After a very annoying conversation with a guy who insists that powershifting is the ONLY way to drive.... even in daytime traffic, I had to give my two cents

I know there are a lot of people who still believe that powershifting serves a purpose, besides shortening the life of you transmisson. Ok, mybe there is a technical explanation that I do not understand. But I do know this. Some of the dumbest people I know are power shifters

No seriously, I would really like to hear intelligent opinions on powershifting.
Here's some quick math I did to see how much of a difference it would make.


The following are excerpts from a flash file of a stock 94 z28

1>2 2>3 3>4 2>1 3>2 4>3
Normal mode WOT 36 73 126 31 67 118
Performance Mode WOT 36 73 126 31 67 118
Manual Mode WOT 37 73 129 31 67 121

As you can see, without anything else taken in to consideration, you can get 1 extra mph on the 1>2 shift and 3mph on the 3>4 shift, before the computer controlled 4l60e decides you're a moron and shifts for you.

Here's some more numbers
Fuel cutoff 1st gear: 5886rpm's
Fuel cutoff 2-4: 5805
Stock tire size: 245/50R16 = 812 revolutions per mile
Stock gear size: 3.23
4l60e gears: 3.06 1.63 1.0 0.7

Using this setup, here are the maximum speeds you could get before banging off the rev limiter, if the manual shift points were removed and you're engine actually made enough power to do so. Also, don't forget about drive line loss, and torque converter efficency, which aren't being calculated.

1>2 2>3 3>4 top of 4
44 81 133 190

Ok, you could get a little more out of those gears. A few MPH. The problem is, that a stock camaro with 3.23s will not hit 190. So it's still debatable if it would make a difference.

Somebody give me some input....
Does it make a difference.

 

that isnt powershifting....thats just shifting the auto manually ...but powershifting in a manual gives lots of benefits compared to granny shifting

 

hehe was gonna say, powershifting seems to help me at the track. Especially since my times are not that common.

 

lol...yeah not to bash you man...but you ask for an "inteligent opinion" on how to "powershift" an automatic

and no...manually shifting an auto doesn't neccessarily cause damage to your transmission, unless you are over-reving it, and that would be more for your engine.

i mean, what is the difference between the computer shifting just before the rev limiter or the driver shifting? nothing really.

that being said, the computer can shift the car more optimally than a driver can, so why not let it.
manual shifting a new electronic trans like in the fbody IS kindda pointless...unless you are cruising around town and want to make noise.

 

If you buy an auto, use it like an auto
I dont think I've ever used 1st gear and I think the only time I've shifted into 2nd was in snow and I will maybe use regular D if I'm on heavy hills and mountains.
Other then that I only use OD

the 4L60E is pretty quick at shifting, I cant see the need to override it.

 

You put a lot of thought into this, but did you know that you do powershifting with a standard transmission ?

A far as auto shifting. Custom program the shift points for your engine and let the tranny do the shifting.

 

Just so you know: Power shifting involves holding the gas pedal to the floor while you push in the clutch and row the shift lever. It must be done very quickly and with precision to avoid damaging the engine.

 

On that last note... as an M6 driver, and only 18 years old... I'd like to know alot more about real powershifting... in an M6.

 

frag...

it takes practice....and can actually be practiced at less than full throttle or redline

when racing all you do is hold the gas to the floor, and when you need to shift you jab the clutch just enough to disengage it, and yank/push into the next gear.

sometimes i'll lift on the gas about 50% just to be safe

for my past 2 4th gens i've only had to push the clutch about 1-2" before it engages enough to shift.

i tend to only powershift into 2nd...since i've missed 3rd one too many times. i still speed shift 3rd, but i take a little more deliberate action to make sure i get the right gear.

and aftermarket shifter or at least a short stick greattly increases proficiency of PS

 

As you can tell by my screen name, I am a big proponent of this!

teke184 is right on with the method. It takes practice. There is a lot more feel to it than thinking. In fact, if you are thinking about it, you are probably going to screw up. But once you get it, its real sweet.

Powershifting is a real fast motion. Your arm and leg are moving together. As you are pressing the clutch in, you are pulling the stick back (1-2 shift). You want the tranny out of 1st and into 2nd just as you have the clutch fully depressed. Then you snap the clutch back out.

All this while the gas never leaves the floor!

As a side note, make sure you have a real good rev limiter. If you miss a gear or don't shift fast enough, you're gonna need it. The factory fuel cut-off is less than ideal. I use an MSD 6AL.

Happy Shifting!

 

Thanks alot guys. So this is safe, as long as you are not bouncing off the rev limiter? I have a Lou's short stick... and if this is safe, I'd be willing to get an MSD ignition so I can power shift with more peace of mind.

Drew

 

The PCM will be rev limited already at somewhere around 5800 rpm. The exact number escapes me, but the point is, you really don't need to change any ignition parts to do this.

 

I still stand by what I said. The factory fuel cut-off rev limiter is not the best way to limit RPM especially if you plan on hitting it consistantly.

As far as safe goes, its murder on the synchros and definitely will cause increase wear and tear on the tranny. I haven't had a problem with the t56 but I destroyed a T5 with heavy abuse. It is NOT something you want to do all the time. But it sure is fun!

 

I have tried shifting my auto manually and it sucks. After you move the lever to the next gear, it stays in the same gear for a sec, then shifts up. I've bounced off the rev limiter a few times doing that. Also, the tach in my car isn't acurate enough to shift the darn thing at the right time before hitting the redline

There are only two reasons you should take the thing out of overdrive is if you are driving in the mountains or going down a big hill. If you are doing a brakestand or laying rubber, I leave it in D1 so I can back out of the throttle if I get a little sideways, and it won't shift into 2nd or 3rd.

 

I disagree with you on some of this,I'm not for sure on on the 4l60's but on my 700r I never use OD until I'm up to speed on the freeway,I've found that it doesn't down shift as quickly from OD to D1and you have to use the brakes more to slow down. For bumper to bumper traffice it never leaves 2nd as it wants to upshift at the point where you'll have to slow down again. Maybe at the track you'll want to leave it in OD ,but my prefferance on the road is use them gears to slow not the brakes.