Megasquirt Timing and Fuel Map Thread

[Jaxx_]

Bumpski, let's get some more info on this thread. Anybody have m10 (turbo or NA) tables that I could use as a base?

probably too late for you, but...

http://www.jaxxd.com/e30/natune.msq

[87-325ic]

Here is my M20 E85 timing map.
Setup is 885 head with a 280/274 cam and a 2.7ETA bottom end. Car runs very good and is very fast.

Most importantly, my Tooth Angle #1 is set to 83 and falling edge. That is important to remember so don't just load these figures in unless you realize what that means!

This is a lot of timing in boost, but it is a 2.7 bottom so the quench is not as good as an 885 head that would require less timing. So this may be way too aggressive for a normal M20B25!

Would like some feedback on the map if anyone has any. I am still going to be making revisions to it once I hit the dyno.

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Tooth Angle #1 is set to 83 and falling edge.

best info here. its a wide world of internet confusion without a reference angle.

[Austrianvespaguy]

Hi all, figured I'd link this here for any other M10 interest. I did a very thoroug writeup including tuning tips and my maps when I Megasquirted my 2002 which can be found here and is great reference for anyone starting out:

https://www.bmw2002faq.com/articles.html/technical-articles/engine-and-drivetrain/megasquirt-efi-and-edis-for-the-bmw-2002-part-1-r287/

and for tuning:

https://www.bmw2002faq.com/articles.html/technical-articles/engine-and-drivetrain/tuning-megasquirt-efi-and-spark-part-2-r292/

I just fired up my new E30 (stock M20B25) Megasquirt build yesterday; started on the first try! :D Will need to now do some tuning but will report back with my base maps once I get them dialed in a bit!

[kyleconstantine]

hey guys so the thread on e30tech is kinda back up and ive read through it again. i keep seeing people referencing the stock ignition map and saying it has the timing peak before peak hp and then timing pulls back to prevent knock at peak hp. however all the images of the stock map are dead. so does anyone have a copy of the stock motronic ignition map?

[ForcedFirebird]

hey guys so the thread on e30tech is kinda back up and ive read through it again. I keep seeing people referencing the stock ignition map and saying it has the timing peak before peak hp and then timing pulls back to prevent knock at peak hp. However all the images of the stock map are dead. So does anyone have a copy of the stock motronic ignition map?

[dvallis]

Oops. Didn't see this thread before I posted another one.

Here is a copy of the best (I thought) fuel and spark tables from e30tech.

[kyleconstantine]

awesome thanks... although thats a little scary ive got a ton more advance than that wot map. i imagine my timing mark or timing light inst accurate and my tooth angle is off.

[turbski]

m20b25 turbo

this was generated on a dyno last year. stock m20b25 franken holset wh1c/ hx35? around 8psi. made 320/320. right before the head gasket let go lol 42# injectors. wastegate only

[SLEEPYDUB]

Why did the headgasket let go? Timing is pretty aggressive in that area for pump gas so that could be the culprit I assume?

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[ForcedFirebird]

Why did the headgasket let go? Timing is pretty aggressive in that area for pump gas so that could be the culprit I assume?

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I would bet on the timing being too aggressive. ~21-22° at 140kpa is pushing the limit on a stock gasket and 93 pump fuel. Even in NA form, the engine doesn't need over 30.

[SLEEPYDUB]

Yea that's what I was thinking. I run a lot of timing too but that's much higher then my map and I'm on e85 and a 2.7/885!

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[turbski]

The gasket was an mls .120 thick. Previous owner installed but never had the block or head surfaced. Timing is definitely aggressive. My thought is because those surfaces were never prepped, the hg never had a chance. It was replaced with a goetze and brand new arp studs. Has been run pretty hard since with zero hg* issues

[ForcedFirebird]

.120?!?! No need for that, the m20 has low enough compression, I have put boost on much higher comp ratios without blinking twice. Also, the MLS gaskets hold just fine in spite of surface prep, if anything you will just get a little bit of oil/coolant weeping. I drill the rivets and spray both sides of each layer with copper when the surfaces aren't fresh.

Really surprised you had an MLS fail without damaging pistons - they usually go first. MY preferred method for boost is o-rings and Goetze gasket, that way you still have a "fusable link". Changing a gasket is much easier than pistons.

[turbski]

that's not to say im not having different problems with it at this time but that's for a different thread I spose

[turbski]

.120?!?! No need for that, the m20 has low enough compression, I have put boost on much higher comp ratios without blinking twice. Also, the MLS gaskets hold just fine in spite of surface prep, if anything you will just get a little bit of oil/coolant weeping. I drill the rivets and spray both sides of each layer with copper when the surfaces aren't fresh.

Really surprised you had an MLS fail without damaging pistons - they usually go first. MY preferred method for boost is o-rings and Goetze gasket, that way you still have a "fusable link". Changing a gasket is much easier than pistons.

100% agreed. I believe I got lucky that time, when the head was pulled the rivets were there, no signs of copper spray. I had posted my findings. the failures were evident from cylinders 1,2,3,4, and was only under boost. The tuner figured we were lifting the head at only 8psi.

upon further investigation and talking with the previous owner (local guy, on this forum) the arp studs correlating to cylinders 2,3,4 for some reason would not hold a torque. I was told they had been on since before he got the car and had been on and off at least 4 times in his ownership. that's when I decided to pony up for another set of arps and go back to the oem thickness goetze gasket.