Back to the question of blipping for multi gear downshifts...
There is a definite advantage to downshifting directly from your higher gear to the lower gear needed in a corner.
- Less shifts means a lesser chance (as a mere human) of mucking up a change.
- With the rapid speed that a racecar decelerates and how close ratio some gear boxes are, it can be hard to stir the box through all the gears in the time allowed.
- The lower you go in the engine's RPM range the less engine torque there is to possibly upset the braking balance. (Once again as we are mere humans...)

I remember an "American Sports Cavalcade" in the 80s where they showed a clip multiple times where Wayne Taylor was doing a 4th to 1st downshift. The English commentator (can't remember his name) was trying to explain for the general audience why it was desirable and how amazing it was that Taylor did it so effortlessly.

This brings up the simple reason why you wouldn't want to try to speed match a multi gear downshift.
- It is a LOT harder to gauge the correct speed to match because we aren't driving gods like Wayne Taylor!

It is relatively simple to hear the correct change in engine speed needed to perform a correct shift regardless of speed because of the nature of the pitch of the sound. In a given car every change of gears between two gears will always have the same change of engine note no matter what speed you are going.
The ratio of speed between gears is fixed. It is called the gear ratio and that should be pretty obvious. Sound is exactly the same. For example an "octave" is simply a doubling (or halving) of the frequency of sound. No matter speed when you change the frequency by a given percentage you will always get the same change in pitch.

So to bring this back to your shifting...
Your ear has been listening to your shifts for years and if you pay any attention you should know what change in pitch each shift should result in. Blipping to speed match is simply making that change happen with the accelerator. When you start doing multiple gears you don't have years of experience listening to that so you have lost a lot of your "autopilot" to help you. It will still be a consistent change in pitch so it is certainly learnable. I just don't know anyone personally that can do it.

It's only seat time...and all of this should occur on a track. That having been said...

Only data and a stopwatch can determine which exit stategerie is best (i.e. 1st v. 2d). If you feel you absolutely need 1st, then all the same rules still apply at this level.

Get your braking and downshifting done BEFORE corner entry. If this is an issue on track, then five straight (no corner) practices a day in an empty parking lot for a month will be a huge help. Accelerate into speed in second and work on braking hard while downshifting into first...all the while working on smoothness and car attitude.

The pros have a raft of tricks with these cars including left foot braking (while keeping the throttle spooled up), anticipation of the boost and an understanding of what the car will do BEFORE it does it...they act WITH the car rather than REACT to it.

Cheers.

.....

On your edit comments to bpu699
"You are flying into a corner, trying to double clutch AND blip the throttle (double clutching usually requires TWO blips. If you're flying into the corner, you shouldn't be TRYING to double clutch - given your terms), ..."

Double clutching doesn't require two blips of the throttle unless you are doing it wrong. You declutch to leave one gear then re-engage when you are in neutral. Then you 'blip' to match speeds with the next gear. Once you are matched you declutch to select the gear and then re-engage to complete the shift. Anything more is wasted motion which isn't necessary and you don't have time for it.
The stiffer the clutch pedal the harder it is to doubleclutch. You are needing really quick pumps of the clutch to perform it smoothly and if the pedal is stiff it slows you down. If you have something with a light clutch pedal it would be good to practice there.

As far as the distance between gears... :)
That is the exact reason why double clutching (or at least simple blipping) would be beneficial.
The freer revving of a lighter flywheel will make it seem like there is less distance between gears but it adds other considerations... http://forums.pelicanparts.com/uploa...1454087625.jpg

Double clutching doesn't require two blips of the throttle unless you are doing it wrong. You declutch to leave one gear then re-engage when you are in neutral. Then you 'blip' to match speeds with the next gear. Once you are matched you declutch to select the gear and then re-engage to complete the shift. Anything more is wasted motion which isn't necessary and you don't have time for it.

The second blip is necessary almost always and absolutely necessary with a lighter flywheel/clutch assy. After the lower gear is selected the rpm needed to accomplish the first part of the task have fallen and the throttle must be blipped again to match road speed (i.e., normal rev matching). At speed, this is critical.

Watch any of several videos of pros racing vintage 911, most often with a 901, (where they are double clutching) and tell me I'm wrong. When I get the chance, I'll post one of mine also.

