Viper xtx se rpm's

[Grim]

Does anyone know what rpm's my viper xtx should be running at? I have 200 miles on the sled and top speed is 84mph at 8400 rpm's then drops back to 8000 rpm's . I'm wondering if a clutch kit would improve my rpm's and top speed. I realize the sled is gear low but still should be able to hit at least mid 90's

 

[shadow44]

That motor was happy at 8900 in the Nytro, I would assume it would be the same in Viper

 

[Grim]

I also noticed the belt sits down in the clutch, I know on all my previous cat sled the belt always sat up above the clutch a little

 

[Yamadog]

Mine is turboed and clutched with overdrive sheaves - I am pulling 8860 at wot and drops back to 8820 - I am seeing over 100 consistently - 106 one time on lake run Friday with a bit more left in it.

 

[Nytros rule]

You should not know what it pulls above 8000 RPM till you have 500 K/300 Miles on that Motor.
The XTX is not geared that low, theoretical top speed is 181 KPH/113 MPH at 8500 RPM which is about 7 KPH faster than the Nytro XTX at the same RPM.
Before you start clutching remember that motor (if it's the same as my Nytro) will continue to get stronger every time out till about 2200 K/1400 Miles.

 

[Studroes144]

8900-9000 is the sweet spot on the clutching. That with a stock engine with no mods. When we did my clutching our best et times came when I would launch and actually tap the rev limiter once or twice and then have it hold rpm anywhere from 8900-9000. Like stated above..more miles and engine break in makes a huge difference in power!

 

[Grim]

I am thinking about a dd clutch kit, just want a kit that's easy to adjust

 

[Studroes144]

I'm very pleased with my setup so far. It's very easy to adjust. Take off the belt, remove some bolts and add or take away magnets. Fairly easy to clutch the viper as the hp has a very broad range

 

[Fowlow]

what set up are you running??

 

[Fowlow]

I have the dd kit coming just wondering anyone try it yet in the xtx

 

[Studroes144]

Mine is a D&D kit. I have 550 miles now and have noticed that I'm hittin the rev limiter a lot more now. Engine breaking in more and making more power. Will be talking with D&D in a day or two just to see what's the best bet. Either a spring change or just add some more weight. Very easy setup to tune and very effective

 

[cannondale27]

Not that I am complaining but I am seeing 8950 pretty consistently although havent had perfect conditions. Best I saw was 98mph and 93 seems to be the most common. Not sure if aftermarket clutching is going to help me at all. They did good on this one! Mr.Ulmer is going to have a tough time tweaking that 2mph more I need or think I need but I bet he will help me get it.

 

[Studroes144]

Yes stuck clutching once the engine gets broke in is pretty well spot on for rpm. As far as top speed mine maybe gained 1-2 mph. It grunts a lot harder and has more midrange which is really the only place u r gonna gain with clutching is in the midrange

 

[Fowlow]

Yea I'm sure it will be just add weight but either way keep me posted on what you find out or try so I'm not wasting my time

 

[freelance]

What kind of mid range numbers are u getting. My XTX SE pulls about 6000rpm at 40MPH but at 75 it's around 7200. Doesn't seem to engage till around roughly 4000rpm.

Are these numbers normal ?? Engine is not overheating. Maybe I'm just not used to such low end torque. My last machine was an AC Z1 LXR.