[Z06] Powershifting Proof
Thread Starter
Melting Slicks
Joined: Mar 2001
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Powershifting Proof
As if you guys needed it but...I was reading the current issue of Corvette Quarterly and they did an interview with developement engineer Luke Sewell about just how he goes about getting the best figures for Dave Hill to brag about.
Sewell elaborated by saying that his sweet spot for launch was +/- 2800rpms on a factory spec engine with 500 miles break in and a full tank of gas. With no other prep and power shifting Sewell achieved
0-60 in 3.98(powershifting)
0-60 in 4.17(not PShifting)
1/4mi. in 12.24@116.88mph(Pshifting)
1/4mi. in 12.50@114.22(not Pshifting)
Even though Engineer Bill Zabritski informed the author that each Corvette is tough enough to handle it(he said every new Corvette powertrain must endure a production test involving 600 trips from rest to sixth with full throttle powershifts), the author advised "we leave it..to the pros, and treat our carefully engineered driveline with respect" :lol: :lol: Sure thing Donny :blueangel:
:cheers: Dave
Sewell elaborated by saying that his sweet spot for launch was +/- 2800rpms on a factory spec engine with 500 miles break in and a full tank of gas. With no other prep and power shifting Sewell achieved
0-60 in 3.98(powershifting)
0-60 in 4.17(not PShifting)
1/4mi. in 12.24@116.88mph(Pshifting)
1/4mi. in 12.50@114.22(not Pshifting)
Even though Engineer Bill Zabritski informed the author that each Corvette is tough enough to handle it(he said every new Corvette powertrain must endure a production test involving 600 trips from rest to sixth with full throttle powershifts), the author advised "we leave it..to the pros, and treat our carefully engineered driveline with respect" :lol: :lol: Sure thing Donny :blueangel:
:cheers: Dave
Racer
Joined: Mar 2002
Posts: 355
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From: Germantown WI
Re: Powershifting Proof (The DBK)
I wonder how many times down the strip it took for them to get the numbers? Wouldn't that be a great way to spend a work week?
I contend that the reason so many rags show the ZO6 in the mid to high 4's, is they really don't have time to learn the cars. The ZO6 might like 2800 rpm launches, while another car wants to leave at redline. One loves the powershifting, where another can't take it. So they compromise by drop throttle shifting and launching at some engine speed they have used on every car they drive.
I know that in my M coupe, a 3,000 RPM launch rewarded you with a huge bog and poor acceleration numbers. To get it to really move, you launched at closer to 5,500 and let the rear end slip a touch to keep the revs up. Do that in the ZO6 and you are rewarded with a cloud of smoke for a city block (I know, I tried it.) Unfortunately the M coupe was also cursed with a relatively wimpy clutch. If you power shifted it often, it would begin to slip and it got slower and slower. Not so with the ZO6 so far!
I contend that the reason so many rags show the ZO6 in the mid to high 4's, is they really don't have time to learn the cars. The ZO6 might like 2800 rpm launches, while another car wants to leave at redline. One loves the powershifting, where another can't take it. So they compromise by drop throttle shifting and launching at some engine speed they have used on every car they drive.
I know that in my M coupe, a 3,000 RPM launch rewarded you with a huge bog and poor acceleration numbers. To get it to really move, you launched at closer to 5,500 and let the rear end slip a touch to keep the revs up. Do that in the ZO6 and you are rewarded with a cloud of smoke for a city block (I know, I tried it.) Unfortunately the M coupe was also cursed with a relatively wimpy clutch. If you power shifted it often, it would begin to slip and it got slower and slower. Not so with the ZO6 so far!
Team Owner
Joined: Jun 2001
Posts: 26,714
Likes: 344
From: Houston, TX
Re: Powershifting Proof (kwillmorth)
The article in Corvette Quarterly also says they use some rather interesting correction factors. Makes me very suspicious. They apply correction factors to 60 degree temp and zero humidity, and .25 seconds for "staging" a foot back (as real drag racers would). What this means, is they may have never actually seen those numbers posted.
But, it is interesting that they basically tell us that the car is designed to handle the powershifting!!!
But, it is interesting that they basically tell us that the car is designed to handle the powershifting!!!
Melting Slicks
Joined: Oct 2000
Posts: 2,524
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From: Stamford CT.
