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.