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      06-12-2011, 11:18 AM   #1
2fast_on4
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Heel and Toe problem

I would like some opinions on the following subject/problem:

My cars' throttle does not respond when the brakes pedal is pressed.
In normal driving this does not pose a problem, but during spirited driving it does not allow for heel/toe technique to be used. I think that this is just wrong for a car of this type.

Is it only my car, or not? Should I check it out with the BMW garage? It has been like that since I bought it new.

Thanks a lot!
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      06-12-2011, 11:35 AM   #2
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sounds like you just aren't pushing it far enough
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      06-12-2011, 11:49 AM   #3
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it isn't technically and specifically heel-toe per say, more like toe-wrapped foot, cos of the design and position of the brake and accelerator pedals. use the top left side of ur right foot to hold brake pressure while wrapping the right side of ur right foot around and tapping the accelerator pedal. of course ur left foot is depressing and releasing the clutch as required. works a charm for me after a bit of practice and it might initially help to have the sport button pressed to improve throttle, and hence accelerator pedal, sensitivity.
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      06-12-2011, 12:44 PM   #4
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Thanks for the replies so far, but I think I should be more clear on the problem:
When the brake pedal is pressed, the gas pedal is dead. For example, when the car is stopped and I press the brake with the left foot, the gas pedal has no effect even if I press it all the way down. The same applies when the car is moving and I am trying to heel/toe.
From what I can understand by your answers, this is probably not normal.
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      06-12-2011, 01:59 PM   #5
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Quote:
Originally Posted by 2fast_on4 View Post
Thanks for the replies so far, but I think I should be more clear on the problem:
When the brake pedal is pressed, the gas pedal is dead. For example, when the car is stopped and I press the brake with the left foot, the gas pedal has no effect even if I press it all the way down. The same applies when the car is moving and I am trying to heel/toe.
From what I can understand by your answers, this is probably not normal.
This is not normal.
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      06-12-2011, 02:31 PM   #6
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^ +1
definitely not normal
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      06-13-2011, 04:18 AM   #7
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^+2

better get ur car checked out man
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      06-13-2011, 05:20 AM   #8
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drive by wire is stupid on these cars
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      06-13-2011, 07:02 AM   #9
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Drive by wire should not exist on sports cars (some would say that I am not very eco friendly )...
Nevertheless, probably the car has a problem there and I will check it out immediately. I hope that I will be able to sort it out with my mechanic.
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      06-19-2011, 07:19 PM   #10
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Holy crap, this issue would scare the shit out of me on track

+3 on this not being normal at all whatsoever. Get it fixed ASAP! >_<
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      06-21-2011, 06:00 AM   #11
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yeah that's weird. definitively get it looked at.

once you get it fixed...as far as technique there isn't enough room to use your heel. you'll need to use the outside of your right foot.

check out Aryton Senna's foot work going around Suzuka

http://www.youtube.com/watch?v=8By2AEsGAhU
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      06-21-2011, 09:22 AM   #12
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Quote:
Originally Posted by spurto View Post
yeah that's weird. definitively get it looked at.

once you get it fixed...as far as technique there isn't enough room to use your heel. you'll need to use the outside of your right foot.

check out Aryton Senna's foot work going around Suzuka

http://www.youtube.com/watch?v=8By2AEsGAhU
Thats how I've been doing it since I started driving.

A little hard getting used to the z4m compared to the e36m, but all cars are different.
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      06-21-2011, 02:44 PM   #13
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Quote:
Originally Posted by spurto View Post
yeah that's weird. definitively get it looked at.

once you get it fixed...as far as technique there isn't enough room to use your heel. you'll need to use the outside of your right foot.

check out Aryton Senna's foot work going around Suzuka

http://www.youtube.com/watch?v=8By2AEsGAhU
The guy sure knows how to drive... Great loss.
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      06-21-2011, 08:36 PM   #14
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Does anyone know if there's a way to either...
1) raise the static height of the brake pedal?
or
2) lower the static height of the throttle pedal?

