The UTVForums.net Project RZR-S started out brand new and bone stock back in November 2008. It was purchased from Mr. Motorcycle in El Paso, Texas.


Shortly afterwords, several friends of mine purchased RZR's and we were off to the races! We headed out to Mescalero Sands near Roswell, NM to see how well they would do in the sand and we documented all of the action:


Out of the box the RZR-S performed remarkably well! There wasn't anything it couldn't do in the sand and the stock BigHorns exceeded my expectations! The factory Fox Shox soaked up all the jumps I could throw at them and they were super smooth compared to the standard RZR's shocks.
Not only does the S do great out of the box in the sand, but it also off-roads like an animal! It crawled right up any rock or ledge, wet or dry! The front tires stick out further than the bumper so you can literally go straight up a wall.
After running the bone stock RZR-S through the ringer, it was time to start modifying it! But the first step was to get a solid baseline dyno run so that I could track my progress and document my results.

So I loaded her up and headed back down to El Paso where there was a reputable Dynojet Dynamometer. The great part about the S is that it's wide enough to work on a standard Dynamometer and there wasn't any special setup that was needed.
The weather was working in my favor and it was a beautiful 85 degree sunny day. A good temperature for a similar day riding out at the dunes. I had a feeling it was a good day for some dyno pulls and that the numbers would reflect close to factory specs, if not dead on! After we got the RZR-S all strapped down it was time for some pulls!

Here's a video of the best pull of the day:


The peak result was 43.53rwhp! Below is the print out of the dyno graphs and all the pulls from that day. It was pretty consistent even as the motor got head-soaked.
On the ride home I was thinking that the numbers seemed high, but after putting a pencil to it and using the factory rated hp and a driveline loss of 20%, it seemed to be almost dead on (55hp - 20% driveline loss = 44rwhp)!

So it was a successful trip and it was even better knowing that I had a good test case in that of the Project RZR-S.
With a good baseline number in my pocket and extensive testing in stock form I was ready to start modifying! There was just one more test that came up that I wanted to perform and that test was to race the Project RZR-S in the Monster Truck Rally held at the El Paso Sun Bowl!

I got the crew together (this guy, 4Nines and glitch), made up a bunch of UTVForums.net swag and decals and we hit the road!

There were nine UTV's total at the event (7 RZR's and 2 Teryx's) and it was a record setting Monster Jam at the Sun Bowl with more than 50,000 in attendance!



A few pics of the UTVForums.net RZR's in the pits:

The track and the action!





We had a blast at the event and it was definitely an experience to remember!

Since most RZR owners have to do modifications in stages, I wanted something that would help the greatest group of owners and members on the site. I needed something that would work well with future modifications and be an overall power adder that I could keep using to push the limits. After reading a lot of posts on the forums and doing a ton of research on forced induction, I decided that the MCX-USA Turbo system would be the way to go!

Not only did they have a great kit out of the box, but they were very knowledgeable and were very helpful when I called them up with my questions and comments.

Base MCX-USA Polaris RZR Turbo Kit:



Since the factory head on the Polaris motor had to come off to install the turbo kit, I decided now would be the best time to port and polish it. Since I was doing the install at Dynamic Racing I had the perfect guys to get the job done! The shop has been porting and polishing heads on turbo and naturally aspirated cars for years! The shop even holds the world record for the fastest Stealth/3000GT in the world with a 8.81 @ 166.79 mph! Needless to say, I knew I was in good hands.

After getting the head back, I was amazed at how much metal they were able to remove and the smooth finish that remained:











After reading about all the issues with the factory Polaris air intake, I wanted to make sure that with my new ported head and turbo kit, that wouldn't have any issues. I started looking around for the best solution and found it in the UMP intake canister. After telling them my plans and what I was looking for, they came up with a custom intake canister that they engineered specifically to be used with the MCX Turbo system (this custom UMP intake canister can now be ordered with the MCX kit)!



Now that I had a solid intake system and my ported and polished head, it was time to start bolting everything on!

Once all of the rear plastic, bed, fenders and roll bar were removed, everything was easily accessible, as you can see here:



Even with my limited experience with these kinds of installs, I found the MCX rather easy to do with basic hand tools and it only took me two days to complete working from 9 to 5 each day.

In the following pictures you can see the install come together:







With everything bolted on and the RZR-S running smoothly, I couldn't wait to get to the dyno to see the results! My initial goal was 100rwhp and if I was anywhere close to that I was going to be happy. It sounded like an easy task, but when you look at the number and the actual horsepower increase that it would take to achieve my goal, it seemed that I might be over optimistic. I would have to pickup 57rwhp to attain my goal, that's a 132% increase in horsepower! That would be a huge feat to accomplish considering all I added was the MCX Turbo kit, a Dynamic Racing Ported Head and a Dynatek Ignition box.

