As noted, I have a Rev MS3 Basic that I bought to replace my Rev MS2 Enhanced. I had my supercharger off being overhauled and was running NA, car was fine with no issues. Finally put the supercharger back on and now it is running very rich (like, as soon as I get above 0 on the boost gauge, AFR goes to 9-10 rich). This morning I pulled out my old laptop so I could compare settings between the MS2 and MS3. I found the Fuel VE table to be noticeably higher on the MS3. Can I just put the old values from the MS2 into the MS3 table, or is there more to it than that since they are two different creatures? I haven't gone this far into things before and I don't want to blow anything up. I appreciate and and all help.

 

The VE algorithm on the MS3 is slightly different, this means that your VE table will not work as it would on the MS3. A fuel retune will be needed.

 

I was afraid of that. Let me ask everyone this, what should I be looking for that is causing this large dump of fuel with boost added to the mix? Like I said, it was running well with good AFRs in NA. Also, when I was running the MS2 it didn't seem like I could autotune while in boost. With the supercharger you have to hit the throttle hard to get the boost in, and it doesn't seem like the computer can keep up with that. My fuel map anytime I tried doing that ended up spiky. Have things changed with the MS3 to better allow this? I have also compared some other settings between the two ECUs, can things like the overrun fuel cut and other settings be transferred over or are those going to be different with the MS3 like the VE table?

I know some if not all of this information is probably out there, but I trust the folks on this forum to provide good usable information and not just theories.

 

I may not be REV but I have spend some with megasquirt and tunerstudio and here are my two cents.

Your overrun fuel cut settings should be fine to re-use. Other settings are also likely fine to use, but it really depends on what they are. Since you changed between megasquirt types I would not copy paste things over though. Do it all manually would be my recommendation.

The reason the car is running differently (richer) in boost vs naturally aspirated is because you're in a different part of your fuel table (among other tables) while in boost. In regards to autotuning the fuel table, you'll always want to be smooth and slow with your throttle input and rpms changes. Any quick inputs you do will make for an erratic and spiky tune like you noticed. This is not unique to megasquirt. Frankly it is easiest to dial this in on a dyno, otherwise it will take a lot of hours on the street to perfect it.

To be honest it sounds like you've gotten in over your head on the tuning stuff, which is okay we've all been there but if you're not going to put in the time to read the megasquirt documentation, tunerstudio documentation, stickied tuning posts on this site, etc. and really learn how all these systems work together I think you'll be happier finding a local friend or tuner who knows megasquirts and miatas, or an established forum member here who does remote tuning. A lot of folks here do offer great free tuning advice, but you'll always need to provide at a minimum your current tune, datalog of the problem, and background info on your car, what's been done, and what the issue you have is, etc. Hope this helps.