Lower gears, using stock drive & 31" tires ?

[Scott in Bellingham]

OK

now I want to Awesome offroad machine based on the EA82 , here are some of the details I would like

 

#1.... run 31" tires ,

#2 ....keep stock diffs 3.9 ratio ,

#2.5. have a lower then stock (all stock, even small 13" tires) 1st gear

#3 ....have lots of ground clearance ,

#4 ....remove all the weight I can ( do not add a ton with extra

........transfercase, diff and framework)( remove all doors, rear hatch,

........rear seats,trim off front)

#5 ....and still drive at normal speeds on the road,

 

heres my question . how to go about this without Mortgaging my house,and making it to difficult to do, it would be Cool to keep all the stock drive( engine, transaxle, diff ,axles),

if there was someway to get a extra low gear out of that transaxle, maybe cut a hole in the side where the HI-Lo gears are and add another set that works through them, maybe drop the transaxle and not the engine and run a chain and sprocket between the 2 , or even gears,and if so what kind of a reduction ratio are we talking about

whats your ideas? Scott

[MorganM]

With a full 6" lift then 31" tires and t-case can fit. Maybe Bushbasher can chime in because I'm refering to him as a reference here.

 

I think you already have an awsome offroad machine. Just need to go out and prove it to yourself

[Sweet82]

The problem with dropping the trans but not the engine and adding a gear reduction would be...

 

you'd be dropping All your gears.

 

So if you went with a 2:1 reduction you'd get a 40 to 1 crawl ratio which may get the job done...

 

But,

 

You'd be dropping your top end speed by half too...so 80 to 40 mph?

 

Short of changing the internal gearing, I don't think there is anyway other than a divorced T-case.

 

Dreaming...

Glenn

82 SubaruHummer

01 Forester

[subynut]

What about just adding some gearing to get the rpms and speedo back to stock?

If my calculations are correct, with 31" tires, if you could change the axel ratio to approx 5.212. That would put the engine back in the powerband.

What if you put the difference between that raito and the stock ratio between the engine and tranny like Scott sugestted?

[Scott in Bellingham]

If my calculations are correct, with 31" tires, if you could change the axel ratio to approx 5.212. That would put the engine back in the powerband.

What if you put the difference between that raito and the stock ratio between the engine and tranny like Scott sugestted?

 

yeh like Ted said , OK with 27" tires I dont use 5TH gear anymore , lets say between the engine and trans we reduce it , ok what kind of reduction ratio would you need so I could again use 5th gear and still go say 70 tops in 5th with 31"s?, thats all you would need , even if top road speed was 60 it would be plenty for a wheeler

[Scott in Bellingham]

 

I think you already have an awsome offroad machine.

 

thank you and I agree with you ,its my family wagon, you know for getting groceries and such, Haaaa Haaaa, my mind is onto my next project, something thats: light, tons or clearance ,good size tires and good low low gears

[Vanislru]

Hey Scott I'm currently looking at the same thing, so far it sounds like a 4.11 or 4.44 gear set can be installed into a D/R trannie, with some case ginding. 4x4 Mudrat knows who the guy in Aus. is that has done this I think. I'm going to have Mudrat do up a trannie with the lower gearin and an lsd as soon as I work out the details. I desperately want lower gears I don't like the bog in 1st and crawling's more like jogging.

[Scott in Bellingham]

Hey Scott I'm currently looking at the same thing, so far it sounds like a 4.11 or 4.44 gear set can be installed into a D/R trannie, with some case ginding.QUOTE]

 

 

with the 4.44 what size tire could you run and keep the stock gearing and keep speedo correct?

[Vanislru]

I can't remember what it worked out to but if you figure the difference between 1:3.9 and 1:4.44 ratio's you can then go to a tire site and match the 2 figures as percentages over stock for the right tire size. I think 4.1 workde out to 28.4 " tires so 4.44 probly around 29.6 or so, I think...

[MorganM]

thank you and I agree with you ,its my family wagon, you know for getting groceries and such, Haaaa Haaaa, my mind is onto my next project, something thats: light, tons or clearance ,good size tires and good low low gears

 

Sounds like you need a Toyota then... or atleast a Subaru with Toyota running gear to give you the clearence, tire sizes, gears, and aftermarket support you want.

[Scott in Bellingham]

Ok after looking inside the transaxle (see picture) looks like major work to get a low enough gear

 

that leads me to the chain and sprocket reduction at the motor, now heres another question, is the Subaru flywheel evenly balanced all around, so if I took it off the motor added a sprocket on the crankshaft then ran that down to a shaft that contains another sprocket, bearings and the stock flywheel ,would it run balanced? ,this would also leave the motor in the stock location up high and only drop the transaxle, I know some flywheels are not center balanced is this one?

[subynut]

Ooohh, there's not much room in there. Wonder if there's room for a vlsd out of a STi in there? I feel a clutch type would cause too much understeer at highway speeds.

anyways, back to out regularly scheduled topic!

Yeah, looks like it would be best to add the gearing between the engine and tranny to compensate for bigger tires. Now, what will this do to the lifespan of the rest of the drivetrain? IE CVs, stub axels, u-joints, etc.. Gonna go figure out that gearing ratio while I pull the other head gasket off me engine.

