Tell me what you think.

'05 cavalier ecotec gear ratios/'06 cobalt ss gear ratios
1st-------3.58:1----------------3.38:1
2nd-------2.02:1----------------1.76:1
3rd-------1.35:1----------------1.18:1
4th--------0.98:1---------------0.89:1
5th-------0.69:1----------------0.71:1
Final drive--3.94:1---------------4.05:1

The cavy gears are way shorter and would put the car higher in the power band when you shift to the next gear improving acceleration. In a drag racing application, it's definitely worth it. And with the final drive and the 5th gear ratio, you are still at a low rpm even at highway speeds which helps you maintain that good gas mileage that these cars get.

 

isn't that the F23 tranny gear ratios? same exact tranny that is found in Cobalts and Ions...I wasn't aware of any changes between the two.

 

well either way i hear alot of pople complaining the gears are too short to begin with. I couldnt imagine them being nay shorter...and like ion said, i thought they were the exact same tranny's

 

It's not the same tranny that is in the ss supercharged. It may be the same that is in the base cobalts and ions. I was thinking of getting it for my ss supercharged since the gears are way to freaking long. This was more a discussion for ss supercharged guys and what they thought about swapping in a shorter geared tranny, basically for acceleration.

 

this sounds very interesting!

I've been looking for a way to improve highway mileage for a while now... and that .69 5th gear combined with the 3.94 final drive would be sweet.

The other gears would be slightly shorter... but with the change in the final drive you wouldn't notice it much at all.

 

yea, that's my point. Shorter 1-4 gears for acceleration, but still a long 5th gear for great (and probably improved) gas mileage.

but keep in mind that this will probably be for the drag racer only.

 

here's the only really bad point... how much power can these things put up with?

 

the f23 seems to hold up to more power than the f35. i know of several cars running 400+hp with the f23, i know the hahn sunfire is 550hp with an f23.

 

interesting...

so... just out of curiosity... what kind of speed differences are we looking at for each gear?
calculating that is too much for me to wrap my head around right now...

 

I didn't read because I was wowed by awesomeness

It is the F23 that is in the LS, LT, and SS/NA

It has a different bolt pattern

First is useless in my 2.4...

 

actualy all ecotec motors use the samm bellhousing bolt pattern, the f23 will bolt up to it however i have no clue on what to do clutch/flywheel wise. im not sure if the 2.0l clutch is the same height, splines as a 2.2/2.4, or if you can bolt either clutch (2.0 and 2.2/2.4) to either flywheel.

axles is another issue, iirc the f35 and f23 use different axles. it would require just swapping them, however if stock ss/sc axles are weak.....

 

Yeah the bolt patterns are the same but you will probably need to shim the transmission to get everything to match up. Just because they are running 400+ horsepower on the transmission does not mean it will last a long time handling that kind of power. I know the F35 transmission is stated to handle 260 TQ, the F23 is listed as only handling 170 TQ. So if you are going to use this as mainly a drag car I don't know how long it will hold up. Another option would be to go with the 4-speed automatic 4T40E or 4T45E which they state will handle 325 TQ.

 

Hahn has been running 400+ daily driven with their sunfire for more than a year with hard launches..

a lot of cavalier guys with turbo's and the Gm supercharger swap haven't had any troubles..

also cavalier axles are stronger
i have a f23 from an l200/ion in my garage been debating this very thing...but i'd like to see speeds first and what not

 

I understand that, the point is you'd be moving to a tranny thats rated to handle less TQ than the F35.

IIRC, fullthrottle on RLforums is running the F35 tranny on his 2.4 block and had to have his clutch and flywheel modified to bolt up correct, I would assume it'd be the same vise versa.

its funny that the gear ratios are shorter for the F23, I always hear F35 guys talkin about how the gears are so short and how the F23 has longer gears. maybe its because of the final drive? i wonder what the F23 would be like with the F35 FD?

 

you are talking 4.05 to 3.94, its not that big a difference at all. if you want a final drive change wait till the turbo balt is out, its an f35 with a 3.83 final drive.

 

wow, lots of debates going on here. GOOD! my point is that the gearing is shorter. I know that the tranny will fit, basically cause you can make any tranny fit if you really wanted. But this tranny will for sure fit.

I'm not sure how much power it will handle and about the axles, but that's when the R&D comes in right? LOL. I know the gears are shorter though cause when I race my friends '04 cavy supercharged, He shifts way before me and we are like a dead even race. He pulls out on me and shifts, I pull back at the top of my gear and shift, then he pulls back and shifts almost immediately, and then I pull even. That's to 100. I'm in 3rd and he's in 4th. crazy.

 

Okay, Figured I'd revive this thread since I'm going to the track this Sunday and I was having a pretty good discussion with a friend on a local board. Check out these numbers if your interested. I may look really hard into building a custom type tranny from the said tranny about, '03-'05 ecotec cavy tranny.

