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G'day all, ive just gotten some 27" tyres on 14" rims for Scooby, and am thinking of changing the diffs a little later on down the track to try to counteract the larger diameter tyres and get the most on/offraod driveability out of the weber powered EA82. What would be the best ratio to get the gearbox back to being similar to the factory gearing?

Cheers Alex

L.Series only came out in 3.7 or 3.9 ratio.. so best checking what you have now. IMO I'd have the 3.9

I'd go the 4.11. Oh, wait, I am - eventually!

To change your diff ratio to anything that's really useful you'll need to do a cut and shut on the pinion shaft to fit the required pinion gear.

Cheap way to go? Probably not, but then again a diff ratio change won't be cheap anyway unless you know how to do the diff back lash and pre-load adjustments. Plus you need to find the appropriate diff ratio that you want to swap to - front AND rear! Rear is easy though.

This is the biggest down fall of offroading the older subi's - and subarus in general in terms of having the front diff located in the gearbox.

Cheers

Bennie

I've been thinking of the same but have not had time to search on here to see if 4.1's can be fitted somehow from a Liberty/Impreza etc.

:mrgreen:

Me too Me too... 4.11 Soon:twisted:

vhr32 wrote:I've been thinking of the same but have not had time to search on here to see if 4.1's can be fitted somehow from a Liberty/Impreza etc.

If you're talking the PT4wd L series gearbox that'd be a cut and shut on the pinion shaft.

Otherwise a foz box would be well suited

Cheers

Bennie

If you don't want to get expensive heat treat > cut > weld > heat treat work down then you can have 3.7 or 3.9 on a part time 4WD box. On AWD you can get 3.7, 3.9, 4.11, 4.44.

Yeah Bennie but some of us don't have the bank balance like you. IMO, I'd go the 4.44 if I was going to all that effort of cutting and joining pinion shafts.

RSR 555 wrote:Yeah Bennie but some of us don't have the bank balance like you.

Be very glad about that!! I can tell you it's not what it seems. And the shaft I got was already cut and shut, Jeff had it behind his version something WRX brumby's engine... So it should be good

I've heard the 4.44 was too short for highway cruising, yes it would be awesome for offroading with the L series low range - good crawl ratio. But I'm after a bit of an all rounder for good offroading gearing with the 27's and good cruising ability for economy when touring.

I have thought about where I'm going with this!

Cheers

Bennie

I have a 3.7 L series part time 4WD box, I find it is very tall and I only have 215/65-14 (25") tyres!

I'll have to look into this cut and shut thing and then see about a matching rear diff which I think might bolt up but have to suss out driveshafts.

4.4 would be sweet actually!

After what you would have to do to the crown wheel if using a 4.44 and a 1.59 I'd be worried about strength...

Phizinza wrote:After what you would have to do to the crown wheel if using a 4.44 and a 1.59 I'd be worried about strength...

I think it's the same as the 4.11, just a different teeth count - but I could be seriously wrong on this as I've not seen a 4.11 and 4.44 ring gear to compare the difference between the two - you can't go much bigger in size of the 4.11, otherwise the diff wouldn't fit in the gearbox casing!

Cheers

Bennie

Phizinza wrote:After what you would have to do to the crown wheel if using a 4.44 and a 1.59 I'd be worried about strength...

If as Bennie says 4.44 is the same size as 4.11 then it is strong enough.

The H6 Foz has 4.11 with 1.59 low range behind a EZ30

My standard Foz box is pretty good 4.11 with 1.447 low range. The main real issue is lack of power from the EJ20. Not a bad compromise though and heaps better than 3.9 with 1.191 low range!

IMO, if you're using EA g/box casings, you will need to modify the crown wheel but if using EJ casings then there shouldn't be any troubles. Never fitting 4.44 into a EA box I really cant comment. I will build a EJ 4.44 AWD D/R with CDL with some spares and report back.. just don't hold your breathe.

Oh right. I heard the 4.44 is slightly larger from someone years ago on UltimateSubaru. But they could of been mistaken. If it is the same size then it might just work. It was a squeeze to fit the 1.59 in with the 4.11...

Personally I can't wait for slightly larger tyres on my Outback. It's 215/60R16's are about 26.1" in diameter and first gear is too low for most onroad driving.
I'm sure for offroad, in low range, first will be nice how it is but I have not needed it yet, the EJ25 has a s*** load of torque!

The 4.44 is only 8% lower then 4.11.
The 4.44 is 20% lower then the 3.7.

Swapping 4.11 to 4.44 would result in about 220 more rpm at 100kph.

Honestly, at the end of the day you are not going to get a Subaru (without an 8" body lift and external front diff) to crawl. But you would spend a s*** load of time trying. I've come to enjoy finding out how far you can get fairly standard Subarus just using some acquired skill.

Very true Phiz and I'm sure it would really depend on what engine you have in front of the 4.44

It's a personal choice for me because I'm not planning on doing long trips in my offroader car.

thanks guys this is all primo info, how would i find out what ratio ive got atm?

Usually there is a sticker on the back of the rear diff.

thanks for that Phizinza... Just went for a crawl under scoob, and hes got 3.7 diffs... but ive during the week ive picked up an '86 touring wagon, which i discovered has 3.9's so ill be trying to swap those over in the near future