U4 4900 RZR build

[JR4X]

I haven’t missed many U4 races since 2012. Decided if I was going to be there anyway I might as well be racing my own car. Having watched tons of hours of SXS’s racing, where as many as 25 rigs take the green flag, and in 15 minutes be down to 4 or 5 cars left running. My dumb idea was this, “I don’t need to outrun these fools, I just need to be able to outlast them” and started formulating a plan.

Since racing is a piss poor investment to begin with I specifically wanted a wrecked machine to start with not a new one. Why??? Because to make a race car out of a golf cart is to throw away half the machine so I wouldn’t mind if half the shit I’d be setting aside was gone already if it saved me the money I was going to spend on upgrades. I know people that DNF every race with between 60 and 70 thousand dollars in their race carts, and I have nowhere near that kind of money to blow on this stupid venture.


I have some friends that have a business buying, fixing, selling salvage auction vehicles. So I put out a request for a low miles/hours stock turbo 2 seat rzr believing that Polaris has the best aftermarket support. It didn’t take long for said friends at Scavengers LLC, to come up with what sounded like the perfect wreck for my needs. Supposedly stock, 689 miles 45 hours showing on it. After shopping around hard for a couple years I still haven’t found a better deal than this one. It all started with this one picture

 

[JR4X]

Upon receiving it it turns out the damage to it was far worse than described. (Who knew salvage sellers would lie about the damage to inflate a wrecks worth) I got it the day before leaving for KOH this year and didn’t have time to look at it other than to asses what was wrong with it. It had been front flipped in a sand dune somewhere, the kind of front flip where someone cased a jump onto the nose, bounced onto its ass without touching the cage to ground. It had pro armor aftermarket harnesses and I’m pretty sure whoever wrecked probably got injured because the improperly assembled belts wouldn’t hold anyone in the seats. More on that later. I knew before I bought it that the front a-arms were broken, happens all the time because they are weak garbage. In the initial sand stuffing the grill got shoved inside the facia and poked a bunch of holes in the radiator ruining it. Had tons of plastics damage but the main chassis is straight-ish as far as I can tell. Also noticed there was a lot of aftermarket stuff on it for a “stock” machine.

 

[JR4X]

 

[JR4X]

After assessing the damage I decided I’d better make it a roller and do some test driving because if it needed a new engine right off the bat I’d run out of money. Another couple of friends helped me out with this part. One, loaned me stock a-arms axles and steering stuff. Another gave me a radiator saving me around $600 bucks. Even though it was missing some pieces I got it driving and got to put about 30 trail miles on it learning that I’d lucked out and it was in plenty good enough shape to continue. At this point in the story is where I realized it was full of race gas, without getting it tested it’s hard to say octane but it was delivered with a full tank of purple 106 to 110 octane. WTF but more on that later. Also was missing front tires and wheels so I had to buy some cheap Craigslist wheels/tires to get it tested.

 

[KrustyTJ]

Looks like a good start

 

[jhama78]

Following along to watch you dump money in a turba golf kart to go racing.

 

[JR4X]

Since I’ve proven in the past to be a terrible driver and testing the cages ability to save my life is a high probability. The RZR got a 1 3/4” .120 wall DOM cage and man did I get lucky. RuffStuff specialties for a short time attempted to get into producing SXS parts. They partnered with Shannon Campbell and made cage kits and chromoly suspension replacement parts. Once RS realized that Polaris and other SXS companies come out with a new model every 2 years they decided it was going to be to difficult to keep up. So after only a couple of years in the SXS game they abandoned that product line. When I called to order one they had one left on clearance, and since I’m sponsored by RuffStuff they made me a killer deal on it.

 

[JR4X]

So I bought my RZR at a time that Polaris held the crown of every single King of the UTV’s. Then I went to KOH pretty much the next day and 2 days later Canam had swept the podium flat murdering all the competition. One of the big factors that helped make that happen was the X3-RC’s ability to run a 35” competition compound race tire while their competition can’t survive with only 32’s on them. Looking through another sponsors catalog. Milestar tires has a 34” competition compound race tire so I set my mind on making my car built for 34/35” tires and not eat itself due to the tire burden. First order of business in that vain is correcting the gear ratio keeping the engine and clutch happy. This is one place most golf cart owners DO NOT address. They just slap bigger tires on them and then get upset when they break it. To lower the gear ratio you have to do it sub trans because of the weird way they drive the front diff off of the rear ring gear with what’s called a snorkel gear. What I would call a pinion is an output not an input. Weird detail to these strangely packed 4x4’s. You can lower both high and low range by changing 2 gears. And then if you so desire, you can compound that low range change by changing two more gears. I opted for the 2 gear 24% across both ranges and so far seems like a made a good choice. I hate talking about gear changes in percentages because that’s a shitty way to address the topic. I have no visual image for 24% lower because, lower than what???? What gear ratio did I start with? Good luck figuring that out because golf cart tool bags just roll right along with percent and don’t care that that doesn’t give a good hard number to compare to. Anyway, it’s harder to get the transmission out of the buggy than it is to disassemble and reassemble the trans itself.

