| Author |
Message |
Joel Belser (Driver)
New member
Username: Driver
Post Number: 18
Registered: 9-2002
| | Posted on Monday, December 02, 2002 - 4:58 pm: | |
The "neutral" that you get when depressing the clutch pedal is not the same "neutral" as when the gear lever is in neutral and your foot is off the clutch pedal. Blipping the throttle when the pedal is depressed may sound the same as a double clutch, but your transmission knows the difference. Most high perf. cars are set up so that you can brake with the ball of your right foot while hitting the accelerator with the heel. If you match rpm's perfectly, you do not need the clutch at all! I use the clutch...Some of the older Ferrari racecars are set up with a central gas pedal, to take advantage of the natural splaying of the feet. Heel and toe as done now requires a strange foot twist, but well worth the effort, especially on the track. |
Hans E. Hansen (4re_gt4)
Member
Username: 4re_gt4
Post Number: 623
Registered: 4-2002
| | Posted on Monday, December 02, 2002 - 4:07 pm: | |
Mitch: Actually, in Corvettes I'm able to turn my right foot inward, ball of foot on brake, and 'general heel area' on gas. This method seems more forgiving of pedal height variations, where as with the 'GT4, the pedals have to be accurately placed, height-wise. I've driven other 'GT4s where the brake was too low when pressed, and with my knees-out position, made blipping the throttle impossible. Fortunately, my car fits me well. |
Mitch Alsup (Mitch_alsup)
Junior Member
Username: Mitch_alsup
Post Number: 237
Registered: 4-2002
| | Posted on Monday, December 02, 2002 - 12:32 pm: | |
Although known as Heel&Toe, on modern cars with normal pedal positions, it is more of "big-toe on brake" with "right side of foot on gas", or even "little toe(s) on gas". Heel and Toe give one the mental image of a verticle actualtion between brakes and gas, while big-toe and little-toe gives mental image of a horizontal actualtion. When I heel and toe, my heel stays in one place while I articulate the upper right side of the foot on the gas pedal, while holding the toe on the brake.
Double de-clutching is a means to reduce the wear on the synchronizers, and to see if you left foot has forgotten how to move quickly. ITs really a mental challange more than a necessity in modern cars--but who really wants to drop the tranny for a rebuild? |
Hans E. Hansen (4re_gt4)
Member
Username: 4re_gt4
Post Number: 613
Registered: 4-2002
| | Posted on Sunday, December 01, 2002 - 10:07 pm: | |
One problem with the dumb 'ole GT4 is that the seating position for a taller guy leaves you with "ball-of-foot and toe" (foot basically backward from the way it should be), as driving position is knees wide apart in a 'giving birth' manner.
Still easier than on most cars, tho. |
James Selevan (Jselevan)
Member
Username: Jselevan
Post Number: 260
Registered: 6-2002
| | Posted on Sunday, December 01, 2002 - 5:38 pm: | |
Peter - My experience is that when done correctly, double-clutching, as with any downshift, will contribute greatly to overall braking by introducing engine drag.
Those of us old enough to have grown up driving "Crash Boxes" like in my 1961 AH Sprite, double-clutching was an absolute necessity. Without synchonizers, one could not get to a lower gear without matching engine and secondary shaft speeds through the use of double-clutching.
When braking hard for a turn (standing on the brakes) in a car without vacuum assist, the only way to simultaneously get to a lower gear (with double-clutching) was with the "heel-toe" technique (left side of foot hard on the brakes while rocking the right side of foot on the throttle). This contributed to rear wheel braking (engine drag) AND, MOST IMPORTANT, set you up for exiting the turn in the appropriate lower gear.
Double-clutching with modern transmissions, I believe, is still warranted to preserve synchronizers (as Hans suggested). Synchronizers are friction devices, and the less they have to do, the less they wear. HOWEVER, as JRV suggests, if you are not proficient witht this technique, then you will likely do more harm than good.
Jim S. |
Graeme Parcher (Ferrarif355)
New member
Username: Ferrarif355
Post Number: 5
Registered: 11-2002
| | Posted on Friday, November 29, 2002 - 1:31 pm: | |
Wayne: We do actually celebrate Thanksgiving up here, but our's traditionally falls on the second weekend in October. Same event, turkey and all, just a different month.
