I'm fast and (mostly) smooth now!
 

I finally got off my ass and installed my NeoBrain :bowrofl: piggyback megasquirt. What the hell was I thinking?, driving the past 8k turbo miles on fmu. Don't buy it from me when I post it, pm braineack instead.

(Piggyback, hi-res, 460cc, map, no variable tps or cops, yet)

Acceleration is great, smooth and consistent power. No rich, then lean, then too rich to run crap. Using a basemap provided by our esteemed brain, we leaned it out a little and then richened it up a bit because of a little knock, and got it about right where we started, just a bit smoother. Reaches full boost (10.5 psi now) at 4100rpm with the GT2860, at 70% duty cycle with 460cc injectors. Starts at 12:1 afr and gets closer to 10:1 at redline (relatively cold ambient temperature).

Before I start messing around, I have a few little hiccups I need advice on:

1. Cold start is so rich it vapor locks and then starts but misses really bad until it warms up a little.

2. At cruise under certain loads, lifting off the throttle a little bit causes it to go rich for a split second and jerk. It is hard to keep it steady at cruise (AFR’s around 16:1)

3. After a 20 mile drive, it started idling at 12:1, although very smoothly. If I restarted it warm (starts pretty well), it idled at 13.5 to 14 to1.

4. My tune seemed to change with the outside temperature, isn’t megasquirt adjusting for air temperature?

I am really sorry about needing so much “hand holding” but I really want to get this right.

Congrats and welcome to the wonderful world of full engine management.

1. You need to lighten up your Cranking pulsewidths at the temps you have had problems.

2. Decel Fuel Amount(%) under Accel Wizard. Lower that number.

3. Sounds like you need to lean it out at idle a bit. The leaner idle after a warm restart is because the Air temp sensor is heat soaking while the car sits. I've fixed the issue of heat soak while the car is idling by moving the sensor but it will still heat soak if I turn the car off for 10-15 mins or so. No air is moving in there so all the hot air in the engine bay just heats up the air in the piping. IAT/CLT related air density settings may help there.

4. MS does adjust for air temp. Are you sure your sensors and reading properly? ie correct easytherm settings. I'd refrain from saying/thinking the tune is changing with air temps until you get it tuned fully.

Thank you! I will work on it this weekend. Can you email my wife with some sort of "e"permission slip?

Sure. Post her email address here along with her pics. ;)

No problem, its a free membership but I just need your credit card number.:jerkit:


I dropped the deccel to 80% and it seems better but it still drops pretty rich and jerks at some loads. At some rpm's I'm hitting 9:1.

I also noticed my air intake temps are 30degrees less than reality. When I scaled back my cranking pulse widths to adjust, its starts much better. How do I fix my intake temp readings? (the GM sensor is working fine, ohms are where they should be.)

I replaced my airdenfactor.inc, matfactor.inc, and thermfactor.inc files (megatune2.25/mtcfg/) with these:

https://www.miataturbo.net/forum/sho...51&postcount=7

What else do I need to do?