All day Viper Clutching..

[Yamadog]

This in my opinion is the statement of the day. Now if you can pull the same or heavier weight to that higher rev limit you will go faster. Problem is none of us can at least not consistently. Only solution is power and more of it. Another possibility is belt slipping.

I was having that problem. I was banging the rev limiter and only seeing 104. changed to 8dn from 8jp and no bangs and saw 111.

 

[Turtle]

This in my opinion is the statement of the day. Now if you can pull the same or heavier weight to that higher rev limit you will go faster. Problem is none of us can at least not consistently. Only solution is power and more of it. Another possibility is belt slipping.

Yes, there is a sweet spot to clutching for rpm. Too much weight the rpm will be low and you can fall out of the power resulting in a lower speed. But if you remove too much weight, the rpm will go high and not be able to grab the belt. There is a sweet spot to getting the most rpm that you can effective grab. To maintain that same grab of the belt and take the rpm up will take more hp. But eventually even with all the hp in world, you will run out of gear. That's when you need to gear up to go faster.

It seems like about 9000 rpm is the sweet spot for getting to 100mph in great conditions. In less than great conditions, the engine doesn't t have enough hp to pull 100mph. If on glare ice, you can probably go faster than 100mph. There are a number of clutch setups that will get there (as noted earlier in the thread) and each one has a different character to the kit. But the MTX and RTX LE models will never 100mph that due to their low gearing.


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[Studroes144]

The higher rev limiter would be awesome in my opinion, would help a lot by keeping momentum up on a launch by not hitting limiter, but I do hafta agree that anything much over 9000 rpm is kind of a waste. Haven't seen it so much on mine but on the stock 2014 cat 7000 they came with too light of weights, rpm was consistent but it would rev like 9200 on the tach, and best speed we seen was 92 mph. Put heavier weights in, got rpm to 9000 and it was much quicker and faster top speed.

 

[cannondale27]

Well when I was going down that frozen dirt road at 106mph banging the revlimiter I was wishing for higher revlimit. Problem is adding even 1g just killed it and not enough power to pull it. And reality is we dont run on dirt which I believe was faster than the snow here lately. Have never seen that 106 again. At that point is when you know only solution is more power. That is where we all are or very close.

 

[cannondale27]

The higher rev limiter would be awesome in my opinion, would help a lot by keeping momentum up on a launch by not hitting limiter, but I do hafta agree that anything much over 9000 rpm is kind of a waste. Haven't seen it so much on mine but on the stock 2014 cat 7000 they came with too light of weights, rpm was consistent but it would rev like 9200 on the tach, and best speed we seen was 92 mph. Put heavier weights in, got rpm to 9000 and it was much quicker and faster top speed.

You put heavier weights in. Now get sled to turn 9200 with those same weights and you will be faster guaranteed. The problem is lack of power. Its done. Cant pull that weight. At least cat now put those heavier weights in stock for 15. We are left to figure it out on our own.

 

[Studroes144]

You put heavier weights in. Now get sled to turn 9200 with those same weights and you will be faster guaranteed. The problem is lack of power. Its done. Cant pull that weight. At least cat now put those heavier weights in stock for 15. We are left to figure it out on our own.

Yupp you're 100% right. I'm sure most folks know D&D did the initial clutching setup on my viper last year, a few days of testing and every day the same exact thing was said, "we just need more power". Sled would do 100-102 on perfect snow, and it would do it in 1000'-1/4 mile, but I could've held it for 5 miles and with my 240+ pounds it wasn't going to gain any more. Now with the turbo it's at 109 mph and completely shifted out in 800-900 feet, just need more power!

 

[cannondale27]

Yupp you're 100% right. I'm sure most folks know D&D did the initial clutching setup on my viper last year, a few days of testing and every day the same exact thing was said, "we just need more power". Sled would do 100-102 on perfect snow, and it would do it in 1000'-1/4 mile, but I could've held it for 5 miles and with my 240+ pounds it wasn't going to gain any more. Now with the turbo it's at 109 mph and completely shifted out in 800-900 feet, just need more power!

No. Now you need more gear. Now the clutches are limiting you. Just like TD max with less power and less gear. Figure out the gear ratio of a 09 Nytro XTX. That sled does a honest 120mph with 7-8lbs of boost.

 

[Studroes144]

No. Now you need more gear. Now the clutches are limiting you. Just like TD max with less power and less gear. Figure out the gear ratio of a 09 Nytro XTX. That sled does a honest 120mph with 7-8lbs of boost.

Yupp new gears going in, 21/41 instead of 24/50. The thing is that stock rtx and ltx gearing is only good for 105 mph unless you can squeak a bit of overdrive out of the clutches, which is what mine did. Could've machined clutches, but truthfully the gearing swap is cheaper. Like u said, the nytro is geared for much more speed than the viper, however in a drag race a nytro xtx vs a viper would be one heck of a race, so the taller gearing must not hurt the low-mid range pull on the nytro and still gives you way more speed when you have the power. Any bolt on guys out there try going with taller gearing yet?

