I'm no slouch when it comes to speed, in fact I bet I'm the upper range as far as Spyder Op's go....But really..Any Spyder can get very ILLEGAL in about 10 seconds....12 if towing a trailer....These things are not being marketed as Drag Racers......If you really want to go fast just buy a " Busa "....Don't ruin the Spyder for the Thousands of Spyder - lovers who are mostly happy with this aspect of the Spyder.....BECAUSE BRP is not going to produce 6 or 7 Different varieties of engine.....If they make a 150 HP engine we are all gonna get it, like it or not.......and if they boost the HP by 10....BRP will still hear the complaints by the same crowd..awh gee Only ten HP........Think about it.....OK off the soap-box.........VOTE BELOW....DO YOU AGREE ....IF NOT LEAVE BLANK......Mike...:thumbup:
I don't understand the horsepower thing. If the RS and RT (2012 and prior) engines are the same, how can the horsepower be different?
All :spyder2:'s have the same crank, cylinders and heads so the bore, stroke and displacement are the same. The part numbers on the cam shafts are different between RS' and RT's so I would assume that they changed the valve timing and duration. They also boasted the compression ratio in the RT's. The connecting rod is a different part number (maybe longer?). The piston is a different part number (different shape top surface?). This would reduce the squish volume explaining the different compression.
The 998cc Rotax Engine has produced 121,127 and 136HP in Modified forms in the Aprila,s?
Its just a matter of When they want to increase the Spyder Horsepower?
Power, Reliability, Cost........Pick Two!
Power, Reliability, Cost........Pick Two!
Thanks for looking that up. I was too lazy and it was too late.pps: A longer rod can't increase the compression, BTW, it just reduces cylinder wall loading. I suspect most of the (effective) compression ratio difference is due to valve timing, not a change in piston dome size. Just guessing, I have never cc'd a Spyder.
We should all hold back a bit on assuming the RS horsepower was lowered. BRP's press releases and spec sheets have been frought with errors. They may have inadvertantly copied and pasted, and nothing might have changed at all. The new parts fiche should give us a clue.
It is my guess, which counts for nothing, That the compression ratios BRP is reporting are not necessarily those seen in reality. There are two compression ratios. The actual ratio is calculated taking the combustion chamber volume and subtracting the piston dome volume. The effective ratio takes valve opening into effect, since compression can't begin until both valves are closed. Technically, this is a measure of compression pressures, but an effective compression ratio can be calculated or volumetrically measured. The cam timing and profile affect this figure.Good point about the published specs being incorrect initialy. We will have to wait and see.
Now getting to compression ratio. It is my understanding that compression ratio cannot be changed by the cam. Wikipedia quote "The compression ratio of an internal-combustion engine or external combustion engine is a value that represents the ratio of the volume of its combustion chamber from its largest capacity to its smallest capacity" Compression pressures can certianly changed by the cam but are not reflected in the compression ratio calculation. There are only two parts that are different from a RT engine to a RS engine. They are the connecting rod and piston. So the compression changed was done somehow with those two parts. If I am wrong on this please explain where. thanks
It is my guess, which counts for nothing, That the compression ratios BRP is reporting are not necessarily those seen in reality. There are two compression ratios. The actual ratio is calculated taking the combustion chamber volume and subtracting the piston dome volume. The effective ratio takes valve opening into effect, since compression can't begin until both valves are closed. Technically, this is a measure of compression pressures, but an effective compression ratio can be calculated or volumetrically measured. The cam timing and profile affect this figure.