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2008 FX Nytro Top Speed - Actual Results

I tested out 89.6 mph today in 1000' gps tested with my 250 azz with hammertimes hitting 8700 rpm with a bender 44/34 helix(measured out 48/36 on a nicad machine)
 

actually at the shoot out the track was getting whooped out according to some of the things I read, so that is hardly running in low snow conditions. I know how conditoins matter, I was kind of poking some fun at him. I am really surprised by all the people worried about top speed on a big bump sled. Race some of these sleds that are beating the nytro thru bumps and see how they turn out.
 
Srxspec said:
Ulmer Racing Gear Testing said:
Test 1
Clutching: OEM Yamaha
Gearing & Chain: 21/39 – 68 Link
MPH 1000’: 86.5
MPH 1500’: 90.2
RPM Snow: 8,500
RPM Hard Pack: 8,800

Test 2
Clutching: Ulmer Racing Stage 1
Gearing & Chain: 21/39 – 68 Link
MPH 1000’: 90.2
MPH 1500’: 94.9
RPM Snow: 8,550
RPM Hard Pack: 8,750

Test 3
Clutching: Same as Test 2
Gearing & Chain: 22/39 – 70 Link
MPH 1000’: 93.0
MPH 1500’: 97.7
RPM Snow: 8,500
RPM Hard Pack: 8,700

Test 4
Clutching: Same as Test 2
Gearing & Chain: 22/38 – 68 Link
MPH 1000’: 93.9
MPH 1500’: 98.6
RPM Snow: 8,470
RPM Hard Pack: 8,640

Test 5
Clutching: Ulmer Racing Stage 1 (lightened tip weight to maintain RPM)
Gearing & Chain: 23/39 – 70 Link
MPH 1000’: 93.8
MPH 1500’: 98.6
RPM Snow: 8,550
RPM Hard Pack: 8,750
Click to expand...

A little information that I obtained in testing Friday morning. I weigh 174 lbs with the gear I had on and the wrenches I had shoved in my pockets so use that as your baseline. Most anyone can go 22/39 (uses 70 link chain) and see the benefit without losing very little (if any) low end performance (even with OEM clutching). For those that are lighter and ride more wide open groomed trail 22/38 (uses stock 68 link chain) will work great without losing very little (if any) low end performance (will need slight clutch tweaking). For those Canadian guys who ride really wide open trails and especially if you're lighter weight and worried about top end go 23/39 (uses 70 link chain), but you will have to adjust clutching as you will be giving up a little low end punch.
Click to expand...
Im in the middle of installing a 128 hacksaw and was going to 10 tooth extrovert drivers and was going to try to leave the stock gearing/clutching for now. Whats your opinion on this?
 
orange said:
funny, box stock at shoot out the sled was running 95 in 1320 ft. if I remember correctly. So I would say you have a dog lol
Click to expand...

My test track is slightly up hill and far from perfectly smooth. All gear changes were made within a couple of hours and air density, temp, and snow conditions were the same amongst all. The shoot out sled was a 135 hp sled as well, just think what it would've done with 139 hp.

;)!
 
unchained said:
Srxspec said:
Ulmer Racing Gear Testing said:
Test 1
Clutching: OEM Yamaha
Gearing & Chain: 21/39 – 68 Link
MPH 1000’: 86.5
MPH 1500’: 90.2
RPM Snow: 8,500
RPM Hard Pack: 8,800

Test 2
Clutching: Ulmer Racing Stage 1
Gearing & Chain: 21/39 – 68 Link
MPH 1000’: 90.2
MPH 1500’: 94.9
RPM Snow: 8,550
RPM Hard Pack: 8,750

Test 3
Clutching: Same as Test 2
Gearing & Chain: 22/39 – 70 Link
MPH 1000’: 93.0
MPH 1500’: 97.7
RPM Snow: 8,500
RPM Hard Pack: 8,700

Test 4
Clutching: Same as Test 2
Gearing & Chain: 22/38 – 68 Link
MPH 1000’: 93.9
MPH 1500’: 98.6
RPM Snow: 8,470
RPM Hard Pack: 8,640

Test 5
Clutching: Ulmer Racing Stage 1 (lightened tip weight to maintain RPM)
Gearing & Chain: 23/39 – 70 Link
MPH 1000’: 93.8
MPH 1500’: 98.6
RPM Snow: 8,550
RPM Hard Pack: 8,750
Click to expand...

A little information that I obtained in testing Friday morning. I weigh 174 lbs with the gear I had on and the wrenches I had shoved in my pockets so use that as your baseline. Most anyone can go 22/39 (uses 70 link chain) and see the benefit without losing very little (if any) low end performance (even with OEM clutching). For those that are lighter and ride more wide open groomed trail 22/38 (uses stock 68 link chain) will work great without losing very little (if any) low end performance (will need slight clutch tweaking). For those Canadian guys who ride really wide open trails and especially if you're lighter weight and worried about top end go 23/39 (uses 70 link chain), but you will have to adjust clutching as you will be giving up a little low end punch.
Click to expand...

Im in the middle of installing a 128 hacksaw and was going to 10 tooth extrovert drivers and was going to try to leave the stock gearing/clutching for now. Whats your opinion on this?
Click to expand...

I would leave the stock gears in as well. The added weight of the 128 will pull RPM down slightly as well and clutching will likely need a little tweaking.
 
Cool, Im just going to continue on with the 10 tooth extros and stock gearing and just go from there.....
 
On a ice road i was pulling 104 with more left. Eats up a 600RR Polaris and really the XP 800 on hard pack trails doesnt even have that much on it
 
96 MPH on speedometer and 9,180 RPM on groomed snow packed trail with tall windshield, wind deflectors, and luggage. Nytro MTX totally stock. Runs low 90's on GPS. Raced a APEX short track over the weekend from about 15 on up, was a dead draw to 90, then he left me. I think with a decent track I may have pulled him, but not by much.
 
MPH

96 mph on lake in -22C and ran out of room. Very fast to 90 mph! Better than my old Attak.
 
Srxspec said:
My test track is slightly up hill and far from perfectly smooth. All gear changes were made within a couple of hours and air density, temp, and snow conditions were the same amongst all. The shoot out sled was a 135 hp sled as well, just think what it would've done with 139 hp.

;)!
Click to expand...

spec, I remember there being the scenario last year with some higher HP Nytros and some claimed it was the exhaust that was making the difference. If that is true what is the situation for 2009? The higher version of 139ish or the lower HP version of 135ish? Just curious...... or is it still a mystery?
 
I've hit 174km/h on speedo. That's after I ditched the stock pipe for a Super-Q. With the stock pipe she could only pull herself up to 168.
 
You guys really need to get more HP to the ground...1979 440's would roll to over 100 mph. :exc:

I guess that nice long travel skid and a track that changes directions several times dosen't help much.

Keep up the good info. Interesting to read, since I don't own a 4/.
 
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