MotoGP shorty pipe?
#31
#33
#34
I meant the D+D Doesn't. Granted I don't mind the noise, but it can quite easily chew through a helmet. I've managed to not **** off a cop in 24K miles, however, if it's not any louder, I'd consider going the shorty.
#36
#38
This pipe would have no effect on the valve at all. A more open exhaust reduces backpressure which allows for more power. BUT all street engines are designed with some backpressure in mind so that exhaust can be muffled to reduce noise. By usuing the Shorty pipe which is basically a straight pipe, the back pressure from the muffler is removed. Altering the back pressure only effects the fuel curve which in most cases can be fixed by jetting unless a lot of mods have been done to the engine which then requires a lot of tuning to get a new curve in place for optimal performance.
The gp pipe IMHO helps top end a lot, since common sense would be that an engine flows more air at 10,000RPM than at 2,000RPM the open pipe allows for better breathing at the higher RPM range since it does not allow exhaust to get caught up in the pipe. But i feel that it does bog the lower RPM's tho. Since not as much air is flowing and the exit speed of the air from cylinder to header in not as fast as it would be in the higher RPM range.
Last edited by utter05; 08-05-2009 at 08:02 AM.
#39
put a short piece of 8-12 inch pipe on your lawn mower for a muffler with no back pressure then tell me how those valves look so yes less back pressure will toast valves in time without the bike properly setup for that "type" of exhaust. you will have too richen up the carbs but still will loose torque and will only gain in the very very top rpm. back pressure serves a much more important purpose then just making bikes, cars, trucks etc quiet.
#40
put a short piece of 8-12 inch pipe on your lawn mower for a muffler with no back pressure then tell me how those valves look so yes less back pressure will toast valves in time without the bike properly setup for that "type" of exhaust. you will have too richen up the carbs but still will loose torque and will only gain in the very very top rpm. back pressure serves a much more important purpose then just making bikes, cars, trucks etc quiet.
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