1.447 Low range upgrade - does it make that much diffeence?

[PGS100]

Hi all,

I am contemplating an upgrade to the 1.447 low range to replace my standard duel range in my 2001 Liberty. I already have some extra clearance with a SLO kit of 2" and upgraded bigger tires that gave me an extra 25mm as well.

I am wondering if the 'improvement' in low speed and torque is significant? After all 1.196 to 1.447 is only a difference of ~20%. I have sort of given up on waiting or ADS 1.61 upgrade, so think I'd best look at the 1.447.

I'm not really into 'enthusiast' style driving trying to test out on every rocky or muddy hill (no issues if that's your thing). My need is wanting better low speed on bush tracks, and on fire trails and on farm paddocks. Current standard ratio just means too fast and no power at low speeds or having to ride the crap out of the clutch.

Wondering if those of you who have done the conversion have some views on the difference it made. I'd also be getting a 20kg VC and possibly front LSD (limited slip diff).

Thanks in advance

Paul

 

[PGS100]

Come'on folks, surely someone has had some experience with this???

 

[Kevin]

I'm sure @El_Freddo could comment

 

[Ratbag]

It really depends on the engine in your Liberty.

With the 2.2L and early 2.5L (EJ251) engines, there is not much torque below about 2200 rpm. The EJ253 in the series II Forester is getting significant torque by around 1200 rpm.

 

[El_Freddo]

I missed this one! Thanks @Kevin

@PGS100 - your best bet is a good used 2L forester gearbox for the 1.447:1 low range. Much better than the 1.19:1 low range.

Put it this way - if you had a choice between a bank account with $119 in it or another with $147 in it, which one would you go for? Ok, rough example!

Your Liberty would have the EJ22E (series 2 that’s an interference engine), so reasonable power. With the foz box it will pull everything into factory spec if you’re running a forester diametre wheel, with advantage of the better low range. You can bolt your upgraded centre diff to this box no worries (if it needs a specific centre diff housing you’ll need one of these).

If you’re going to throw in a front LSD, you might as well go all out and throw in an L series 1.59:1 low range in a 4.111:1 ratio box, or for ultimate crawl ratio, find a 4.44:1 diff ratio to throw in. Both of these will require the crown wheel shaved to clear the L series low range.

Awesome L series low range conversion here to give you an idea of what you’re in for with this mod.

If you’re going to split the box to mod low range and front diff stuff, I’d look at getting a phase 2 gearbox. The casing and gearsets for 1st and 2nd are thicker. The low range will fit in same as the phase 1 box as will the front LSD. Your upgraded centre diff with matching housing will bolt to the back of all EJ gearboxes.

I hope that helps you out. Gearboxes are fun stuff to get involved with. It’s a bit like Alice down the rabbit hole

Cheers

Bennie

 

[PGS100]

Thanks for that El Freddo, (and Kevin for the nudge). That sounds like a pretty involved process. My thinking was to get a 1:447 box already set up from All Drive Subaru, and maybe look at some refinement of gear ratios, rather than trying to fit an older L series low range box. I'm not really set up for that kind of mechanical work unfortunately. A lower rear ratio might help get the crawling capacity up perhaps?

So what I'm hearing is that the 1:447 would make a noticeable difference??? Not a crawl gear, but significant improvement on the 1:196?

Thanks again in advance.

Paul

 

[JonB]

The difference between your current high and low range is 20%, the difference between your current high range and the new low range will be 45%.

another way of looking at it is that the difference between the your current range and the new low range is 20% (1.447/1.196 =1.209), so your revs will be 20% higher for the same speed, or your speed will be 20% lower for the same rpm.

 

[PGS100]

Thanks JonB.

That's a helpful way to look at it. Have you had hands on experience with a 1:447 yourself, or know anyone close who has?

P

 

[El_Freddo]

My thinking was to get a 1:447 box already set up from All Drive Subaru, and maybe look at some refinement of gear ratios, rather than trying to fit an older L series low range box. I'm not really set up for that kind of mechanical work unfortunately. A lower rear ratio might help get the crawling capacity up perhaps?

You don’t fit the L series gearbox, just the low range

All drive will do you a box of your specs - at a cost. 1.447 low with 4.44 diff ratio would be the best way to go.

Thanks JonB.

That's a helpful way to look at it. Have you had hands on experience with a 1:447 yourself, or know anyone close who has?

Everyone with a 2L SF forester in Oz... how they’ll compare it could be a little more difficult.

@1WD Foz - you remember your low range before you pumped up to big tyres? Willing to share?

Cheers

Bennie

 

[JonB]

No direct experience with like for like vehicles PGS100, too many variables, especially in tyres when people set their cars up.

i personally like an auto in the situation you’re describing, not suggesting it’s right for your needs though. Currently trying to work out the best option to get 4.44:1 digs in my SH XT.