How to Match Revs During Hard Deacceleration?

turn your right foot sideways on the brake and push the accelerator with your heel. you can always get it all done before you enter sounds like you are trying to do too much at once with the car as well. thats an awful lot of weight xfer going on with it being downhill, turning and trying to decell at the same time. i would get everything slowed down first and change my line to minimize the time spent braking and diamond the turn to where i could drive out better.

 

I'm assuming you are on a track, yes? If so, you're braking too soon. You should be trail braking as you turn in and praying to Jesus, Moses, and Allah all at the same time.

Let me walk you into T2 at Laguna in a Skippy MX-5 car. You have been flat out in 4th all the way down the main straight. You let your momentum carry you to the outside of T2. Out of the corner of your eye, you count the 4 Marker, the 3 Marker, the 2 Marker, and as soon as you see the 1 Marker, you turn in and dive bomb the entry apex. (T2 has two apexes. One on the entry, one on the exit.) You also slam on the brakes with your right foot (technically you're supposed to threshold brake; but when you think you're about to die, slamming seems more appropriate). Within milliseconds you realize that you might just live, but you need to downshift to 3rd. So you lift ever so slightly, reach over with your right heel, blip the throttle as hard as you can, and then bang a downshift. Then after a few more milliseconds, you lift some more and bang another downshift to 2nd. Meanwhile you have passed the turn-in apex and are cranking more wheel and lifting off the brakes. Then, if you have done everything right and the racing gods are smiling upon you, you should be at the top of the arc and can start rolling on the gas for the exit.

To get back to your question, if you have to think about how hard to blip, you ain't going fast enough.

Of course, if this is the turn in to your driveway, you might want to be slightly more cautious.

Dale

 

I use the left side of my throttle foot to push on the brakes and the right side of my throttle foot to blip the throttle pedal. This blip is coordinated with the depression of the clutch pedal and the movement of the shift lever. The blip is timed to just before the gear selector selects the next gear and then you let the clutch out starting out rapidly and then slowing in mid stroke to catch the revs in the friction zone of the clutch.

 

I kinda thought so, after all, racing is racing. If you ain't praying, you ain't racing.

Dale

 

I found these two helpful.

http://www.turnfast.com/tech_driving/driving_heeltoe

And

[ame]http://www.youtube.com/watch?v=cPj9XXW25GA[/ame]

 

Here is a video I took of me driving BimmerWorld BMW M3 racecar this past weekend at Laguna Seca. This car has a decent pedal placement from the factory but it is nothing compared to a Ferrari. The pedals are a lot closer together in a Ferrari and I have found this technique works really well.

The basics of it are to use mainly the ball of your foot just under your big toe to do the bulk of the braking. You can use as much force as you would like to apply the brakes with this part of your foot. As you are getting ready to downshift roll your ankle over so the side of your foot comes in contact with the gas pedal and give the gas pedal a big blip to match the revs. Using the ball of your foot allows you shape your foot like you are on your tip toes the event the brake pedal moves past the gas pedal.

Ask away if you have any questions.

[ame]http://www.youtube.com/watch?v=8eiwFZ9LG5o[/ame]

 

You know what would be cool, if you could have a window showing where you are in the track map. I was trying to guess. But since I didn't know your point of beginning, it was hard to tell.

Dale

 

If I had used my AIM SmartyCam I could have done just that but this was shot with a GoPro. I know the video comes into focus with me entering T10 and I then make a downshift to 2nd for T11 to head onto the front straight. Let me know if that helps.

 

Yeah, it does! T10 is really cool isn't it, and then I can tell when double blipping in T11 as you slip and slide out. Man, I love Laguna.

Dale

 

I think T9/T10 at Laguna is about the perfect combination of corners. camber changes, elevation changes, gear changes, and it's damn fast. good times

 

In general you should finish your down-shifting before turning in - you don't want to be down-shifting in the corner. Once you have turned in, you are holding a relatively constant arc (perhaps slightly increasing to allow putting down power as you exit). Trail braking is advanced and used to help the car on turn-in (puts weight to the front). Starting performance driving, it is good practice to also complete braking in a straight line before turning in. So, you will be braking and down-shifting simultaneously in a straight line right before turning in (using heel and toe to match revs and double clutch if you care to extend life of your transmission). Once you master all that you can experiment with trail braking. My $0.02.
Jes

 

Some use the classic heel and toe and some use the ball and right side of the foot as you do. I do it like you because I started on Ferraris and the 348 I raced for years had perfect pedal position for your method. To me doing this well is all about pedal position. The real problem for newbies is that they don't know what a good pedal position is. Perhaps a pro like you can manage any car but a hack like me needs the pedals in the right place. To me that means that under hard braking the level of the brake pedal is at the level of the gas pedal so I roll over easy and the gas pedal needs to be close enough to the brake pedal. My Z06 SCCA T1 racecar is almost perfect but I had to extend the gaspedal so I could reach the pedal. My 550M I still have not fixed. The position of those pedals are lame to the point I have to heel toe the car. I always say I'm going to fix it but there is always another project.

My question to you is how do you manage pedal position issues in all the different cars you drive? Do you just live with it? Does your crew chief change things for your driving style? Or it is just standard operating proceedure to fix the pedals to the right place?

Left foot braking:
On a similar vain after the ball/side of the foot shift how do you transition to left foot braking to trail brake in? I left foot brake automatics daily driving so my left foot is good. My problem is that after my shift and into my transition to LFB I always have too much of a release on right foot then back on the brakes left foot which upsets the chassis in transition so it is not smooth. Any comments on that? Maybe I'm just lame and uncoordinated.

