Spinelli, that is only true of touring and street stock series that use a gearbox with synchro gears. Synchro gears wear quickly, break and slow down a shift so before the advent of semiauto boxes, double clutching was necessary for longer format racing to save the straight cut dog boxes. In Sprint races or for big budget teams in series that didn't limit gearboxes, they would crash gears but that is an expensive habit and of limited time saving. Different drivers have different techniques for shifting. But double clutching is still used in real racing cars. Spinelli you are right as far as touring cars and street stock racecars are concerned and also street cars, but true purpose built racecars are stuck in the 30's because as it turns out, that is the quickest way to shift for a very skilled driver. This weekend I'm going to elaborate and write up a report on the history of double clutching with quotes from books I have which have diagrams how it is done and quotes from drivers in the 60s-90s
I'M at work right now but this is going to be my weekend project. I have the chapters of the books pocket out, I'll scan them and make a Google Docs with the info. Keep your eyes peeled
Sorry Guy Moulton but you are incorrect, not only can dog boxes be shifted without the clutch, but they can be shifted much quicker than street cars with syncros. Pretty much every race car uses dog rings and almost all can be shifted without the clutch. Watch any race of a formula 3, formula 2000, formula 1600, etc etc in the last 40 years and you'll see lots of drivers doing clutchless shifts. In fact I've done it myself in a f1600, a couple different f2000s, and a BMW powered open prototype looking thing (450ish Hp). NASCAR drivers do it all the time, GT drivers, etc etc. When on full throttle coming to redline you kind of preload the shifter and when you hit redline and give the gas ba quick lift the gear jus so nicely but quickly goes into the next gear. Now.... due to no syncros if you do this wrong a few times you can destroy gears on teeth VERY quickly, and I have seen this happen first hand at the track and even helped with the teardown/repair of the car. True double clutching is what I explained in my first post (double pump of the clutch, while blipping in between pumps )while in neutral) and again, it hasn't been necessary to use it in like 40 years. There are odd cases here or there like in a situation where yiu are trying to be extra extra carefull, but even most of those times the driver would just use the "normal" clutch way for downshifts and upshifts, rather than actual double clutching. If some guys want to double clutch on up and/or downshifts because it may save the wear and tear by 2% over using the clutch in the normal single pump way that's cool, but it hasn't been needed, or even remotely common since like the 40's or 50s or whatever it was (sometime "back then"). It wasn't about trying to save that last bit of wear and tear, it was just something you had to do or the cars would just not change gear at all. It was a normal requirement of driving.
I read Carroll Smith's book "Drive to Win" a couple of months ago and he talks about shifting a wee bit, and basically says that every driver should learn to clutchless shift, as there is no point in heel/toe driving when you can clutchless shift perfectly fine in most race vehicles. I'm trying to remember exactly what he said, but that was the gist of it. He also said skipping gears when downshifting is the best thing to do. No need to cycle down through each gear when you can just skip them, which also helps control engine braking more as you aren't having to keep matching your revs and correcting your braking input for the change in engine braking at the rear wheels.
It actually makes perfect sense. I was forgetting that with a clutchless change you would be left foot braking
From my experience there is no need to blip or use the clutch when downshifting with h-pattern dog box. I know some prefer to blip or clutch, but it's really depends on you driving style. If you use the clutch in a dog box you have greater chance of damaging the dogs. I recommend reading Hewland's advice on the matter here: http://www.hewland.com/svga/advice.html
I forgot I have a copy of Skip Barber's Going Faster. Remembering I skipped ahead to the chapter on shifting. Per Skip Barber if real drivers are really good they can complete downshifts without using the clutch pedal. ( Move lever to neutral, blip throttle, shift into lower gear.) However Skip Barber recommends double clutching (or double de-clutching) to downshift. Again upshifts can be accomplished without touching the clutch pedal but Skip reccomends (if I understand his book) a partial depression of the clutch pedal while letting off the gas in order to rev match. To what extent can a dog box transmission be modeled in rF2? I hope ISI simulates real life transmissions to the extent possible. SW
http://isiforums.net/f/showthread.p...nd-double-de-clutching-in-racecars-discussion I posted a discussion to clear things up. A lot of it depends on the driver and whether he needs to save the gearbox. That said, Skip Barber, Bob Bondurant, Piero Taruffi, Niki Lauda and lots of others say to clutchless upshift and double-clutch downshift. But I am not expert. 3-time Formula 1 Champion Niki Lauda- who raced from the late 60's to the 80's in various cars starting with hill climbs, spanning the early F1 wings era up to the turbo and ground effect eras says of double clutching: Check out my google doc for more info https://docs.google.com/document/d/1_FOy_HHySYqa8mAVErdvh_McYkwhG2FRn3oTvYcqSJE/edit?usp=sharing
Unless I'm not remembering correctly, I don't think I saw the guy do a single double clutch in the entire video version of skip barber going faster.