Re: Powershifting Proof (jschindler)
That's true, but I have done better than the 3.9 many times at the track. So wonder about there methods, but not that the Z06's 01 and 02 can run the times in good conditions. Ric
Intermediate
Joined: Oct 2001
Posts: 46
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From: Upper Marlboro MD
Re: Powershifting Proof (Power Shifter)
PowerShifter,
Do you powershift all gears going thru the 1/4 mile? 3rd gear seems like it would be pretty hard to hit, but with some practice I'm sure I could do it.
I'm going to the track tonight and I will try powershifting 1st-2nd and 3rd-4th, that should shave off some ET and pick up a lil mph. I also installed the Borla Stingers so we'll see if they pick the car up any.
Do you powershift all gears going thru the 1/4 mile? 3rd gear seems like it would be pretty hard to hit, but with some practice I'm sure I could do it.
I'm going to the track tonight and I will try powershifting 1st-2nd and 3rd-4th, that should shave off some ET and pick up a lil mph. I also installed the Borla Stingers so we'll see if they pick the car up any.
Melting Slicks
Joined: Oct 2000
Posts: 2,524
Likes: 0
From: Stamford CT.
Re: Powershifting Proof (normjack)
Norm, Yes I power Shift 1-2-3-4 in the quarter. An aftermarket shifter is very helpfull insuring no mised shifts. JS, A few members that are much better at math extroplated 0-60 times off of some of my et slips, Any one able to get a low 1.8 60' that can power shift will be under 3.9 on a good surface. IMHO Ric
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Melting Slicks
Joined: Feb 2001
Posts: 2,243
Likes: 1
From: Ooltewah TN
Re: Powershifting Proof (The DBK)
Just remember guys... is an extra .1 or .2 in 12 seconds of fun really worth a tranny/diff rebuild. Drive it hard, but don't abuse it and it will last for years and years!!!!
Melting Slicks
Joined: Oct 2000
Posts: 2,524
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From: Stamford CT.
Re: Powershifting Proof (wtknght1)
Chris, It's point of view. I would be of the opinion that road raceing is tuffer on parts than drag raceing. Power Shifting is not abusive if done corectly. Make too much of a mistake in any fourm of raceing, it will cost you. Yes? Ric
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Ric,
Powershifting essentially is only bad when you don't hit the gears fast or miss completely, correct? Isn't it the time spent between the gears that is bad. So the faster you do it, the less harm done?
Powershifting essentially is only bad when you don't hit the gears fast or miss completely, correct? Isn't it the time spent between the gears that is bad. So the faster you do it, the less harm done?
Team Owner
Joined: Jun 2001
Posts: 26,714
Likes: 344
From: Houston, TX
Re: (scorp508)
Ric,
Powershifting essentially is only bad when you don't hit the gears fast or miss completely, correct? Isn't it the time spent between the gears that is bad. So the faster you do it, the less harm done?
Powershifting essentially is only bad when you don't hit the gears fast or miss completely, correct? Isn't it the time spent between the gears that is bad. So the faster you do it, the less harm done?
Le Mans Master
Joined: Jun 2001
Posts: 7,331
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From: Admit Nothing, Deny Everything, Make Counter Accusations.
Re: Powershifting Proof (wtknght1)
>is an extra .1 or .2 in 12 seconds of fun really worth a tranny/diff rebuild.
I guess it depends on whether you want to win or not. I am not sure I understand why someone would dragrace and not try to go as fast as possible. I made about a dozen 1/4 mile passes in my 85 Z51 4+3 and powershifted every single gear during every run. My stock 85 was always among the fastest (if not the fastest) stock L98 cars at the track.
I never powershifted on the street and the transmission held up just fine. I agree that powershifting subjects the drivetrain to extra stress, but how often are we actually drag racing at the track anyway? A few powershifts a year is not going to kill the car. If you tend to drag race a lot the stock drivetrain will probably fail anyway, even if you don't powershift.
I guess it depends on whether you want to win or not. I am not sure I understand why someone would dragrace and not try to go as fast as possible. I made about a dozen 1/4 mile passes in my 85 Z51 4+3 and powershifted every single gear during every run. My stock 85 was always among the fastest (if not the fastest) stock L98 cars at the track.
I never powershifted on the street and the transmission held up just fine. I agree that powershifting subjects the drivetrain to extra stress, but how often are we actually drag racing at the track anyway? A few powershifts a year is not going to kill the car. If you tend to drag race a lot the stock drivetrain will probably fail anyway, even if you don't powershift.
