What is stock m20b25 Air/Fuel Ratio???

[Aptyp]

Doing much research for my turbo project and haven't been able to find anything on this topic. I see everything from 11-13 and I'd like to be a little more certain as it makes a big difference.


Also, I've used generic equation for volumetric efficiency, does anyone have anything more specific? Did factory ever release all their notes on various m20 engines?

TIA, Art.

[LowR3V'in]

at wot? or what are we talking about here?

[Aptyp]

Well, it stays fairly the same throughout the range (I would hope) but at high rpms would be good.

[LowR3V'in]

http://forums.bimmerforums.com/forum/showthread.php?p=879968

There's a stock dyno with afr.


another one here.

http://www.e30tech.com/forum/showthread.php?t=67155

Just curious?

[Aptyp]

thanks man, that second link with pic before turbo was exactly what I was looking for

[nando]

this depends on engine load an RPM. You'd have to be more specific - say, what's the target AFR at 5000 rpm, 100% load? or, 1500rpm, 56% load? etc.

and anyway, using a VE calculation is nice, but you don't need to do that, there is nothing specific about the M20 that needs a special calculation. Just target 12.5-13:1 above 100kpa and you'll be fine. within a few percent of 13:1 is fine, you aren't really going to make a bit power difference with fuel, that comes from proper ignition advance.