I have a ported jug tuned to about 8500-9000rpm , its is starting on .030" over bore, Mikuni VM32, 3/8 Reed spacer, stock cage dual stage reeds, 20cc Hemi head, S-band at ~40%, 3 deg. .80mm, Currently on Toomey B1 pipe, w/ freshly packed DG Type II silencer.
At this point the Toomey has around 8 inches 2" X 3/16" of fiberglass heat wrap across the middle of the belly, which has done surprisingly well at Widening the band a little, when you first get on it from a stop or after a slowdown, power is down low for a few seconds of Wot until the extra insulation causes heat to build in the pipe and its effective rpm to rise. Pretty neat you can feel the difference between a long period off the throttle and just dropping a couple gears for a curve. Ride easy and it stays cooler, ride hard and temp goes up this effect is quite exaggerated by just a little heat wrap ,possibly because the Toomey is Fairly thin.
It has been a neat experiment and timing adjustments can make quite a difference in the effect, but in the long run a pipe designed with a particular rpm in mind should come quite a bit closer to being ideal, although the extra heat due to making more power does bring the rpm range up somewhat versus a stock motor.
Maybe a better question is the best way to determine a good estimate for exhaust temp range, to better calculate tuned rpm of a given pipe?
Of course would also need cone characteristics, that support the type of powerband I am looking for which the Toomey does, I just am not sure how it will match the new porting. But that is a whole different can of worms.
At this point the Toomey has around 8 inches 2" X 3/16" of fiberglass heat wrap across the middle of the belly, which has done surprisingly well at Widening the band a little, when you first get on it from a stop or after a slowdown, power is down low for a few seconds of Wot until the extra insulation causes heat to build in the pipe and its effective rpm to rise. Pretty neat you can feel the difference between a long period off the throttle and just dropping a couple gears for a curve. Ride easy and it stays cooler, ride hard and temp goes up this effect is quite exaggerated by just a little heat wrap ,possibly because the Toomey is Fairly thin.
It has been a neat experiment and timing adjustments can make quite a difference in the effect, but in the long run a pipe designed with a particular rpm in mind should come quite a bit closer to being ideal, although the extra heat due to making more power does bring the rpm range up somewhat versus a stock motor.
Maybe a better question is the best way to determine a good estimate for exhaust temp range, to better calculate tuned rpm of a given pipe?
Of course would also need cone characteristics, that support the type of powerband I am looking for which the Toomey does, I just am not sure how it will match the new porting. But that is a whole different can of worms.