Vr6 tuning map couple question about resolution and AFR

Hi Gentlemen, so i'm hoping to have some input on my selected AFR's as well as a spike that i'm seeing in my ve table. i added a ton of resolution in the area of the spike and it seems to be flater but i had to give up res higher in the map and maybe that's too much? My altitude is 4200 feet so my boost kpa is 82 so at 155 i'm 11-12 psi i'm hoping to run about 12.5 to 12.3 afr at that psi and 11,9 ot 11.7 to 20-25psi.. Also i haven't been able to get all my tuning done in one day are there any tricks to basically start where i left off , i feel with the type of correction ms uses my afr's will be off since my ve table is being tuned at different temps

I found that when i was tuning megasquirt (in our area here anyways) their MAT correction was absolutely whack.

Try flattening out the mat curve. Give it maybe 1 percent per 10-15 degrees celsius. I like to use where my car normally sits, for the

centre of the correction, and then go in 20 degree steps up and down, and use like 2% correction per step. So, if mine likes to run normally at 30 degrees C, i would do this

70 -4%

50 -2%

30 0%

10 2%

-20 4%

The idea behind the MAT correction, is not for it to change your AFR every time you get in the car, but to compensate for broad temperature changes. Ive found that at what ive shown above, i get very little change during pulls on the dyno. That is in our climate here anyways (alberta, canada)

hope that helped.

So I couple of concerns first MS changed their setup the MAT follow the ideal gas law as of the pro coming out it was a big change in their firmware. So were you tuning pre MS pro? My climate is mountain desert

Any thought on my AFR's some one said I was lean in the MS forum but I don't think they realized I'm not at sea level

Honestly i realize its based on the ideal gas law, but it doesnt seem to really work correctly. I had massive sways in AFR that i had to keep correcting, due to changing temps. it shouldnt be that much. Even in andre's tuning videos, he makes mention that he finds that 2% approximately every 10 degrees of temp, seems to work quite well for him, with his experience. I find that in my climate here in alberta (3700 ft above sea level) and with ever changing temps, 1% per 10 degrees or so works well (depends on iat sensor location, etc). You could do it scientifically with a dyno, by setting a desired afr, getting the IATS hot, and then observing your afr, and changing the MAT compensation table to get it back to the AFR that you had set previously.

As for your afr, it really depends on the car and how it likes what you are doing. I personally, would start at 11.8:1 or so at the 11 psi mark, tune the timing portion, and then go back and play with the afrs to see if any extra power is realized, and if it knocks, etc. On the higher boost i think i would be around 11:1 and work my way up from that, but im just cautious (=

And btw, it was ms3x and ms3 pro i had these issues with. Alot of people say its too sensitive. Again, it comes down to where the sensor is, etc. But regardless, you need to tune the MAT table to keep your afrs solid. When tuned properly, the afr should not move, no matter what the air temps are.

Was MS a system that you were able to get as stable as industry expects? I find mine hard to get just right but this obviously was before this knowledge today so thanks for The tip!

yeah i got it pretty good, our work on it has been cut short a few times due to mechanical issues, etc. It was an s10 with a 6.0L engine/s300sx turbo. When we first tuned it, i did not realize how truly effed the MAT table was, so i kept chasing my tail with ever changing AFRS. Once i figured that out tho, it was fairly clear sailing. We still have some work to do on the map once he gets his setup completed again (old engine blew up due to overheat).

Megasquirt simply has SO MANY user tunable features, that you can really mess things up easily or miss things. Its a good ems as long as you dont use it on a denso ignition system like a 2jz. I have honestly found it the most challenging to tune in some cases. In other cases not so much. I did an rb20 with a big turbo, ms3x harness made by me, and it turned out very well. Made around 270 wheel on 11 psi or so. Every other ems, i have found easier to tune and get right tho. Ive tuned haltech, link, vipec, nistune, AEM ems, and HONDATA, all easier than MS...LOL!. But if you keep at it, youll get it. Just get your foundation right. Also, make sure your dead times are properly tuned before you even do anything else.

Hope i helped a bit (=

Cool thanks again this brings hope! Lol sound like I'm chasing my MAT table then too beside needing to get it a little closer. I'm running ID 1000's and got the info for ms from ID themselves so it should be close that's one thing I don't like about ms on ms2 it's very plain on dead time setup but I'm running 1.069 at 13.2 and a correction of .17

Just speculating, but maybe your mat table is the culprit for the hump in your map at that point. Maybe your iats are getting higher, and its applying a large correction that you are chasing. Just an idea.

So I think you're on to something at 165 Iat I'm removing 3.5 degree of timing that's right at that rpm on average hmmm I bet that's why it falls flat and blows out a cloud of black smoke with a pop lol