and speed shifting?

 

shifting without using the clutch

 

I've always known that method as syncro shifting but hey, I was wrong once before!

Power shifting and speed shifting are one in the same IMO, but there appears to be different definitions out there:

http://en.wikipedia.org/wiki/Manual_...ced_techniques
Power shifting (a.k.a. speed shifting)

This is an advanced technique that gives a speed boost to the car when upshifting. This should only be used in racing applications (and probably only in very short races), as it is very hard on drivetrain components, especially if done improperly. Even done properly, it generally puts undue stress on the drivetrain, and shortens the lifespan of the driveline components.
To perform a power shift, keep the gas pedal on the floor (instead of lifting) while pushing in the clutch. At the same time, quickly shift to the next gear. Quickly re-engage ("pop") the clutch as soon as the new gear is selected. If done properly, the car will receive a "bump" in acceleration (due to the jerk of the decelerating engine) as the clutch is re-engaged. If done improperly, it can result in engine or transmission damage, sometimes catastrophic.
Shifting without the clutch

It is possible to shift gears without using the clutch at all, by careful throttle manipulation. When transmissions were unsynchronized this was usually the easiest method, and still works in modern cars, although it requires a lot more practice than the usual methods described above.
Although the technique works in synchronized gearboxes, it is inappropriate in nearly all circumstances. A synchronized gearbox has a small clutch called a synchronizer (or "synchro") in every forward gear which brings the input and output rotation to the same speed before allowing them to engage. Like the main clutch, these synchronizing clutches use friction. These synchronizing clutches will allow for a margin of error when engaging without the main clutch. If the engine speed is somewhat too high or too low, the synchro will essentially take on the job that the fully engaged main clutch isn't doing. However, a synchro ring is not intended to do the job of a main clutch. Its job is to spin up or spin down just the input part of the transmission that is assumed to be disconnected from the engine. It is not intended to speed up or slow down the entire engine. Such experimentation done on a regular basis will prematurely wear out the synchro rings, which will have to be replaced.
On cars with a freewheel, such as the older SAAB with a two-stroke engine, shifting without the clutch is standard procedure. But actually, the freewheel is a form of clutch: one that is disengaged whenever the input rotation is slower than then output rotation. One must disengage the freewheel by allowing the engine revolutions to drop, which is analogous to pressing the clutch pedal.

On the other hand, these guys are using it your way:

http://www.turnfast.com/tech_driving...shifting.shtml

Some of you may be tempted to learn the techniques of "speed shifting"--shifting without using the clutch--in the interest of saving time. Many schools and professional racers have shown over and over that there is no speed or lap time advantage to this, and it carries a much higher risk of gear box damage

 

I'm no expert, but powershifting sounds like it would be pretty hard on the tranny. Is it worth the potential reduction in ET? How much can you knock off?

 

I'd say 2 or 3 tenths in the quarter. I know lot's of people with manuals in thier 05+ stang that will powershift the 1-2 shift then just "quick shift" normally for the 2-3 and 3-4 shift.

 

Donkey Donut

 

1 to 4 gas stays on the floor.

 

Never Ever Lift (the loud pedal) if you want good ET's. If you are afraid of breaking something and you possibly should be then you shouldn't be racing it. Just my .02.

 

That might be the dumbest thing I've read in a long time... If you're spinning the tires and fishtailing, your "good" ET is already shot. Why drive it into a wall (or the other car) trying to be a macho moron??

 

Agreed,

Last night at the track I f'd up and spun hard on the first run and probably would have hit the wall if I didn't lift. Some ball-busting from my friends was a lot better than causing God knows how much damage that insurance wouldn't cover.

 

The point was to powershift for the best ET..... What are you talking about hitting the wall? Macho Moron? Where did all that come from? I never said hold it to the floor and hit the wall. C'mon guys give me a little credit, I may be newto the forum, but I've raced for years. My timeslip that I provided is on my stock Pirelli's so I think I can handle mine, thanks for being so polite and turning what I said around. Nice way to treat a new guy. Besides I just reinteratted what JP said.

 

Hey... what you said was: "Never Ever Lift (the loud pedal) if you want good ET's". That's dumb.

If you were talking about powershifting, you should have been specific.

 

I'm sorry I apologize for not being more specific. I said never ever lift the loud pedal in reference to the statement above.

My fault.

 

Just a friendly suggestion... if you're going to respond to a 2-month old post, maybe you should quote it so it's clear to the readers.

 

Sorry a newb here. I have been reading for a while decided to join and post my times after making a few passes at Mustang Week.

 

odd.... the 1-2 shift is where I need to granny it the most

 

What happened to the guy who said he was doing burnouts in 2nd gear? That was kinda funny is a sick sort of way...

 

I only do burnouts in 2nd gear... not enough wheel speed in 1st.

 

So do I. 1st gear burnout would not heat the tires up well enough.

Line lock on and dump 2nd gear @ ~5000 rpm.

 

Strangely enough, I haven't even been able to get to a track since I installed the line locks.