Venting on powershifters

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 :D

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. :D

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 :D...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. :confused:

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 :D

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. :D

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

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! :D

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. :cool:

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! :metal:

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! :D

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 :rolleyes:

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

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. :cool:

If you do that, I'd worry about heat building up in the tranny. Your gas mileage will be worse too because the engine is needlsy spinning at a higher RPM. Which also leads to wear on the engine from spinning at unneccisary RPMs. I guess you could drive like that if you needed a brake job and were putting it off for as long as possible.

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. :cool:

The electronically controlled 4L60E is pretty good at shifting properly, I've found. Yeah, it's no human controlled M6, but autos have come a long way with the advent of computer rather than vacuum/cable control. There's no real point to downshifting manually in average use unless you want to engine brake or are going up steep hills that need more torque and want to lock it out of OD.

Another thing is that keeping it in second doesn't let the converter lock up (which won't lock up unless you're in third gear, which in normal driving patterns is around 30 MPH).

i can get .2 more out of my car in the 1/8 mile by powershifting compared to granny shifting my M6. i havent seen any negative effects. ive been powershifting varius t5s, tremecs and t56s for over 10 years and have never broken a trans. but i never miss a gear either. i dont powershift if im not at the track tho.

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. :cool:

Brakes are cheaper than transmissions. If you can pick which components you want to wear more quickly, pick the cheaper one.

Not trying to be an a$$,but....

AronZ28: heat build-up is why trans coolers were made. I think you are misunderstanding me. In stop and go bumper to bumper in D1 the trans very rarely shifts up to third,and when it does it is usually time to step on the brake to slow down. I'm not talking driving 30mph up,I'm talking up to MAYBE 25mph.

kefkafloyd: If what your telling me is true,then WHY would you even have to downshift for long hills,the computer should not let the trans upshift under torque,right? Plus I'm talking city driving here not open road. As I said earlier I've found that the trans doesn't downshift out of 4th as quickly as (at leastfor me)it should and when it upshifts in to OD in town it's like the renouned skipshift in the Vette,just no power there if you need it.

nateh: I've been driving for a good many years and I've never had a trans go out from engine braking. If the trans can handle high rpm upshifts then it should be able to handle downshifts as well. People tend to just get lasy and think that just because it's an automatic they only have to put the car in drive (OD) and that is all,and for the most pat in everyday driving that will do,but then WHY even put thoughs gears on the selector just put "Forward & Backward,with Park" in the middle. I say the car has gears use them when needed and appropriate.

I'm not trying to change anyones driving habits here just saying this is how I use my Autotrans,and I've never had a problem with any of my cars by doing so. :)

tell me how your rear, trans, and especially trans mount look after 30k miles of constant brutal manual trans powershifting in constant daily driving... ;) But thats whats expected..

I've never raced in OD, so much easier to just shift by yourself...I get alot better times in the 1/4 by powershifting. Especially since OD is NEVER needed in the 1/4. top out 1st, top out 2nd, maybe 5000 in 3rd and then throw it in OD to slow down and get on the pit road.

My brother has done the same thing with his th-350 for 3 years now and is yet to have a problem. I leave it in OD on the interstate unless a car pulls up and wants to have some fun, then i knock it back down to 3 and go full throttle.

Just my thoughts,
Dave

Not trying to be an a$$,but....

...

nateh: I've been driving for a good many years and I've never had a trans go out from engine braking. If the trans can handle high rpm upshifts then it should be able to handle downshifts as well. People tend to just get lasy and think that just because it's an automatic they only have to put the car in drive (OD) and that is all,and for the most pat in everyday driving that will do,but then WHY even put thoughs gears on the selector just put "Forward & Backward,with Park" in the middle. I say the car has gears use them when needed and appropriate.

I'm not trying to change anyones driving habits here just saying this is how I use my Autotrans,and I've never had a problem with any of my cars by doing so. :)

It's a fact that excessive engine braking in lower gears with the 4L60E will result in wasted clutches. An old TH 350 or 400, you could beat to death. The 4L60E is not so forgiving. There are lots of people this has happened to.

kefkafloyd: If what your telling me is true,then WHY would you even have to downshift for long hills,the computer should not let the trans upshift under torque,right? Plus I'm talking city driving here not open road. As I said earlier I've found that the trans doesn't downshift out of 4th as quickly as (at leastfor me)it should and when it upshifts in to OD in town it's like the renouned skipshift in the Vette,just no power there if you need it.

If it's not downshifting fast enough, you're not putting enough pedal to the metal ;p The tranny, in a certain speed range, will keep the car in third gear so long as you have enough throttle before a certain point and until a certain MPH (I believe it forces a shift into OD somewhere around the 110MPH range?). I've experimented with this - once the computer automatically downshifts, so long as you hold the pedal in that position or do not go below a certain throttle threshold (IE the computer can see that you're going back to low torque requirements), it will stay there. However, you would downshift anyway just to prevent the possibility of the OD kicking in. You can program these sorts of parameters with a programmer, and a shift kit also helps. The tow-haul mode on most trucks, for example, is a quick and dirty way to use programmability to help trannies shift properly under circumstances that require more torque rather than high speeds.