 

[06h3]

Cool thread, I havent really seen a U4 SxS build before.

 

[JR4X]

 So after all my test driving I was pleased with its performance and it was time to really dive in on the build. I see a lot of golf cart owners upgrade one tiny little step a time and just keep blowing money on little pieces as they break and still have a buggy that they break with little effort. I don’t have the time or patience for that shit so I went full nuclear right off the bat. Long travel, boxed internally gusseted a-arms n trailing arms. 300M ball joints and axle shafts. Chromo tie rods rod ends and 7075 aluminum radius rods. It was at this point I learned that turbo S models get larger CV’s than an XP and that if I slightly relocated my front diff I could fit the biggest CV’s available. I also decided that with a little bit of fab work I could just go ahead and use Turbo S suspension which has some benefits over anything available for the XP’s. So back on the jack stands it went.

 

[JR4X]

 

[JR4X]

 

[JR4X]

Break time from the build to go play with it and take a little care of the one that takes such good care of me. This little gal doesn’t only support my racing habit, she spurs me on. I was entertaining the idea of this at the end of last year and instead of complaining about. Instead of just being ok with it. She was pushing me to do it because it makes me happy, regardless of what it cost. I disguised a test drive trip in July into a good weekend where I proposed to her. Where she obviously said “yes”. While this might not be many women’s ideal spot to be proposed to. It’s THE best spot in the world to my woman. She loves tent camping in the forest more than anyone I’ve ever met. We’ve been archery elk hunting in this area and tent camping since the end of August.

 

[JR4X]

Rules allow doors to still open but if they open have to be secured with a secondary positive latch. Got these from UTVkingz, awesome fit and super easy to install.

 

[JR4X]

Covid-19 and the boot licking supplicants that give the politicians the power/ability to shut down the country has literally ruined every plan I’ve had so far this year. Between vendors, shipping, travel bans, cancelled events it took way longer to do anything this year than it should have. That said, I was finally able to make one hard push with the help of my dad and brothers. We wired in the PCI coms. Got the Patagonia SXT’s from Milestar mounted on some Raceline beadlocks. Number plates. A RuffStuff front bumper with a 4500# race model Superwinch. UTVkingz spare tire carrier. Baja designs led rear light bar. PRP GT seats with G2 5 point harnesses.

 

[JR4X]

 

[JR4X]

So at this point I’m 24 hours away from making a 24 hour drive to Tennessee for it’s first race. Thinking I’m ready to go I load up my co-driver who’s never ridden in it before. Take him to a straight stretch of road thinking I’m about to launch his brain into orbit. Punch the throttle it stumbles on it’s face and goes into limp mode. Now in a panic I’ve got one night to figure out what’s wrong with it. At this point, I have a built rzr with what I BELIEVED to be a stock engine. I get to doing some investigation and find the diamond that came with my rough wreck. Back to the race fuel and all the aftermarket stuff I mentioned earlier.

This is not only my first rzr, but the first one I’ve ever even been around. Turns out it had shock therapy’s the works suspension tuning. Has a B&M gated shifter. Has had a blow hole belt cooler on it. It had Evolution Powersports stickers and parts all over it. I didn’t realize those parts were not stock because the silicone boots and hoses were the matching orange color. When I had taken my chick to propose I had topped off the gas tank with 93 octane at the pump. The fuel I thought it was supposed to take for a stock 168 hp XPT. This thing had been upfitted with Evo powersports stage 6 big turbo kit. Vent to atmosphere BOV, tuned for 110 octane race gas. Luckily I didn’t burn anything up by mixing fuels, it just fouled the spark plugs. Supposedly this makes it about 250 horsepower. I’m not going to dyno it, I don’t care. It’s a rocket. My little brother Kevin who’s been a co driver as long as I have had this to say after his first ride in it. “That thing has way more power than anything that weighs that little should have”.

 

[JR4X]

So throwing some new plugs in it got it back to to pulling full boost launches just in time to throw it in the trailer to ship it Tennessee.

 

[JR4X]

I was a little worried about driving so far to tech a brand new build for the first time but it passed with flying colors. There were IIRC 16 new cars in the tech line and I watched car after car being sent away to fix one thing or another before JT Taylor would pass it. I was waiting for my fix it ticket and was pleasantly surprised that we got it right the first time. Always a good feeling.