[Scott in Bellingham]

heres a mock up

 

 

 

 

 

looks like about a 9" raise, and about 2-2 1/2"move engine forward

[Vanislru]

There's got to be a way to swap a few gears. If the main gear/ front diff's gear ratio is changed plus your rear diff then you're done [forgive my lack of terminology I'm completey wiped]. There is a post somewhere with a copy of all the gearing in all the trannies subes have Ill try to find it tomorrow and PM 4x4 mudrat to see if I can track down this guy in Aus.

[TurboSPFI]

Can you actually change out the gears that're inside the transaxle?

 

Machine new gears?

[Sweet82]

heres a mock up

 

looks like about a 9" raise, and about 2-2 1/2"move engine forward

 

Nine inches is a substantial raise...

A raise like that would raise your center of gravity and change some of the handling we enjoy.

 

Why couldn't you raise it just enough to have the gears & chain clear each other?

 

I'm assuming theres something in the way?

[Scott in Bellingham]

Nine inches is a substantial raise...

A raise like that would raise your center of gravity and change some of the handling we enjoy.

 

Why couldn't you raise it just enough to have the gears & chain clear each other?

 

I'm assuming theres something in the way?

 

 

 

with chain & sprockets if one is 4 " dia another 8" thats 6+ " between shafts also on the bottom need a set of bearings which end up tucked under the rear of engine,

 

with the vehicle raised 8-9 " that would leave the engine in the stock height , and allow clearance for 31" tires, remember this is all brainstorming nothing set yet

 

Scott

[Sweet82]

I realize it's way more complicated but...

 

What about a gear to gear transfer?

 

Smaller gears would allow a tiny offset between the motor and tranny.

[bushbasher]

this chain drive or even gear reduction before the tranny will increase the torque load on the tranny, while reduction after the tranny doesnt.

 

the t-case from a suzuki samurai will give you high range reduction which will solve highway gearing, and it also has low range which will give you all the reduction you could ask for off-road.

 

I used a lada niva t-case which also has high range reduction but I wouldnt recommend it or ever use it again in a sube. The case is made of cheap russian aluminum (which I broke), the drive flanges are offset, and the mounting system is very difficult to deal with.

 

However, the big problem with the t-case route is the front suspension. On an ea82 the suspension arms are not swept back like an ea81 and they will interfer with the cv shafts if you try to stick a diff in the front. You would either need something like 9" of lift (I cant remember the exact amount) Or redesign the whole front suspension, possibly incorporating ea81 stuff. I ended up relocating the subframe forward 3" and making custom a-arms that swept back 2" giving me room for the cv shafts, plus 1" more wheelbase. This gave me better tire/firewall clearance for the 31x10.5s, and also allowed the front diff to pack up higher without hitting the transmission.

 

Still, this could be less work than trying to make gear or chain reduction between the motor and tranny that will hold up to the rpms and torque.

[Scott in Bellingham]

this is good stuff, do you know what the sammi tcase ratios are?

 

this chain drive or even gear reduction before the tranny will increase the torque load on the tranny, while reduction after the tranny doesnt.

 

the t-case from a suzuki samurai will give you high range reduction which will solve highway gearing, and it also has low range which will give you all the reduction you could ask for off-road.

 

I used a lada niva t-case which also has high range reduction but I wouldnt recommend it or ever use it again in a sube. The case is made of cheap russian aluminum (which I broke), the drive flanges are offset, and the mounting system is very difficult to deal with.

 

However, the big problem with the t-case route is the front suspension. On an ea82 the suspension arms are not swept back like an ea81 and they will interfer with the cv shafts if you try to stick a diff in the front. You would either need something like 9" of lift (I cant remember the exact amount) Or redesign the whole front suspension, possibly incorporating ea81 stuff. I ended up relocating the subframe forward 3" and making custom a-arms that swept back 2" giving me room for the cv shafts, plus 1" more wheelbase. This gave me better tire/firewall clearance for the 31x10.5s, and also allowed the front diff to pack up higher without hitting the transmission.

 

Still, this could be less work than trying to make gear or chain reduction between the motor and tranny that will hold up to the rpms and torque.

[Scott in Bellingham]

I realize it's way more complicated but...

 

What about a gear to gear transfer?

 

Smaller gears would allow a tiny offset between the motor and tranny.

 

 

 

2 gears will revearse dirrection, would require 3, if it could be done compact would be ideal

[TurboSPFI]

I seriously think you guys are going about this all wrong, why couldnt you just switch the gears in the transaxle out with a new set that could be custom made?

 

I know gears can be made, why not just make a new 4lo gear? new gearset for 1-5th gears?

[bushbasher]

I seriously think you guys are going about this all wrong, why couldnt you just switch the gears in the transaxle out with a new set that could be custom made?

 

I know gears can be made, why not just make a new 4lo gear? new gearset for 1-5th gears?

 

Because making gears is beyond the capabilities of 99% of machinists. And the ones that can are going to charge 5x what we already have put into our cars.

 

There are methods of changing gears without remaking the whole shaft. It is possible that a pair of gears from some other transmission with the same center to center distance (not very likely) could be machined and welded/pressed onto the existing shafts in the DR tranny after the existing gears are machined off the shaft. Then of course it all has to be heat treated again.

[TurboSPFI]

interesting.

[Mike W]

A "Rock Block" would be nice for those running divorced transfer cases. $1350...ouch. http://www.trailtough.com/transfercase_driveshaft.htm