Bob Rouleau

FWIW, I believe that all EGas cars have this feature. When you consider that you no longer control the engine directly, a safety feature which assumes that the engine has "run away" when the brakes are depressed while the engine is accelerating and the car is in gear is not a bad thing. If the ECU fails with WOT you're at the mercy of electrons. I believe that ALL E-Gas ECU's have this safeguard. It does make left foot braking impossible though and a friend of mine with a turbo had an exciting ride when he tried it in a corner. Instead of maintaining boost, his engine quit! Some experimentation showed that:

The car must be in gear
The clutch must be engaged
The engine must be developing power (i.e not coasting)
The brakes must be applied

It seems to take a few seconds for the fail-safe to engage. It is not instantly invoked.

It does not effect heel and toe since the clutch is depressed, nor does it affect sitting still and blipping the engine in neutral or with the clutch depressed

Marco Polo

Bob, that was not my experience. Granted, I was not under hard acceleration, but I was holding speed when I applied the brakes. The vehicle speed dropped so quickly (and I am not practiced at using my left foot on the brakes), that I suspected the brakes simply over-powered the light throttle. So, I repeated the test several times, adding anticipatory throttle: same result. And, after getting off of the brake pedal, there is a beat of pause and the engine speed comes back up.

twisted

To look at this even further, Porsche built and designed this car for the track. So when one tries to left foot brake the car or to check the brakes going down the main straight on a track, instead of maintaining rpm and power the DME cuts fuel and engine timing, so when you get back on the gas or should I say when the DME allows the return of fuel the DME has to start over at some point with the timing program also. So in the long run we loose out on even more performance, we loose out on rpm, fuel and engine timing. What a joke!

Bob Rouleau

Twisted -

You can go very fast without left foot braking after all. It's more of a nuisance on a turbo than a GT3. It would be nice if there was a "delete EGAS" option though. EGas is made necessary by traction control (PSM) which the GT2 and 3 do not have.

Karl S

I think e-gas is needed more for emissions and maybe a little for fuel mileage than anything. The Cup car doesn't use e-gas, so it's not like PAG doesn't make the mechanical parts any more.

Karl

Viken

Correct. This is the primary reason for e-gas on today's vehicles.

Bob Rouleau

Viken,

I am intrigued. While I am sure there are some emissions benefits by having the ECU control the colume of air and gas to the engine, how would you build a PSM system with a mechanical linkage to the throttle body?

I recall reading that the engine cut off was a safety feature to prevent "unintended acceleration" if the ECU screws up. That made sense to me since control of the throttle is a micrcontroller with embedded software. Thank gawd it isn't Windows!

Karl S

I confirmed today with a UK owner that the ROW GT3s do not have the throttle cut out when left foot braking, so this "feature" is clearly there on NA cars for emissions and gas mileage, not safety.

Karl

mds

twisted's sources suggested an approach worth considering. Play with the wires from the brake and clutch pedal switches to the computer. For example, rewire so that brake pressure also activates the clutch switch. Or something similar.

M758

I have been reading this Egas thread with interest. I don't have the money for a GT3, but enjoy reading your stories

Anyway my 2001 VW GTI (1.8L Turbo) has an electronic throttle and I figured I'd give this left foot thing a try.

Well here is what I learned.

1) Light braking with throttle applied as no impact. Full or part throttle it still works.

2) Hard braking (short duration) no impact. Again the throttle was active.

3) Hard Braking (Long Durtion) Throttle shut down and stays inactive will brake applied. Even when you pull the brake unless you pull your foot off the throttle is also dead.

So it seems to me that is "feature" is safety thing just as Bob proposed. It is an emergency "oh ****" response for run away throttle.

Not sure if it Mandated by the US or is something car Mfg applied for their own safty from potential lawsuits, etc.

It does seem like its part of a program and I'd bet some one can crack that code and change the parameters to allow usefull left foot braking.