Has anyone noticed that if you push the brake pedal while also on the gas the gas shuts off? Do any of the after-market ECU programs change this?
I dont like the stock program because there are times I like to tap the brakes while on the throttle. On the track it is nice to confirm brake pressure prior to a brake zone. Also, it's nice to be able to smoothly overlap gas and brakes while left foot braking. On the street, when someone is tail gating I like to be able to give a 'head fake' by flashing the brake lights while staying on the gas.
Not so. I heel toe and I get gas and brake at the same time. Maybe you are feeling the little delay in the throttle?
it's not a delay. I also heal/toe. but that is a good point - Julianchan. The issue exists only when you dont also have the clutch depressed.
Orton (and possibly others) have an ECU flash that "corrects" the behaviour you mentioned.
DL
Interesting thing about the clucth. Learn something new each day.
I could not reproduce this effect this morning. I was cruising in third gear at about 3000 rpm. While on the gas, I pressed the brake and the car slowed down as expected but the engine was still under load which meant that "gas" was still being applied.
I'll try again on my way home but am I missing something here? Greg, are you at VERY low rpm when you do this? I know on Hondas, the fuel is cut off below a certain rpm and manifold vacuum conditions. I'm sure it is common ECU practice these days. However, I don't think anyone should be driving the car below 1000 rpm.
Hummm. I'm suprised that it didnt do it for you. I experienced it usually above 3K. when the ice melts here I will try it some more and see if RPM or gear is a factor.
Maybe you were pumping the brakes as opposed to tapping which made the car think you want an abrupt stop?
Okay, I think I reproduced what Greg was describing.
When at constant throttle, say at 3000 rpm, and you depress the brake pedal the rpm's and speed will drop as expected while the engine loads up. Let's say the RPM's drop to 2500rpm when you apply the brake (gas pedal has not moved from original position). When you release the brake, the rpm and speed remain the same and does not accelerate back up even though the gas pedal position has not changed.
It's like the throttle plate closes with reduction in RPM and then "re-associates" itself to the gas pedal position.
I can think of several reasons why it does this and how it might even improve the left foot braking technique if we can relearn the skill. However, to me, this is more of a curiosity and doesn't effect how I drive the car. It doesn't seem to effect the heel-toe technique and I don't left foot brake on the street.
Good find.
This is a safety mechanism that prevents you from driving with both feet. Most cars with e-gas have this. Sport Chrono turns this safety off when in Sport mode, one of the reasons so many people find it easier to heel toe with SC.
This is a characteristic of all cars with Bosch Drive By Wire fuel injection. If you simultaneously press the gas and the brake for a set amount of time, the throttle body will close. The feeling will be a loss of acceleration.
Go find and open parking lot and keep the accelerator at a constant spot.
Next
, apply the brakes without lifting your right foot. Keep dragging the brakes. The car will begin to lose significant power.
I have yet to hear to hear of an aftermarket tuner turning this off in their programming. I'm sure it can be done. I'm just stating that I have never heard of anyone actually doing it.
I have a friend that runs a Porsche in Grand-Am. He told me a way that his race engineer defeated it. Tough to left foot brake with this feature...
I have yet to try it. This post will motivate me to do so.
I will keep everyone posted.
So this means that BMW story could never happen to our cars? Wonder if that BMW had bosch as well.
Thanks Mike! I look forward to hearing abour your progress on this.
Yes this has been covered before somewhere.
If you are in gear, in motion, with the throttle partially down and then cover the brake peddle for over 1 second, the throttle cuts. At this point, whilst holding the brake on you can push the throttle to the floor with zero effect. Once you release the brake the throttle will activate as normal. If you release the brake with the throttle to the floor, you will jump to maximum acceleration.
However, if you hit the brake first (as in heal-toe) then hit the throttle, the throttle acts as normal, hence being able to blip the throttle with the brake on.
The thing is, if you have throttle, and then tap the brake with the left foot it does not effect or switch off the throttle. It only has effect if you hold the brake for a second.
Jack