I'm not saying what you're doing will harm the tranny, the difference is probably minimal. I just don't see a point most of the time to downshift manually (and there are only two times I do, and I've mentioned them above). Coincidentally, this is also what the majority of drivers do.

Most of the time, the computer shifts better than you. The only time you really need engine braking is to keep your brakes from heating up too much (which would be coming down a steep hill and you're trying to obey hte speed limit or coming off of the highway). In town? The benefits are minimal, and there isn't much risk of overheating the brakes. Just drive the car normally unless you really need to engine brake, it's better for you and for the car.

If it's not downshifting fast enough, you're not putting enough pedal to the metal ;p The tranny, in a certain speed range, will keep the car in third gear so long as you have enough throttle before a certain point and until a certain MPH (I believe it forces a shift into OD somewhere around the 110MPH range?). .

You are not describing a "downshift" here. I'll try to give an example: Next time your on the road and you are up to speed(say 35-40mph)and you are comming to a stop see how long it takes for the trans to DOWNshift to 3rd and how much brake you have to use. Then try just using drive and take your foot off the thottle and see how much sooner you slow down using less brake. You can argue fuel mileage ,but at 35-40mph OD has probably JUST kicked in so were is the savings,not to mention the "extra wear and tear"on the trans making shifts for short periods up and down. Remember I an talking City street driving not highway.

Plus I think we Hi-jacked this tread,and I applogize.

It's a fact that excessive engine braking in lower gears with the 4L60E will result in wasted clutches. An old TH 350 or 400, you could beat to death. The 4L60E is not so forgiving. There are lots of people this has happened to.

Shoebox I have been under the impression that the 4L60E was tuffer than the TH700R. What your saying is it can't handle this type of driving? I know GM had probs with the early 700's ,but the later ones have less problems,but (knock on wood)my 700 has not givin' me one bit of trouble. I have added a shift kit,an OD kickdown valve,and a cooler,and a poly trans mount and the cobination seems to work quite well. So maybe everything that I've heard about the L60 being superior isn't nessarly the truth.

Again sorry for the hi-jack. :bow:

I've never driven a third gen with the 700R4, and I don't know its quirks, so I guess you can drive it any way you want. But if you are shifting the electronically controlled 4l60e yourself, I'll have to smack you around.

I know what you are talking about with keeping it in D instead of OD in town. On my old car I would do that because it didn't have much power around 40 mph when it shifted into overdrive.

You are not describing a "downshift" here. I'll try to give an example: Next time your on the road and you are up to speed(say 35-40mph)and you are comming to a stop see how long it takes for the trans to DOWNshift to 3rd and how much brake you have to use. Then try just using drive and take your foot off the thottle and see how much sooner you slow down using less brake. You can argue fuel mileage ,but at 35-40mph OD has probably JUST kicked in so were is the savings,not to mention the "extra wear and tear"on the trans making shifts for short periods up and down. Remember I an talking City street driving not highway.

Plus I think we Hi-jacked this tread,and I applogize.

We did. However, what I did describe is a downshift - a downshift is any time the tranny goes from a higher gear to a lower one. Whether it occurs from slowing down or speeding up is inconsequential. :) PLus, OD on the 4L60E doesn't kick in until 45MPH (and will come off at 40 MPH).

In town... there's not enough space where you'd be just slowing down without using brakes anyway. In the end, you'll still have to replace your brakes and rebuild the tranny at some point. Whatever floats your boat, but I feel it's just a placebo effect for you. :)

Have you considered installing a shift kit in your car? It really does make a huge difference (I love my Transgo!).

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

Actually... I've probably heard about 5 or 10 names for both manually shifting an automatic and clutchless shifting. I've also heard both refered to has powershifting. I guess I should have used a more accepted term. But thats what he was calling it....

Anyway, as far as REAL powershifting goes, you all suck! I spent 2 years looking for a M6 and finally gave up and bought an A4. but in all my previous cars, I never completely powershifted on the track, I did all the time in daily driving, because I could shift slow enough to time it. But doing that on the track will fry your syncro's. What I did do was tap the clutch just barely past the free travel point right as the shifter was going in to the next gear. Timing is critical. I would let off the throttle about 1/2 in first gear and probably about 1/4 in the others. That seemed to work quite well for me.

P.S.
http://web.camaross.com/forums/showthread.php?t=334891
See, I told you people refer to manually shifting an a4 refer to it as power shifting.... Don't shoot the messanger. :D

LOL, don't get sucked in. Sounds like someone else did not know what they were talking about and decided to create a new meaning for the term.

It's a fact that excessive engine braking in lower gears with the 4L60E will result in wasted clutches. An old TH 350 or 400, you could beat to death. The 4L60E is not so forgiving. There are lots of people this has happened to.

That's 100% truth.

I speak from experience ;)

Mike