thanks

 

Find your favorite slow speed curve and rev match just before you go in... you should be in gear as you enter the curve with the clutch out. There should be NO engine whine as you let the clutch out if you blipped just right. Now get on the gas just enough to "set up" the suspension as you go through the curve and then power out with as much throttle as you can without sliding outward much. The goal is to do this smoooooooothly. Once you get the hang of this, try positioning the car in the curve using your throttle. Extra throttle and you will go wide, lifting off the throttle and the nose will tuck in.

 

I have been thinking about this thread and the way I drive...

and Ive come to the conclusion...

I dont down shift while braking to help the car slow down... But I do it to help bring out the rear end a little bit to set up into the corner... The way I run my car Im not "Drifting" but slightly slide into the corners, and it helps bring out the rear end when in a higher rpm...

hard to describe i guess...

 

it is incorrect driving technique to use the engine to slow the car down...

unless you absolutely have to..

rev- matching is to save your clutch, and keep your car always in a proper gear.

heel-toe-ing to slow the car unsettles the car usually, and besides, thats what the brakes are for. you should heel-toe every down shift to rev-match, and that will also double your clutch life (if you do it properly).

there is no point in double clutching... this is a modern transmission.

 

I respectfully disagree. The debate between brakes OR transmission to slow the car will continue forever. And I think that the correct answer is “both.” Use the brakes, transmission and your skills together for maximum control and performance.

 

Your description sounds like classic trail braking technique. If you are releasing the brake as you turn in AND rev matching with heel-and-toe, you will find most cars will rotate slightly. The fact that you are in the power band when you release the clutch makes it feel as though the rear of the car is slightly loose. If you can catch this slide accurately and predictable, lap-after-lap, you'll gradually find your lap times dropping.

Better shut up for now- this will be a topic better explored in a future driving techniques article for Sport Z Magazine!

 

yeah trail braking

durrrr...

 

Here's an awesome video of a guy who knows how to downshift . One thing I noticed is that he doesn't skip a gear when downshifting. I cheat sometimes by going from 4th to 2nd, skipping 3rd. I've never driven an M3 but I hear their clutch/tranny is buttery smooth making downshifts easier (albeit, this car is not stock).

http://www.bmwtransact.com/microsite...ing/index.html

- John

 

The only reason I find to use engine braking while slowing the car, would be to artificially change the brake balance. This is what left foot braking is for. Or if you'r rear brakes are gone and you still have 2h of race to go...

All top level drivers and instructor agrees on the "Use the brakes to slow down, not the engine" argument.

What slows the car is the tires. I can lock all four wheels using the brakes. Adding the tranny to brake more is not going to help. It feels you brake harder, but you're not.

We are borderline driving techniques on this topic. So what works for one might not work for others. If anybody really wants to improve is car control, he should try multiple driving techniques, long enough to get comfortable with it. And then decide what is faster.

I'll be waiting for you on the Engine braking is not helping side of the fence

Skipping a gear while downshifting is not cheating. Heck, if you're driving a car with an H gate tranny, no reason to loose time, concentration and risk unsettling the car 2 or 3 times at corner entry. Do it once, do it right. Use your resources on threshold braking.

 

oh my days, I can't beleive on a sports car forum people are asking how to change gear!!!

Heel and toe, engine sounds lovely with a little blip and you change under breaking, hmm hmmmmm.

 

Shift as late as possible. I am in the heel-toe downshift to rev match not slow down. The only thing I would add is, leave the car in whatever gear you are in, hit the brakes as hard as possible, i mean stand on em, after you slow down to the exact highest speed possible for your car on the turn you want to make, right before you want to step on the gas WOT, then you should down shift to the gear that will put you in the sweet spot of your power band. This will allow you to take that corner at the highest possible speed.

At BeaveRun I was standing on my brakes at 125 feet out at over 115mph. Slowing to about 50 and making a quick left right turn which I would accellerate out of to about 70.

The technique as described by Carroll Smith to determine if downshifting helps stop a car is this.

