob