rich = advanced?

[kapowered]

Does a rich mixture cause the computer to advance the ignition timing? Just wondering.

[Jeff240sx]

Nope. The mixture is as stoichic as possible, measured with the MAF, injectors and afc.
The ecu will advance the timing up a little, based on octane and a few other things. Not air/fuel ratio.
-Jeff

[d240t2]

ECU doesn't know octane. ECU only retards timing if it senses knock...it doesn't advance it further if it thinks you have really good gas. Timing is only a function of TPS voltage, MAF voltage, and RPM.

Also, the KA knock sensor is crap. The stock ECU ignores it after 5k rpm anyways...since the motor is so noisy. JWT makes the ECU ignore it completely in their larger injector programs, like the one for my car, with 50lb injectors. They figure that if you need that big of injectors...you are making a lot more power, and a lot more noise...and since the knock sensor is useless anyways, they might as well get rid of the function so they don't have to worry about if the ECU is retarding timing or not, due to knock.

Dennis

[Jeff240sx]

Yea. That's what my whole octane post was about. Knocking. Since the timing on my s14 is really advanced (hence, the manual recommending premium fuel only), it would have to retard due to knocking if someone put lesser fuel in. I really knew what I was talking about.. it just didn't come out right
Anyway.. thanks for enlightening me about the JWT ecu and 5k tho!
-Jeff

[d240t2]

Ignoring the knock sensor at 5K and above is a stock ECU thing...just to make sure you understood that. Some JWT ECUs don't ignore the knock sensor (like mine does) although they still ignore it above 5K. The ECU will also retard timing if it senses a fault in the knock sensor circuit. Only more recently (Summer '01) did JWT figure out how to get rid of that stuff, too, according to Clark. My ECU (Nov 01) ignores the whole knock sensor circuit...so one day, when I get the urge, I'll remove my knock sensor (dead weight) altogether.

Dennis

[moose]

you can tune it though. If your running a higher octane gas, you can program the computer to advance the ignition timing. It's been done.

[d240t2]

you can tune it though. If your running a higher octane gas, you can program the computer to advance the ignition timing. It's been done.

Or you can just advance the distributor. You'd be hard pressed to see more than 5whp gain from this mod though. You can gain more with a standard JWT reprogrammed ECU...but more like 8whp is probable.

Dennis