M8RGT clutch setup what are you running?

Catman 42 · Mar 25, 2010

Weight 80 cat with engagement grind
Spring 140-320 with two slick shift shims
Cam angle 36-44P fixed
Spring Orange stock AC with shift assist and 1 shim
Gears 56/64
Boost 10lbs
Track 162 PC
Alt. 2000-7000
Tried this out today 3/27 poor little engine had a hard time swingin 80's. peak rpm 7700 at 10 psi 7900 at 12 6000'. Very sluggish after about 15 mph. Installing 77g for next ride.
Does anyone think the helix is too steep?

Catman 42 · Mar 27, 2010

Am I the only one on the forum running an 8?

???

Woody67 · Mar 27, 2010

how was your peak rpm?

Catman 42 · Mar 29, 2010

Update

Sunday 3/28 77g Cat with engagement grind also installed another shim on the drive spring so 3 total and on the driven for 2 total. Engagement 4500-4600
8000ish rpm at 7000' at 10 psi. Excellent track speed for spring snow in the Stuarts also I really liked the responsive throttle you could buzz the tops off the whoops. I am concerned that in pow that it won't backshift and will bog down. I believe I will remove the third shim from the drive and try a 34/42 and remove a shim from the driven.
Any input would be appreciated. Until the cam comes I will try a SLP BLK/RED 120-320 with 3 shims in the drive.
I am having a hard time telling just where the engagement is so now I am bringing the rpm up slowly until first contact is detected and recalling that rpm on the racepak so the BLUE/PINK was 4900 and the BLK/RED is 4600

Weight 77 cat with engagement grind
Spring SLP BLK/RED 120-320 with 3 slick shift shims
Cam angle 36-44P fixed
Spring Orange stock AC with shift assist and 2 shims
Gears 56/64
Boost 10lbs
Track 162 PC
Alt. 2000-7000

hatchers · Mar 29, 2010

most people dont know what clutching they are running

others get it tuned for what they want and leave it alone

at 10K elevation and 14lbs the twisted race kit clutching was perfect....16lbs was good enough, anything above this it would almost over rev on hard pack

i bounce between two different sleds......so i get stuff mixed up. With that said, i got a solid red pri spring with 79grams of D&D weight, this weight backside profile rocks!!!!!, 36/43 torsional heliz with a polaris/Team org/??? i know its one finish size down from the stiffest spring they sell at a polaris dealer

sorry i cant be more help, been clutching the stock 2010 for a few weeks and my memory is full

Catman 42 · Apr 1, 2010

Section 3 lake 3/30

As I suspected with two feet of fresh powder it pulled down to 7500 at 10 lbs. It would pull 7900 at 13 lbs. By the end of the day the snow was settled and setting up and the rpm went to 8000.

Weight 77 cat with engagement grind
Spring SLP BLK/RED 120-320 with 3 slick shift shims
Cam angle 36-44P fixed
Spring Orange stock AC with shift assist and 2 shims
Gears 56/64
Boost 10lbs
Track 162 PC
Alt. 2000-7000
Fuel 100LL

jgw50 · Apr 1, 2010

FYI...

On my dyno and my own turbo kit (gt2871 turbo, pretty standard setup, water / air IC and 10 lbs of boost, 2007 M8, avgas) my max horsepower was 7600-7650 RPM. Power ramped up relatively slowly at those RPM's but after 7600 RPM, power dropped like a rock. Like 15% loss from max at 7750 RPM, 25% loss from max at 8000 rpm. I clutch to 7500-7600 RPM and RPM's stay pretty constant on anything but hardpack. The lesson I learned from my dyno plots is that its much much better to be clutched at too low of RPM than too high. I might lose 5% power at 7500 RPM, but at 150 RPM over 7600 I was losing over 15% of my max power.

For clutching I'm running

purple / white primary
79g big dog weights
35/47 helix (need to double check, but that's really close)
stock secondary spring.

I engage at 4000 RPM and wouldent mind getting that a little higher. Might try a primary spring shim if I get around to it.

I honestly think the water / air IC keeps things much more consistant power wise on my sled. I know my IC pump quit working for a while and the thing was borderline unrideable. With it running my fueling / clutching doesnt seem to need any adjusting no matter what the conditions.

If I get the track spinning from a stop on hardpack, i'll go 8000 RPM though. Dont really know how to get around that one!

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M8RGT clutch setup what are you running?

Catman 42

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Catman 42

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Woody67

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Catman 42

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hatchers

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Catman 42

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jgw50

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