Turbocharged Polaris RZR Pro R ECU Tuning / N/A to Forced Induction Torque Based

First I wanted to introduce myself, my name is Patrick and I run a small powersports shop in Ogden, Utah USA. I purchased the VIP package and have learned more than I ever imagined, HP Academy has been an invaluable resource.

I'm currently working on a personal project, a 2022 Polaris RZR Pro R that been outfitted with a turbocharger. It was a complete turn key kit that has ultimately turned out to be nothing of the sort. I have been plagued with ECU tuning issues since day one. At this point I have basically been told they don't have a tune that works so I'm on my own and have set out to build my own tune for it.

This leads me to the questions I have. The vehicle has a Bosch MG1CA007 ECU which utilizes torque based tuning. While I have a little experience with Can-Am's utilizing this tuning strategy they are all machines fitted with a factory turbo. This Polaris is an entirely different beast. I'm struggling with making the proper adjustments needed to take a N/A machine making 225 HP to 450 HP.

My first table in question is the Throttle Body Airflow table. Common sense tells me this has a significant effect on the ECU's torque model. Since this has gone from N/A to 14 PSI of boost I would imagine I would be making significant changes here? Any input would be greatly appreciated.

Next is the MBT timing table. My understanding is that this table always plays a huge role in the ECU's torque model as well. The question I have here is how to approach this table without access to a dyno? I would imagine that MBT timing would need to be retarded for a boosted application, although I'm not 100% sure?

For now my last question would be the optimal torque and torque to load tables. Because these tables are in percentage and not actual torque values I would think raising the normalized torque value to the appropriate value and leaving them alone for now would be my best approach?

It seems that this ECU is similar in ways to Ford torque based ECU's but also has some significant difference so I'm just struggling to find any practical examples out there. Unfortunately in the powersports world it seems everyone is tight lipped so it's difficult to get advice. Also, it seems all the "other" powersports shops are struggling with the same thing since this type of torque based ecu is relatively new to our industry.

I have attached some screenshots below. Thanks a ton in advance for any insight you can give.

Patrick,

I'm so glad to hear you've got a lot out of the HPA courses!

I've never tuned that ECU so I'll do my best to help.

I agree the throttle body airflow table looks like it would need significantly modified, and my concern would be since the ECU isn't expecting a turbo system, it may not have related functionality to account for the impact that has on airflow. Is there a MAP based compensation for the TB airflow table?

You may end up having to fudge the VE table to rather high values to increase fueling due to unexpected additional airflow in some areas.

I would expect to need to increase the max expected torque, then rescale all tables based on the % of that max TQ expected under various conditions and then adjust all load based tables as well.

Torque to Load and Load to Torque generally require equal inverse relationships. You mentioned Ford so you've likely dealt with that part a bit.

I don't see the MBT timing table here, but I expect it to be the same up til atmospheric pressure only, and yes, how far you are from the MBT table value at any given time will impact the estimated TQ.

I'm not sure how much this info helps, but hopefully there's a little something in there for you.

Hi Patrick

Im a Noob too! Enjoying learning what I can where I can. Might be late to the table but Id love to see where you ended up with your tune on the Pro R turbo?

Ive got a 2022 Pro R with Weistec Turbo kit. No help from Weistec and there tune is locked. So here I am with a spare ECU to give this a crack! The tune the kit come with runs fine but has an issue with decreasing revs, its hanging at 2600RPM before dropping to idle eventually..Also a little on the lean side. Replaced manifold and manifold gaskets checked all for leaks and no leaks. The stock pistons broke all ring galleries so had to do a full rebuild. Reduced the comp slightly with new pistons and also the rods.

Im going to be working with a local company shortly but they has little experience in the SXS also but they have extensive experience in race cars etc. If I can help them out with your experiences with this Im sure it will get us to a good start.

See the stock screenshots! Would you share your final changes since this post?

Cheers from New Zealand!

So after months of working with HPTuners and another local shop we were not able to resolve the issues we were having at high boost levels. I was able to tune the car just fine to about 10 PSI but anything over that the ECU would shut down injectors. Long story short, HPTuners said they knew there was a problem but didn't have a fix or ETA on one. (would not say if it was an issue with finding and defining more tables or something else)

At that point I went stand alone ECU and moved on with life. I saw on Erik Brooks Facebook (HPTuners) that he fixed the problem in the latest HPTuners BETA release, but the car has been sold so I'm unable to confirm. I also recently heard that Gilomen Innovations has a work around, but also have no personal experience with their tune.

I'm definitely not a quitter, but honestly believe that at a certain power level the stock ECU just becomes too difficult to work with. Not saying it can't be done but the juice isn't worth the squeeze. Again, at lower power levels it was extremely easy to tune with stock ECU and HPTuners.

Are you using HPTuners?

Yes Im using the beta version of HP tuners. Its frustrating that HP tuners say the words "support" all the time but they offer no support when you have an issue you cant solve. There must be a way as the locked ECU we have works great but just have this hanging idle issue. Cheers!

I can tell you a big problem seems to be that HPTuners provides you with a stock ECU file after you unlock the MG1 ECU. Normally you would be looking at your actual stock ECU file when tuning, but not so with the Pro R. There seems to be some subtle differences between certain build dates and I think this causes issues like your describing. My car had idle surge issues at first but I was able to tune the car myself and clear that up. Only issues after that were high boost and the ECU torque management not being able to be adjusted properly.

Send me a couple datâ logs and maybe I can help you out.