Sounds like blipping the throttle is all that is truly required on the street. I assume most F owners don't necessarily use these techniques.
This has become a great thread. Very imformative. Thanks for your input/advice. Now if I could just afford that 355.....I could practice. Maybe in a couple more years...
Graeme
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Rob Lay (Rob328gts)
Board Administrator
Username: Rob328gts
Post Number: 2847
Registered: 12-2000
| | Posted on Thursday, November 28, 2002 - 10:24 pm: | |
Not really needed on the street, but driving on the track you HAVE to either heel toe or double clutch to keep the car stable under downshift braking. If you're braking hard with the brakes and drive train with your revs not up there, then you're likely to end up looking the way you just came from.
Not in the Ferrari, but here's a lap of me racing at Motor Sport Ranch CC in the Spec. RX7. The 2nd turn at the end of the long straight you can hear me rev it as I'm downshifting. There's also a couple other areas I do the same, actually anytime I'm downshifting.
http://www.spec7.org/videos/MSR1_29_5lap2002.mpg
On most cars it's really not a heal toe, it's more of little toe roll. The left edge of your foot is all the way down on the brake and when bliping you just roll the right side of your foot over the gas without a change in pressure on the brake.
Like JR talks about, sometimes you're in a sitauation where you just have to touch the brakes or you're trail braking and need to keep the revs up. In many cars the best way to do this is through left foot braking. A really skilled race driver will actually do something different on different corners. They may heel-toe, they may double clutch, they may left foot brake, they may power shift. A good driver has all their skills in the bag and pull out whichever one will make them the fastest. |
peter brinzey (Ferraripete)
New member
Username: Ferraripete
Post Number: 25
Registered: 11-2002
| | Posted on Thursday, November 28, 2002 - 10:18 pm: | |
as a note, heal -n- toeing is an art and when done properly virtually uses no engine braking.
dependant on the cars pedal configuration...best w/ toe on the brake and heal on the gas. toe is better for brake modulation. 911's and ferraris are set up this way w/ gas pedal hinged at the floor.
double clutching can be used for upshifting and down shifting. blipping the throttle between clutch depressions on the up shift is actually counter productive...does sound cool however.
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JRV (Jrvall)
Junior Member
Username: Jrvall
Post Number: 202
Registered: 11-2002
| | Posted on Thursday, November 28, 2002 - 9:57 pm: | |
right ...tranny's without syncros sure...because the actual term originated from the real old days of cars and trucks without syncro's and carried over to cars with slow/crappy syncro's like british cars...lol....but I think the technique has been refined to eliminate the extra step.
I eaced go-carts for years before I started racing cars and used a simular technique to heel and toe, in both of my racing Porsches I never liked heel & toe but I used throttle steer alot.
Smoothness and comfortability is what counts...different people are comfortable & confident using different techniques
pure race trannys used striaght cut gears (not heliacal), without synchros so had to be double clutched up & down |
L. Wayne Ausbrooks (Lwausbrooks)
Member
Username: Lwausbrooks
Post Number: 489
Registered: 8-2002
| | Posted on Thursday, November 28, 2002 - 9:56 pm: | |
Hans, makes sense.
I'm having connection problems with my AOL right now and it's driving me nuts so I'm going to sign off for tonight. Hans and JR: Good night and happy Thanksgiving! Oh yeah, and happy whatever-they-celebrate-up-there-in-Canada to you Graeme!
Wayne |
Hans E. Hansen (4re_gt4)
Member
Username: 4re_gt4
Post Number: 596
Registered: 4-2002
| | Posted on Thursday, November 28, 2002 - 9:40 pm: | |
Wayne: When double-clutching a syncro gearbox, you are attempting to do at least part of the work of the syncros. Syncros are a friction device, so relieving them of some of their work saves wear and tear. |
L. Wayne Ausbrooks (Lwausbrooks)
Member
Username: Lwausbrooks
Post Number: 488
Registered: 8-2002
| | Posted on Thursday, November 28, 2002 - 9:30 pm: | |
JR, I'm not sure about the straight cut gears, but I know that if you don't double clutch (or double de-clutch) while down shifting any tranny without synchros, you get a big CRUNCH.