Mark a starting spot on the ground. Be sure you get to the same speed 45-60 as you pass this mark. Once you pass the mark step on the breaks and downshift. Mark you stopping distance. Repeat 3-4 times noting your closest stopping distance. You will notice that all of these runs will be different and you will probably get shorter on each attempt. Now do the same thing and ONLY use the brakes DO NOT DOWNSHIFT. You will end up with a good average that should fall within the range of your first 3-4 attempts with DOWNSHIFTING.

I have tried this and it demonstrated something I didn't believe. Downshifting does very little, if anything to slow down a modern car. But boy it sure does jerk you around alot and FEELS like your hitting a wall. (Thats your drivetrain screaming in agony by the way)

 

I agree on other things you said - especially the bit where brakes are for stopping a car. However I would respectfully disagree on two points.
1. Heel and toe is the technique used to rev match while braking - your "toe" does the braking while your "heel" does the rev matching. It is not a rev-matching-only technique. Done correctly, the car will not become unsettled. Heel toe allows you to double clutch if you want but you don't have to do so. It's merely an option.

2. double clutching does save even wear and tear on a modern transmission that have many synchros for each gear. if you've ever heard or felt some grinding as you pop the trans into first while moving along (or even at a dead stop), then you should have double clutched or rev matched to properly line up the gears in your transmission. you're just using up your synchros when forcing it into gears. Also, if you slow and don't immediately shift into a gear (i.e. you're debating if you should go into say second or third gear and you're waiting in neutral), your transmission will coast to a stop internally. Finishing the double clutch (by reving appropriately in neutral then popping into appropriate gear) will allow you to shift into gear without forcing the synchros to work hard.

Finally, heel/toeing and double clutching technically wear out your thrust bearing more so technically your clutch's life may shorten just a bit.

From my own experience, heel/toeing also allows you to drive a beater car that can't idle without stalling and double clutching will allow you to drive a car home whose clutch no longer works

on a different note, I think in F1 now it seems like for a while they were coasting into turns (save fuel?) - it was eerily quiet. Now I hear aggressive downshifting. Not sure why although I can speculate that it might have to do with the sequential gearboxes they use now versus "regular" gearboxes in the 90's.

 

hehehe sorry confused. I was reading this thread and got me interested. I guess i'm just "normal driver" but now i'm curious haha My question is...

Lets say you're going at the speed of 60mph on a 5th gear.

So...you're suppose to tap the gas up to maybe around 3k then downshift to 4th...

Wouldnt that cause you're car to go faster and jump forward? Not sure if i'm making sense haha.

Can someone explain that to me or maybe i'm missing another step before switching it to a lower gear w/ the rpm in 3k.

THANKS!

 

I'm also an average driver but I enjoy learning and practicing good technique.

the idea behind all this rev-matching etc is so that when you put the car into a lower gear, it doesn't jump forward (too high rpm) *or* jerk (too low rpm) as the engine spins up to the correct rpm.

So, for example, say you're doing 50 and want to shift into 4th. This might be because the road just cleared up in front, you want to set up to accelerate out of a turn, etc. It's *not* so that you can slow down (brakes are for that).

50 mph is about 3k rpm in 4th. If you're in 5th and going (I dunno what the rpm is, I'm pretending it'll be 2500 rpm) 2500 rpm, if you just push the clutch in and bang it into 4th, the engine has to "accelerate" to 3k rpm. the car will jerk as you engage the clutch. if you're pulling serious G's in a turn or driving on wet or snowy roads, that jerk could be enough to break the rear tires loose and spin you off the road. rev-matching prevents this loss of balance/smoothness/whatever you want to call it.

in addition, there is a third shaft in your transmission (connects the input/engine to the output/driveshaft shaft). I end up calling it the neutral shaft since I don't know what it's really called. if you put your transmission into neutral (i.e. the input shaft is NOT connected at all to the output shaft) then this third shaft literally stops spinning after a few seconds. if suddenly you insist on jamming it into 4th gear at 50 mph, the neutral shaft must be accelerated to the same rpm as the engine (say 3k rpm in our example). this is not good. the synchros force the neutral shaft to the right speed inside the transmission. since sychros are friction based, they wear over time. replacing your transmission is more costly than a clutch. so given the choice, wearing out the clutch a little more is better than wearing out your transmission.

