Thread: Why I tune to 12.0:1 A/F ratio (0.82 lambda) and why you should too. (all welcome)

I would like to ad that every setup its diferent ad it will act diferent small turbos big turbos.. fmics fuel types etc.
cheers.

I don't like a lean misfire, but I idle around 16:1 and don't have any issues. I live at high elevation with extremes in temperature in both directions. Over 100* in the summer. Below 0 in the winter.

To each his own I guess. I like to keep things conservative, hence I use the JWT computer. I make only minor adjustments to the fueling and timing. The best way to tune is to find out the threshold for the motor. Once you know where it detonates, you can back it off and make it conservative for all conditions. If you don't know where you are going to knock at, you may be leaving a lot on the table tuning-wise.

^^ Of course you wont notice any lean misfire because the low lobe on you cams doesnt have overlap.... Neither jpsr20det because he was running stock cams
But try to run that lean on a set of Tomei 270 cams jejeje..

I have only worked with the 4g63 dohc engine. Many have made high 400-low 500hp on stock engines, still running as much as 20 degrees of timing, at 11.6 or so afr. They all ran 100 octane in them for the high boost tunes. The boost comes on much stronger with the extra timing, than with less fuel.It is proven to work this way.

I know it is more complicated than this, but I'm not smart enough to elaborate anymore in terms I understand.

How many miles does it take for this to take effect? I have seen many factory tunes that go deep in the 12's on N/A cars. Almost in the 10's on boosted cars, with factory settings. These cars often times can last hundreds of thousands of miles if properly maintained.

Just curious!!

Very good reasoning, I like it. Keep it comming.

Very solid point.

Anything else?

I'm not familiar enough with stock tunes to add anything useful. I know somewhere around 12.8:1 tends to get most power N/A. I'm only familiar with one factory tune. From what I now, the BMW e30 325is starts around 14.3:1 peaking at 15.0:1 at torque peak and then going to 14.5:1 by redline (this is all at WOT). I know this goes against everything you've ever learned, or thought you learned. Maybe it was a bad reading that day on the dyno. I don't know, I wasn't there.

People always say our factory tune is too conservative N/A. Too rich. I don't know, I've never measured a stock SR20DE fuel delivery curve.

I'd love to see what sort of ratios some stock turbo cars are running. Something tells me it's a lot leaner than you think.

If I'm wrong, and it's real rich then I would concede that engine life and engine part failure is not something to be too worried about. Personally I don't run into cars running rich for long, or often. I usually try to lean it out if I have any say in the matter. Friends don't let friends run pig rich around here.

I've seen one car with a dead wideband that was a result of running rich for a couple of weeks. We were able to rescue it by driving around hot and lean for a night, but we got lucky.

I know I haven't exactly answered the questions asked, but I don't have enough experience right now to answer them.

JAJAJAJAJA ^^^^^Exactly if you check a factory Nissan Turbo tune you will say wow the wideband doesnt even read LOL the come runnin on 10's afr at WOT... and in All Motor cars I have seen 11.9 on nissan factory ECU and they come like that from factory and they dont damage any parts..........

Yes, they do. It's just acceptable to Nissan and most people. I prefer to be better than that.

Then you will learn the hard way