Because even with toe-toe application (as opposed to heel-toe), I still find it rather annoying on track, especially if I'm already braking quite hard, and need to stay on the brakes decently hard. But the throttle is too high at this point to roll my foot around.

^ Hope that made any sense?
Basically my brake pedal is too far down towards the floorboard to roll my right foot around and reach the throttle pedal with enough control to perfectly blip every single time
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      06-22-2011, 01:16 AM   #15
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1) bolt a block of 2x4 to the brake pedal.

2) No.

I'm going to suggest that all your heel-toe ills can be cured by adjusting your driving style. Do your blips earlier in the braking zone, in fact as soon as you start braking you should be blipping and downshifting on the MZ4.

As to the OP's question, look at the Toyota unintended acceleration issues. Almost all modern BMWs with electronic drive-by-wire throttle will disengage the gas pedal commands when the brakes are fully engaged. Disclaimer: I haven't tried this, but in theory when you are standing still with the brakes pressed the accelerator will only allow you to rev up to ~2,000 RPM.

However I have not found this to interfer with heel-toe at all, even with California Speedway requiring a 2 gear downshift (3 if I feel frisky) and a 120+ down to ~45 mph scrub. IF I'm not mistaken, and I rarely am mistaken, the throttle overide only comes on when the brake pedal is pushed past a certain point, like when you're trying to punch the brakes through the floor in a panic when the car is accelerating out of control.
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      06-22-2011, 02:39 AM   #16
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Quote:
Originally Posted by The HACK View Post
1) bolt a block of 2x4 to the brake pedal.

2) No.
I'm not sure if you were trying to be funny, or if you were mocking me, but I don't quite appreciate this as a precursor to my serious question/concern...
Not sure why you would even post such a thing? I hope you were just joking....

Anyway......

Perhaps it only pertains to turn 2 @ Laguna Seca (since that's all I've ever "run hard"), but I come down the slight left-hand turn 1 bank coming into the Andretti hairpin in 4th gear, and usually downshift to 3rd.
I feel that there's no way I can blip for the downshift immediately after I start braking in the braking zone, because the engine would over-rev going down into 3rd. I therefore, usually start braking relatively early (not wanting to lock up the wheels) and brake a bit longer, then go for the downshift, immediately followed by the turn (while still trail-braking slightly). And this is exactly where I'm having some issues in terms of the heel-toe (or rather, toe-toe). Because again, at this point, my throttle pedal is "higher" off of the floorboard in contrast to the brake pedal, which is depressed quite a bit and is closer to the floorboard. Any advice?

Also, I don't believe the tidbit about there being a throttle rev limiter when applying the brakes from a standstill. Not sure about the extreme case that you mentioned though, when applying the brake pedal past a certain point while the car is accelerating out of control, etc.

Last edited by mfanatic325; 06-22-2011 at 03:19 AM..
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      06-22-2011, 03:09 AM   #17
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I'm about as serious as I ever am on teh intarweb. I've seen racers alter their brake pedals by welding a block of iron or bolting on a thick aluminum extension to artificially "raise" the brake pedal a few inches. Not the most elegant solution but it works. Don't be afraid to try it.

As far as blipping at the beginning of the brake zone and over-revving it...If you are indeed bouncing off of the limiter as you blip and downshift then you are over blipping your throttle anyway. The point of heel and toe downshift is to match the amount of deceleration to the next lower numerical gear's multiplication, therefore if you were to execute the blip and downshift at the beginning of the braking zone, you wouldn't have to blip as hard and you will only be in your first 1/3rd of your brake pedal travel making modulating the throttle easier. The typical mistakes I see when learning how to heel and toe is waiting until the end of braking zone to do the downshift since by then your RPM would have dropped too much and your foot already buried on the brakes to effectively blip the throttle, and it requires a much larger "blip" to accomplish the increase in RPM needed to account for the large discrepancy in road speed/deceleration and gear multiplication.

