Polaris RZR Performance

The Polaris RZR UTV.  The Yamaha Rhino can be credited with starting the side x side performance craze, but Polaris certainly brought it to a whole new level.  The RZR really is an impressive machine in 2-seat or 4-seat, but like all stock machines, it can be made even better.  The big question is, where do you start?  There are many different things that you can do to your machine, but some will give you better performance gains over others. You no longer need  a totally modified engine with a big bore kit and ported heads to give you more power, there are easier (and cheaper) ways to gain more performance out of your RZR.  By upgrading your machine’s ECU tune, exhaust, fuel mixture and even tires, you can make dramatic changes.  Plus, upgrades to each of those areas can be done fairly easily with minimal tools.


ECU tuning

Your stock machine comes with performance, safety, and the average driver in mind. Some of that “Safety” can get in the way of overall performance when you are talking about speed limiters and torque limiters. Also the average rider may not need extra power and a blistering top speed. Also todays fuel injected machines come tuned with fuel saving and emissions in mind which may not be utilizing all of the machine’s power when you put the pedal to the floor.

ECU tuning is a cost effective performance enhancement. When you get the right ECU tune it comes with many benefits. Like adjusting your cooling fan on and off temperature and removed speed limiters in all or most gear. But the biggest impact is performed. Generally setup to be used with premium fuel so that performance spark timing can be used and not trigger engine detonation.

The fuel mapping on your RZR is set to meet the average riding conditions of the average rider.  More fuel does not always mean more power, but when speaking up, adjusting from a stock fuel map generally there are some easy horsepower gains to be had by adding fuel so that the air fuel ratio reaches performance and not fuel economy. When you add in other performance modifications like the following, more fuel is required to get the most out of those parts. And lastly, if you’ve got a turbo charged machine,  adding some boost will crank up the power quickly and in most cases very safely when combined with the right fuel maps.

Aftermarket Exhaust

When people start thinking about making their RZR faster, performance exhaust is often the first thing that comes to mind.  When you upgrade your exhaust, you are able to shed extra weight, gain more power and make it look and sound much better over stock.  Either a full system or a slip on will you’re your desired results.  Both are fairly easy to install and can add instant power and throttle response.

Aftermarket RZR exhausts like Trinity Racings Stage 5 allows more air to exit the engine, and of course, more air means more power.  You do have to make sure that the new exhaust meets the decibel regulations of the area and has a spark arrestor if you ride in an area that requires one.  You should also consider adding an air intake and re-mapping the air/fuel mixture.

Air Filter and Intake

Just like an aftermarket exhaust, an aftermarket air intake will help your RZR’s engine breathe easier to make more power.  On their own, an exhaust and an air intake do a good job boosting performance, but they really shine when they are installed together.  An aftermarket intake will not only allow more air to enter the engine, but they generally are better at keeping the debris out too, which is its main function anyways.  Most performance air cleaners are fairly easy to install, depending on which one you choose and which RZR model that you have.

The stock airbox can unfortunately be a pathway for dirt into the engine. Care should be taken to ensure that your air filter is sealed well in the airbox and that all hose clamps are tight. When you are ready to step to the next level and replace the restrictive airbox and air cleaner system, a full replacement like the Velocity Intake System not only adds excellent performance over stock but seals tightly to keep out the dirt.


Fuel Controller

If the ECU tuning is not in your budget of if you do not want to make permanent modifications consider using a fuel controller.  Controllers like the Dobeck EJK allow you to change the air/fuel mixture to what it should be for your unique riding conditions.  Having the optimal amount of the fuel mixture will allow your engine to make the most power possible and to run smoothly.

And importantly, if you have made any other stage 1 upgrades, like an aftermarket exhaust or a performance intake kit, you absolutely should add a fuel controller to your machine  Those additions will most certainly require a different fuel map than what comes stock on the machine.  Most fuel controllers, like the EJK and or AFR plus, plug right into the stock wiring harness and sensors, which makes the physical installation fairly simple if you know what you are looking at. Complete with detailed tuning instructions these controllers are certainly geared toward the novice enthusiast.



Many riders don’t readily consider upgrading the tires as a performance mod, but they certainly can be if you choose the right ones.  Your tires are what puts it all together and if you are not getting the best traction possible, you are just wasting the power of your machine.  The RZR is a very versatile UTV, but you can hone it in to be very good in certain terrains.  When you match a specific style of tire to the type of terrain that you want to dominate, you can get the best hookup possible and put the power down.

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pwrTune RZR 900 ECU Tuning

After countless hours tuning and testing on our AXIS UTV dyno our Polaris RZR 900 ECU tunes are tested perfected and ready for you. Our RZR 900 ECU tunes apply to all 2015 2016 and 2017 RZR 900 models. This includes 900 trails and 900S models two seats or 4 seat models.

