Power Shifting.... Powershifting..... How is it done... I think i am a bit confused.... Is it where you hit the clutch shift and release the clutch and never lift off of the gas?

 

In a word, YES! Sometimes called flat shifting by us old timers.

 

Ok thanks.... sounds like it would be very hard on the drivetrain.... wonder if Ranger powershifts his stock Z06 to get those times...

 

My opinion relates to Corvettes at stock/near-stock power levels. Owners pumping more power thru mods and running slicks no doubt have experience that differs from mine. Here is my view.

Powershifting is very much a mixed bag.

(1) Power shifting won't lower your times unless the traction is extremely good. That generally doesn’t happen on Corvettes with stock tires. On drag radials that are well-heated and with very good track prep, traction will definitely support a power shift from 3d to 4th, and 2d to 3d, but not necessarily the 1st to 2d. Try it both ways and see which is faster. Just remember if the power shift makes the tires spin, some easing of the throttle may make them spin less, which may lower the ET.

(2) Power shifting definitely increases the risk of damage to the tranny. Most of the Z06 racers I know personally that power shift have had their trannies rebuilt or replaced. My trannies have been fine so far; but I power shift ONLY when conditions reward it. Otherwise, I shift very fast but ease the throttle.

Making strong shifts work well requires very fast leg speed and well coordinated movements of the right hand and clutch foot.

It take practice to get the moving parts of a very fast shift synchronized. Leg speed governs the pace. The legs (clutch and throttle) must move in two directions. The shfter hand moves in only one direction. And the movements need to occur fast and in proper sequence. Practice, practice, practice.

My experience has been that the magic to strong shifts under heavy acceleration is to practice, practice, practice. To reduce wear, I practice with the engine off and omit the throttle but include the clutch. 1-2, 2-3, 3-4...repeat. Sets of five. I do perhaps 50 sets per week and then 10 sets between passes in the staging lanes. This routine embeds muscle memory and makes each shift a preparatory queue for the next.

I always ensure the oil temp is above 100 degrees, before banging the shift drills. With that in mind, good time to bang through the drill is at the completion of the daily commute to and from the office.

Ranger

 

When I power shift, the throttle leg remains motionless. Years ago before I learned that automatics were more adaptable to drag racing, I raced a pretty well warmed over '56 T Bird, that had a Corvette T10 in it. When people came and saw it in the pits, they were surprised to see a clutch pedal. It looked and sounded like an automatic, on the track.

RACE ON!!!

 

Ranger, thanks for that truly illuminating post. I would have guessed that you powershifed all the time, and your workout routine is pretty interesting to say the least! Could you (or someone) discuss "loading" the shifter? I understand that racers will apply pressure on the shifter so that it moves in the desired direction when the cluth is pressed in.

 

I don't preload the shifter. Rather I preload the tension in my right arm and gloved-hand, the major queues I use for the "next shift movement."

Ranger

 

I powershift mine all the time.

http://www.corvetteforum.net/c4/mrmo...ovspanuzzo.wmv

 

Sweet video.. It actually does sound like a Automatic!

 

See if you can find the shifts in this pass

11.55 117.69 1.64, stock Z06 except CAI and DRs

Ranger

 

http://temp.corvetteforum.net/c4/mrmojo2//shiftvid1.wmv

 

Dude, you are my new role model.... I have been struggling to launch my car and get better times.. Your tips got me to at least cutting reliable 2.0 60' times on a Goodyear GS3's at 20lbs Just 4 passes and I can feel a difference.. Prior to your tips.. I cut 2.1 and higher 60' times and would run 13.0's After tips.. I ran 3 2.0 60's and 12.8's in a row!

I am pretty sure more practice will net me 1.9's.

I'd love to have you drive my car just so I can see what it's capable of... Look at my mod list in my avatar... What in your estimation is it capable of with street tires..(Assuming you behind the wheel)

Do the 4.10's help me or hurt me?

 

Ranger

You have to drive my car once

 

and that will be more times than you have!!!!

(sorry JD, just busting on you)

 

I betcha J will NEVER say that to me....

 

With your dyno at 345 rwhp/345 rwtq (assuming those are SAE), I think a reasonable bottom is about 12.40-12.50 at a DA of 500'-1500'. In an 01 Z06 with that power on stock tires, I went 12.14 at a DA of 1700'. That dropped to 11.94 on drag radials at minus 660' DA. Your car is heavier than a Z06 and the that car's M12 tranny ratios give a slight advange along with the bit broader torque curve of the LS6.

I'd suggest raising the rear tire pressure on those GS3s to 26-27 psi. At 20 they're probably cupping.

Best times will occur when traction is maximized on the launch and shifts. So you want to go to the best prepped track within a reasonable distance.

I'd also make notes on every pass as soon as you park with a slip in your hand, and use the results to plan the small changes for the next pass.

The 4.10 gears help once the tires are hooked, but require more finesse on the launch; generally that means a more careful squeezing of the throttle.

Above all, your times will drop as you accumulate passes and study the notes from each day at the drags and build a log. The quest is to reinforce good habits and break the bad ones.

Ranger

 

Hey Jay. Not sure I'd want to put my C5Z zero-breakage record on the line again. Plus I might give you mild discomfort by burning out your stock tires in pursuit of a 1.7x 60' that is the straight path to 11s in your car.

Ranger

 

I was concerned about cupping too.. But I thought hey if Drag Radials don't cup why would these...
I'll raise the pressure next time.. Also I did notice that the lower pressure eliminates the wheel hop when I do lose traction...

speaking of taking notes...
I noticed accidently I left TC on... It actually helped me.. For one simple reason... These Goodyears are quiet tires.. they don't let out a lot of noise when spinning till it's too late... the TC helps remind me quickly just how agressive a pedal squeeze I can get before I lose traction. this little thing helped me get my consistant 12.8's

 

That's a useful training aide for the street.

But if TC is activated during a run, it will clip the ET significantly.

Ranger

 

Yes I agree... But like a training aid it lets me know how far I can go.. Then once I know the limits.. I can then put it back in Competition mode and launch away..

By the way.. my TC has been desensitized by my custom LS1edit tune.. My tires have to spin pretty good before it hits me.. Before the Tune, the slightest chirp activated TC, now the tires have almost make a complete revolution to kick in..