SlingShotRX7

For those that dont know:
WOT = WIDE OPEN THROTTLE (floored)

anyways.

Speed shifting is shifting gears with out using the clutch.

What is it called when you shift without letting off the throttle??
And do any of you do this with your FD?

its a natural movement to let off the gas while clutching and shifting.
wondering if anyone actually shift while they stay on the gas,
and what effects it has.

thanks

KevinW

iTrader: (1)

i havent in my fd but in audi S4 i picked up around .3 of a second in the quarter mile and a few MPH.

SlingShotRX7

so im assuming, not letting off the gas in between shifts, gives you better times.

Im wondering if this has any adverse effect on the car.

jagwrjack

iTrader: (3)

I always understood speed shifting or wide open shifting as stabbing the clutch
each shift, while keeping the throttle to the floor.
If your racing, there's no point in doing it another way.
If you do it and miss the 2nd to 3rd shift most of the time, welcome to the club.

Jack

RE Suzuki

I think it's called "power shifting"

DigDug

Yep, power shifting. Goodbye synchros!

POS7

^^ what they said powershifting.

Does powershifting noticably reduce tranny life? This is a technique I use with motorcycles, especially 2strokes because these bikes are high revving and you powershift to stay within the power band. In other words, normal shifting drops the rpms (bike takes time to build up power again). Powershifting keeps the rpms up while shifting, resulting in little to no powerloss after you shift.

As far as I know, it has no real negative effects on bikes (as I have been doing it for years).

Cars may be a totally different story, as digdug said it may kill your syncros.

quicksilver_rx7

When you shift, there is a certain number of RPM's that the engine must fall to allow the tranny gears to synch. That's what syncronizers are used for in passenger car transmissions.

18-wheelers are not syncro-mesh, and they shift without using the clutch at all (except from a dead start) unless they "double-clutch"

(which means: push in the clutch to move from first into neutral, then release the clutch and push it in again to move from neutral into second gear).

The trick is to get good at it without grinding.

Practice = Perfection, and you don't have to worry about tearing up the tranny or wearing out the synchros

dgeesaman

iTrader: (7)

Speed shifting = regular shifting as fast as possible and not letting off the gas.

Power shifting = shifting but only stabbing the clutch pedal and not letting off the gas.

Clutchless shifting = shifting without using the clutch

Speed shifting is hard on the clutch and tranny somewhat but only causes problems if the gear doesn't engage perfectly - you won't have time to back off to neutral before grinding them. Powershifting is harder yet on the synchros and clutch, and requires very good timing and pace. Clutchless is very hard on modern synchromesh transmissions, especially when the RPMs aren't matched.

IMO, when you get fast enough in the 1/4 that speed shifting isn't enough, then you have already installed a transmission designed for faster shifting. Otherwise, your budget has no problem keeping a spare tranny or two around for when (not if) they break.

Dave

quicksilver_rx7

if you want consistency, use an automatic.

dgeesaman

iTrader: (7)

Are you advocating clutchless shifting on this car? If so, I think you're full of hot air. (Or are you advocating double-clutching because it prevents synchro wear? If that case, it's going overboard)

Truck and motorcycle transmissions are not designed like the RX-7s transmission. Without synchros you can smack them from gear to gear a little bit. Do that on this car and mis-time it a bit, and you'll grind your synchros and bent the teeth on the clutch sleeve. RX-7 trannys are tough WHEN DRIVEN PROPERLY.

Unless you've got experience rebuilding these gearboxes after that kind of abuse, then I'd love to know how that works. I'll bet your tranny fluid is full brass shavings.

Dave

quicksilver_rx7

NO, I'm NOT advocating clutchless shifting, or double clutching. Apparently you didn't "READ" my post. If you would "READ" my post, I was simply telling the guy that it can be done. I NEVER SAID that I was an advocate.

dgeesaman

iTrader: (7)

I did to re-read it a couple times and still it wasn't clear. So by process of elimination, "Practice = perfection" is about regular speed shifting?

Dave

Ripzta

In Oz we call it flat changing (shift w/ clutch but still WOT). I've only flat changed 2nd to 3rd once and wheels churped :p. Tried again and crunched 3rd! Still have tried again...

tcb100

I "power-shift" (WOT and using the clutch) routinely at the drag strip.

My new Mazda tranny lasted about 30 runs. Syncros are shot. Probably not a good idea.

Ripzta

Heya TCB100, 11.69 and 11.80 damn those are quick times! Street tyres?
Hows the launch kit help? And how much boost where you running?

tcb100

No, not real street tires. Mickey Thompson ET Streets.

I'm not really sure if the launch kit matters when using the ET streets. The kit does reduce wheelhop some at launch on street tires. They do wear and start to clunk after awhile though.

As far as boost goes, as much boost as the tired (80,000 miles) stock sequential twins will produce, for me 17-18 lbs on 103 octane race gas.

APEXL8T

I WOT with clutch. As log as cutch is in shft and the let out (with out missing) I dont see the synchro problem.( I may be wrong) But...a shift like your motor bike is different because it has DOG RINGS in place of brass synchros. These are made to hit hard. They look like a ring with swedges on them. The synchros has many fine teeth.