I'm hatching an idea.....Do you hate heel and toe? Purists, don't read this!

[Heywood-Yablowme]

Interesting...I am not using HPtuners...yet.Was waiting on the Harropp before jumping into that .....one step at a time.

[silver]

just to be clear also...................both Eddie's and my atom's last time we went to the local track (to me) had problems with the ecu / throttle seeing out of whack information and in talking to Darth he explained that the ecu (blank cobalt one) could be programmed so that the minimum rpm for that limp mode code was abover the operating rpm of the motor thus rendering it useless...which should be done on the atom so that you don't go into limp mode ever, as it has almost gotten me into danger a few times.

[bolus]

of course the only problem with that is if the throttle decides to stick wide open.  hopefully there isn't a brick house in front of you at the time

[Heywood-Yablowme]

Just put the clutch in...

In the course of my many years behind the wheel of lots of cars...I have experienced at least a dozen stuck throttles,and never had an instance to panic. You pop the car in neutral if automatic,or declutch.

Once was with a '42 Chevy big block,dual carbs on top of a 10-71 supercharger. The owner had rigged up a fake flapper to open on his intake scoop.I must have been the first poor slob to put that thing to the floor, as that link to the flapper fell out,and down,jamming the throttle wide open   A few seconds of tire smoke more than I had expected,and I managed to click it into neutral,where it bounced off the limiter till I hit the key. I did have to change my undies after that one...

[silver]

[quote="bolus"]
of course the only problem with that is if the throttle decides to stick wide open.  hopefully there isn't a brick house in front of you at the time
[/quote]

or just flick the ignition switch to off........or put it in nuetral...or just push the clutch in at least there's still 3 ways to save yourself.

personally i think I'd just hit the ignition switch............it's not like you're going to lose your power steering or power brakes.

[bolus]

[quote="unknown"]
Just put the clutch in...
[/quote]

My limp mode is turned off to so I take the same risk.  I just wonder sometime if I could react fast enough (you know 0-60 in 2.x seconds) to save the car in time. 

[silver]

well who is saying that this specific limp mode would even kick in if your throttle was stuck wide open.........from my experience, this has never gone into limp mode under full throttle only under initial throttle it instantly goes into limp mode

[bolus]

pedal position vs throttle position is compared.  If the throttle is wide open and the pedal is not depressed it causes the limp mode.  it usually kicks in at what 3000 rpm?  now it wont kick in to 8000 rpm

[silver]

I can say that every time mine has kicked into limp mode it's been just above idle.....such as start the car, let it idle, as soon as you depress the accelerator (not even hard) the ECU kicks into limp mode.

I have never had this occur under heavy throttle

so what your saying is that 1 part thinks the car should be at full throttle and the other part sees that you've barely pushed the pedal in, therefore it's a mismatch and it goes into limp mode.

is that the gist of it.

[Terry Kennedy]

[quote="silver"]
so what your saying is that 1 part thinks the car should be at full throttle and the other part sees that you've barely pushed the pedal in, therefore it's a mismatch and it goes into limp mode.

is that the gist of it.
[/quote]

There are at least two different parts to this:

1) As the accelerator pedal is depressed, one signal goes up and one goes down by the same amount. If this isn't seen, you get one type of fault.

2) The verified signal from the accelerator is compared to the position of the throttle and if there is a miscompare, you get a different fault.

[Alec]

[quote="silver"]
[quote="bolus"]
of course the only problem with that is if the throttle decides to stick wide open.  hopefully there isn't a brick house in front of you at the time
[/quote]

or just flick the ignition switch to off........or put it in nuetral...or just push the clutch in at least there's still 3 ways to save yourself.

personally i think I'd just hit the ignition switch............it's not like you're going to lose your power steering or power brakes.
[/quote]

Well my Honda engined 245 didn't go into limp mode when the throttle stuck open on the Alpine Tour.

I also think that if I'd used any of these suggestions then I wouldn't have made it round the next couple of bends I was faced with.

Killing power/drive to the rear wheels going into the first bend would have probably sent me into a spin and the drop on the right-hand side was unsurvivable, as was the rock face on the left.

Full throttle with my foot hard on the brakes resulted in what was basically a power slide, and managing to control it round the bends is probably what saved me.

Now if it had stuck on a straight road then I might have had time to think about doing one of those options.

[Heywood-Yablowme]

I don't follow you on putting the clutch in and causing a spin.There will be no engine braking and the car will be freewheeling.Clutch it and foot on the brake.No problems. Not the same as lifting mid corner...

[twebb]

There are systems out there that will allow for an automatic blip on downshift to match revs.  I think a number of folks are using one by Motec.

A simpler solution is to add a piece of metal to the throttle petal and design it so that the heel toe is easy to accomplish.  I sat in Kent Prather's MGA, 6 or 7 time National SCCA Champ, a few years back.  He had the same heel toe problems.  His solution was to add a piece of stout spring steel to the bottom of the throttle pedal that is shaped somewhat like an "L" except the leg faces to the left.  The left facing "L" extended perhaps half way between the throttle and the brake.

This allows for very little right to left movement of the right foot to aply both the brake and the throttle on downshift.  It was a very simple and elegant solution to a problem a lot of people have with the mechanics of blipping the throttle.

If it were easier to blip with a thumb mounted button, I imagine the racing world would have adopted this method a few years ago.

Cheers

[WorkingOnIt]

[quote="unknown"]
Just put the clutch in...
[/quote]

And your brakes still work.  During the "runaway" Audi  BS  in the 1980's, Car and Driver did a test where they compared stopping distance with throttle off and full open.  Full throttle stops from 80 mph were remarkably close to regular stopping distances.  (I seem to remember around 10 to 12% longer, but am not sure of the number.)

[Heywood-Yablowme]

I figured I could use my thumb throttle and give my foot a rest on those long sessions

I think the button will not be tollerated by the ecm,like Terry has mentioned. I will have to see what kind of signal/return is going on in that circuit,and if it can be manipulated.

Hmm...five wires....