 

[JR4X]

Teched in and lined up to qualify. Never ran this thing at race pace. Making excuses for being a loser here but also I took a big fat desert car to race in the trees. My car is now 78” inches wide and ran with a bunch of 64” cars. In my qualifying run I hit a rock or a tree with the right front and learned for the first time that the power steering also has a “limp mode”. The PS shuts off if you hit something to hard. Not knowing I could just cycle the key and get the steering back, I finished my qualifying run with manual steering, getting 12th out of 13. That’s alright I wanted to start in the rear anyway because I’m learning as I go.

In the real race they start us 30 seconds apart. We take off and pass two cars in the trees in the first 1/4 mile before running into a traffic jam of already broken and stuck RZR’s. It takes a minute to clear the course. When they do, a couple of the smaller tired cars in front of us couldn’t take off up hill with muddy tires. When they attempted to go they would just spin their tires. They winched out of the way and I was nervous when it was my turn that I’d also just sit and spin. We must have done something right building this thing because when I hit the gas we shot up the hill with little problems. Passing more stuck/broken cars in no time.

Then it happened to me, exactly what I make fun of Golf Carts for doing. It broke. There was only one real rock obstacle there and the 64” wide cars could drive between two trees and go around it. My fat ass car did not fit around it. I cleaned it smooth in practice but when in race mode hit it with too much skinny pedal. Took a bad bounce and put the pedal to the floor and felt something break and start vibrating. Got off to the side of the course and found the front diff housing had broken. All 4 feet that the diff uses to attach to the chassis broke off. We tried using ratchet straps to hold it together but there was nothing to attach to and as soon as I tried to go it cut the straps. So we called the race and stayed out of the way. Believe it or not I accomplished all of my initial goals. Got tech'd in, and my family got to watch all our hard work take the green flag for the first time.

 

[JR4X]

I knew the front diff was a ticking time bomb but hoped it’d finish one race. Oh well, time to upgrade. The XP diff is tiny and while probably sufficient for 29’s clearly not going to cut it for 34/35’s. Once again in the name of going full nuclear I decided to bypass the money blowing on trying to make an XP diff live (even though there’s a billet housing available) and jump straight to the biggest upgrade there is. RS-1/Turbo S diffs are completely different and everything about them is bigger. It wasn’t a fun swap because the new diff doesn’t even fit in the old diff space. But HCR racing has a conversion kit and with enough cutting and disassembling you can the smash the S diff in there. It’s such a tight I can’t even take pictures of it. You can’t even see it in there. But it’s in and we’re all back together just in time for race number 2 in Moab Utah at area BFE next week.

 

[JR4X]

Here’s a crappy picture of the hole you have to cut where the old diff used to mount. The bumper and skid plate covers the hole up. I’ll weld a patch in over it when I tear it back down for race prep this winter.

 

[SLOWPOKE693]

I give you lots of credit for wanting to build a U4 SxS. Nothing about smashing one of those things through rocks seems appealing to my wallet. Rock racing is an expensive habit!

Scoring that Rzr with the motor mods already in place is like a once in a lifetime deal. Great job...

Good luck at Area BFE next week!

 

[SLOWPOKE693]

What brand chase light bar are you running? I need one for my car but the Star brand bar im looking at is on perpetual back order from everyone....

 

[JR4X]

It’s a Baja designs “RTL BAR”
https://www.bajadesigns.com/products/RTL-30-Light-Bars.asp

I don’t plan on racing KOH with it but we’ll see now. When I started this mess. There was 2 real huge desert races, and two Lucas short course tracks on the schedule. I wasn’t going to Tennessee or Oklahoma before covid cancelled Mexico, Tonapah, Reno and Sacramento.

 

[SLOWPOKE693]

BD is mighty proud of their light bars. Damn

 

[JR4X]

BD is mighty proud of their light bars. Damn

yeah, when I bought it I didn’t have time to shop around either. My dad says the one on the 4500 car was $150 off of Amazon. Not BD but looks similar. If I had my shit together I’d have shopped around first. It’s a nice piece though, It’ll be a shame When I break it in half in a roll over.

 

[SLOWPOKE693]

I seriously contemplated the $150 Amazon light bar but couldn't find any real reviews. You may have just made my mind up knowing it holds up on the 4500 car.

 

[SLOWPOKE693]

Are you going to be at the Cross Bar Ranch U4 race in OK? If so, im going to go so I can check your ride out. Your Dads ride also.

 

[JR4X]

Yep we’ll be at Davis/Ardmore for the finals clash at the crossbar ranch. Just got done pre running Moab. Holy Shit! I don’t if any SXS will finish but we’ll find out Saturday.