I am trying to squeeze a few more MPG out of my 97 Legacy Outback. Stock differentials are 4.11 gears, and I believe there is an available 3.70 gears from other applications of different years. Does anybody know if this is possible? Do you know what applications carried those 3.70 gears? FHI p/n is 722011001.

 

Maybe I could find a loaner car, from the dealer, they want like $2400.

I am trying to squeeze a few more MPG out of my 97 Legacy Outback. Stock differentials are 4.11 gears, and I believe there is an available 3.70 gears from other applications of different years. Does anybody know if this is possible? Do you know what applications carried those 3.70 gears? FHI p/n is 722011001.

 

Maybe I could find a loaner car, from the dealer, they want like $2400.

 

Just saw this. It was attached to the 'welcome' thread.

 

No wonder it never got any replies.

 

You get this handled?

I am trying to squeeze a few more MPG out of my 97 Legacy Outback. Stock differentials are 4.11 gears, and I believe there is an available 3.70 gears from other applications of different years. Does anybody know if this is possible? Do you know what applications carried those 3.70 gears? FHI p/n is 722011001.

 

Maybe I could find a loaner car, from the dealer, they want like $2400.

 

sounds like a lot of work for "a few more MPG" and you can buy a lot of gas for $2400. like a 1000 gallons. thats good for 25000-30000 miles.

 

just my $0.02

 

-=Suberdave=-

http://www.suberdave.com

If you want to modify something other than the sake of modifying it, good.

But those gears might not even be that beneficial, espaically at that price.

 

Longer gears dont necesarily mean better mpg. With the lack of torque you'll have to rev the engine even more than normal to keep you moving.

 

For 2400$, buy a 1000$ CRX or something and get 45 mpg on gasoline.

as Brucey mentioned, talller gears aren't necessarily the answer. but I thought I'd elaborate...

 

lifted EA82 wagon, if I try to use 5th gear, I have to use so much more throttle, that the gas mileage goes down by almost 10 mpg! cruising at ~4k rpm in 4th gear is WAY more effecient.

 

 

also, keep in mind that in order to change your final gear ratio, you have to change the rear diff AND the transmission (or have it regeared )

 

it's a bigger job than most cars

Install a vacuum gauge and make sure it always reads as much vacuum as possible ofcorse that will slow you down a little, but it will really help with economy.

 

I found that while crusing at 100kph (60mph approx) I was getting about 5Hg then I let my foot off a little and managed to get a constant 8Hg of vacuum, now I keep a good eye on the gauge to make sure I'm not wasting fuel.

 

I don't think changing the diffs will help too much and like the other guys said, the money is probably better spent on something else, like a new air filter, oil filter, oil, tune up, spark plugs and so on, all those things might get you even better economy.