HERE, at 1:30, one can see the double blip. The 5.5" Tilton clutch requires a tiny amount of travel at the pedal, so you won't see my left leg move, but here I move directly from 4th to 2d gear while double clutching as my syncros were worn(while hitting the gate at 3d, as is my practice).

Without the double blip down there, I'd be sideways.

https://www.youtube.com/watch?v=Crud43y7qcI

(If the above is confusing it is because it is mostly missing. Read the original statement HERE)

Your two statements are kind of contradictory. Is it "row through all the gears" or jump shift because "many guys who read here daily do it and do it well..."? Your editing leaves out the part where they are opposing techniques.
(I'd be surprised you can find someone here who on a regular basis performs double clutch, multi gear (jump shift) downshifts.)

Both of my statements stand up. First one is simple. You shift once and you have one chance to make a mistake. You shift twice and you have twice the opportunity to screw up.
That isn't the same as twice the probability. That is where my whole second explanation of why it is hard to accurately speed match multi gear changes. Because it is hard the probability of mucking up is higher so that is why mere mortals need not apply (including pro drivers).

Ask the engine/transmission builder/pro level driver and I think you will find he will agree with my statements. In short: If you have the ability to perfectly match speeds when double clutching there is no wear during a shift so jump shifting during a downshift does nothing except reduce the needed actions of the driver.

We aren't Wayne Taylor so I suspect we ALL stir all the gears during our daily drives. But I like to constantly learn so from time to time I practice "more advanced techniques" to challenge myself. (Hell I practice left foot braking but my left foot will never be sensitive like my right foot. I needed to start that in my twenties to turn it into a true reflex. But I still practice it...)

Jeff Gamroth will tell you that he advises (and practices) selecting and engaging ALL gears through the process of braking into a corner. He insists that the opportunity to upset the car is greater if one skips.

Others will indeed skip. (I do at times) Pat Long and Leh Keen work all the gears all the way down. I will maintain that an accomplished driver never thinks once about his "rev matching" as this action is as natural as breathing and it matters not whether he is downshifting once for a corner, or four times.

I hold several track records in several classes, but what do I know. I'm old and slow.

But I can use my left foot....

Double blips are not required or desirable when double clutch downshifting.

When racing, I typically downshift through the gears but not all the time. Turn 11 at Sears Point is an example where I go from 4th down to 1st. Turn 2 at Sears Point is an example where I skip shift. I go from 4th straight to 2nd.

Bill,

Think about this statement you made:

"Double clutch is a way to shift a transmission that lacks syncros"

How could that be true for double clutching AND not affect synchro life on transmissions with synchros?

This is a nice vid:

https://www.youtube.com/watch?v=Z9HVkGSa694

[QUOTE=winders;8977126]Double blips are not required or desirable when double clutch downshifting.

QUOTE]

So you're telling me that with your tiny clutch/flywheel that the revs stay up long enough that you (if you're double clutching) can blip in neutral, get the clutch in, engage the lower gear and then release the clutch without needing to blip again (if even a little bit) to match revs to road speed.

Not in my car and I have the same setup. I'll find that video of one of the factory boys driving a vintage car. Double blip each time...

I'll go get Kibort if you don't play nicely.

On my daily driver 325i I've been heel and toeing and double clutching since I got the car, the pedals are nicely set up for it. I must be doing something right because at 200,000 miles the clutch is original and the trans still shifts smoothly.

When it's done quickly and correctly, particularly on a track or mountain road it is quite rewarding and ads to the driving experience of a sports car. It is something that manufacturers who are ditching manuals for PDKs, have forgotten about and think they know better when it comes knowing what we want.

Some cars have gotten so fast that goofing up at speed can be a real drag. The fact that F1 cars have paddle shifters may have something to do with the trend as well.

I avoid 1st. My approach is as you describe above - 2nd gear, and as with all my corners in the 930, on the gas waay earlier than you are used to in a NA car. So you have an extra degree of difficulty with the notorious lag, and an extra judgement of the timing of the throttle. Depending on the corner type I am often nailed to the floor before hitting the apex. You could wait til all straight and you would be safe but loosing bags of time and watching NA cars fly past. So you want your braking well done on the straight and on the gas as you arrive at the corner. This changes your braking points a little - sometimes I can't brake as deep/late into a corner as the 930 brakes would let me, because I need to be on the gas, spooling up for a fast exit. Slow in, fast out usually wins.
So try 2nd gear , forget the 1st downshift (save on one upshift = saved time) and finish braking fractionally earlier and straight on the gas. You should juust be beginning to turn - or about to start. You have to judge when the whoomph is going to kick in. :-)
Alan

Very helpful...

