Turbo_F1

so i was driving home from work and was shifting from thrid to forth and then my leg was feeling usually heavy. So I pulled the gear out of third and lightly placed pressure toward forth. The rpm is falling from 3k downward. In the time it took me to think how heavy my left was felling to place it on the pedal, the gear fell into forth without any effort.

Now, and let me emphasize this, I am not ignorant, but i am certainly not in the know, is it ok for all components invovled with the clutch and transmission for this to occure and keep occuring(it kind of fun)?

Thanks

YayeR

yeah it's fine. that's called rev-matching and it's actually easier on your transmission (at least your synchros) than slamming gears using the clutch.

DamonB

Like anything else if you know how to do it correctly there is no harm. Doing it incorrectly will break things quickly.

I frequently upshift and downshift without the clutch when stuck in stop and go traffic but I always use the clutch when driving "fast".

All the clutch does is remove the load from the gears in the tranny. If you time it right you can breathe the throttle for an instant and do the same thing without using the clutch. Breathing the throttle will let the gears unload due to lash in the gear mesh. You have to time it perfectly though; not recommended for the ham fisted among us.

BLKTOPTRVL

No, it is not good for the car. Keep doing it and sooner or later you will kill your syncros. No matter how well you think you are matching speeds, sooner or later you will miss once, twice, thice. Each time, you are doing a little more damage to the trany. Why bother when you have a perfectly good clutch to use?

I learned how to do it years ago when my clutch cable snapped. I was able to get the car home from a long distance by shifting without, and starting in first gear. The starting in first gear probably did incredible damage to the starter and to the trany - much more than the shifting, but again, if you have a clutch, you might as well use it.

NCMontegott

iTrader: (5)

the only advantage of shifting without depressing the clutch is that you are able to accelrate faster. but if you wanted to be able to shift without the clutch all the time why dont you just have you trans refitted with dog clutches

BLKTOPTRVL

Why would you be able to accelerate faster when you have to lose time matching speeds? Are you talking about slamming it into gear without the clutch at high speed?

dohc-vtec_eg

can someone explain this plz. i want to try this on my car but i dont want my tranny to blow

Kento

Then don't, because learning how to clutchless shift on a synchromesh transmission will only lead to worn/broken synchros. An FD transmission can't take very much abuse before you're left with a junk gearbox. If you have a POS daily driver with a manual transmission, you could probably learn on that, but in the end, why? It's only something that someone with a lot of experience and skill behind the wheel should do with any semblance of regularity, and you can only do it in certain situations.
Uh, you mean a "dogbox" transmission, meaning the gears (not the clutch) use dog engagement instead of synchromesh rings.

adam c

iTrader: (2)

If you are too lazy, or not smart enough, to use the clutch when you shift, you deserve the expense that you will incur when it breaks. There is NO reason to shift the car without using the clutch.

YayeR

except that it's fun. you're right it's not any better, i was just trying to tell him that it's normal in that it's not a symptom of a problem.

FLA94FD

At low RPM say 2500 in 3rd let off the gas and gentle pull back to 4th and it will slip right in with no problem. If you must do it. Before I had my trans rebuilt I did all the time and the rebuild had nothing to do with clutchless shifting the output shaft was damaged when a rear end dropped.

quicksilver_rx7

Kinda pointless unless you are aspiring to be a truck-driver.

"10-4 rubber duck"

rynberg

Exactly. My grandpa, who was a long haul freighter, made it about 600,000 miles on clutches shifting that way....

t-von

iTrader: (8)

It's actually fun doing this very now and then(especially when giving someone a ride who has never seen it done before). It's perfectly safe if you know what your doing.

dgeesaman

iTrader: (7)

I agree. Some gearboxes are designed to handle clutchless shifting (trucks, etc), and some synchromeshed boxes can deal with light abuse as well. But the FD gearbox is optimized very well for clutched, synchromeshed shifting and straying out of that mode of operation is IMO destructive to the transmission, either in the short or long term. I've done it, but on my daily driver. I know I'm not consistent enough at rev matching to bother attempting in on my FD, which has all new synchros and much more traction and engine torque on each end of the gearbox waiting to shred them.

You gain very little, if anything at all shifting clutchless in this car. On trucks, or older manual gearboxed cars, it's a different story and for different reasons.

Actually the shift ring assemblies inside the tranny are called clutches as well. So the term dog clutch isn't exactly wrong, but it's not my favorite. Many variations on these terms depending on who you talk to.

Dave

NCMontegott

iTrader: (5)

yes the term dog clutch can have vairants but to my knowledge that is what they are called (thats the only term we used for them when we rebuilt trans with "dog cluctches")

DamonB

That's not true of most synchromesh transmissions unless you are abusing it. The synchros themselves only like to move so fast and forcing them by banging the stick around hard will at best wear them out quickly or at worst break them instantly.

I shift without the clutch only in heavy rush hour traffic where I'm rolling slowly and my left leg is tired. Shifting this way is actually slower because I have to match speeds perfectly but my left foot enjoys getting a rest on the dead pedal

NCMontegott

iTrader: (5)

you also have to remember that syncros only match speed at a certain rpm so technically i am incorrect but having to remove the pressure of the clutch and then enguage the next gear takes time, but if you do not have to depress the clutch then you are making up time while accelerating.

DaveW

Exactly correct. The key here is that with the clutch DIS-engaged, you are only using the synchros to match RPMs between the output shaft (car speed and mass related) and the trans input shaft and gears and its associated rotational inertia. With the clutch engaged, you are adding the flywheel and engine rotational inertia to that of the input shaft. Unless the two RPMs are almost exactly matched, the additional load WILL ruin the synchros, since they are not designed to cope with the additional rotational inertia of the flywheel and engine.