The largest performance gain to be had with ECU tuning is normally fuel trim settings and spark advance. But for the RZR 900 it appears that Polaris has significantly held back performance. Call it torque limiter or shaft saver, the stock ECU setting do not allow your machine to achieve full throttle. If you watch the YouTube video below you can see a clear example of this. When you push the pedal to the floor of your RZR 900 the electronically controlled throttle blade opens up all the way for almost a second, then throttles back to about 70-75% throttle. If the video continues the machine further throttles back at about 50mph to only 60% throttle.


PwrTune ECU tuning for the RZR 900 and 900S addresses this issue and allows for full throttle blade opening when you put the pedal to the floor as you can see from the second half of the video.  Along with that we have optimized fuel and spark timing depending on what fuel grade you select and also any other performance modifications you have made such as RZR 900 intake or performance exhaust. Other modifications include the elimination of speed limiter in both high and low gears. Increased RPM limiter is suggested to be set at 8700 up from the stock 8300rpm rev limit but the specific limit is your choice. And finally you can choose which temperature you would like your cooling fan to turn on or off for increased cooling efficiency.

All of our tunes are backed with our free Warranty/Recall Flashback Protection. If you have a problem in the future, trans takes a crap, EPS blows up, and you gotta take it in for warranty work. Or more annoying another RZR recall?? Come on! No worries, we’ve got you covered with Free Warranty/Recall Flashback Protection. What does this mean? Basically, if you have an issue and need your stock ECU back to stock, we will flash it back to stock for you no charge. Check our website powersportsEFI.com for details. If you have turf mode, active decent, or any option these tunes will work great with no check engine lights or running/starting issues. Since we adjust your stock tune and don’t just wipe your ECU with someone else’s adjusted tune we don’t have the random problems other tuning shops have.



We have fresh ECU’s available at an additional charge ready for immediate shipping. Or you can send in your ECU for reflash tuning. Your stock file to be read and saved with your name and ECU serial number before adjusting your specific ECU tune to the specifications you have requested. Your ECU will be tuned and sent back out to you the next business day. Contact us today and send in your ECU for performance tuning. If you are not ready yet to step up to a pwrTune ecu reflash we stock many other performance products for your RZR including EJK Fuel Controllers.

For more details, visit us at: www.powersportsefi.com

Dynomometer (dyno) Muffler Exhaust System Part 2

Our 55 gallon drum for the dyno muffler has been modified with a 4 inch inlet at the bottom, provisions for feet, and necessary in this drums case the top has been cut off. Now the drum is ready for some sound deadening exhaust packing. Because the drum is such a large diameter compared to what a normal muffler would be we have a lot of room for material which should ultimately help keep the noise down. I needed to get this project completed quite so I could continue product testing our RZR Turbo Velocity Intake system, and also had a RZR 900 S coming in for a new intake design and pwrtuneECU tuning.


Not really sure how well this entire project will work out, initially I did not want to use a large amount of expensive exhaust packing to fill the drum.  I have several large rolls of BGF techmat high quality exhaust packing at the shop, but filling the drum would require two entire rolls and if the drum muffler did not work out the packing would be useless. So instead I decided to fill with pink home insulation from home depot on the outermost edges, and I would use one layer of real exhaust packing on the inside that would contact the perforated core. I started with a small square of insulation at the bottom (see pic) and about half of a roll of the unfaced pink insulation placed that I placed into the drum filling the bottom half of the space. I carefully put an inner layer of the white exhaust packing inside that so the half the drum was packed. Then I inserted the perforated core before I filled up the rest of the drums. It didn’t look like I could fill up the drum and then put the core in, nor did it look like I could put in the core and then fill the drum, so I did half and half. The inner perforated core that I used I also got from home depot, it was a 40”x40” sheet of aluminum about 22ga. covered in triangular holes.  Normally for a muffler the holes in the core would have been too large allowing most of the exhaust packing to easily escape. But since the muffler core it would start at a bottom 4” diameter and taper up to an 8” I didn’t see the packing easily escaping running at max 1000cc Polaris RZR UTV motors. We on our dyno we run.


I finished the packing with the pink insulation on the inside and one layer of exhaust packing on the inside, you can see from the two pics the packing with core sticking out. Next I cut a hole in the drum lid and used an HVAC 8” starter take off for the outlet. Placing the lid on the drum the muffler core came into the 8” take off about 2” just enough to secure of with some high temp tape. The 55 gallon drum has now been converted into a dyno muffler with a 4” inlet at the bottom and 8” outlet on the top. The last thing I wanted to do was install a fan at the outlet to help keep the back pressure down and then will be ready to test.


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