help with a 3.90 gear ratio swap???

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Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

help with a 3.90 gear ratio swap???

Post by Snow-Attack »

ok so my brother who shouldnt own a subaru in my opinion lol!!! burned up somthing cause he can do a one wheel rear wheel burnout now :roll: so what did he burn up??? so now what he wants to do is change the car to a 3.90 gear ratio. what would it take to do that??? i know he will have to replace the rear diff but does he have to mess with the trans? and how do you change the gear ratio in the front diff?


thanks
Ben
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
BB
First Gear
Posts: 71
Joined: Sat Nov 18, 2006 2:15 am
Location: Somewhere, Canada

Post by BB »

Well, Ben,

What is your brothers current transmission? We're missing a lot of key information here.
Bruce Beveridge
Mech. Eng

'94 Impreza L- DOHC EJ22T Swapped again.
'94 SS - Swapped again, 5MT, Flipped, RIP
'94 SS - Swapped 5MT - DOHCEJ22T, VF37
Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

Post by Snow-Attack »

oh my bad
.... it is a MT 1994 NA wagon "MI" edition AWD....what else would help????
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
BB
First Gear
Posts: 71
Joined: Sat Nov 18, 2006 2:15 am
Location: Somewhere, Canada

Post by BB »

NA 5MT... I believe you have 4.11 gears. Why would you want to go 3.90? you loose torque, making you car feel slower. Do you often attempt to drive above 120mph? Then why swap?

Its possible that there is nothing wrong.

However, you may have a weak center diff. Not worth changing unless you feel like doing a tranny swap.

Remember higher final drive (bigger number) means more torque. More torque means (for me) more drift.
Bruce Beveridge
Mech. Eng

'94 Impreza L- DOHC EJ22T Swapped again.
'94 SS - Swapped again, 5MT, Flipped, RIP
'94 SS - Swapped 5MT - DOHCEJ22T, VF37
Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

Post by Snow-Attack »

um ya im pretty sure all the NA subaru's from 90-94 came with 4.11 gears....and its not just weak because he just fried it trying to slide on wet pavment all the time. ok can someoen tell me where the front and center differentials are located????


thanks
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
BB
First Gear
Posts: 71
Joined: Sat Nov 18, 2006 2:15 am
Location: Somewhere, Canada

Post by BB »

both are located in the transmission.

Had a bunch in my hands today.

Image

At the far right hand side of the picture is the ring and pinion for the front differential.

At the far lower left hand side is the layshaft tip where the center differential would be If I hadn't taken it out. Both parts are only serviceable by transmission disassembly. You can change the center with the trans in the car. The front you cannot.

BB
Bruce Beveridge
Mech. Eng

'94 Impreza L- DOHC EJ22T Swapped again.
'94 SS - Swapped again, 5MT, Flipped, RIP
'94 SS - Swapped 5MT - DOHCEJ22T, VF37
Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

Post by Snow-Attack »

you rock dude thats the most helpful thing iv'e got so far!!!!
so my next question is how do you go about and where can you get the parts to change the gear ratio???

thanks guys
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

Post by Snow-Attack »

ya it does have 4.11 gears and the main reason he wants to do it is because he is one of those hypermile people now lol he used to beat on the car and now he drives it like grandma i know one wheel burnouts on dry pavement arent normal!!!!! lol
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
BB
First Gear
Posts: 71
Joined: Sat Nov 18, 2006 2:15 am
Location: Somewhere, Canada

Post by BB »

go to any junkyard and look around for a 5 speed. Bend over check the rear diff foil sticker for the correct ratiio. If its 3.90, Grab the following parts:

Flywheel
Clutch
Clutch pedal assembly
Pressure Plate
Transmission
Rear Differential & Rear drive shafts (maybe).

That should keep you covered with lots of spares.

Case of your finest cheap bear, and start wrenching.

Honestly, I dont know why you'd want 3.90 gears. Just weld up your rear diff. It will be way better for burnouts, launches ect. Then if you're doing 2 wheel rear burnouts after welding then you know for sure your center diff is weak. But you can still drive with a shot Center diff.


BB
Bruce Beveridge
Mech. Eng

'94 Impreza L- DOHC EJ22T Swapped again.
'94 SS - Swapped again, 5MT, Flipped, RIP
'94 SS - Swapped 5MT - DOHCEJ22T, VF37
Snow-Attack
First Gear
Posts: 68
Joined: Sun Dec 16, 2007 5:35 am
Location: Cheyenne Wy

Post by Snow-Attack »

well the point is he has grown out of beating the piss outta it ie. no more burnouts and drifting lol and now he wants to get better fuel economy hence the higher gears....
1994 subaru legacy
MI winter package heated seats,mirrors,dark grey interior,5MT 202k,wrx 16" wheels
1992 Touring Wagon LE
td04 turbo,wrx tmic,tinted windows,sti pink struts,lowering springs,16" wheels,wrx brakes,remote start,keyless entry,alarm
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