[roger albert]

Wow, Glad you started this thread D.C.

Steve, that was one ass-kickin' post. Great info. I know testing and documenting and then reporting all of that stuff takes a fair amount of time, but besides you're own edification, please know it's appreciated. Except for the mufflers and filter, that's the exact setup I'm about to have. That would imply I'll want something around stage 4 and will have to play with the Lamda sensor to see what happens. Anyway, thanks.

Back to D.C.s question. The way most engine controllers work, is that when a sensor is detected as failing or disconnected, the computer substitutes a fixed value. On most systems this limp-mode is on the rich side (though my stupid '86 Audi is on the lean side and sucks - corrected by Audi in '87, btw) Anyway, it would seem that dumping the sensor put's this particular ECU into a pretty rich mode. The minus is of course very likely worse economy, but probably not bad if you're correspondingly light on the throttle. Though you're still getting the rev limiter and ignition curve advantages of the BBPower chip, you've essentially thrown away the fuel mapping benefits.

The question in my mind is, where is the limp -home/failed-sensor fixed fuel value stored (probably the ROM) and if so, is that assumed value different for the BBP than the stock chip (i.e would pulling the lambda have more, less, or the same effect on ECUS that are stock vs BBPower fitted) ?

Anyone know?

later
roger