I am usually late braking just short of the apex, and applying has at the apex.... But then you have to brake down to a pretty low speed prior to the corner, as you can't carry the braking into the turn...

Will practice...

Still seems first gear would be way faster on exit...

Try both - 1st and 2nd. 2nd works for me (and leaves you less busy in a tight corner). Applying gas at the apex will leave you in the lag zone on exit - where you want the power. It is counter intuitive and you have to take a brave pill and un learn what you may do in a NA car. It is definitely a different technique, but I am sure you will get comfortable with it after a bit of practice , and getting the timing right and hitting exit on full boost is something only a turbo (930) driver can experience :-). Depending on the corner you moderate the rate you get the pedal to the floor - but you are definitely well ahead in that step than in a NA car.
Probably getting OT - but just answering your query. You can PM me if you want.
Regards
Alan

Yup. in my turbo speed3 it took me a few sessions to perfect managing the lag. Much less than the 930 I am sure, but I had to manage it. It quickly became subconscious. My problem was that coming out of a hairpin in 2nd, my car was trying to put down 280lbs-ft through the front wheels at 2000-2500rpm, while turning. Too much and you don't make the turn. Balance that with a bit of lag, and a new patch of pavement with pebbles on corner exit, and the torque biasing diff got a lot of work. Fun though.

1st gear would be unusable in my case. No way to put that power down. and even with second, by the time I was straightening the wheel, I needed to go to third, so 1st would be a shift with way too much lateral G's. Trouble.

For the 911, I just don't see stock 1st being useful on the track. Might be too much torque to keep the car stable, and with a slower shifter, you would be out of it so fast that gains might be lost with the extra shift. Just keep the momentum up in second. Mind you, my 911 has a shorter second (with extra power and less weight), and it eats our hairpin up right now. Vicious.

Agree - using the turbo power usefully in first is a challenge on its own, and more gains made making full use of 2nd - for me at least.
Alan

gotta say the another reason for heel toe, rarely mentioned, is to clear and sharpen the motor on decel esp hotrod engines with carbs. such a great sound. and no automatic or paddle shifter car will ever be able to make that sound during hard braking into a corner. it's a preamble to the loaded wail of exiting the turn. ya know?

+1+1+1
The sound of a good downshift is hard to beat. Quickly followed by another, and another. Ooooh.
Alan

Hurley Haywood and Motoman heel and toe session in GT3:
https://www.youtube.com/watch?v=YqYeusE8ksk

OK I've dabbled with H&T here and there and have never found a true need for it (I'm strictly a road motorist, not a track driver). As far as I understand the most important element of H&T is to rev match to keep the car's momentum from hiccuping when you release the clutch during a downshift. Here's my technique that ASAIK achieves the same result, what am I not understanding?

1. Brake
2. While continuing to brake engage clutch and shift into lower gear
3. Get off of the brake and hit the accelerator to roughly rev match
4. Then release clutch and accelerate further

To me the wasted time/element of H&T is that you 1. Brake 2. Clutch and downshift 3. Blip the throttle to rev match while staying on the brake 4. Release clutch 5. Pivot your foot back to be fully on the accelerator and then hit the gas.

Seems like a slower (more steps involved) process than my technique because after the H&T blip rather than fully hitting the gas you then are still partially on the brake and need to pivot your foot to be on the gas. Clearly I'm missing something so help me out.

Tom and I made this video to help with the understanding of the benefits for implementing the heal and toe double clutch process

https://www.youtube.com/watch?v=0TYD4aOvN80

Ian

Sigh....

Before synchro box's existed one had to match revs to shift gears efficiently...also. On the earliest cars and even up into the 40's many vehicles came with the accelerator in the middle and the brake right/clutch left. GP driver from the 1950's, Mike Hawthorn, always asked to have his rides set up like that
That is where the term originated as it was very easy to step on the brake with the ball of your foot to the right of the accelerator and touch the accelerator with your heel.
We have simply learned to do the same with a bit of ankle gymnastics with the 'modern' layout.