Race Director
Joined: May 2000
Posts: 12,712
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Re: (jschindler)
It's tough on the clutch, too. While the clutch is in the engine is against the rev limiter. When you let the clutch out in the next higher gear, it has to drag the engine down to about 4600 revs against full output. This also subjects the entire drivetrain to a significant shock load.
Duke
Duke
Racer
Joined: Mar 2002
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From: Germantown WI
Re: Powershifting Proof (Power Shifter)
.... I would be of the opinion that road raceing is tuffer on parts than drag raceing....
As an example, at Willow Springs, you shift up (3-4) only once, just before turn 7, which is a right hander over a hump. You actually short shift the car going up the hill to keep the rear end planted as you go over the hump. If you power-shifted at redline, you be doing so with the car just becoming un-weighted and would most certainly end up going into the dirt tail-first. Buttonwillow, Laguna Seca, Vegas, all require smooth shifting to keep the car stable. I can't think of too many tracks (Phoenix maybe) where you can bang upshifts on road courses without getting all squirelled up in a corner or over a change in elevation.
Road racing is basically hard on brakes and tires. If you're smooth, the rest of the car is not under a lot of extreme duresss. Drag racing abuses the driveline to a much greater degree IMHO.
Safety Car
Joined: Oct 2001
Posts: 3,504
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From: Insert Wittty Comment here
Re: (SWCDuke)
I have driven both ways. Powershifting or quickshifting
There is time to be picked up in powershifting provided the car doesn't spin too much.
Also in that article it states GM runs the car full of gas. I run mine empty. I can also powershift all 4 gears. In fact in top speed racing I powershift into 5th.
They launch their car at 2800 I I launch at 4200. I ran an 11.933 they ran a 12.28
As for powershifting, my motto for all my cars has been: If it can't take it I don't want it.
There is time to be picked up in powershifting provided the car doesn't spin too much.
Also in that article it states GM runs the car full of gas. I run mine empty. I can also powershift all 4 gears. In fact in top speed racing I powershift into 5th.
They launch their car at 2800 I I launch at 4200. I ran an 11.933 they ran a 12.28
As for powershifting, my motto for all my cars has been: If it can't take it I don't want it.
Team Owner
Joined: Mar 2000
Posts: 83,383
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From: Boston, MA
Power shifting in road racing is pretty rare stuff. On road race tracks being smoooooth mean much more than a few non-seconds saved shifting.
Melting Slicks
Joined: Feb 2001
Posts: 2,243
Likes: 1
From: Ooltewah TN
Re: Powershifting Proof (Power Shifter)
Road racing is most definitely tougher overall on the car than drag racing...I'm just not a fan of saving .1 or .2 if nobody else is paying the bills but me. I pride myself on being very fast, but very smooth and good to the equipment (knock, knock). One or two drag races a year shouldn't hurt anything and the car should most definitely take it with no problems at all. I'm also big on consistency. When you're real rough on the car, you tend to make mistakes that not only cost you time, but sometimes big $$ as well. You may be able to turn a blazing lap (or time) once, but can you do 10, 20...50 times with no mechanical problems. One blazing time looks good on the sheets, but seldomly wins anything.
I'm just a big advocate of driving hard, smooth and being good to the car too, because I want it to last a long, long time. That's what I teach the students at the schools (HP driving/DE events), because it's just not worth the overall cost(s) if you break something...unless you are racing for big $$$!!! Drive it hard, but well and it will last for years and years and you'll have no problems - from experience!
I'm just a big advocate of driving hard, smooth and being good to the car too, because I want it to last a long, long time. That's what I teach the students at the schools (HP driving/DE events), because it's just not worth the overall cost(s) if you break something...unless you are racing for big $$$!!! Drive it hard, but well and it will last for years and years and you'll have no problems - from experience!
Melting Slicks
Joined: Oct 2000
Posts: 2,524
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From: Stamford CT.
Re: Powershifting Proof (wtknght1)
Chris, There is a big differance between what works well in a road race and a drag race. It's a mistake in my opinion to belive the techneques interchange, some do some don't. Ric. PS, I drive hard, but try to be smooth enough to not be overly abusive to the car allso. So far So Good, but sh$t can happen when your haveing fun. Especialy when you only have 12 sec+- to get it done!!
[Modified by Power Shifter, 2:15 PM 4/19/2002]
[Modified by Power Shifter, 2:15 PM 4/19/2002]