ok..now that the 2.4 is gonna have full HPtuners support does that mean we can effectively add boost now...say a 2.0SS supercharger stage 2 swap?? or are we still very limited with boost due to the high compression ratio??

 

I wouldn't exceed 5-8PSI unless you plan to upgrade some engine components and the tranny.

 

the trans will hold more than you think , its the same trans in the cavaliers and people are running 12's with it

a lsd is a must though

and with hp tuners you can tune it any way you want , either n/a or boost

 

I don't know how this weak trans got started either. Its a Getrag tranny. They are VERY stout. I mean most people think they are made out of zip ties and rice noodles inside. They will hold some power just don;t abuse the crapola out of it...then when and if it does go get a G85 from an LSJ.

 

the 2.2 and 2.4 use the same F23 getrag , the 2.0 uses a different trans

 

what about the auto tranny is there any differences? other than the obvious.

 

The automatic should be able to take a decent amount of punishment.

This same tranny is used in several GM vehicles that produce more power than the Cobalt. So I don't see any problems arising with it.

Again, investing a little in a tranny cooler wouldn't hurt.

 

As stated you can tune the way you want. Also with this kind of tuning compression is not that big of a deal. I would rather have the 2.4 ecotec boosted than the 2.2, or 2.0.

 

Jegs has some very nice tranny coolers with electric fans. Plus a nice racing torque converter will be good, also I found a website that makes LSD's for the 4t45e.

electric fan tranny cooler: http://www.jegs.com/webapp/wcs/store...tegoryId=10529

LSD for 4t45e: http://engineered.net/eplsd.htm

and I'm sure the company that makes the LSD kits can lean towards the direction for other 4t45e transmission parts

 

I'm amazed by how little some of you guys seem to know about your engine. The 2.2 eco with the POWDER metal rods typically sees 280-300whp before it breaks, and your 2.4's have FORGED steel rods. The 2.4 bottom end should be good to about the same hp as the LSJ, with the exception that the higher static compression makes it harder to achieve a detonation free tune at those power levels. Hahn is already pushing a 2.4 solstice to 290 whp on stock internals, thats about 15 psi.

As for the tranny, the only getrag F23's that I've heard of breaking have either been driven excessively abusively (idiots wheelhopping the crap out of the car and not letting off, mis-shifting, grinding gears, etc.). I still have yet to see one that I can say 100% can only be blamed on excess power.

 

do the Rods on the 2.4 or the 2.0 fit on the 2.2? just wondering cause it would probbaly be an easy swap, and probably better for the guys with 2.2 that wanna run some high numbers

 

Correct me if I am wrong, but arent the 2.0, 2.2 and 2.4 essentially ALL the same motor? From what I have gathered, only the stroke is different on the 2.0 (destroked, forged internals) and the 2.4 (longer stroke, forged internals). So all you would need to swap is the rotating assembly (crank, rods, pistons) to achieve either a 2.0 or 2.4 liter motor.

 

the block itself is the same, but the 2.2 has a 6 bolt flywheel pattern where the 2.4/2.0 have an 8 bolt flywheel. So if you could find a clutch flywheel combo that works, you could swap.

The rods? I'm not sure if they're exactly the same or not. The 2.4 rods might be shorter.

 

2.0 and 2.2 have the same bore , and different stroke

the 2.4 is larger bore and stroke

 

2.4 is just longer stroke.

 

According to GM's website:

2.0l - bore 86mm, stroke 86mm
2.2l - bore 86mm, stroke 94.6mm
2.4l - bore 88mm, stroke 98mm

Here's the link:

http://media.gm.com/us/powertrain/en...html#chevrolet

 

Well, the "rumor" starts when you go to the GM Powertrain site and look at the specs for the F23 transmission. GM wouldn't bother setting a maximum torque spec for the tranny unless there was a reason for doing it. As such, they build the tranny to withstand the power coming from the engine they are mating it to. In this case, the 2.2 and 2.4 only. It's rated to withstand 170lbs-ft for a normal lifetime. Anything higher than that and you decrease the life of the tranny.

 

does the happy dance , does the happy dance



i was correct

2mm bigger on the 2.4 bore

 

That makes no sense at all, aside from the fact that the limits have been exceeded many times before.

Do you really think that GM would release a tranny thats within a couple ft lbs of tq within its so-called "limits?"

 

and yet somehow there are cars with that trans racing two and three times a week making more than 250 hp and not blowing out transmissions.... As long as you don't drive it like a moron, anything 320ish or less shouldn't be shattering that trans. My engineer buddies tell me that its typical for a part to be designed to be twice as strong as it needs to be for a given task to have a built in margin of safety. Beyond that, the cobalt is going to be one of the highest volume GM cars for many years to come, junkyard supply will end up just as plentiful (and inexpensive) as cavalier parts have become. And, as mentioned, you can always swap an SS trans.

 

It makes perfect sense because this is GM we're talking about here. To build that tranny to withstand lots of power would cost them more money. When they cheap out on so many other things in the car, do you really think they are going to put more money into building a tranny when they do not need to??????

I'm not saying the tranny is going to shatter into pieces putting 200lbs-ft of torque into it. It's not, it just won't have the lifespan that a tranny with normal power output would have.

 

If you're making this statement cause of compression and possible detonation, changing the ignition timing will prevent that from happening.

If you're saying that cause of strength of the internals, you should be able to push it further if you chose to.

Another thing...you can't say to people in generalization of 5-8 PSI...size, trim and style of turbos plays into effect of the CFM amount per PSI.

 

Your engineer buddies obviously don't work for GM. There have been GM engineers on other forums such as GMinsidenews defending themselves because some people think that the car we get from the factory was exactly how it was designed. The fact is GM gives the supplier the specs for the part, tells them they are going to pay XX amount for it. So now the supplier has to figure out how to build that part CHEAPLY to make money. Why do you think Delphi went to court to have it's GM contracts thrown out?

The torque rating given is an indication of what you could run through the tranny and expect a normal lifetime from it. If you put more power, it's not going to explode, it's going to wear out sooner.

And yeah, you could swap in an SS trans since it is tougher. Odd how it's torque rating is over and above what the Stage II kits with factory warranty put out if those numbers GM publishes mean nothing isn't it......

 

everyone gets lucky once in awhile.....

 

I still don't see it because you would have several liability issues if the tranny was that weak. You would have people with bone stock 2.4's going in for tranny work because it can barely stand 163ftlbs of tq, theres no way they would build a motor that pushed the tranny to its limits like that. On a mass production car? no way...