XFE gearing swap
 

Hello all,

I'm wondering if anyone can shed any insight on swapping the taller gearing from a Cobalt XFE into a regular cobalt. I THINK it should be a straight up bolt on if i can find an XFE tranny in good condition. It would give a good drop in FE. I'm also wondering if it would be cheaper to just swap out the gears in the diff (as i think it's the final gear ratio that they changed)

-Steve

No experience with the cobalt.

Trans of the same make and year should have the same parts(mounts anyway) so. . .?

This would be a 2007 car, attempting to mate up to a 2008 or 2009 Tranny. I think it's the same.... BUT...? Surely someone has done this somewhere? To me it's just begging for longer legs... I role down the highway at 2300 RPM, and like, 30% engine load. The XFE is definitely a step in the right direction.

I think i might stop into a transmission shop, and see what they think. If they quote me hundreds of dollars that'll be a no go for now at least. It's probable they'll say 'if it ain't broke don't fix it'.

On a side note: I've been spending too much time on the site. I've yet to do any big mods, but i'm thinking of doing a front air dam, wheel skirts, moonies, i've already decided to switch to synthetic fluids, and i'm seriously looking at an ignition kill switch, because i've been EOC coasting down hills for the past two days.

LOOK WHAT YOU'VE DONE TO ME! :P

I have a buddy who works for the local Chebby dealer.
I'll ask him if he knows the answer to your query.

I would greatly appreciate that!

I'm a little hesitant to be optimistic about it.

Different model years past 2000 tends to mean parts aren't identical. Alot of manufcaturers do it on purpose to help out dealers(a large part of dealer revenue is parts and repair). If the parts are more difficult to salvage and repair then they get more business.

That said. . .cobalt might line up. The dealer acquaintance will enlighten us though. . .^_^

stevey_frac -

This may or may not help, but here are some similar threads about an XFE tranny into a Saturn Ion, which also uses an Ecotec engine :

Saturn ION XFE? - SaturnFans Forums
Gas Mileage For Those Interested - SaturnFans Forums

I also think they just changed the final drive just like you said.

Here's another website with lots of gear ratios :

Manual Transmission Ratios

CarloSW2

stevey_frac -

More GM tranny stuff :

2009 GM Car Engines & Transmissions

CarloSW2

Interesting reads. Looks like no one has done it though. From everything i can tell, the transmissions are the same, but the XFE has a taller final drive ratio. That means the difference is in the differential, and shortly thereafter i'm out of my league. I wish it was a simple as the Saturn fifth gear swap.

I do believe that it is more of a difference then 50 RPM at 60 MPH. The car i drove was very agressively taller geared when I was car shopping.

I'm afraid if it's not something you can do yourself, it's definitely going to cost in the hundreds of dollars for labour. The transaxle itself will be in the hundreds (if you can't just get the differential gears).

Another one bites the dust! :)

I've sent an email to a transmission shop asking them about the work. We'll see how/if they reply, and what they have to say.

I just read a report saying that they expect oil to hit $200 / barrel by 2014. I think we are truly about to hit the last days of gasoline cars...

Any savings i can squeak out look more important when you consider oil that expensive!

Stevey. . .the only way oil hits prices like that is in the event of another speculator runaway freight train.

I've worked with some guys in the oil industry and there won't be any shortage of oil for production sake any time soon.

Shell just dropped new reports into alot of offices paying their geologists to go back and run scans on old wells because a substantial number of wells have refilled partially. When you consider that and about 1/4 of the wells that are already located and accounted for in barrells are not tapped I doubt oil runs out or production or supply even slows in the least over the next 20 years.

Speculators are the single cause behind gas prices. Go talk to an oil company and they will tell you its not their fault and they aren't making the profit that causes the price inflation.

If you look at oil prices over the past three years, we are currently on track to repeat the previous spike to $140 / barrel by the end of the summer. Regardless of the cause... it's still happening.

Yes and no. . .Its completely off topic but im happy to continue over private discussion of if someone else wants to start a thread. If anyone else wants to know why I don't believe that will happen just msg me, I don't want to hijack yet another thread. . .The bounty on my head is already too high lol.

Back on topic.

Gearing changes allow you to fully realize the fruits of aero and weight improvements.

Aero & weight reduce the engine torque required at a given road speed. Changing gearing reduces the air flow through the engine (in itself a major cause of engine friction) and in a gas engine that means a lower fuel burn, all this at the same road speed. If you don't regear the vehicle yopu have to use a more closed throttle to acheive lower air flow and a throttle plate is nothing but an entropy generator.

You would think regaring would be more effective on a gasser than a diesel but the high compression of the diesel is another good reason to minimize air flow. Unfortunately, gearing is expensive. These arehigh-precision bits of machinery that require complex manufacturing tecniques which means high cost. Still, if you really think oil is going to $200/bbl, your choice may boil down to coughing up the cash for gearing or just not going.

This engine is a monster in it's class. A 2.2L beasty with good old fashioned torque. The average size engine in this class is 1.8L (a full 20% smaller), and I believe there is a 1.6L contender. Despite this, the cobalt gets very good highway fuel economy. Part of that is lower gearing, but they didn't go far enough from the factory for my tastes. Even without considering any other modifications, there is NO reason for this big engine to be turning over at 2500 RPM and sitting at 20% engine load on the highway. This thing is desperately asking for longer legs. My calcs predict that it would be much more comfortable sitting at 2200 RPM, which is still higher then an XFE final gear swap would put me. This would up engine load to around 30%

If oil does hit $200 / bbl, I fully expect that i'll be pushing my car to work on all the inclines, then coasting down the declines.

Either that, or i'll have the first cobalt with a full boat tail.
-Steve

The best possible thing you could do is to rip out the gear you want larger and find a custom one. . .thats expensive and laborious. Trans swap with a relatively new trans will always be expensive. Swapping out a civic trans from 92-96 is cheap because they are plentiful. Your XFE trans not so much. In your case if you are doing it yourself it honestly might be cheaper to pop the trans apart and find something really enormous to fit in there.

New trans on a new car will run about a grand or more. New gear could be as little as 50 bucks. . .but instead of a 1-2 day thing its a saturday sunday all day, monday night, tuesday night and wednesday night to get it back in the car.

If you're not doing the labor this is not worth it at all.

Even if gas costs 8 a gallon it takes forever to recoupe the 2K its going to cost in gas. . .

If you aren't doing it yourself and if its over 500 bucks you are far better off just ripping extra weight out of the car. . .Spare seats, insulation AC lines, veins compressor, manufacturing your own fiberglass shell(including the hours spent learning and screwing up several copies). . . You might get 10 mpg extra on a huge gain of mpg, which I doubt. It would take forever to pay that down even with an extra 10 mpg. . .

If you think its going to get that bad take all the trunk lining stuff out, the spare tire, the metal frame for the trunk and put in strong mesh netting and coat the underside in a big gortex bag, take the carpet out, dash, door panels, speakers, fans, glove box.

Doing all of that would get close to giving you the same mpg increase and its less than 100 bucks for water proof fabric and mesh netting for strength. . .

Lighter wheels and tires when you have to switch and losing as much weight as you possibly can are also cheaper than paying a mechanic to do this, trust me I work in a shop lol.