That, and by completing your downshifts earlier it gives you an opportunity to concentrate on the end of braking, the part where you have to taper off and transition to turn-in as smoothly as possible in order to apply throttle as early as possible, in order to go fast.

This is the sort of thing that having a professional coach or an instructor willing to sit in the passenger seat that EVERY driver will benefit from. I never pass up the opportunity to take an instructor buddy out to critique my driving nor do I pass up the opportunity to ride with another instructor to learn what they're doing plus offer them some pointers of my own.

And I would suggest watching some pro in-car videos and listen to the engine note at Laguna Seca. I'll venture to guess that they almost always start their downshifts right after they start their braking, even for the hairpin. Not saying that I believe we are all skilled enough to do what they do, but as far as "best practices" for track driving is concerned, it never hurts to see what the people who gets paid to do what they do best, do.
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      06-22-2011, 03:13 AM   #18
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P.s.: If my suggestions offend you, I highly recommend you put me on ignore. Because in my 12+ years of posting random rants on various car related forums I haven't found it within me to change the way I post...

Which is to say that the Republican party will have a better chance of winning the black vote against Obama than me warming up my cynical ways.
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      06-22-2011, 03:46 AM   #19
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I'm glad we're still on good terms!
That explanation/advice was more along the lines of what I was looking/hoping for and I appreciate your input. I just had to ask for sure whether or not you were trying to insult my intelligence lol because you never know these days with the "intrawebz". No facial emotions to read off of, nor tones, etc.

Quote:
Originally Posted by The HACK View Post
If you are indeed bouncing off of the limiter as you blip and downshift then you are over blipping your throttle anyway. The point of heel and toe downshift is to match the amount of deceleration to the next lower numerical gear's multiplication
this I already know...otherwise I wouldn't be able to pull off halfway decent/respectable times @ Laguna, now would I?

So anyhow, it looks like my problem/issue is braking for too long before I initiate my downshifts. Or rather, I'm taking the term "blipping" the throttle a tad bit too literally, and am therefore looking for a larger change in RPMs between shifts. When instead, I should be aiming to initiate my downshifts a tad bit sooner (clutch out sooner, blip less but sooner, make my gearshifts sooner, and clutch out sooner rather than later) and then continue trail-breaking if need be, all while smoothly engaging/committing to the hairpin or turn.

Last edited by mfanatic325; 06-22-2011 at 03:53 AM..
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      06-22-2011, 11:18 AM   #20
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Sorta OT, but when you blip, is the clutch pedal out or in?

I usually pull the shifter out of gear without putting the clutch in, blip, then clutch and downshift.
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      06-22-2011, 11:27 AM   #21
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I don't understand why you pull it out of gear w/o clutching?
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      06-22-2011, 11:39 AM   #22
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Quote:
Originally Posted by The HACK View Post
As far as blipping at the beginning of the brake zone and over-revving it...If you are indeed bouncing off of the limiter as you blip and downshift then you are over blipping your throttle anyway. The point of heel and toe downshift is to match the amount of deceleration to the next lower numerical gear's multiplication, therefore if you were to execute the blip and downshift at the beginning of the braking zone, you wouldn't have to blip as hard and you will only be in your first 1/3rd of your brake pedal travel making modulating the throttle easier. The typical mistakes I see when learning how to heel and toe is waiting until the end of braking zone to do the downshift since by then your RPM would have dropped too much and your foot already buried on the brakes to effectively blip the throttle, and it requires a much larger "blip" to accomplish the increase in RPM needed to account for the large discrepancy in road speed/deceleration and gear multiplication.

That, and by completing your downshifts earlier it gives you an opportunity to concentrate on the end of braking, the part where you have to taper off and transition to turn-in as smoothly as possible in order to apply throttle as early as possible, in order to go fast.
Thanks Hack. I actually do what you recommend ("blipping" as I start braking), but I was having some second guesses as to whether I should wait until later in the braking cycle. I will keep working to refine/improve my blipping at the early point (practice practice practice). And yes, my instructor had me doing it "the right way"....but hearing it again here helps reinforce that.
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