anyone total ignition advance on a 93 EFI Festiva?

[fujioko]

Hi,

I installed a Megasquirt II on my project car a few weeks ago. My car has a bone stock 1993 Festiva EFI engine in it. Some of you may remember this car its a 94 Mazda Miata with a Festy engine.

I plan on publishing all my instillation notes when I finish this project.

Anyway the car runs great but I'm still unsure about my ignition profile.

I have run an insane amount of advance (36* total) and no problems. I'm thinking I may have a problem with my ignition driver board or something. I'm told that I should be getting huge detonation at 36* total advance. I'm not really sure what to expect, but the engine runs fine.

This is sort of an odd question, but does anyone know the total advance the festy engine can take at like 4500 rpm?

Thanks

Jim

[KingFish]

Wish I had a answer for you Jim, but it sure is nice to see you back! Glad to hear the B3 is working out well, are you reaching you r MPG goals?

[Movin]

That depends on the calculated engine load and the air density - altitude.
At 4500 rpm it could be 28 btdc, or 48 btdc. It all depends on the calculated
load. I have no experience beyond this with what you are using, perhaps some
who use these aftermarket ecm's will chime in.

[fujioko]

Hi,

Thanks!

I have 15K miles on the car already. Its a blast to drive!

My best MPG yet was 43, but averaged 41 most of the time. No special driving, however results may vary.

So far I have gotten over 40 mpg with the megasquirt but my tune is still way off. The car runs great, but the megasquirt crowd don't think my tables are any good. I still have a lot of learning to do.

The MSII is wired exactly as in a Festiva. I'm not sure if anyone has MSII a 1.3 Festiva before I'll definitely keep this site updated.

I forgot to mention, The 1.3 in the Miata is almost bone stock. The only difference is I'm using a Miata CAS instead of a distributor. I have a custom circuit board to make the CAS function exactly like a Festiva distributor. The Megasquirt is set up as if it were firing a distributor. The circuit board converts the signal to drive the coil packs. So it's theoretically the same......

I'm thinking the custom circuit board may be cutting the megasquirt signal too soon and limiting my total advance.

Jim

[fujioko]

Good point, Here is what the car is doing....

I can go WOT 100% load at 16.5 AFR and 25-35* advance and 2000-3000 RPM and I don't get any detonation. This is apparently imposable and I tend to believe something odd is going on. I would have notice flaming pistons punching holes through the hood. its got me stumped.

[Movin]

You should be 40 to 44 at cruise for mileage based on my experience
but should drop quickly to 30 - 34 under acceleration, again, there are
those on here with these systems, probably more for performance
than mileage but maybe they will join in.

[Movin]

Good point, Here is what the car is doing....

I can go WOT 100% load at 16.5 AFR and 25-35* advance and 2000-3000 RPM and I don't get any detonation. This is apparently imposable and I tend to believe something odd is going on. I would have notice flaming pistons punching holes through the hood. its got me stumped.

At wide open that is lean,

[fujioko]

Yeah, I'm running a lean mixture in cruise. I'm doing this as a MPG project.

The car actually runs awesome when I go rich in the high 13-low 14's. Drove it for a few days like that for fun.

jim

[fujioko]

It getting late, I forgot to mention the car runs at 16-16.5 in cruise and currently under high loads I am running at 13.5 AFR.

When I was just setting up the system I did run it a bit leaner in the upper table but didn't like the idea. I never actually ran it with 16.5 AFR under 100% load like I previously said. Like I said it getting late.

Thanks for pointing that out!

jim

[fujioko]

You should be 40 to 44 at cruise for mileage based on my experience
but should drop quickly to 30 - 34 under acceleration, again, there are
those on here with these systems, probably more for performance
than mileage but maybe they will join in.

Ok, so total advance can be as high as 44*. I think I need to check out my ignition setup.

Thanks

Jim