Overreving with my 23 khaos boost 165.

[Murph]

Dyno is a tool.... not an absolute.... unless you are selling products or trying to win forum arguments.

OP... set your sled up to whatever rpm you are happy with 7500-8500... it is your sled.

You asked about 80gram weights and mention 4 grams heavier-- so you have a 23. 2023 runs a straight 46* helix. 23 fuel map pulls harder than a stock 22.

People responding had your best interest in mind when they suggested 8500 rpm is fine on a boosted motor. Polaris engineering sets up RMSHA sleds to pull 86-8700, RMSHA racing is not about longevity but power. I can assure you the sleds are faster at 86-8700 rpm. I have the on snow data logs (versus dyno charts) that show both track speed and GPS speed.

Performance wise, RPM does not equal RPM. Riders need to pay attention to track speed. Clutch settings, helix, mass distribution/ profile on weights affect this. 8600 rpm and 30mph track speed is not good. 8400 rpm and 50mph track speed (as close to similar conditions as possible) is better.

To the OP, if you add 4 grams of weight to your sled and change nothing else, you should feel lower engagement rpm (more mass overcoming spring 165lb starting rate), and a reduction of around 400 peak rpm. Will it make your motor last longer?..... unknown.

 

[davesilb]

Back from my testing my 23 boost khaos 165. I had taken the stock 76 gram weights out and installed 80 gram weights with the only other change putting in a adjusting screw in the secondary to keep it from pulling the belt so tight at idle or real slow speeds. Top RPM went from 8500 plus to a more reasonable 8300. Differently seemed to pull stronger then before. Engine sounded so much better. I may in the future try 82 grams if I can find them. Also seen the fuel mileage increase as I had hoped. I would say it also helped the heating problem 5 to 10 degrees which I have no answer as to why but never the less it seem to. Also the stop helped the momentary throttle lag when getting off the throttle.

 

[Jeffy Mac]

Lol

 

[davesilb]

Dyno is a tool.... not an absolute.... unless you are selling products or trying to win forum arguments.

OP... set your sled up to whatever rpm you are happy with 7500-8500... it is your sled.

You asked about 80gram weights and mention 4 grams heavier-- so you have a 23. 2023 runs a straight 46* helix. 23 fuel map pulls harder than a stock 22.

People responding had your best interest in mind when they suggested 8500 rpm is fine on a boosted motor. Polaris engineering sets up RMSHA sleds to pull 86-8700, RMSHA racing is not about longevity but power. I can assure you the sleds are faster at 86-8700 rpm. I have the on snow data logs (versus dyno charts) that show both track speed and GPS speed.

Performance wise, RPM does not equal RPM. Riders need to pay attention to track speed. Clutch settings, helix, mass distribution/ profile on weights affect this. 8600 rpm and 30mph track speed is not good. 8400 rpm and 50mph track speed (as close to similar conditions as possible) is better.

To the OP, if you add 4 grams of weight to your sled and change nothing else, you should feel lower engagement rpm (more mass overcoming spring 165lb starting rate), and a reduction of around 400 peak rpm. Will it make your motor last longer?..... unknown.

Thanks for the input Yours was one of the better replies. Made perfect sense to me except the comment RPM does not equal RPM ! Did you mean to say RPM does not equal HP? Above you will find out how my test of the 80 gram weights turn out for me.

 

[Murph]

Thanks for the input Yours was one of the better replies. Made perfect sense to me except the comment RPM does not equal RPM ! Did you mean to say RPM does not equal HP? Above you will find out how my test of the 80 gram weights turn out for me.

Rpm does not equal RPM......
meaning slightly lower rpm shifted out further on the primary is better than higher rpm not shifted out as far on the primary.
That is when you need to look at track speed in addition to rpm. Track speed is engine power delivered to the ground.