SCORE San Felipe 250 thread

badassmav

Well-Known Member
Jun 11, 2013
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Jamul
The driveshaft(s), and its multitude of operating angles, slip joints, and soft carrier bearing, was a major concern of mine from the beginning. Could the alternator, which is positioned at the fixed end of the drive shafts at the front diff, be a primary cause of the failure. At this time, I can't see how. Did it contribute? Possibly. When operating at angles, the kinematics of the u joint cause the rotational speed of the shaft to speed up and slow down 4 times per revolution. If 2 joints do not share a common operating angle, they will be in a constant battle to control the velocity of the shaft at these 4 points of rotation. This causes a phenomena you may know as harmonic vibrations. These indifferent operating angles exist at both ends of the drive line, and will be addressed in the coming weeks. I would be curious to hear from others who have experienced the same failure (if any) with their xp 4 1000.
 

///Airdam Clutches

Active Member
Nov 14, 2014
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i cant say that i have ever seen this happen, in any racing environment. from the looks of it, i would take a gander at the engine mounts closely. from all the figuring i can do, it seems only logical that the engine mount would have had to fail as well as the carrier bearing together in order for the driveshaft to pull off the transmission. the engine would have had to rock backwards a good bit to pull the driveshaft off the trans splines. could this have possibly been the culprit for the multiple belt failures? seems like in our testing and the bit of the parker race that he ran, we had upwards of 200 miles of hard testing, running parker, dyno time, and shock tuning time on one belt with zero problem. almost all of those miles at absolutely full throttle. then to get to SF and start blowing belts every 30 miles seems unlogical and to have a top speed in the 60s as marc said in his race report. seems like something wasnt kosher for sure.
 

badassmav

Well-Known Member
Jun 11, 2013
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Jamul
I found that the driveshaft we had made was approx. 1/2" shorter than stock. Not being familiar with the Polaris RZR, the lack of full spline engagement at the rear diff when the shafts were installed did not raise a red flag. I assumed the shaft, being it was made with a new stock one in hand for dimensional reference, was the proper length. I should have been more alert after having to relocate the alternator pulley on the driveshaft as a result of the vendor misplacing it prior to welding it to the drive shaft. Another good example of why you should perform as many mods in house as possible.
 

crazywatson

#13 - UTVUnderground Approved
Jul 30, 2009
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Ah I forgot it's a 2 piece drive shaft. Everytime I've seen blown belt issues the center to cetnter was off from engine to transmission. They seem to move sometimes and cause issues.
 

///Airdam Clutches

Active Member
Nov 14, 2014
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the center to center distance between the primary and secondary (engine to transmission) is one of the most critical, and overlooked measurements of any and every RZR. when the engine and transmission walk around (which they do A LOT) the belt will be operating at an angle, which overheats the belt causing blown belts. i found this out in the east coast endurance races. from the hard ruts and jumps in these endurance races, guys that i set up that were perfect the day before the race, would start losing RPM and running differently and start blowing belts half way thru the race with the belt temp gauge still showing good readings and laser temp gun showed the clutches to not even be hot. after disassembling the clutches and checking the belt alignment, and finding that during the course of a race it will get knocked out of alignment. this puts the belt operating at bad angles and blows the belts.

this is why i designed this brace assembly to hold the clutches in the proper alignment and not allow the engine and transmission to flex. i have been using clutch braces on the east coast endurance race machines with amazing results and great luck on helping some of the fastest guys hold a belt and win races over and over this last year. Marc was running one of these braces on his new RZR race machine. i doubt the engine and trans alignment were out of spec, this brace is designed to hold it all together. After such an impact from the driveshaft, i cant say that the engine and trans are perfectly aligned now. i am quite sure its in pretty bad shape.

when you get my clutch brace kit, i ship it with an alignment tool so you can adjust the clutches to spec, and also check it and your friends from time to time. keeping the clutch (engine to transmission alignment) within spec and in proper alignment is extremely important, something i recommend to every single racer and duner. literally should be part of every single pre-race maintenance program. the clutch alignment is just as important as tire pressure and radiator fluid ect. with a bad belt alignment you will blow belts continually.
 

///Airdam Clutches

Active Member
Nov 14, 2014
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another good question. marc ran that machine from day one start up, to the parker race, then we spent another 7-8 hours of running full throttle in havsu the next day, plus he spent a whole day in imperial valley testing with fox, all on the same belt with zero issue, while testing in havsu the day after the parker race we were seeing 80mph speeds without much issue and running 65+ thru some gnarley rocky whoops with no issue.

then he gets to SF and changes the belt before the race, somehow can only do 63mph top speed on the road following the side of the highway, and blows belts every 30 miles. not sure. cant figure that one out. i have been racking my brain trying but something doesnt add up. something was definitely wrong. by the looks of the carnage, there were quite alot of things wrong
 

JoeyD23

#utvunderground
Jan 9, 2009
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www.utvunderground.com
RZRs Fill the Podium at San Felipe 250

Minneapolis, January 29, 2015-SCORE International’s San Felipe 250 is the first race of the 2015 SCORE racing season and 14 UTVs, 10 being RZRs, would line up to take the checkered flag.


Scott McFarland, in a Polaris RZR would take the win with Polaris Factory Racers Johnny Angal finishing second in his Baja 1000-winning, No. 1921 UTV Inc.RZR XP 4 1000, and Matt Parks in his Jagged X No. 1932 RZR finishing third. RZRs finished the day not only filling the podium but with the top four positions in the class.


“It was a great start to the season for RZR,” said Donna Beadle, Polaris Race Team Manager. “Each year becomes more and more competitive in the UTV class and we look forward to another exciting year of desert racing.”


The next SCORE race is the Baja Sur 500, a point-to-point from Cabo to Loreto, on April 16-19.


Johnny Angal is sponsored by Polaris, ITP Tires, Method Race Wheels, Rigid Industries Lights, Fox IBP Shocks, Lone Star Suspension, wrap by Wolf Designs.


Jagged X is sponsored by Polaris, Muzzy Performance, Walker Evans Racing, OMF Performance, Factory UTV, Cutting Edge Manufacturing, Vision X Off Road Lighting Systems, Polaris Racing Lubricants, UTV Underground, Mountain States Contracting.

About Polaris www.polaris.com.
 

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