Info that you need to understand this conversation:
My tire height: 26", 26.5" at most with flexing
The tire height that I want: 25"
Our tranny numbers: look above
Cavy tranny numbers: look above
My MAX RPM: 7500


I looked up a calculator, and with my current setup, I should be around 6000-6500rpms in 3rd when I cross the line, depending on my trap speed.

With that other tranny, I'd be between 6800-7100 rpms, if I was using the other tranny but with my final drive, I'd be between 7000-7300rpms.

Now if I had the tires I wanted, I'd be between 6500-6800 on stock tranny, 7200-7500 on the other tranny, and 5400-5600 in 4th gear if I had the other tranny but with my final drive. So really, unless I start making a bit more HP, I'm pretty much going to be crossing the line in 3rd gear no matter what, unless I put together a hybrid type tranny that I want.

 

just fyi i'm also looking into bolting an F23 to an LSJ, but its the bottom end i'm swapping and not the trans (since my car has the F23)

I have an lsj block ready to go as well as an F23 just gotta see if they want to play ball together.

as was posted earlier, in regards to the clutch.. I really have no idea how that will work out. Time to break out the measuring tape or start drilling up my spare fidanza flywheel for the L61

 

Bout ******* time someone responded to this damn thread. /end rant.

I think this is a great idea. The gearing in our cars is weird. Let me know how this goes. PM me. Thanks.

Awesome.

 

PICTURE UPDATE:

behold.. the 2.0 LSJ block mated up to an F23 transmission from a Jbody:







everything is identical to the 2.2 so far as mounting goes. this block also has a factory flywheel and clutch bolted on it, and clearly it fits very easily into the F23. Whether or not it would work with the clutch system in the F23 is still yet to be seen. the small gap is because I didn't have bolts to hold it together, but it slips together very easily.. splines are the same count, etc... so this proves that the LSJ can bolt up to the F23.

Can anyone get me pictures of the inside of an F35 so I can compare?

I justt need to get measurements of a Jbody flywheel/clutch assembly to really find out if the F23 throwout will function properly with it. If thats the case, you guys could use an F23 straight off a Jbody, but would also have to use their throwout bearing setup.. wheras all i'd have to do is run a cobalt flywheel/clutch.


absolute worst-case scenario, I'll cut a hole in the F23 bellhousing so I can physically see if the throwout matches up to the clutch of the LSJ properly or not.

Another possibility is a cobalt utilizing a clutch kit for a jbody.. i'm just not sure if it'll bolt directly to the flywheel of the LSJ.

I need some pictures of LSJ clutches, and flywheels, and the inside of the mating surface of an F35 if anybody's got them.

This is definetly worth further investigation. I was thinking about starting a new thread in regards to this swap.

 

My question is why would you downgrade to an F23?

Look at all the issues Beck is having with his supercharged 2.4 with the F23, GM rates it at ~180TQ max. If you are going to go to all the trouble of swapping trannies, why not go big and get something made to hold the power?

 

to be honest, I'm doing it more so to upgrade to a 2.0 block with oil squirters, a good bore x stroke, and a good rod/stroke ratio. It has all the makings of a very high revving engine that'll last at the RPM.

I'm not sure why everyone has trouble with the F35 or the F23, I've never seen anyone blow up an F23 that wasn't f-in around with it.

The hahn sunfire is making over 500hp at the wheels with an F23, and I'm pretty sure Raven (3800 turbocharged Jbody) making over 400hp with an F23

don't think that just becase '23' is less than '35' doesn't mean its a 'downgrade'. The only weak point is the diff, which an upgrade to the quaiffe unit will more than take care of the problems.

 

cheap and WAY better gearing for acceleration/drag purposes. It's a better tranny overall. Plus, seeing as how the splines and everthing are exactly the same, It's not really weaker. Some people just get bad apples. There are plenty of people riding around on high hp/tq f23 trannys.

This is the perfect swap for someone looking for more aggressive gearing.

NEW QUESTION though, DaFlyinSwirl

Is it possible to use the final gear in the f35 so that the gearing is just a tad steeper? Or is that just too much work? I know a few tranny guys that could swap it out, but I'm just wondering if it would work.

good info to know as well. Depending on cost, I may just weld the diff. I'm a drag racer, not any other type.

Now to find a f23 trans.

 

I'm not sure on the internals, but the getrags are tightly packed, so swapping gearsets might not be possible. I've never messed around with the internals of a transmission just yet.

the Jbody gearing isn't that bad.. just gotta rev higher


also, the F23 is way more readily available in junkyards and such, goes for about $400 in local yards whereas the F35 is almost double that.

You should be able to implement the driveshafts from a cobalt too. The "equal length" driveshafts are really just an intermediate shaft bolted onto the rear side of the engine. Should be a direct bolt on.

I'm looking into the flywheels and clutches now, should have more info later today.

 

You'll have more parasitic loss with the F23 over the F35. 3 axis vs. a 2 axis transaxle.

I really feel the best solution is to upgrade to the Quaife close ratio 6 speed conversion, Quaife LSD if not equipped and an Exedy single disc clutch. I would bet that combination will hold more power than the sleeves and rod bearings of the LSJ block can withstand.