Buying a Cobalt?

[J-Ri]

EDIT: I re-typed much of this post, as I found many of the answers I was looking for, but have a couple new ones now.

I am thinking about buying a 2008 Cobalt SS, just wondering how owners like them (all Cobalts, not only the SS). Have you had any real problems with them? Is it still "the same car" that you test drove, or have you come to like it less? More? Would you buy one again?

I had heard that GM raised the redline RPM on the ecotecs a bit beyond where it should probably be so that they could claim higher horsepower numbers... any truth to that, and if so, what can the engine safely do? I'm not buying the car to race it ever, and I've only had my Grand Am to the redline twice... once to keep from ending up under a semi. That said, I'd probably never need to hit the redline if the horsepower numbers are what GM says, but I just want to know. Has anyone had the 2.0 Turbo on a dyno?

Is the RPO code G85 (Limited slip differential) a real, clutch pack limited slip differential, or is it a traction control system where the EBCM brakes the spinning wheel slightly? The salesman I spoke with thought it was the latter, but from what I've read, that "traction control" is standard whereas G85 adds roughly $450. Or is it just the standard traction control that simply limits engine torque when a wheel spins? That's the only traction control I've ever heard of... and I can do that with my right foot... I don't need to pay $450 for the computer to do it for me! At any rate, a real limited slip differential on a FWD car would lower the "streetability" significantly, right? I can't imagine turning a corner with it if it has a high enough breakaway torque to help on acceleration. I could feel the rear LSD on my 3/4 ton truck on tight turns, I wouldn't want to think about front on a small car!

Does the 2.0 Turbo have an A.I.R. pump for federal emissions, or just specific states? I saw a picture in some sales material at the dearership that had what sure looked like an A.I.R. pump running off a second belt. I think having an A.I.R. pump might make me choose a different vehicle...

The closest Cobalt SS is over 1,000 miles away from where I live. I am considering buying a Cobalt Sport, since there is one 400 miles away, that way I could at least drive the car before I buy it. If I did that, I would be installing a turbo on it... which I am guessing would probably void any waranty on the engine? I am also wondering why the SS has a 2.0L in it... does a 2.2 or 2.4 not fit with a turbo, are the 2.0 cylinder walls thicker? Is the 2.0 turbo at the top of the power/weight ratio already, so they can't put a larger engine in it legally? It seems like a 2.4 with a turbo would sell even better

Thankyou for any answers to the above questions.

[-Jayson-]

GM didnt raise the redline on the ecotec motors to give it better HP numbers. The 2.0T has a redline i think of 6250. I have the 2.0 SC which is basically the same motor and i daily hit the rev limiter of 7000RPMS, 27K miles and no problems at all, engine is running great. 2.0T stock dynos usually put down 230-240WHP.

the G85 limited slip is a real limited slip differential. The traction control is its own independent feature that pretty much cuts spark when it senses the wheels spinning. This LSD isnt designed for straight line performance, its designed to improve handling. It sounds like you dont understand exactly what an LSD does, might want to read up on it at howstuffworks.com.

The 2.0, 2.2L and 2.4L are basically identical engines, they just have different internals. The 2.0L has been stroked to lower the engine size and allow for higher revs. It also has forged rods and crank. But all the engines share the same block. There is nothing legally preventing them from putting a bigger engine in the car, there are no laws governing HP/weight ratios. 2.4L with a turbo isnt possible from a factory stand point, that engine makes its power through compression, 11.5:1 which is insanely high to make a factory boosted car like that, also the bigger displacement means longer stroke per piston, something that isnt really wanted on high reving 4 cylinder motors. Engine displacement on forced induction 4 cylinders isnt as important as compression ratio and PSI. When you put boost on an engine you are increased the cylinder size. The 2.0L is the amount of air the engine can suck in per 2 revolutions of the motor (its a 4 stroke), but when the 2.0L is running under boost, the engine is sucking in much more than 2.0L, so its displacement is more so variable.

[J-Ri]

Originally Posted by -Jayson-

This LSD isnt designed for straight line performance, its designed to improve handling. It sounds like you dont understand exactly what an LSD does, might want to read up on it at howstuffworks.com.

Thanks for the reply. Could you please explain how a limited slip differential helps handling? Or just give me the link to the page that says how. I did look it up on howstuffworks.com, but it didn't tell me anything new. If you have something that makes both wheels want to turn at the same speed (and the inside wheel will always turn slower than the outside wheel when cornering), and takes "X" amount of torque to overcome the grip in the clutch packs, then how can it possibly increase the handling if some of the grip on the tires is required to overcome the breakaway torque in the clutch pack?

I can see on a FWD car how it might not hurt the handling as much as on a 4x4 truck in RWD mode, but I just don't get how it could help. With a locking differential on the front of a truck, the best you can expect to turn is about 1/2 as much as with an open diff, and then you're slipping a tire. Limited slip obviously won't lay any rubber down, but it still takes traction to overcome the clutches.

[-Jayson-]

hmm okay

the type of limited slip differential in the cobalt isnt the same as a locker lsd. With a car that doesnt have a LSD its called having an open differential. Open differentials work in the way that if one wheel starts to slip then the other wheel is limited by the HP in the slipping wheel. That is why when you drive a fwd car in snow and it gets stuck, only the stuck wheel spins. The wheel with traction doesnt get enough HP to move because the slipping wheel is limiting it to the amount of HP it takes to slip it.

With a LSD based transmission, closed differential, this is corrected. Both wheels operate independently of eachother. So if one wheel starts slipping the other wheel isnt limited to the amount of HP that is causing the slipping wheel to slip. It can put as much HP to the ground as it can before it slips.

So how does this help handling, well when going through a tight turn at high speeds, the kinda that would cause the wheels to start to slip and understeer, each wheel again is operating independently. So while making the turn physics are going to push the weight to the outside wheel. WHich means the inside wheel will be much easier to spin, if the inside wheel starts spinning than you loose power going through the turn. With the LSD the outside wheel is able to continue providing its fullest amount of power to the ground.