Left foot braking and PSM

[Loonycat]

I wonder if you guys can help me with a PSM issue I'm trying to overcome. Paranoid as I am about rusting dics on my 996 C4S I give it a run up and down the local main road after washing the car to warm the brakes. But here is what happens:
1. 40mph in a straight line in 3rd gear
2. Swing left foot over to lightly drag the brakes and try and generate some heat under power
3. Engine cuts out, slow to crawl
4. End up lifting off brake, floor throttle then brake, floor throttle then brake (repeat until traffic light)

Is it PSM spoiling my left foot braking efforts? Why? Surely anyone going quick would like the option to steady the car with a touch of left foot braking while under power? I tried to switch off PSM but it still did it.

Appreciate any thoughts. Or alternatively any covert ideas as to how to keep the discs dry when washing!

Cheers
Loony

[johnfm]

Your answer lies in the wonders of e-gas

[Loonycat]

Hey John - thanks for that. Just did a search and have found that e-gas is some Bosch fuel management function to limit fuel wastage depending on the conditions. So I expect its simple brain thinks braking means no fuel required.

Cr*p! Any way to override it or am I stuffed?

Looks like I'm going to have to become more proficient at the floor throttle / brake heavily school of disc drying....

[DanH]

You can trick it, but I've forgotten how. Think you have to initiate braking come off the throttle fully and then apply it again.

[Don]

Chaps - I do this precise thing in my 986BoxS. Left foot gently on brake, gentle throttle to keep the car moving.

I can't remember how long I can do this for - I'll have to go out and try it today and see what happens. I'll also do that lift-mash throttle into carpet thing whilst braking to see if that works...

Very interesting.

[gfreeman]

Easy solution??? Buy a GT3!

[Don]

Had a go at this...sure enough...after a few seconds the throttle died back.

Never really noticed it before! Live and learn etc...

[johnfm]

gfreeman said:

Easy solution??? Buy a GT3!

I think the MK2 may have had e-gas too - certainly the US models do. The MK1s had a good old fashioned throttle cable if I recall correctly!

[nbetts]

The early 996's... pre-glovebox I think, did not have e-gas. The model with the digital speedo in the right place...8-)

[willr]

See
Renntech

[Loonycat]

Cheers for the link Will - interesting discussion over on Renntech about this issue. They raise an interesting point that in blipping the throttle on downchange while braking the throttle works fine. E-gas apparently works after a delay of 1.5 seconds so allows heel toe (noooo - please don't start 15 page thread at mention of this! You are all driving gods ok?) but doesn't allow sustained dragging of the brakes while under power.

I'm going to try getting off the throttle then back on again while braking to see if that works- one of the Renntech dudes thought this might be a winner. Will try it tomorrow after the car gets a bath.

Flippin electronics....

[Loonycat]

Just tried this again today after washing the car and Dan you are right. Initiate braking, accelerate then come off the throttle and back on again. If you've kept the brake engaged you fool e-gas and it lets you accelerate while dragging the brakes. I went up and down Bayswater Road for a few times in 3rd gear with a reasonable pressure on the brake pedal (must have made the traffic behind me nice and confused). Not much good for the pads but it did clean the discs up beautifully - they had a film of rust on them. So discs are back in good shape (I think) and the car is sparkling again with its 3 coats of Zymol - lot of effort to put it on right but worth it.

On a side note I was behind an identical atlas grey C4S for much of the way and I have to say the turbo body 996s do look much more aggressive than the 997s from the back IMHO, especially from low down. They weren't kidding when they called them wide bodies 911s !