Heel/Toe work keeps your car balanced when downshifting thru corners.... not moving the point of balance forward violently as a normal downshift would.

Like riding a bike, when you get it you get it.

H&T and double clutching / double de-clutching are related of course, but not the same thing.
Rev matching without double clutching does achieve the benefit of reducing momentary locking of the rear wheels upon selecting the lower gear. Not as much of an issue on the street, but on track it can happen frequently under threshold braking. Helps reduce shock to the drivetrain a bit too.
Properly executed double clutching also gets the trans input shaft spinning at more equal speed to the output shaft to ease the engagement of the gear hub and dog/synchro gear. While not necessary, it does further ease the shock and wear on trans parts compared to rev matching, and certainly compared to doing neither.

OK now! That is very helpful, seems that double clutching is the element I didn't understand (balancing the tranny speed). That combined with H&T starts to make sense now to me, thanks!

This is starting to penetrate my slow revving brain, thanks!

I don't like this technique as compared to a H&T blip on throttle. You run the risk of burning your clutch out by getting on the gas before you release the clutch. Bad technique. Blipping the throttle then releasing the clutch means the flywheel is free spinning and can take up the load on the clutch progressively. It is easier on the clutch than a normal downshift.
Alan

I've use the 'heel/toe' technique for ever. Also I've never had to replace a clutch. I heel/toe and sometimes double clutch to keep the clutch and engine speed nearly the same. I have replaced a clutch but only if I had the engine out for another reason.

So if I understand this correctly the advantage of blipping the gas during a H&T versus what I was doing is the clutch is engaging while the power is spooling down versus engaging while the power is being added assuming the clutch engages at equal revs in both instances?

The only good reason to doubt-clutch with a 915 is if you want to make the synchros last longer. Or, if you think it is cool. You certainly don't need to do it. There is no performance advantage in doing it. There is a great reason to do rev matching on downshifts which is to prevent a sudden increase in engine braking.

I practiced heel'n'toe in the 944, and would use it often. When I bought the 911, I didn't initially find the pedals conducive to it (and a sloppy 915 was a lot to deal with at the same time), so never used it.

Until one day I was decelerating on the (curved) approach to a roundabout on a semi-greasy country road where the entrance with priority was completely obscured until you were basically almost on the white line and could see down it.

Without any conscious choice, heel'n'toed the shift keeping the weight distribution & braking constant while selecting an appropriate gear for the decision point. And I've used it in the 911 ever since.

If all you use it for is to keep the weight bias the same so the car isn't unsettled by you coming off/reapplying the brakes while downshifting - good enough reason right there, in my book.

Many seem unhappy with the 911 pedals and the way the accelerator tends to be lower than the brake engagement point. I find hanging the ball of the foot off the brake pedal, turning the foot sideways and rocking the foot to blip with the heel works great. Never felt the need to modify or adjust the pedals - as they seem about perfect to me.

I abandoned attempts to left-foot brake long ago though; muscle memory seems to want to drive the left foot down as though it's on the clutch; takes a lot of practice to get past that, it seems...

Also, gears are in a constant mesh.....they never crash into each other unless something breaks.

Cheap, easy, quick fix for the pedal relationship when using the stock pedals. VW Beetle gas pedal rubber slipped over a piece of wood paneling glued to a piece of plywood and bolted to the stock pedal.

http://forums.pelicanparts.com/uploa...1669583605.jpg

http://forums.pelicanparts.com/uploa...1669583605.jpg

http://forums.pelicanparts.com/uploa...1669583605.jpg

If we're doing videos, this just shows you're not really a boss unless you can do it in Gucci loafers.

https://www.youtube.com/watch?v=kzLjZWrpzmQ

^^^I was about to post that video too, truly an art form with the feet.

It's actually the way he feathers the gas that's most interesting to me.

In my opinion, your technique is perfectly fine for the street but it doesn't function well on the track where your braking and cornering forces are much higher.

Heel toe is more faster on track, and will keep the car more balanced as there is less time when the car is not being balanced via brake/throttle. You downshift while still braking.