So I just took my car out for a quick test ride to see what shifting at 3k feels like, and wow am I impressed. Screw fuel mileage, the car is so much more fun and smooth shifting at 3k. I almost wish I could disable the fuel economy part of the dic so I wasn't tempted to look at it. My clutch only has about 2k on it (dealer put a new one in before I bought it because the previous owner burned it up, probably shifting wrong). My clutch doesn't slip yet, but I might as well take some preventative measure now.

 

I have an '07 and I've kind of notice the same. If I start in a rolling in 1st gear at about 3500rpm and stomp on the gas when it gets to about 5500 it slips and shifting fast to 2nd it slips the whole gear even into 3rd but keeps moving. But after some doing over the slipping starts to fade. I hade the clutch and flywheel check and it was ok, so don't know why it does it. I also have a 99 Z24 with mods/ tunning and if I launched like that, the engine just wants to rip off the frame even with solid mounts. That's what I want on my SS, just trying to figure out the best way to launch from a dead start.

 

Artn clutches more or less rated by torque rather then horsepower?

Horsepower would be a combination of torque and rpm
So if you shift at a higher RPM, and your horsepower output
is the same, the clutch is exposed to lower ammount of torque.

 

ok so i am somewhat of a noob and i'm not entirely sure how to tell when my clutch is slipping, i can sometimes watch the rpm's climb and i've always thought i was spinning the tires, also what is powershifting, is it shifting w/o the clutch? or something entirely different?

 

could i make it stop slipping if i have made i smoke cause its really bad now

 

smoke is good. It's sexy racing in the fog...



I'm not serious about that lol. This is a good thread. It's nice to know my driving instincts have led me to drive with good 4-banger habits. I always shifted around 3k... It just always felt smoother and easier on the engine. Shifting earlier is like riding a mountain bike and shifting up too soon...you just end up working so much harder than you need to for some acceleration.

 

FAIL, that wont fix a slipping clutch!

Same thing happened to mine so i started taking it easy, and within a month it was good to go i could get on it as much as i wanted but eventually will will face one obvious fact, our clutches suck ass and you NEED to replace it. im gonna put in a stage 2 and light weight flywheel whithin the next 2 weeks.

although my car wasd at 60,000 when it started acting up.

 

I say he's right! I slipped the clutch bad in 2nd and 3rd like 2 weeks ago, and right after that it's been gripping like new!

 

True story, but i WILL slip again in the near future, i always shift at a higher rpm thats just how i drive, so maybe thats why mine started gripping after the initial slipping, but a month later same problem. mine normally slips in 3rd gear.

 

If it slips in 3rd than it would slip at the same RPM under WOT in 4th or 5th. So say the Gods of physics, and one shouldn't argue with them.

 

I really am confused, as my car cobalt has a light that comes on around 2k ish telling me to shift for best gas mileage. I understand to pull the clutch out right away rather than easing into it, but i don't understand how shifting higher rpm makes the difference?

This is not a flame i just have questions

 

A higher RPM allows the clutch to grip faster because the engine has enough power to turn the wheels. If you shift too low you have to allow more time for the power from the engine to engage the wheels and so as not to stutter people tend to ride the clutch when doing this. Within reason the quicker the clutch engages the better because there is less time of the two pieces just rubbing together as they match speed. A higher RPM allows this.

I have always thought that the clutch in this car was weird.

 

I think it slips the same distance of clutch travel, only when the RPMs are higher, it seems to bite quicker.

 

This theory is total BS. I have tried the 3k rpm shift, etc for over 4k miles now, and this is what I'm still getting... YouTube - 2006 Cobalt SS/SC pull

If your clutch is slipping, forget all this "shift at 3k rpm" and "don't take it easy" crap and get yourself a decent clutch. The fact is, our OEM clutches suck *****! They are crap. If you want to make any power at all, powershift, run DRs or slicks, etc, get the best clutch you can afford at have it professionally installed. Period.

 

You can't abuse the stock clutch and expect it to last. Plain and simple.

 

I agree that the stock clutch is worthless. Anytime I race from a dig I can always plan on Second gear slipping from overheating more than likely on the second pass. Hopefully I won't have problems much longer because as soon as it starts to warm up around here I'm getting an aftermarket clutch and flywheel. Anybody have any suggestions as to which clutch/flywheel setup has worked best for them? I want a new one but I can't decide what to get.

