apex06 said:
I've raced 3 800xps. Two were the 137 and they weren't in the running and the 3rd was a 120 with 1.25 on it, he had the jump on me, 2 lengths out of the gate and that was where he stayed until about the 1000ft mark then I would go by at a walking pace. Is that realistic definitely. Stock apex has 150 hp and weighs at least 150 lbs more and is 3hp less than the skidoo. Knapp must have an exceptional attack, bone stock and beating all these xp skidoos and 1000 cats that weigh the same and making at least 15hp more. On snow you can have a sled with stock clutching close and another with bang on clutching and you might see 3 lengths difference, expecially with the 4stroke. Do a 1000ft run and have it clutched at 10500 or 10700 and you will see at most 2 lengths difference. Only big differences you are going to see on snow is if one sled has better traction over the other. If anyone would like to offer me advice on how to make mine faster I'm all ears. I have the Ulmer airbox mod, ignition controller, PCMIII, which I"m told is only good for 3hp total and runs 10000 out of the gate and runs at 10700 at the 1000ft mark. Can I beat a 1000 mach, no, why, because sleds weigh the same and he has close to 15hp more than me.
Couple things that I believe makes mine fast. And a couple things that you pointed out that may be holding yours back.
I'm using a 23/40 gear to get it rev higher sooner with the stock clutching.
Also multiplies tq. to front drive. Mine will run 10,500 out of the hole and climb to 11,000 using the stock clutching. When I put in the Pro-Line/Dalton setup it will come out at 10,700 and climb to 10,800 and accelerate even harder then stock.
I also run the Ski-Doo 137" Iceripper XT ,sharp stud, single ply track. It weighs the same as the stock track. I don't have to swing all the stud weight around and it hooks decent and won't give up 5 MPH to a track with 144 studs in it.
I also make sure to keep the engine cool, and cool air going into the stock airbox. I tried the mod airbox and found it inconsistent at different points in the powerband. The little bit of added power at wide open throttle was not worth the upper midrange loss. I think it looses some ramming effect due to reduced pulsation at certain RPM and frequencies. Mine was quicker with a stock box.
I'm not so sure about the F1000. They weigh only slightly less than our Yamaha's, make 10 more HP than an Apex, and have a narrower powerband. Now you take and stud the F1000 and that will slow it down enough for the Yamaha to get around it.
The XP 800's I've run, have not even been close, which has been quite surprising. I'm sure the doo-boys will get it figured out next year.
Overall though, the fourstroke RX-1/Apex runs real strong after they are well broke in. It takes a lot of miles though. Like over 2000 miles to fully take advantage of them.
Running the stocker this year has been a lot of fun. It really surprises the two-stroke guys. When I ran the turbos in the past, after you raced someone once, they never wanted to race again. It's exciting again.
Rods and other engine pieces bouncing off the road in my rear view mirror....lol
