Doing an ECU flash on the Polaris RZR XP Turbo is one of the best upgrades you can do to get more power out of the 925cc engine.  You might ask why, how, or what do we know? As a well recognized vehicle tuner that has been in business since 2001, we are also off-road enthusiasts and RZR owners ourselves.  The RZR XP Turbo is no different than any other turbocharged vehicle.  It has a turbo, fuel injectors, an exhaust, an ECU that controls the parameters.  Tuning these vehicles is just like tuning any other car.  It comes down to understanding calibrations and how to safely and reliably get power out of these Bosch ECUs.  Lets start with some facts related to Tuning the Polaris RZR XP Turbo.

  1. 2016 XP Turbo has 144hp while the 2017 has 168hp.
  2. They are controlled with a Bosch ME17.9.74 ECU that can be bench flashed (most common) or flashed with through the diagnostic port.
  3. Some tuning options available are plug and play piggybacks where a majority are tuning the actual ECU.
  4. There are several different software versions on the ECU which can be from recalls, updates, etc.  However the ECU are easily interchangeable between vehicles since there are no immobilizers like a car.
  5. Tuning the ECU alters parameters that affect boost levels, engine timing, and air fuel mixtures.  Stock boost levels are about 1Bar or 14psi.  Tuned RZRs are generally around 17-18psi. Typical safe AFR for a turbo vehicle is 11.5 – 12.5.
  6. Different Dynos are NOT created equal.

So with basic understanding of how tuning on the Polaris RZR XP Turbo works, we took a stock 2017 RZR to our Mustang Dyno here in Gilbert, Arizona. (Our tuning products are available worldwide for all types of octane, mods, and conditions, but we do testing here when applicable to show the results on our standard 91 octane.)  To start our tests, we need to have a baseline of how the car ran stock.  Along with the baseline, we need to have a benchmark of what people expect to see.  Our benchmark was a competitor’s ECU flash that is very respected in this industry.  Since we had the ECU here, we could swap it out with the stock one to run back to back tests.  This allowed us to see what the gains, power curve, boost levels, and afr should look like as the current standard.  Keep in mind, the Mustang Dyno reads VERY low compared to others.  This is nothing new and why it is nicknamed “The Heartbreaker”.


Our baseline test on 91 octane gave us peak torque of 129ft/lbs and peak horsepower of 115rwhp.  Typical rear wheel drive vehicle drivetrain loss doing a 3rd or 4th gear pull is about 15%.  Because of the CVT transmission on the RZR Turbo XP, the drivetrain loss we are getting with a Parasitic Multiplier of 1.00 is 32%.  Our tests were run from 10mph full throttle and cut off at 65mph for the stop test.  In all the tests we did (over 100 pulls), the power always fell off after 65-70mph.  Horsepower gained pretty consistently from 25mph to 65mph on our test.  This gain was roughly 13 rear wheel horsepower which equates to a 20 horsepower gain with a 32% drivetrain loss.   One of the tougher sections to tune on the RZR is the torque.  The ECU like other vehicles has torque limiters which can be changed.  Like a car with Sport Mode, you can change how much the electronic throttle plate is open.  Typically the throttle is open only about 80% in its standard form.  “Sport Mode” is allowing the throttle to open near 100% which gives you a more responsive and sensitive throttle pedal.


On one of our early test scenarios, you can see how the competition beat us out in torque when we tested it back to back.  Our boost levels were just slightly higher from 17.4psi to 16.6psi.  With similar AFR in the 11.5-12.5 range, the power curves should be about the same up top.  Torque is equally as important to top end horsepower.  However this can be dependent on the driver and driving style. Someone drag racing or from a dig might want more torque.  Where a person who is staying higher up in the RPMs or more mid to top end speed might want more horsepower.  Getting a balance of both is the ideal situation.


Going back to the calibrations, we created a new file we call Mod9.  This file had more torque than our run 14 test.  The additional amount of torque would provide that out of the whole feeling, where the mid range and top end would pull strong to give you very linear power gains.  Compared to the competition, they made slightly more torque on these test runs, where the VR Tuned flash made equally slightly more horsepower.  This can be caused from differences in boost and timing.  In respect to the competition which helped us benchmark our new VR Tuned ECU Flash for the RZR XP Turbo, with this file, we felt we had achieved a good end result.  So now what can we test?


