AnyonePower shift?

YzGyz

Anyone power shift in a strait line race? how long do you think your drive train will last if did it 2 x/wk? How long will your drive train last if your boosted?

Dwnshift

Not long

zae757

Not long at all

phunk

I do it 5-10 times a week from the 2-3 and 3-4 shift. Rarely 4-5th gear but a couple times a month I am sure. The 1-2 power shift I almost never do since installing the turbos (no reason to bother, its all wheelspin down there). But when the car was still all-motor I used to occasionally. The 1-2 power shift is the hardest to time and I will screw that one up often enough to discourage me from trying frequently. Its easier to do on a prepped track when there is no wheelspin leading into the 1-2 shift.

At 60,000 miles, my trans shifts smooth as butter except for into 5th gear. 5th gear scratches if I try to shift into it super quick. It has been this way since shortly after buying the car. Regular shifting its fine. My 350z was the same way also. I had even worse driving habits with that car because I was younger when I owned it. But the trans always held up minus the 5th gear quick-shifting scratch.

If you have a stock clutch and flywheel, you will get a nasty THUD from the dual mass flywheel bottoming out when you power shift. My differential mounts gave out last year. I was suspect of my engine mounts being worn and replaced them with solid mounts last year also. If you are going to do it just a couple times a week, assuming you do it correctly, you will be fine. But dont be surprised if the flywheel springs bust or drivetrain mounts let go over time.

__________________

YzGyz

I have had a lot of people tell me, "you tranz and rear end will bust on you fast by power shifting and not speed shifting." I then go on and ask them how bad is power shifting compared to launching a car form the dig. I bet launching form the dig puts a lot more stain on the drive train than power shifting. I don't do it often at all. I only do it once in a while on the street when someone wants some (75 drops to 3rd, gas and power it into 4th around 7200). I don't race much, but when I do, I do it to win.

My buddy also says your rear end plays a big part in how long things last. He tells me he has broken his rear end snapping shafts by power shifting. He runs drags radial and low psi running around on the road with his buddies. He said because his rears stick so well, the repeated torque beats on the shafts and breaks them.

phunk

the only thing power-shifting does is reapply power to the drivetrain with a lot more load and shock. Its not going to noticeably wear the transmission more because compared to a good normal quickshift, the RPMs are barely any higher, maybe a few hundred RPM. The extra shock doesnt seem to overwhelm it based on my experience.

Driveshaft is bullet proof, rear end is bullet proof. Ya the axles could break... but I think that is only going to happen if it was severely hurt by a launch and then let go during a shift. My stock 350z axles lasted about 50,000 of power shifting on the regular. My 370z is on original axles. Both cars only saw hard launches a couple times ever, as I do not generally go to the track, and nothing hooks up well enough on the street to even try and launch. Differential mounts and engine mounts are the most likely failure points. Assuming you arent missing shifts and grinding the hell out of the trans.

__________________

clintfocus

Enlighten the road course guy over hear, but what is the true definition of a "power shift"? is it just shifting fast and jumping off the clutch quickly?

phunk

power shifting is shifting without letting off the gas pedal.

for some reason, lots of people think power shifting is shifting without using the clutch pedal at all. id LOVE to see the incar video of a drag racer trying that with a standard transmission.

__________________

phunk

theres very little purpose behind it, but it does contribute to getting where youre going quicker.

For one, its just one less thing to worry about when focusing on shifting as fast as you possibly can.

As for actually making the car accelerate faster... sort of, it can. Since you will hold the engine at redline for the momentary duration of the shift, once you left up the clutch pedal, you get a mini "neutral-drop" effect, similar to the surge in wheel power an average automatic transmission gets when it upshifts. The inertial energy in the flywheel and crankshaft gets sent to the tires as the drivetrain has to suddenly slow the engine speed down to stop slipping.

edit: This is the same exact energy that causes the wheel chirp when you shift very fast normally, it just amplifies it with a little more RPM.

__________________

brancky3

It certainly helps a lot in a turbo car. I used to have a 2001 Audi A4 1.8T with a big turbo (GT2871R) that consistently ran a 13.1-13.3 second quarter mile. With powershifting I got it down to 12.7 since it kept the turbo spooled between shifts - probably exaggerated a little because its a (relatively) large turbo for a 1.8L engine but it was definitely faster

__________________

clintfocus

i have too much mechanical sympathy for such a maneuver

GSS138

For road course guys its something you save for that special moment. TT Record, first place Vs. the guy right next to you, etc. It will gain you some time but use sparingly.

__________________
Current Mods: Vorpal Weapon +5.

phunk

eh its really not too extreme. people really blow it out of proportion. if i can do it several hundreds of times with over 600 flywheel hp with big sticky tires and an aggressive unforgiving clutch, surely most other setups can get away with it here and there

__________________

synolimit

Ffs ftw.

__________________
13 370z-

YzGyz

Thant is speed shifting. Power Shifting is upshifting w/o letting your foot off once it i down.