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Was just watching the Rolex series from Laguna Seca. They had a "foot cam" on the driver of Patrick Demsey's car. He was rev matching on the down shifts without using the clutch. Just heel toe. The announcer said "only time these guys use the clutch is leaving the pits."
How do they do that without lunching the tranny? Is it possible to do that with our cars?
 

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Aren't those cars all sequential?

It's possible to shift any car without the clutch if the timing is spot on. A very few times I've caught myself doing that, the muscle memory or whatever just sensed the timing was right, as much by sound as anything I guess.

Braking just right makes as much difference as the throttle blip under heavy competition braking.

Many racers have "brought her home" with failed clutches or lost gears.
 

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Clutchless shifting

As someone else said. It is possible to do with any tranny. The question is whether it was built for it and how much damage it will do.

Race trannys have dogs for sunchros i.e. metal gears. They grind but do not break so easily. Street trans have soft bronze synchros that are quiet and easy to shift with the clutch. Porsche used to have baulk ring synchros which are very hard to shift without the clutch.

Bangin gears i.e. not getting into perfect synch when shifting especially when power shifting breaks trannys really fast, no matter who made them.

Racing transmissions have tougher synchros, tougher (wider) gears, different gear materials (9310) and are usually warmed up before use. They are also rebuilt after every race, because once the gear teeth or syncho dogs break off, they go through the trans and grind the rest of the gears up!

Anton

Was just watching the Rolex series from Laguna Seca. They had a "foot cam" on the driver of Patrick Demsey's car. He was rev matching on the down shifts without using the clutch. Just heel toe. The announcer said "only time these guys use the clutch is leaving the pits."
How do they do that without lunching the tranny? Is it possible to do that with our cars?
 

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Most race cars with dog gear sets also utilize an engine ignition cut system, hooked to a strain gauge in the shifter or shifting paddles. Move the shifter (with pressure) and the system will momentarily cut the ignition/fuel/ignition timing retard, which takes the engine's load off the gearbox for a brief moment. Effectively, it's the same as what a stab of the clutch to disengage the gearbox from the engine would do.

Depending on how it is setup, you then have the potential to upshift with a flat throttle, and also downshift without a clutch. But there are a lot of different variables/combinations/options as to how to set them up.
 

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i only use the clutch to start from a stop, or to coast to the grid in the FF. hewlands are dog boxes, no clutch needed, just rev match. - but you do need to rev match to get it in gear....
 

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He was rev matching on the down shifts without using the clutch. Just heel toe.
Wait. If you are not using the clutch, why would you have to heel & toe? You have two pedals, you have two feet. Left foot brake, right foot power. The only reason I can see to go clutchless is so that you DON'T have to heel & toe.
 

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Wait. If you are not using the clutch, why would you have to heel & toe? You have two pedals, you have two feet. Left foot brake, right foot power. The only reason I can see to go clutchless is so that you DON'T have to heel & toe.
some people have uncoordinated left feet and can't threshold brake...

we were discussing this on apexspeed and one thought is that in formula cars it is much easier to left foot brake, while in production cars it more difficult. due to pedal travel and pressure. but... a lot of older formula car you cant get to the brake with your left foot due to things like steering shaft between your feet.

on mine, i can. i mostly left foot brake. then there is the argument that if you can heel and toe well, is there any benefit anyways to left foot braking?
 

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It's actually pretty easy to down shift without the clutch (at least if you're just cruising around calmly). I've only done it a hand full of times but if you're in gear and cruising or accelerating gently when you want to shift, lift on the throttle at the same time as you pull it out of gear... with no load on the tranny it slides right out of gear, stay off the throttle and then somewhat quickly but gently move the shifter to the next gate and hold it lightly against the gate (use your fingers on the shifter, not your whole hand for the sake of feel) and it'll pop right in to the next lower gear when the revs drop down to match. Apply throttle now that you're in the next gear and off you go. I'm not very good at rev matching on up shift even with clutch so i have no interest to try that.
 

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some people have uncoordinated left feet and can't threshold brake...

we were discussing this on apexspeed and one thought is that in formula cars it is much easier to left foot brake, while in production cars it more difficult. due to pedal travel and pressure. but... a lot of older formula car you cant get to the brake with your left foot due to things like steering shaft between your feet.

on mine, i can. i mostly left foot brake. then there is the argument that if you can heel and toe well, is there any benefit anyways to left foot braking?
Traditionally left foot braking is HARD to master, especially more than H&T and in cars that aren't Formula based/similar.

Improved stability, smooth transition, trail braking, building boost. It's VERY handy in FWD cars.

I'm not very good at it, but I haven't driven many single seater cars. I prefer H&T/three pedals/two feet.
 

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I got used to shifting without a clutch during my early years when I went through tractor trailer driver training and earlier than that with a friend from work who has his comp racing license and learnt on my Mini. It's easier on certain cars. I found imports are easier. Friend's Nissan's and Mazda's were real easy. You just have to play around with it. Depending on the car, just move the shifter around a bit and tickle the following gear up to see where you need the rpm's to be. When downshifting, you need the rpm's higher before you do it. Once you get used to where it needs to be, than you're golden. Cant say I do it with the Lotus too often though.
When I had my Jeep, I could find that I was left foot braking a lot. Certain vehicles allow more room and/or pedal placement for better control so you're not applying too much pressure.
 

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It is possible to shift without using the clutch, and I do it every so often, but you have to perfectly match the engine speed to slide the shifter in gear without grinding. Unless you got it down perfectly, I don't think it's such a good idea to do this, because try too hard, you'll be grinding gears and you know the end result if you abuse it too much.
 

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I never use the clutch on race and track days on my bike. :evil:

Just gotta blip the throttle and time it right. Never had any issues either with the same transmission for 7 years.
 

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Not a good idea on a Lotus. Clutchless trans dogs are cut with a pent-roof design so they can partially engage. With flat topped dogs like the Lotus you will eat them up a bit and shifting will degrade.
 

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I've never had any success smoothly, repeatably and quickly shifting gears without the clutch on a syncro box. I'd had to do it a few times when clutch hydraulics failed, but it was messy.

A proper race box with dog rings is a joy to work with. It takes some practice but the shifts are so quick and solid. And I recenlty drove a sequential with a pneumatic shifter and controller that handles the blip going down and retards power for no-lift going up and all I can say is I need to perfect my left foot braking.
 

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That's all it is really good for, gently limping home and avoiding a tow.

LFB in a Lotus specifically would be even harder than usual... those pedals are so damned close!
 

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Wife had Beetle convertible. We were in rush hour traffic in middle of Holland Tunnel when her clutch cable snapped.

"What will we do??!!??", she asked, in a bit of a panic.

"You're going to let me drive."

Aside from having to shut the car off to move from a standstill, it wasn't a problem. (It helped that I hated that car...)
 

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I've never had any success smoothly, repeatably and quickly shifting gears without the clutch on a syncro box. I'd had to do it a few times when clutch hydraulics failed, but it was messy.

A proper race box with dog rings is a joy to work with. It takes some practice but the shifts are so quick and solid. And I recenlty drove a sequential with a pneumatic shifter and controller that handles the blip going down and retards power for no-lift going up and all I can say is I need to perfect my left foot braking.
i have to say i prefer left foot braking, and when you get a dog box right... its lovely! flappy paddles just seem to lack too much romanticism for my taste though... i have my limits on technology!
 
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