The Polaris RZR XP Turbo uses a Bosch diverter valve that can very similarly be found in cars like the Volkswagen or Audi 1.8T or 2.0T vehicles.  These are also used as a pair in the Porsche 911 Turbo cars which we have expertise in.  The Bosch valves are a diaphram and spring design where they can bleed boost off when performance is increased.  When these valves go bad, they can flutter causing a honking sound.  The boost levels run on the XP Turbo are almost identical to what is run on the Porsche 996 Turbo of 1.0 bar to 1.3bar when tuned.  A common practice when you do a ECU Flash is to upgrade the diverter valve.  Our manufacturing company, Agency Power, has produced these billet diverter valves for years.  These are an OEM replacement that is a spring and piston design.  The spring is slight stiffer and the piston allows for smooth pressure release when you are on and off the throttle.  We decided to test to see how effective the Diverter Valve upgrade would be.  As you can see on the dyno, the run without the valve started to dip at 40mph to 58mph.  The run with the diverter valve held the boost more constant from the beginning of the test all the way to the finish without any significant changes and actually held slightly more pressure than stock.  This shows that on average, the stock valve was bleeding off .4-.7 psi of boost that the ECU was trying to give the turbocharger.

So how do we flash ECUs here at Vivid Racing?

There are several reading and writing tools that can be used to professional read out the ECU for tuning.  The most common way to do ECU tuning is what is called a Bench Flash.  This process involves opening up the ECU and connecting to the front as well as using a “boot” pin to read out the full or partial file to change the mapping area.  One of the tools we use is called the Frieling iBoot.  This allows us to read out the full 1536kb file which includes the eeprom and processor or just the 1504kb processor.  Another tool we have here is the Alientech KTag which works similarly but reads out the map tuning data area of 307kb only.  Once the file is read out, opening it up in a calibration software to edit the binary code is the key step.

rzr-turbo-2017-ecu read


One thing we do not do is “pot” your ECU.  Your ECU is your property and if you choose to take it elsewhere, upgrade your software or performance, you should have a right to do so.  A new ECU from the dealer such as Ride Now is about $500.  If you want to remove the resin, it can be done if careful.  However you can risk permanently damaging your ECU.  Here is a video we found on how to remove this resin that is placed on the boot pin –


Another way to flash the ECU which will be released by VR Tuned is through the OBDII port.  The MED17.9.74 ECU can be ID through the OBDII port showing which software number you have.  Once we identify the software version, we can then send you a new tuned file so you can write back through the OBDII port.  In addition to the tuned file, we can provide you with a stock file in case you need to visit the dealer for warranty purposes.  This process does not require the opening of the ECU which is a clear indicator the ECU has been tampered with.  Flashing the ECU requires our iFlash OBDII to 8 Pin connector cable and using our iFlash PC software.  Once you install the flash client on your PC, you can flash between the stock and tuned file at your desire.  This also allows for easy updates for different tunes or updates as you go through the modification process.  With this cable, we allow customers all over the world a easy way to flash their RZR conveniently.  You can view our similar flashing instructions here.  Below is a photo of the iFlash software and a short demo video.  This will be released April 2017.


What STAGE Flash is this?

In our opinion, stage flashes are extra costs you don’t need to pay.  This has been done time and time again in the car world.  A tune for a stock car or a car with an exhaust is the same.  So what do we call ours?  Its the VR Tuned Polaris RZR XP Turbo ECU Flash.  The only time you should upgrade your ECU flash is if you are changing motor parts, fueling, or forced induction such as a larger turbocharger or adding a turbo/supercharger kit to a NA vehicle.  When adding basic bolt on parts such as exhaust, intake filter, blow off valve, induction tube, there is no need to get another flash.  With VR Tuned ,we give you the best flash the first time.  On a RZR XP Turbo, when you add an exhaust that is less restrictive, your turbo will breathe better.  It will spool up faster from less back pressure.  The faster the air can come in, the faster the air can go out, the turbo will be happy.  The ECU will adjust to these small changes without any issue.  Whenever we do an ECU flash, we ask you for your current mods, environment such as elevation, octane used, and any special requests such as raising the rev limiter.  This helps us be aware if your vehicle truly requires a special tune different from a normal performance flash.  In the event you decide to add a part to your vehicle later and think there is a change needed, we will be more than happy to assist you in your needs or advise you what you should look into mechanically.


Final Dyno Sheet Stock vs VR Tuned


Up next is our tuning on the 2017 using larger injectors.  If you have questions on this ECU flash, ordering for your vehicle, or other RZR performance parts, please contact us at or call 1.480.966.3040 x222.  We appreciate your comments below!



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