BG -

Having done a couple Proformance days and an IRDC school (along with a few auto-x schools) I have to say that they really didn't offer any specific instruction on heel and toeing.

I already knew how so I didn't ask but my Proformance instructors simply had me working on proper lines more than anything else.


Proformance insurance apparently prevents them from allowing passengers except for instructors.

Alfa lapping days are different though - you can have passengers ride w/ you if you run the "A" group IIRC so you could at least ride with someone and get a feel for the technique - pink hat and all.

 

Hey Jody

When ProFormance taught me heel/toe downshifting it was the basics, then followed by "ok, now don't practice it here -- practice it on the street first'. Trying to nail a perfect heel/toe on T2 on PR at 130mph is not the way to learn -- get it right at 40mph numerous times until it's second nature, then start applying it on the track.
For up-shifting, I like a nice 8,500 rpm (ow whatever your car's redline is) so that you get to hear all the glorious musical notes that your car is capable of.

Now, as for compression-braking -- this is where you are using your ENGINE (it has nothing to do with your transmission) to perform the braking by forcing the engine to spin without any gas being applied. THIS IS BAD. ProFormance teach "Engine is for going, brakes are for stopping". The forces put on the engine during compression braking can be enormous, and can cause a broken connecting rod, or much worse. Replacing brake pads/rotors are cheap in comparison to replacing an engine. A well-executed heel/toe explicitly tries to *prevent* compression braking by rev-matching the engine rpm to the transmission. A poorly executed down-shift without rev-matching causes a short burst of compression braking and this can even lock-up the rear wheels briefly (ABS cannot activate when engine is braking). There are times when it's necessary (usually when someone else is funding your driving) say for example at 150+mph and the brake-bias is setup front-heavy (as is typical) and you wish to do some ad-hoc brake-bias adjustment by applying some engine braking to the rear in addition to the regular brakes. This is something for extremely experienced drivers.

The most important thing is track time. A day or two spent with 1-on-1 instruction is great, but the most important thing is to get out there on the track as much as you can. Nothing beats seat-time. Then remember the GOLDEN RULE: "Technique and skills FIRST -- speed later".

 

BB,

thank you kindly for your info. yep, i definately need to get some more instruction. i want to be sure that i'm doing the heel/toe technique correctly before i practice a bad habit. poor boxster! she's been good to me while i've learned all of this! i want to treat the ol' girl the way she's meant to be treated!

thanks for your technical info. it allows me to see the "big picture" as to why/why not to do what i have done.

=)

 

You are using the engine to slow the speed of the transmission.

 

Why wouldn't you use the compression of your engine to aid in the deceleration of your car? Is this porsche specific? Are transmissions in boxster's the "weak link"

If you don't compression brake at the track, are you going into corners with your clutch in and engaging it again coming out of it? That seems like it would be much harder on your transmission/clutch than rev matching into the lower gear and allow the compression of the engine to aid you in slowing the car down along with braking and heel toeing into the next lower gear while braking to continue compression braking.

That's the whole point of heel toeing, to use the engine to slow down quicker before you enter the turn and be in the best gear possible for coming out of it.

Another thing to take into account is your pedals. When the brake is further away from the gas, it makes it really difficult to heal toe.

 

Nobody in their right mind would go into a corner with the clutch in.

I heel and toe to attempt to smoothly transition from braking into (and sometimes during) the turn and to be in the proper gear upon exit.

It has nothing to do with enhancing braking. It's all about managing the weight/balance of your car.

 

 

using the engine for braking is bad form in any car.

 

So you mean to tell me that you guys don't compression brake at all?

Maybe it's just a porsche thing...

I could see how it's bad for older WRX's with weak transmissions. But the ZF in my car is notorious for being over-engineered and can take any form of abuse I can throw at it, which really makes me question how abusive it really is...like a woman that likes to be choked a little in bed =P

I don't know a damn thing mechanically about cars outside of E36 M3's, but I assumed your tranny's were in similar boats.

Why do you think compression braking is bad for cars?

