sure can.

 

Care to enlighten us, oh wise one?
Look,
the only knowledge that you've expressed so far is that you don't know how to read a thread, and you obviously have no idea what's going on inside your transmission. We've discussed this already, yes we've discussed that it's not necessary with synchros, and we've even discussed WHY it's useful on a tranny WITH SYNCHROS... Do us and yourself a favor if you want to contribute anything further to this thread and READ IT, PLEASE.

You do realize that your statement makes no sense, right?
The WHOLE POINT of double clutching PROPERLY is that you don't wear on the clutch OR the synchros during a downshift. If you'd have read the thread you'd understand why.

On top of that, I don't know where you think double clutching is "newbie-ricer-boy", nothing about it is flashy or showy. It sounds no different than a normal rev-matched downshift, it is simply mechanically smoother. It takes a ton of practice and discipline and is purely functional. How does that make it "rice"? If it was something that thug-boy sideways hat and baggy JNCO-wearing techno-thumping I.C.E. slammed 'til they scrape neon-lit primered body panels 20" chrome wheels and vinyl sticker-b*tches were doing, maybe there'd be some association, but I don't get it.

So please, either enlighten us all on your magic techniques or read the WHOLE thread before you decide to add your ignorant commentary. The thread is full of solid information that doesn't need senseless banter cluttering it up.

like this:
WOW, how can you be so knowledgable in so few words?

 

haha wheelhaus, i love your description of the "riceboy"

 

for the sake of keeping an informative thread I will just stick to the facts instead of making this a pissing contest.

Way back on page one someone brought up the technique of throttle blipping while the clutch is still disengaged durring a downshift on a modern syncronized transmission. Upshifting while utilizing double clutching is pointless on our cars because in the time it takes you to shift, your syncros and gears slow down to come close to matching the reduced engine speed when you trottle off durring clutch disengagement. That is the technique that should be used for downshifting a syncronized transmission with modern syncros. There is a miniscule increase in wear to the syncros, however less wear on the clutch because you are only "cycling the clutch" once. If you dont believe me, you can feel free to call up a driving school and ask them what the proper downshifting technique is for downshifting a modern syncronized transmission. In road racing, your clutch or a shift fork will go much faster than you will wear out a syncro; and in drag racing double clutching is moot.

 

Ok, now I see your point more clearly. I wholeheartedly agree that double clutching for an upshift is almost completely useless. When you upshift, the synchros are naturally slowing down to match speeds. a single clutch action is plenty, as you can also use this extra oomph between shifts for accel.
You're completely right when you say double clutching for drag racing is moot, and it will actually cause you to lose time between shifts.

However, downshifting is different. The synchros are forcing the input shaft to speed up, which is much much harder on them. It is a miniscule difference, but synchros are relatively delicate so the relative difference is much larger. (I don't double clutch every downshift, hell, I rarely do it at all, but the principle is sound and factual). Eliminating the synchros for a high rpm upshift helps to eliminate some friction, and that helps to eliminate heat. The 6sp has a bit of a problem with heat, so anyhting to reduce it is welcome.

A proper double clutch downshift prevents clutch plate wear, and synchro wear even how minute it may be. And granted, fork wear is sublective. Bhcevo's description says it best... Clutch in, neutral, clutch out, rev match, clutch in, gear, clutch out, go (or repeat). these actions mean the only items that are being used are the diaphragm and the fork, and the engine. If they are sound designs, there's no reason for them to wear out prematurely. This is especially good for cars that have underbuilt synchros (such as many have reported with the Evo).

I agree that synchros are there for a purpose, and they're still a wear item. The benefit of eliminating them form the equation (even though you may think it's too small to worry about) is still valid. Be it learning to drive a dog box before you actually get one, or simply learning for the joy of it, it's not needed per se, but it's a stretch to say there's no reason. Whether you think it's ultimately worth it is up to you. However, its still the (mechanically) smoothest and least harmful way to downshift.

 

i agree with you man.

 

almost everybody thinks that you can only double clutch on upshifts. the fact is that you can do it on both up and downshifts but more people only use it for upshifts so they think you can't do it on downshifts. it really isn't necessary (double clutching isn't very necessary to start with on a car with synchros), but that doesn't mean you can't do it and it has absolutely nothing to do with fast and the furious. the driver in the video is a pro driver and if you really know how a transmission works, you'll understand why double clutch downshifts work. upshifting and downshifting when double clutching uses the exact same principles, to manually rev match. I do this on every downshift in my every-day driving and I know exactly what I'm doing.

"However, in order to downshift, engine revs must be increased while the gearbox is in neutral and the clutch is engaged. This requires the driver to shift into neutral, release the clutch pedal, apply throttle to bring the revs up to a suitable speed, depress the clutch again, and finally shift into gear. This operation can be very difficult to master, as it requires the driver to gauge the speed of the vehicle accurately and is often conducted as cars in front slow down."

and also go here to learn more about transmissions:

http://www.waycoolinc.com/z...

please no more telling me this isn't double clutching; it's basically double clutching on a downshift that uses heel and toe to blip the throttle. this is also another reason why I posted this vid - to show people what it is. ... (more) (less)


* QUOTED FROM exotictofu86*

 

your link is broken, xander.

 

I didn't think I'll post in this thread again (as it has been done to death several times), but anyway...

Heel & toe, rev matching and double clutching are driving techniques. They're in no way mutually exclusive nor always inclusive and really some people use different terms to mean different things.

you can rev-match with/without heel & toe
You can rev match with/without double clutching

you can double clutch with/without heel & toe
you can double clutch without rev matching althogh it would defeat the object of the exercise, so when you double clutch, the whole point is to rev match.

you can heel & toe with/without double clutching
and again, when you heel & toe, the aim is to rev match so not rev mathcing when heel & toe is possible but a bit pointless.

you can do both while up/down shifting but there is no need (synchro or not) to do it on upshifts. At this point, upshift = going from a numerically lower gear to a higher one, like 3rd to 4th as opposed to going up in gear ratio.

Say you're in 3rd doing 5,000rpm and you want to shift up to 4th. At this vehicle speed or thereabouts, the engine will want to be in a lower rev in 4th than in 3rd, and since the revs drop when you lifted off the accelerator, you can time it so that when you slot it in 4th the revs pretty much right. Since you can't use the accelerator to slow the engine down, there's little you can do by way or rev matching using the accelerator, unless you're taking a long, long time between gears in which will be slow in any case. Now if you some how are coasting at 60mph and want to slot it into gear then getting some revs up would be a good idea.

Then there's the thing about certain things being pointless. Well a certain degree of rev-matchin is a good thing anyway but there are certain things that are not needed as we have synchromesh boxes and there are things that are flat out pointless such as the above.