After contemplating what turoal said about BRP changing the 800R exhaust valves to open only after hitting 7400 rpm as apposed to the older revs at 5800rpm, I read the shop manual and this is what I understand.
The valves operate from several 3D maps not just one and in addition these valves open partially at 6200 rpm and fully above 7900 rpm. This may be as Al said, to keep the engine quiet at lower speeeds but the manual also states that if the throttle is mashed, the ECM can pick a map that will by-pass the partially open mode completely. Sounds like BRP did their homework to give us best of both conditions. The question I'm left with is, would this thing pull harder if the valve opened fully at 5800 rpm?
Hear is Al's post from the XP clutching thread:
Originally Posted by turboal
no , actually we kept the gearing once we got the end loadcorrect . you could gear down , just need a bit more tip weight to get the up shift back .
we used the 2mm over size rollers to achieve this '.
we combined this with the shaving of the power valves 200ths . this puts the export opening when the guilletines are closed back close to were it was on the 06 model 800.
they use the opening of the power valves at 7400 as a wa to beat the sound emmissions test on the tail . you can pass by at 45 mph and not be intothe power valves as when they open they exceede 100 decibels .
the larger opening allows the pipe to come to pressure sooner and gives you the mid range pull you are used to on the older 800 motor it oopened at 5800rpm and in its closed position it was a 30 mm opening and the r motor is 25mm.
The valves operate from several 3D maps not just one and in addition these valves open partially at 6200 rpm and fully above 7900 rpm. This may be as Al said, to keep the engine quiet at lower speeeds but the manual also states that if the throttle is mashed, the ECM can pick a map that will by-pass the partially open mode completely. Sounds like BRP did their homework to give us best of both conditions. The question I'm left with is, would this thing pull harder if the valve opened fully at 5800 rpm?
Hear is Al's post from the XP clutching thread:
Originally Posted by turboal
no , actually we kept the gearing once we got the end loadcorrect . you could gear down , just need a bit more tip weight to get the up shift back .
we used the 2mm over size rollers to achieve this '.
we combined this with the shaving of the power valves 200ths . this puts the export opening when the guilletines are closed back close to were it was on the 06 model 800.
they use the opening of the power valves at 7400 as a wa to beat the sound emmissions test on the tail . you can pass by at 45 mph and not be intothe power valves as when they open they exceede 100 decibels .
the larger opening allows the pipe to come to pressure sooner and gives you the mid range pull you are used to on the older 800 motor it oopened at 5800rpm and in its closed position it was a 30 mm opening and the r motor is 25mm.
