tragic00

so i dont know if this is normal or not, but my car wont downshift into 1st unless i'm pretty much at a dead stop. other than that the transmission acts fine, no grinds no nothing it feels great. its kind of annoying during autocross where i need to downshift into 1st i jsut wanted to check to see if its normal or not.

Mahjik

iTrader: (1)

Pretty much normal.

OriginalEmanresu

In just about every manual trans Ive driven, 1st is only there to get you started, after that Ive never had to drop out of second (Or rather, been able to). I agree it is very annoying in an autocross when 2nd might only get you up to 3500 coming out of some of the slower turns, especially in a rotary which is really made to run up high.

prescription 7

iTrader: (5)

Keep those revs up

7_rocket

iTrader: (6)

Wouldn't it do damage if your down shifting into 1st if your not already at a full stop?

FD3S2005

iTrader: (11)

match rev and it will allot you aslong as your not over reving it.. not sure if its bad for the car but iv done it

The Driver

iTrader: (4)

Normal

dinosaur

it slips right in 1st with Double-Clutching. Takes a lot of practice though.

http://video.google.com/videoplay?do...88575741675515

mikeric

iTrader: (20)

Double clutch and rev the hell out of it.

As stated, it is pretty much normal and you really don't need it unless you are performing very low-speed turns on an autocross. For the most part, leave it in second and drive the hell out of it.

RotorDream

double clutch....... mmmmmmmmm fun stuff

FurryRoadkill

I have a question. I watched that video, and the driver engages the clutch to shift to neutral, releases it and rev matches, and the engages it and shifts into gear.

but why release it after shifting into neutral? why not just keep the clutch engaged while you rev match and then shift into gear? does that make any sort of difference?

RotorDream

ive wondered that too, you can rev match without depressing the clutch at all for that matter, yea its dangerous and ive never done it on my FD, but i used to do it on my M3 just to see what would happen

Mahjik

iTrader: (1)

The easiest is just just explain what double clutching is:

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

Now, I've never needed to do it in the RX7, but then again I'm not an AutoX expert. I'm sure if I was a competent AutoX driver like some of the posters in this thread or around the forum, I probably would to get 1st when/if I needed it.

I do double clutch in my M3. The reason is because the transmission uses very heavy fluid. So during the cold months, it's take a long time for the fluid to warm up and the shifts to become smooth. Sometimes, the only way I can access the lower gears during this time is to double clutch.

Mahjik

iTrader: (1)

Another good video of the concept:

http://www.youtube.com/watch?v=0j-3xIZK-Bk

FurryRoadkill

ok i read the explanation of what double clutching is. But i still dont understand why there is a need to release the clutch when the gearbox is in neutral. I suppose i'll do it though, just for proper technique.

tt7hvn

iTrader: (5)

i don't understand why blipping would not accomplish the same thing; considering that the tranny already has synchros double clutching is pointless

FurryRoadkill

i think "blipping" is the same thing.

and i was just wondering about the technique, not whether it was necessary or not.

FD3S2005

iTrader: (11)

i do the double clutching, more like the heal n toe but i dont release the clutch like the guy in the video i just push the clutch as im moving the shifter to what ever gear im going to i tap the gas to rev match and release the clutch when its matched

dinosaur

going to first when the car is not at a complete stop can be difficult, think about when you are costing to a stop light and it changes to green a moment before you are completely stopped (aprox 2 to 3 MPH). You are too slow for second, but you can't get the shifter to go into first. Thats where this works well, and thats the only time I use it, in all other gears, heel and toe is all you need.

dgeesaman

iTrader: (7)

When you pull the car out of gear and choose the next gear, there are 3 sets of rotating parts, all going a different speed. There is the engine, which connects to the transmission input shaft/countershaft/gears, which engages by the shifter to the tranny main output shaft and driveshaft. The clutch sychronizes the engine and tranny parts, and the synchros / gear engagement synchronizes the output shaft.

Without a double-clutch, the countershaft and gears within the transmission are going a different speed than the engine and output shaft. The synchro of the next gear has to brake those parts to the output shaft speed as you put the shifter into gear. If the synchro system doesn't sufficiently synchronize the speed of those rotating parts you get a grind.

The double-clutch engages those spinning parts using the engine end. That's why you let the clutch out and blip - you set the speed of the countershaft and gears. So if you have your engine rev's in the right place, that gets the c'shaft and gears spinning at the right speed so that when you shift the synchro has a lot less work to do.

You'll see this done on synchro-less transmissions such as dog-face engagement racing trannys and heavy truck trannys.

The alternative is to push it into gear deliberately and let the synchro have enough time to fully brake the countershaft and gears.

dinosaur

thats a good explanation of what's going on. Double-clutching is something I learned many, many years ago when I had am MG Midget, they didn't have syncros for first gear. All other gears in the Midget had syncros, British engineering, go figure.

FurryRoadkill

wow.

thank you for the in depth explanation. Transmission stuff always confused me.
I will disengage the clutch in neutral from now on... well when i need to double clutch anyway.

Hitokiri_Gensai

iTrader: (2)

hrm... i heel toe downshift... habitual.

AdamBench

+1

i never downshift with out matching

Rotors R Cool

I completely understand the concept of double-clutching. But I suck at double-clutching while heel toe downshifting. Is there a special way that you guys learned to do this.

I wish I had another car that I could use without the fear of ******* up the FD's gearbox.

BTW are all dog-boxes synchro-less?