 

Mitchel, c'mon, man...have you ever taken ANY driving courses/schools of any sort? Or did you learn everything from driving your own cars or even maybe from other folks who think they know what they're talking about. It's not just Porsche specific not to use compression braking at all. I learned this from my experience at the Porsche driving school, the M5 driving experience, the BMWCCA novice school and from driving on all those back roads. Always use the brakes to slow down before the corners. I learned to practice heel/toe techniques coupled with trail braking (which in this case would be ideal for Porsches because of the rear weight bias) before coming into a corner. We practiced this over and over until we got this right. It's absolutely crucial to keep a sense of balance between front/rear/side to side as master the driving dynamics of keeping your car moving smoothly whether you're going faster, slowing down or braking. I do agree with BB that it'd be ideal to practice this at normal "speeds" where it's safe, not on a busy street, etc. Maybe in a lone deserted road way out in the boonies or something. I haven't been able to successfully heel/toe consistently with my P-car yet because it's a completely different setup than the cars I used at PSDS with the ceramic brakes. The brake pedal is much more sensitive with a ceramic setup than a steel rotor setup.

 

I'm not saying that I rely solely on engine braking and not my disc brakes, I do it in conjunction with my disc brakes.

Engine braking doesn't hurt (my) car. Coasting in 4th with the clutch in, letting the revs drop to 1k, and letting the clutch out without rev matching is what wears down your clutch and stresses your drivetrain. I assumed it was the same for porsches since they are engineered to a higher degree of performance than my car was. Maybe I was wrong?

There's 100 explosions per second going on in my engine at 6k rpms, rev matching to a lower gear and compression braking will not hurt anything.

It's common practice among people in E36's due to our near 50/50 weight distribution and drivetrain engineering, maybe I'm being ignorant for assuming that the application of this technique is practical for mid engines cars (Porsches). I've never driven a porsche, let alone spiritedly.

And Jason, I've learned a lot directly from the mistakes I've made and I take the advice of people who give good advice. As far as the people who "think" they know what they're talking about, no offense, but you're out of your league knowledge wise in comparison to them (I can post his lap times around PR in a lesser car than yours if you don't believe me)

I taught myself how to heel/toe and rev match properly in my old Ford Aspire of all things. I learned how to counter steer from my many years of driving in Eastern Washington while growing up in my old A4 and 325i. I taught myself how to properly take a corner and trail brake in my M3.

One thing you have never done is ride with me, I suggest you come along some time...it's probably been a while since you've ridden in something a DECADE old =P

 

As liggy mentioned, heel and toe to
be in the right gear as you exit a turn. Not to "slow down quicker."

 

There's the basics of heel+toe.
http://www.dietersmotorsports.com/te...el_and_toe.htm

Engine Braking (explained well in a nutshell)
http://www.everything2.com/index.pl?node_id=1181314

Why not get a head start and do some reading, you obviously have some time at work =P
Rev Matching
http://www.everything2.com/index.pl?node_id=1249174

 

If you heel toe/rev match, there is no compression braking. THAT'S the whole point of heel toeing.

"On the race track, as you approach a corner, your right foot comes off the gas pedal and presses the brake with the ball of the foot. Before the braking is done, you need to shift gears so when the braking is done you can immediately be back on the gas. When the braking is almost done, your left foot pushes the clutch pedal in, and your right hand downshifts. However, while you've been slowing down, the engine speed has dropped. If you let the clutch out now, the car will jerk severely as the engine works like a huge brake. If you're at the edge of traction limits (which you should be), you'll lose control of the car. To prevent this, something needs to rev the engine back up to the right speed before the clutch is released."

 

Mitchell -

Seriously...

You should just stop.

How about you post your lap times before calling out other members with more experience than you.

How fast do you get around PR using your combination compression braking and E36 disc brake setup?

If you're relying on compression braking to go faster you're not doing it right.

If your car has ****ty brakes and you need to save them - then they should be upgraded. Having to rely on compression braking is only slowing you down.

My S2000 can run an entire 1 hour session with just upgraded pads and ATE Super Blue without any braking issues - and it's a car blessed with 50/50 weight distribution.

As I learn a bit more about the C2S I'm finding that:

1. the PCCBs are amazing.

2. As Atomic mentioned - trail braking is needed to counteract the extreme rear weight bias of the 911.

As I mentioned earlier - since you didn't seem to pay attention - a driver uses the pedals to distribute the weight of the car for maximum benefit.

Achieving that balance is the fun part. Education and seat time are the ways to learn it - and I certainly need more of both.