 

I'm the same way; I can LFB in an automatic all day long but can't do it to save my life in a car with a third pedal. I blame uncoordination.

 

Perhaps Mr. Rohrl can be of assistance?

[ame]http://www.youtube.com/watch?v=s0ieRNmgxiA[/ame]

These other vids are pretty neat to watch, too:
[ame]http://www.youtube.com/watch?v=klMur6TPkrM&feature=related[/ame]

[ame]http://www.youtube.com/watch?v=w7hYzTXceZE[/ame]

 

Being able to hop from car to car and adapt to different pedal positions starts with having a good fundamental understanding of how to heel/toe and starting with a foot position that can be adapted. One of the first cars that I ever raced was a Showroom Stock Neon. This car had the worst brakes and pedal position of any car I have driven. In order to heel/toe I really had to push on the pedal with my foot in a tip-toe type position as the pedal travel was excessive and then roll my ankle to try to touch the gas pedal. Sometimes I would find if I didn't have my foot in the extreme tip-toe position then I would be on the brake and the gas at the same time. Then imagine how the brake pedal travel would change over a 3 hour race length as the pads wore and the system kept getting hotter and hotter. This was the beginning for me to understand how to heel/toe and adapt my foot to whatever car I was driving. In my opinion the basics of the position I use helps any driver to be able to adapt to any car or to be able to adapt for a car throughout the length of the race period.

Think about it this way. In the 24 Hours of Daytona, a lot of the GT cars will have to change brake pads about halfway through the race. The starting driver gets a nice set of fresh pads and a good stiff pedal. The pedal travel stays the same throughout his stint in the car. The next time in the car at roughly the 6 hour mark the pads are about 50% worn so the pedal travel is going to be softer and further than it was when starting out. The driver has to adapt to this pedal travel. It may mean putting his foot in a different position, using a slightly angle, using more of their ball of their foot, etc. Then imagine when he gets in at the 11 hour mark when the pads are almost gone. So with all of this being said a pro learns how to adapt his feet and not think about it. The pro has the basics down so well that once he gets in the car at the heat of the moment he adapts without really knowing it.

On the BMW M3s we are racing in the Continental Tire Sports Car Challenge we are required by the series to retain the full stock braking system (pedals, master cylinder, ABS, rear caliper, front caliper and rotor upgrade though). Because of the rules the pedals have to stay pretty much in the stock position much like your T1 car. We can bend the brake pedal if needed but the BMW has a pretty good position from the factory so it isn't altered. Now in a Rolex GT car, Porsche Cup Car, World Challenge Touring Car or something similar where a complete racing brake system is used, the pedals are adjustable. These systems have a completely new customizable pedal assembly that can be moved in just about any position needed. This is where I will get my car chief to move the pedals in a position that better suits me. Most of the time the reason for moving isn't for helping me to heel/toe but to help out with fatigue in the car. We will move them so my legs are more comfortable when applying the brakes or the throttle.

Sorry for the long post but I hope this answers your questions. Let me know if there are any other questions.

 

Why are you double-clutching on downshift? The clutch should be depressed once...brake and throttle blip with the right foot whilst downshifting all while the clutch is in....then release the clutch. One smooth motion.

 

Double clutching is common (probably the norm) among racers to help synchronize gearbox at shifts - an art. This will extend life of synchros and gearbox. Just google it. Maybe difficult at first, but will quickly become 2nd nature, particular if you do it on your street cars as well.
Jes

 

Agreed. No second blip is required to "save" the synchros if you do it quickly and near the end of the braking zone.

I don't blip dog-'box (non-synchro) transmission or transaxles at all. Just move the lever quickly.

That Rohrl video of the Gruppe B Audi is incredible! All those pats just to keep the turbo spooled up...

 

Each to his own.
Jes

 

amazing

 

I have never double de-clutched going down gears and don't understand why. As I understand it, if you heel/toe correctly the input shaft will be spinning at the correct speed for the next gear on the first blip.

On a dog box heel/toe is not an option and the only way to get the next gear in my experience. The dog ring just won't interlock with the desired gear otherwise, but you can make some horrible grinding sounds. The first time I took a dog box apart and saw how the dog rings and driven gears interfaced made very clear to me how important heel/toe RPM matching is. Done right, a dog box is awesome, as shifts take literally 10s of milliseconds

 

If you have: engine output - clutch - transmission input shaft - transmission output, then the double clutching is to match the speed of the transmission input shaft and transmission output at a given gear. When you downshift, you need to speed up the transmission input shaft. This can only be done with the clutch released (pedal not pressed down) and car in neutral. Otherwise you are just spinning up the clutch input but not the transmission input. So, at first clutch disengagement you take transmission out of gear and in neutral, blip the throttle to speed up transmission input shaft, press down clutch pedal down again, select gear and let out clutch pedal. If you do it correctly there will be no work for (=stress on) the synchros, and if you are fast you blip throttle once and engine RPM matches upon engagement of the lower gear, so that balance of car is not upset. If you are slow (when learning it), you can essentially just hold the gas at the correct position from neutral gear position until you have re-engaged transmission in lower gear.

So, single blip, but double clutching. I think this is consistent with ProCoach's comment regarding single blip, but you need double clutching to relief synchros of work. If not, then please correct. Hope this makes sense.

Jes

 

For comparison I'd like to see some clips of that girl who competed with him during the groupB audi quattro years. She also drove a quattro and I think wond the rally world championship too.