Traction control

[Chris Conlon]

Christian Hack wrote:

> I am currently looking into a DIY TC system myself and someone
> mailed me and suggested a fly-by-wire system with a variable
> resistor on the pedal and say a fast enough stepper motor on
> the actual throttle. This would obviously make it real easy
> to shut the throttle. Would a stepper motor be fast enough
> do you think?

I had heard that the traction control on the NSX worked, in
part, via the ECU having the ability to close the throttle
plate somewhat. (They didn't say if it was 100% fly by wire,
if there was a second restrictor butterfly just for the ECU,
or if the ECU could "offset" the butterfly angle set by the
driver's foot.) Any more info on this type of fly by wire
system (in actual practice) would be greatly appreciated. I
can see needing this sort of thing down the road.

> Someone suggest dropping cylinders by stopping the injectors.
> Could there still be a small amount of fuel from previous cycles
> which would result in a very very lean mixture or is that
> unlikely to cause a problem?

Well, there probably will be some fuel left over, but if you
were running at 12.5:1 before you hit fuel cut, and fuel only
gets down to 25% of normal, that's still 50:1 afr. Even if it
did ignite, and somehow detonate, the total energy released
is roughly 1/4th of normal. In practice it'd be way less, and
not enough to ignite or damage anything if it did. This is my
opinion anyway. (FWIW I hit fuel cut almost daily, under boost.
No problems yet.)

   Chris C.