Tuning in the 21st century - Tuning experts inside please!

[ForceFed70]

The megasquirt EFI conversion is coming along nicely. The ECU is built and I'm currently in the process of doing the installation into the car.

I would like your input on some of my tuning settings for initial startup and testing.

Please take a look at the attached tuning tables and let me know what you think.

Note:
The scale on the left is in Kilopascals... it's a measurement of vacum. 100kpa would be no vacum thus indicating full throttle. 0-15Kpa would be a near vacum and would be rarely seen..only on decelaration...maybe. You could basically look at it as throttle %. 100kpa being full throttle, 0 kpa being no throttle.

 

[ForceFed70]

here's the target Air Fuel ratio table. I've been told that "all bets are off at idle". Meaning it's hard to tell what AFR you'll want at idle.

What do you think?

 

[ForceFed70]

Here's the ignition advance table:

Don't worry about the multiple 100kpa and 5200rpm entries. I imported this table from an older version of megasquirt.. the new version (MSII) has a larger table for better resolution. I plan on fixing it once I have a good idea of what I want my advance to be.

 

[ForceFed70]

And here's the cold start advance table:

 

[ForceFed70]

So what do you guys think? The closer I can get these settings now, the less tuning time I'll have to spend later. Thanks.

 

[351carlo]

You're waiting an awful long time to put full timing into the motor. Personally I would shift my full timing over at least 1000 rpm on full throttle (assuming this to be the 90-100 range) and make it a more gradual increase right off idle.

Think about how soon a mechanical distributor comes in. By 3200 RPM I'm at full timing.

Other than that, cool stuff.

 

[ForceFed70]

You're waiting an awful long time to put full timing into the motor. Personally I would shift my full timing over at least 1000 rpm on full throttle (assuming this to be the 90-100 range) and make it a more gradual increase right off idle.

Think about how soon a mechanical distributor comes in. By 3200 RPM I'm at full timing.

Other than that, cool stuff.

Hmmm... your probably right. Think I'll change it so that full timing comes in a little quicker. I keep wanting to say "mechanical advance" but that's obviously the wrong terminology.

 

[Bullitt]

at the upper end of the map, specifically like say below half throttle at the top of the RPM range you're going to want to start cutting timing and fuel significantly. basically you want the engine to reduce in RPM when you let off, but if you keep full timing and such it's going to want to "stick".

i also think you're too rich most places. basically you want to be near optimum "power" fuel ratio at like 75-80% throttle and above and below that you can be significantly leaner.

let me dig through some of the old FSAE stuff i've got and see if i can you get our AFR plot...

 

[ForceFed70]

at the upper end of the map, specifically like say below half throttle at the top of the RPM range you're going to want to start cutting timing and fuel significantly. basically you want the engine to reduce in RPM when you let off, but if you keep full timing and such it's going to want to "stick".

i also think you're too rich most places. basically you want to be near optimum "power" fuel ratio at like 75-80% throttle and above and below that you can be significantly leaner.

let me dig through some of the old FSAE stuff i've got and see if i can you get our AFR plot...

Hmmm... I basically set everything up so that during "cruise" it would be lean. And everywhere else to be rich (but blended between the 2)

I cruise at approx 2000-3000rpm.

Everywhere else, I was told it's a good idea to keep it a little rich for optimal throttle responce/performace. Since the engine doesn't spend alot of time in these scenario's (high vacum AND high RPM) the impact to fuel economy should be minimal.

But I do agree... the table looks like I'm rich most of the time. I'll sit down and take a closer look.

I wasn't aware that the timing/afr made a difference when it came to how quickly the engine "revs down". I figured that the throttle plate controlling the amount of air entering the engine was the only factor.