 

I realize this is an old thread and I have only skimmed through it but is the SC clutch a semi centrifigal design? I havent seen one of our clutches before but if GM used that style of clutch to reduce the amount of pressure needed to disengage the clutch it would explain evryones observations.
For those that havent heard of them it uses a combination of spring pressure and weights on levers to give you the total ammount of pressure you need for the clutch to hold. As the clutch spins the weights it applies more pressure to the clutch but still leaves a light clutch for shifting. Usually only used for racing to reduce some of the stupid pedal pressures you would have to run to keep the clutch from slipping on high torque engines.
Again not saying this is the case here because I havent seen one of our clutches but I thought it might explain why our clutches seem to perform differently from other vehicles. I'm not even sure if these style of clutches are still used but since I have been driving for over 30 years I remember having to use them on some of the old muscle cars. They might not need to use them anymore because of the clutches being hydralic.

 

It's a normal hydraulic clutch just like any other car. The issue is that they tend to engage high from the factory and, coupled with the drive by wire system, makes it easy to slip without even realizing it.

When your foot is off the gas and you push the clutch in, if you do it too quickly, the car is still holding the TB open for emissions purposes. If you use the clutch to slow the motor down between shifts, it won't last very long. Look at 06blackg85ss, for example. He had well over 300whp on the stock clutch for tens of thousands of miles. For a bolt-on motor, it's more than enough if you use it correctly.

 

I gotta tell all of you (mostly youngsters, I'm 61) that I've driven professionally for more then 35 yrs, big rigs and buses. And what the Author says is right on. I almost NEVER shift a rig at below max RPM's. That is the key to proper engine performance and clutch longevity. Now in my 06 Cobalt ss, sc, which I bought new, I don't go max R's, but I do usually shift above 3000, I also skip 4th gear unless I running hard, and have never had a problem with the clutch. I have over 40k on my Cobalt. Yea I know your thinking he's old and probably drives like an oldster, and that may be true to some degree, ( I hate tickets)but I do love hammering the throttle and playing with anyone who wants to do so. These Cobalt's were made to be driven, so do it. Just do it safely.

 

damn I remember reading this when I was first checking out the forum... 120k miles later and driving in the manner stated. I'm still on the original clutch.....

 

86k ****-driven miles, 3.5 autocross seasons on R-comps, more than a couple of 1/4 mile passes, wailing on her at every on ramp and wherever I can get away with it - and my original stock clutch is still fine. People who are having problems with these clutches need to learn to shift better, period, lol.

Stone629 - nice vid. Pretty good odds that what you're seeing there is wheelspin, not clutch slip. Does it do it the same way into 3rd? If it was the clutch, it would slip even worse into 3rd. Driven hard, it should just scrape the tires a little into 3rd on a WOT shift from redline. WOT from redline 1 into 2, what you see in that vid isn't unusual, and it's usually the tires. Throw some slicks on it and try again - if it's the clutch, it'll get WORSE 'cuz there' more grip at the wheels to pull against. If it's wheelspin, it'll get a little better for the same reason.

 

For your information you have a destroyed clutch, or your throwout bearing/clutch rod have finally bitten it and you have no pressure, I am pretty sure it's done.

I race track hard and heel toe often, the car drives insainly well at 3k, I used to shift at 2k range, but it would flip out, and if you pay attention proof this is right is how both 60mph match up at 5th (just my own epiphany) and the throttle seems to blip itself. The Cobalt SS is a different breed it defies all I know about clutches from an RX-7 93 TT or Mustang GT 89 which I own, or the numerous other big cars I've driven, the Cobalt is the oddest feel I've ever known. But I tried it and I think it's good, but don't slack off and forget to check the brake fluid levels too, our throwout bearings can slip out fluid pretty commonly and should be watched. I don't really know why I never carried this over from the track sooner, it feels so much more alive, and some minor slippage has been eradicated.

I run hard decent number of improvements to car on the stock clutch, and it does fine it's all in the driver, if you drive it into the ground it's your shifting habits nine times outta ten.

 

I had my stock clutch for 70k and the car had stage 2 and 3 ,2.7 with 60 and now tvs @ 20 psi no problems with slip. Yesterday i swap the clucth and is very true it was glazed the flywheel and the pressure plate.

 

Your hypothisis makes perfect sense to me!!! My turbodiesel vw beetle did the same thing, only when I drove it "spirited" did it not slip, but I could feel slip when I only rev'd to 1,500rpm to shift. I would agree that the ss/sc has a "picky" clutch. I always have rev'd to about 3,000rpm, but thats due to exhaust sounds GREAT

 

i replaced my clutch, pressure plate and slave cylinder after it started slipping, went to bleed it and it leaked brake fluid. took it all off and put on the old slave cylinder, bled it, same leak. anyone have any suggestions? about to have to pay mechanic to look at it.