D
Deleted member 12676
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Here are the results of my testing different exhausts on my piston-ported 48cc engine with 6.9" long intake tract (carb slide to piston). From not being able to climb street1 it was finally able to climb at 17.5mph without losing any top speed. (The X signifies inability to climb w/o pedaling.)
Street 1 is a fairly steep incline. Street 2 has a lesser incline. "Flat" is a flat street.
length__street 1___street 2______flat
_10"_______X_______18.0mph____25.0mph (standard)
_16"____13.5mph____20.0mph____25.5mph (+6" pipe added before muffler)
_23"____17.5mph____22.5mph____25.0mph (+13" pipe added. 1.5" notch cut out of side of center exhaust tube inside muffler 1" after it enters muffler. disc baffles removed.)
It is unknown what the results would be without the longer intake tract but from my experiments everyone should have an extended intake anyway. The easiest way, what I did, is use the intake manifold that zig-zags off to the side which is longer than normal and is made for those whose carb and frame wants to occupy the same space. Sorry but I forgot who I ordered it from.
Street 1 is a fairly steep incline. Street 2 has a lesser incline. "Flat" is a flat street.
length__street 1___street 2______flat
_10"_______X_______18.0mph____25.0mph (standard)
_16"____13.5mph____20.0mph____25.5mph (+6" pipe added before muffler)
_23"____17.5mph____22.5mph____25.0mph (+13" pipe added. 1.5" notch cut out of side of center exhaust tube inside muffler 1" after it enters muffler. disc baffles removed.)
It is unknown what the results would be without the longer intake tract but from my experiments everyone should have an extended intake anyway. The easiest way, what I did, is use the intake manifold that zig-zags off to the side which is longer than normal and is made for those whose carb and frame wants to occupy the same space. Sorry but I forgot who I ordered it from.
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