if you rev (in neutral, clutch released) just over 3k rpm, this will accelerate the neutral shaft to whatever 3k+ rpm you just blipped the engine to. then quickly push in clutch and pop it into 4th as the neutral shaft rpms drop past the sweep spot. this way the synchros do zero work and you're in gear with no jerks, no synchro wear. You might have to blip once in gear to get the engine back to 3k rpm so that there is no jerk when you let the clutch back out. this bit is what double clutching does.

heel/toe is where the whole time you're doing the above, you're braking with the toe of your right foot. you actually use the upper left part of your right foot for the brake, the lower right for the gas (your foot points to about 10 o'clock, i.e. it's tilted). this will allow you to brake 100% while downshifting so that you are in the right gear when you come out of the turn.

I use all of the above every day driving to/from work.
heel/toe - virtually all downshifts and even general braking. I very rarely have my right foot only on one pedal. useful for entrance/exit ramps, slowing for stopsigns/lights, etc.
double clutch - I use this to get the car into first gear while rolling. useful for pulling into a gas station, rolling along in bumper to bumper traffic, coming up to stop signs. normally I'm on the brake as well so I'm heel/toeing as well.

hope this helps.

 

If done properly, your car should not jump. That's why it's called rev-"matching". If you don't match the rpm for that speed in that gear, your car will jump if you revved too high, or feel like you hit the brakes if you didn't rev high enough.
I think you should be closer to 4K rpm @ 60mph in 4th gear.

 

I think that the tread originally addresses one scenario (downshifting on the street) and now includes a new circumstance: downshifting when racing. Casual drivers may be reading advanced racing techniques (heel-toe) and getting a bit bewildered.

Racing: if you approach a turn in forth, and would like to negotiate the turn in third, I suggest that you do NOT downshift IN the turn, but before the turn. Either before, while, or after braking. Agree? Disagree?

 

Ahh...thanks for explaining all this to us newbies.

 

Heres a link to video that show short examples of heel/toe
http://videos.streetfire.net/Player....F698D69942&p=0

 

Racing.

Downshifting has to occur at some point. However how good you (we, I) are at heel and toeing, we will upset the car a bit. When to do it?

I do it just after my main braking phase, while I’m easing off the brakes (freeing some grip in case I miss my rev match a bit), but still under braking. Once the down shift is done, I do my turn-in while trading more brakes for steering.

I trail brake in all turns, on of off the track, whatever the car. I haven’t encountered a car that was naturally oversteering enough it didn’t need some trailbraking help.

Then there are the “track-specific” shift points. Between turn 1 and 2 at Putnam Park for example. I do turn 1 in 4th gear and downshift to 3th while I cross the track for turn 2.



F1 cars - Sequential gear box does not allow the driver to skip gears. He has to row through all the gears. The Tranny ECU does it for him. Rev matching and double clutching (not sure of the double clutching part) between each gears. In some turns, if the car has to go from 7th to 2nd for example, the driver will hit a button before pulling on the downshift flipper to get the tranny to downshift multiple gears on its own.

 

"heel/toe is where the whole time you're doing the above, you're braking with the toe of your right foot. you actually use the upper left part of your right foot for the brake, the lower right for the gas (your foot points to about 10 o'clock, i.e. it's tilted). this will allow you to brake 100% while downshifting so that you are in the right gear when you come out of the turn."

I personally do it the other way, almost use the arch of my foot to brake and the top right to blip the throttle. But at the end of the day, find a technique that works for you.

Heel and toe isn't just for the circuit, used on the road it helps a smooth down change, but remember to let the brakes do the braking, just ensure your in the right gear for the speed you are going. I also find heel and toe is pointless at low revs, ie around town etc, but greatly improves the drive when revs are higher, when screaming round the country lanes etc.

If your new to heel and toe, PRACTICE doing where it doesn't matter if your foot slips off the brake, or you blip the throttle with the clutch still engaged.