 

[cannondale27]

Yupp new gears going in, 21/41 instead of 24/50. The thing is that stock rtx and ltx gearing is only good for 105 mph unless you can squeak a bit of overdrive out of the clutches, which is what mine did. Could've machined clutches, but truthfully the gearing swap is cheaper. Like u said, the nytro is geared for much more speed than the viper, however in a drag race a nytro xtx vs a viper would be one heck of a race, so the taller gearing must not hurt the low-mid range pull on the nytro and still gives you way more speed when you have the power. Any bolt on guys out there try going with taller gearing yet?

Summer project. My top gear will be shot by end of season anyway!

 

[Studroes144]

Mr. Sled, on those stock 8gl weights did excell recommend specific settings or specific weight to be used in the specific areas? Got a buddy running a viper with a barker can and his is on the rev limiter all the time, he wants it clutched but don't want to spend the money, just wondering if I can throw any old screw and nut in there to make his stock weights heavier. Just getting it off the rev limiter is the biggest thing at this point.

 

[turbo800]

I'm working on tuning in my Heavy Hitters from Thunder Products. I found it interesting they have the same profile as the stock 8BU-10 weights in my MTX. If I roll into the throttle it will stay off the rev limiter, but if I going into a dip and pin it out, she bangs the rev limiter....so I'm working on getting weight in the right places

Still running the factory G-G-G primary spring, and I love how the HH'ers don't have the engagement hump. Much more fluid and seamless!

I'm also running the Gates Carbon belt (40C4340) in the Nytro length. It runs the same RPM as the 8DN belt did...

 

[tapex_07]

No. Now you need more gear. Now the clutches are limiting you. Just like TD max with less power and less gear. Figure out the gear ratio of a 09 Nytro XTX. That sled does a honest 120mph with 7-8lbs of boost.

I've mentioned switching the gearing up a while back. And at the time, really wasn't acknowledged... I still think that gearing closer to the Nytro XTX should result in similar speeds. Maybe not N/A, but turbo should have the power to pull it and not loose much (if any) on bottom end..
I ran 24/37 gearing my SRX and that was a rocket. Stock drivers 9t 2.52. Considering the 9t 2.52 vs 8t 3.0 is a diff of .41xxx" (8t are larger) I would think the Viper XTX should be able to pull a 22 or better top gear without sacrificing to much bottom end. 135hp vs 180hp.

 

[MrSled]

Mr. Sled, on those stock 8gl weights did excell recommend specific settings or specific weight to be used in the specific areas? Got a buddy running a viper with a barker can and his is on the rev limiter all the time, he wants it clutched but don't want to spend the money, just wondering if I can throw any old screw and nut in there to make his stock weights heavier. Just getting it off the rev limiter is the biggest thing at this point.

I never weighed them over all or each screw that was added to the stockers... My sleds are loaded and I will be out of town for at least a week and wont be able to get you the info. I would have to pull a weight and then set them on my gram scale to tell...you could try calling Excell... he might be able to assist you.

 

[STAIN]

I went from 24-50 to 21-41 gears. I only have made a couple of lake runs--pulling to 109 when I let off. My clutching isn't done yet....it never is!!!

 

[NOS-PRO]

I'm working on tuning in my Heavy Hitters from Thunder Products. I found it interesting they have the same profile as the stock 8BU-10 weights in my MTX. If I roll into the throttle it will stay off the rev limiter, but if I going into a dip and pin it out, she bangs the rev limiter....so I'm working on getting weight in the right places

Still running the factory G-G-G primary spring, and I love how the HH'ers don't have the engagement hump. Much more fluid and seamless!

I'm also running the Gates Carbon belt (40C4340) in the Nytro length. It runs the same RPM as the 8DN belt did...

Turbo - Let me know your setup as I have a couple setups with the HH's and weren't too bad. Plus was using the stock 43° helix. With the Thunder Products black primary spring, I was at.....
48.2 gram Heavy Hitter weights with ¼ allen buried, ¾ allen in behind it in the heel.
3/8 aluminum with thick washer in middle.
3/8 aluminum with thick washer in tip.
Engagement was 3,800-3,900 (which is just a tad high)
Secondary setup
Silver Yamaha spring set at 6-2 (tried green spring (soft) but for backshift the silver worked better)
Stock helix 43 straight

This would easlily do 91 in very wet conditions and was with the carbon fiber belt.

Another setup with the stock primary spring would be.....
1/4 inch allen screw in the heel
3/8 aluminum in the center and 7/16 steel with 2 thin washers in the tip.
Stock 43° straight helix and pink secondary spring.
Carbon Fiber belt