anLS1x2

I did a search for "what is double clutching?" and I didn't get anything or I just gave up reading through the endless threads ! I am not new to driving a standard but I am new to driving a performance one. SOOOOO what is double clutching? I have some more questions too but I think I will bring those up later if I can't find a "search" for them. Thanks for your help guys.

8-Pack

Double clutching is, revving the engine, clutch engaged, shifter in neutral to get both sides of the transmisson spinning at the same speed when you downshift. Not necassary on our cars because of synchronizers. It is a good idea to bring the rpms up before letting the clutch out when you downshift however. Try searching for rev matching, which is what I just described, there have been a few long posts about rev matching and double clutching.

sunsetz28

iTrader: (1)

Ricers like to double clutch.

MeentSS02

iTrader: (11)

Did you just get done watching the Fast and the Furious? Just curious...

You don't double clutch cars with synchros. It is just not needed. That is the synchro's job.

You are thinking of powershifting, which involves leaving the gas to the floor while you rip into the next gear. This puts a fair amount of stress on your driveline, but will make you faster.

I, for one, granny shift (just normal shifting). I am also slow. Therefore, don't ask me how to shift if you want to go fast. But the above is what I know.

TTopJohn

Even on cars with syncros, double clutching still makes the shifts smoother. I do it about half the time when downshifting. Makes the shifter snick right into gear, rather than apply pressure, wait a half second for the syncros to do their job, then the thing goes into gear.

STLTA

this may not sound right or be right with syncros, but i agree. i do it, not all the time, but it does smooth things out. i also rev match most of the time.

P Mack

iTrader: (6)

I always do it when downshifting. Synchros will last forever if they're always spinning at the right rpm before engaging the gear. Also the shifter goes into gear instantly and you don't get jerked forward like you would if you just slipped the clutch without rev matching. I would be willing to bet most ricers don't when downshifting even though Vin Diesel says to double clutch when UPshifting.

P Mack

iTrader: (6)

anls1x2, when downshifting the sequence is clutch in, shifter to neutral, clutch out, rev to rpms you will be at in lower gear, clutch in, shift to lower gear, clutch out.

MeentSS02

iTrader: (11)

When I made my statement, I was talking only of upshifting...on downshifts, I double clutch as well. It makes it MUCH easier to do a nice 6th to 2nd downshift.

So the bottom line is this:

1. Don't double clutch on upshifts unless you don't care about going fast
2. Do double clutch on ridiculous downshifts (like 6th to 2nd) to save on synchro wear.

405pathfinders

Question: Why do I let the clutch out prior to rev. matching? Why not keep the clutch in, rev. match for the lower gear and THEN let the clutch out? Seems like an extra step, but then again the transmission to me is like a woman.....mysterious and sometimes scary.

camaro99z

Yeah, I do the same thing. Just leave the clutch in when rev matching. Does that put more wear on it or something?

777

iTrader: (21)

i wouldn't think so when you let the clutch back out i think it lines the synchros up a little better but then again i don't know for sure...double clutching is used in nascar where they don't have synchros...also in ups trucks and 18 wheelers...that way they don't have to go replacing synchros all the time...i know your original post simply stated what is it...but you should just rev match...push clutch in rev the engine to where the rpms should be in the gear you are going to be in and let the clutch out...it should be smooth

P Mack

iTrader: (6)

The reason you release the clutch before you rev is to get the input shaft spinning at the same speed as the engine, which is the whole point. To shift into a lower gear, the input shaft has to accelerate to a higher speed, which is normally what the syncro's do. When you engage the clutch, you use the engine to accelerate the input shaft to a higher speed instead of the synchros.