gary55
Well-Known Member
I think you meant stinger ID at 58% to 62% of head pipe ID with 12x dia. length for start point didn't you? 23x.60=13.8. Okay now I get it you meant 40% less than.Stinger I.D. is the most important part of tuning the pipe not for where it hit's but for how much it will over rev after the hit,smaller I.D runs on past the peak better than a large one but the large one produces more torque below the hit so again you have to find the happy medium.12 x the stingers I.D. for length is correct as a starting point but the stingers I.D. should be around 40% of the port flange or head pipe dia,so where most of these have less than a 23mm port flange dia 40% of that is only 13.8mm so 14mm is really the starting point and as port dia and or head tube dia increase so does the stingers I.D. . The length of a 16mm stinger should be 7 and a 1/2 inches but 8 will work fine since as stated above the length has little effect on power output, but rather in DB output and by putting the stinger further toward the belly reduces DB levels quite dramatically and right in the belly almost in half with very little effect on power.
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