As far as modern cars with synchromesh, I personally only depress the clutch pedal, blip the throttle, and release the clutch. No double anything. According to Frere, some drivers still prefer to "double de-clutch" even with synchroed gearboxes. Can't imagine why.
As for heel-and-toeing, before I perfected this technique, I found that I couldn't blip the throttle while downshifting into a corner that required hard braking. The result would be a less-than-smooth take up as I let out the clutch. It was really a challenge to practice using one part of my foot to blip and the other to brake and to time the whole thing perfectly. I must say, though, that it is a pleasure to execute this maneuver correctly. Still, I find it awkard to pull off when driving cars that I'm not used to and it's nearly impossible to do in my Porsche as the pedal offset is tremendous, with the brake pedal being several inches higher than the accelerator. |
JRV (Jrvall)
Junior Member
Username: Jrvall
Post Number: 199
Registered: 11-2002
| | Posted on Thursday, November 28, 2002 - 9:11 pm: | |
Wayne, wasn't the step of actualy letting off and pushing the clutch a second time used in British cars or Tranny's with striaght cut gears?
Modern (60's to present) German and Italian syncro's don't really require the second step imo.
you are correct used mostly with downshifting. |
L. Wayne Ausbrooks (Lwausbrooks)
Member
Username: Lwausbrooks
Post Number: 487
Registered: 8-2002
| | Posted on Thursday, November 28, 2002 - 9:06 pm: | |
I should add that, as for double de-clutching, it is a necessity when driving a non-synchroed "crash box" but simply blipping the throttle while the clutch is disengaged once works just fine on a fully synchroed, modern transmission.
As for heel-and-toeing, try taking your foot off of the brake in order to blip the throttle while downshifting into a turn and you'll see why it is necessary. It allows one to brake, blip, and downshift all at the same time. The term usually does not refer to the "go-cart" technique that JR mentioned. |
L. Wayne Ausbrooks (Lwausbrooks)
Member
Username: Lwausbrooks
Post Number: 486
Registered: 8-2002
| | Posted on Thursday, November 28, 2002 - 8:59 pm: | |
I find it interesting that there are so many interpretations of what these terms/techniques are. With respect to JR, the way that I was taught is echoed in Paul Frere's book, "Sports Car and Competition Driving." According to Frere:
Double clutching (actually "double de-clutching") is performed during downshifting: "when the gear lever has been moved into neutral, the clutch pedal is released for a brief moment while the engine is being accelerated (throttle blip) before the clutch pedal is pushed in again and the next lower gear is selected."
Heel-and-toeing is performed during downshifting while braking at the same time: "Heel-and-toeing allows the driver to simultaneously brake and speed up the engine (throttle blip) while making a downshift, with or without 'double de-clutching,' to adapt the engine speed to the lower gear and avaoid a herk when the clutch is reengaged." |
JRV (Jrvall)
Junior Member
Username: Jrvall
Post Number: 198
Registered: 11-2002
| | Posted on Thursday, November 28, 2002 - 8:36 pm: | |
Double clutching is blipping the throttle before selecting the next gear....using the matching r's of engine & trans as a second clutch...per se. I use that technique still to this day. It's helps the trans and sounds really cool.
Heel & toe refers to something akin to trail braking....where you're hitting the brake with the heel of your foot and using the toe of the same foot to feather the throttle. used widely in go-cart racing where you needed to keep the r's up....I personaly don't like that technique with cars and feel it tears them up. |
Graeme Parcher (Ferrarif355)
New member
Username: Ferrarif355
Post Number: 4
Registered: 11-2002
| | Posted on Thursday, November 28, 2002 - 8:22 pm: | |
I've imagined what heal and toe pedal work refers to, but I've never actually asked the question! Can someone help describe the technique? Also; is double clutching simply the technique of depressing the clutch twice, or is there more to it? |