So I headed back down to the same dyno in El Paso, trying my best to keep everything the same as when I dynoed it the first time. I was crunched with time as the National UTV Rally was less than a week away. I couldn't be picky when I went and I would just have to take what I got. Unfortunately, on this trip I would not have the weather in my favor. The first time I dynoed it was an 85 degree day and now it was 100 degrees in the dyno room alone! I was still confident in my goal and strapped the RZR-S on the dyno.

After the first run I had done it! A 103rwhp with the belt slipping at peak torque and the intercooler too hot to touch! In the absolute worst conditions for an air-to-air intercooler to work and I still beat my goal! This was even on the base MCX boost setting of 11 psi. Not that I needed it, but I was planning on running at least 15 psi at the National UTV Rally with race gas! Needless to say, I couldn't wait to get there!

You can see in the graph below the dip where the belt starts slipping. To compare my original best of 43rwhp to this new personal best I had both pulls put on the same dyno sheet (the original pull is the blue line on the bottom of the chart).



I was stoked about my new numbers and I only had a few days before I got to show my stuff at the National UTV Rally in Moab, UT. I raced back home and did some last minute tuning, which come to find out later was the wrong move.

I had brand new black Maier plastics sitting at home from RZR Headquarters and a wicked custom cage from LoneStar Racing that I couldn't wait to get on and only a day to get it all done!

Once I got back home I only gave two quick rides with the new tune to friends, which included raising the rev limiter to 7,000 rpms. This was a very bad idea since I was running the stock crank still. At the time I didn't think much of it, but after just driving it a few times and revving it up to 7,000 rpms I bent the crank. I was convinced that it was something else that I had installed or a loose ground because it was still running fine, but it wouldn't idle and I had completely torn the RZR apart to install the new cage and plastics. It was the day before the big rally and I was going no matter what. So I loaded up the RZR-S and prepared to headed out.

The LSR cage turned out even better than I was envisioning! All the pannels are removable and are attached with zeus fasteners. The biggest improvement that it offered, and this wasn't something I was planning on, was how much bigger the half doors made the interior! Before the factory side nets would get in the way and it was really irritating. Now after the doors, it felt roomier and gave me a nice comfortable armrest.







I had also installed 3'' padded H-Style Crow harnesses that I ordered from UTV Crap. They are very comfortable and will definitely keep you in place and safe.



I figured once I got to the rally there would be someone there that could help me with the idling issue and I would be back in business. After talking with several dealerships on the phone on the way to Moab and having several people, including MCX themselves working on the Project RZR-S, we still couldn't figure it out. Finally I just went out to run it and bam! The crank finally bent enough to seize the motor.

If I hadn't gotten greedy right at the end and left the tuning and rev limiter on a conservative tune I believe I wouldn't have had an issue. The base MCX-USA Turbo Kit is super reliable in stock form and was designed to run within the stock rev limit. So, if you are running the stock crank DO NOT raise the rev limiter!

At least it looked good sitting at the show and I got to go! Thankfully MCX-USA had several other UTV's at the show and I was able to test drive all of their turboed UTV's over the week!

As soon as I got back from Moab I started working on fixing up my motor bigger and better! I got with Dale at Dirty Dawg Performance and sent him my motor so that he could work his magic.

We decided to do a welded crank (the only stronger option at the time), a custom cam from DDP and a set of custom ordered low compression pistons from CP. The final compression ratio with the new pistons on the new motor was a safe 8.6 to 1.



I also installed a nice set of adjustable clutch weights and springs from Dirty Dawg Performance. This made a huge difference as I got out of the hole much quicker and harder and it kept me off the rev limiter at the same time.



After about a month of work on the motor I was back in business! I couldn't believe how silky smooth the new motor was with the cam and CP pistons! It just hummed down the road and you couldn't even tell it was the most powerful RZR on the planet, until you rolled onto the throttle that is! All four tires would start spinning in the dirt at 40 mph and I could put it into a drift with just a blip of the throttle!





The new motor work seemed to complement the turbo fantastically and it was an absolute screamer! I wasn't able to get it on the dyno, but I did get a chance to do some racing and a Dynolicious run to back it up:

The result was 124rwhp!!



Shortly after doing all this work I had the opportunity to get my hands on one of the new Crank Works billet stroker cranks and I jumped on it!



I knew that the welded crank was just a temporary patch and wasn't going to support all the power that I eventually wanted to make or the revs I needed for a good top speed. So, out with the new motor after about a month and on to a permanent fix!

Stay tuned for the next level of modifications that are even bigger and badder than the last!

**Update**