Cool. I'll have to try and make a point of trying it both ways to see which works best for me; it's always just been more intuitive to blip, then shift for me... Once the clutch is engaged, though, blipping should have no bearing on what happens inside the tranny or shifting and it just makes sense to me that the little extra time the tranny has to spin down while you blip first would help synchro wear and gear selection...

 

You ready for this kids?

source - http://www.wisegeek.com/what-is-double-clutching.htm


source - http://en.wikipedia.org/wiki/Double_declutch

For those of you who can't read, here's a nice video http://video.google.com/videoplay?do...88575741675515

I can come up with these sources all day....

The truth of it is that double clutching is NOT necessary (like I said before) as this is the job of the syncro. However, if you want to make your syncros last longer and have smoother downshifts double clutching is the way to go.

Just because I'm a new member here it doesn't mean I haven't owned/raced fast cars in the past. And there's so much wrong with the F&F I don't even know where to begin. Nothing tops the floor panel falling out of the eclipse for no reason at all. Why it was even there to begin with is an even better question.

 

Double clutching is useful for worn out trannys, very old cars, semi's, and some of the older/cheaper race cars.. For people that are wearing out their syncros in 75k miles, what the hell are you doing to your car? I have owned many cars and have gone through a lot of clutches, but only once ever needed to replace the syncros (and that was on a heavily abused car that was on it's second clutch during my ownership.)

 

You don't need to put in neutral. All you need to do is press/hold clutch, rev match while downshifting, release clutch. Why double-clutch it? Double clutching is for cars without synchros/worn synchros and the F+F crowd.

 

+1

Unless the synchros are being affected somehow WHEN the clutch is still depressed, it is an utter waste of time to do that double clutching crap.

Single-clutch-press downshifting FTW!

 

Besides, a perfect rev match will utilise very little of what the synchros do anyways, right? As long as there is no lurch and surge after the shift, you are doing the tranny a favor.

 

Synchros wear out after lots of regular downshifting. I used to own a mint 93 dodge stealth twin turbo. http://people.umass.edu/dthornic/pho...lth%20(13).jpg It drove like it did from the day I bought it to the day I sold it. I drove a bunch of other peoples 3000gt/stealths while I owned it and a good amount of them had grinding gears and less miles on their cars than me. I went for a ride with most of them and could see that it was from their driving style. Most of them downshifted every time they came to a stop and did not rev match. Some did crude rev matching and still had problems. I've witnessed it first hand.

Honestly, I don't really care how you guys shift and most of you won't experience worn syncrhos in your time of ownership, since these cars are still very new. However 7-10 years down the line, double clutching will make a big difference in how your tranny will shift.

 

Like I said, double clutching is for cars with no/worn synchros and the F+F crowd.

I ALWAYS rev-match... it's second nature to me along with heel-toe shifting. I do it every day so when I actually need to (touge or auto-x) I don't need to think about it... it just comes naturally.

 

"The purpose of the double-clutch technique is to match the rotational speed of the input shaft being driven by the engine to the rotational speed of the gear you wish to select (directly connected to rotating wheels)."

Rev matching by just blipping the throttle while shifting to the lower gear will only increase the engine speed to the rotational speed of the gear you want. It will not increase the speed of the input shaft because the clutch is disengaged. This is where your synchros will come in and match the revolutions for you. But just like your clutch, they will wear out over time.

 

You can come up with sources all day Spoolin but since Wikipedia is openly editable by the public, Ill stick to my own theorys.

 

I drive my -Z- like I stole it. Perhaps that is why the local Nissan -Z- dealer is currently installing tranny #5 in my car.

My advice.........baby the -Z- tranny if you don't want to have it replaced every 7.5 months.

 

The synchros become worn because of a lack of proper double clutching. At this point, you will have to start double clutching or your gears will grind on every shift and eventually strip.

Here's more reading for you http://www.triumphspitfire.com/healtoe.html

Proper heel-toe technique includes double clutching.

The reason you believe you think your fine by just doing a simple rev match is due to the fact that your synchros are making up for the slower input shaft speed for you. (as they are designed to).

I've yet to see anyone else post a source showing that simple revmatching downshifting will not cause wear on the synchros.

Like I said before, most of you won't see the bad effects of non-double clutching downshifts in your time of ownership. Just like most of you will not have to replace the original clutch (if you're stock). So you don't really have to worry about it. I was just correcting the OP because both he and his friend are wrong.

 

I agree that wiki is a poor source, however if you click on the sources below like I did, you'll see that that wiki summary is very accurate.

Just google "double clutching" and you'll see what I mean.

I'm surprised so many of you are so set in your ways and too stubborn to even read about how to put less wear on your synchros. But whatever, its your tranny, not mine. Mine will shift like butter for its entire life, much like my stealth did.

 

Ive yet to have problems with my current, and if I get a Z it will be under factory.After that I would probably lean towards a getrag anyways.

 

Good info Spoolin Z... it does say in there that it's more for older cars though.

My tranny will be built before my synchros go bad anyways, so even if it DOES wear down the synchros I'll be fine.

 

i downshift to 3rd and brake until i get to 18mph or so, then switch the neutral...i figure it puts less pressure on the brakes and its not a ton of shifts to screw up the trans

 

Ugh... that's a whole other can of worms...

 

If you plan to rebuild anyway you can go crazy

Happy to see at least one person listen.

 

I do the same.

I'll spend $50 and an hour of labor putting on brake pads vs putting on a new clutch, resurfacing my flywheel and possibly replacing synchros anyday.

 

granny shifting FTW F&FFTW