clutching viper 780 again

V

viperhauck

Member
Joined
Jan 27, 2007
Messages
281
Age
44
Location
Sweden
Need some advice. For now I have 8dn-20 weights with unknown rivets, looks big. Unknown spring (its all red spring) Sec. 51-45 helix and green spring. The sled feels good. Just want some thoughts anyway. Maybe it could be even better. It have mr viper700 race case and cylinders. Cpr pipes and bored carbs. Agressive trailriding and good acc is what I looking for.
 

I would be using 8ca's or 8bu00 weights with that, will be alot more aggressive.
 
Now I have been testing a little this weekend. 8ca weights with 2 "medium" rivets. Dont know the the grams. Viper oem spring in primary. One shim. 51/45 helix and green spring. Engagemant 5200 rpm, extremly aggressive throttle respons. very good backshift, feels explosive on throttle. racing vs a nytro who has 145hk dynoed. In the start wins the sled who has the best grip. Up in speed no difference. Feels like the sled stop upshiftning in higher speeds. The rpms is little high. around 9200 and sometimes up to 9400. what is my next step.
 
OVER REVING. ADD SLIGHTLY MORE WEIGHT TO TIP OF THOSE 8CA. THEY ARE A GREAT WEIGHT FOR RACING BUT HAVE A OF VERY SHALLOW PROFILE AT TIP. 3:16 (yammie tony)
 
Mac said:
The Simons CPR pipes are designed to run 9300 RPM.
Click to expand...

If so the rpms is good. But something needs to be changed or should a nytro have the same performance? Maybe is the track (1.75")
 
I think $200 is an excellent price for CPR pipes.
Jeff at CRP told me the RPM should be 9100 off the line then slowly creeping higher to finish at 9300 at top speed. I believe the reason is because maximum torque is achieved at 9100 and maximum HP is at 9300. I run the Heavy Hitter clutch weights. I like the ajustability as the kit comes with all the hardware needed to fine tune RPM. Wow 5200 seems very high to me and 9400 is overreving.
Just keep in mind if you are at the end of a high speed pass and the clutches have shifted as far as they can go (bottomed out) your RPM will overrev.
 
Mac said:
I think $200 is an excellent price for CPR pipes.
Jeff at CRP told me the RPM should be 9100 off the line then slowly creeping higher to finish at 9300 at top speed. I believe the reason is because maximum torque is achieved at 9100 and maximum HP is at 9300. I run the Heavy Hitter clutch weights. I like the ajustability as the kit comes with all the hardware needed to fine tune RPM. Wow 5200 seems very high to me and 9400 is overreving.
Just keep in mind if you are at the end of a high speed pass and the clutches have shifted as far as they can go (bottomed out) your RPM will overrev.
Click to expand...

what kind of top end speeds are u pulling with your set up?
 
Only 103 - 104 GPS. I have 8 tooth extroverts with studs. I should gear taller. Its very fast to one hundred. My secondary is bottoming out. No ice for testing yet this season.
 
I know my gearing is low but it must be possibly to make it run hard/fast up to topspeed. My gearing is now 22/40 with 8 thooth drivers.
 
viperhauck said:
I know my gearing is low but it must be possibly to make it run hard/fast up to topspeed. My gearing is now 22/40 with 8 thooth drivers.
Click to expand...

Your currently geared at 2.05 with your set up, thats pretty steep, those are ratios I would use for 500ft drag racing on grass(good traction). about 90mph or so with that set up, you can plug that into a mph calc and see what it should be at 1;1 but youd likely be higher then 1:1 because the clutch will want to shift further. Another thing is your also longtracked which changes it some as far as clutching/gearing, longer track is more rotating weight to turn.

The thing with deeper gearing like you have is your also gonna have less traction in snow, because your multiplying the torq output and it makes it harder to hook up on snow. Sled will be quicker in a short run if traction is available but slower in a longer run. You have to gear the sled for what your doing with it, most times guys will gear the sled slightly higher mph wise then what they can actually achieve because the sled will end up being faster. This comes from the clutch being efficient, the deeper gearing makes the clutch belt speed increase, and go into a higher ratio bending the belt tighter, the tighter you bend the belt the less power travels thru it because of drag, its easier to bend something in a larger radius then a tigher radius.

without getting into a big discussion on over drive and all which sparks up all kind of debates, i would say try to take some gear out of the sled first and re clutch it, it will go faster if thats what your looking for, faster top speed or faster in what distance? You have to set it up for whatever your doing 90% of the time and just deal with the 10% win or lose, youll be alot happier with the machine overall then setting it up for the 10% and dealing with losing the 90%
 
I want it to be a killer up to 100mph. No need it go faster. But i still want it be trailfriendly with good backshift.
 
How do you keep the engine from moving on that sled? The engine on my srx will move if I have heelclickers on it.
 
Install torque arm

torquarm.jpg
 
The srx already has a torque arm. The motor moves forward.
 
Last edited:
viperhauck said:
I want it to be a killer up to 100mph. No need it go faster. But i still want it be trailfriendly with good backshift.
Click to expand...

deep geared it will be quick on grass, but in snow your spinning the track and not getting traction, back off the chaincase gears some and youll be pleasantly suprised at how much better traction and holeshot you can get on snow.
 
You must log in or register to reply here.


Back
Top