Foz AWD systems / Sand capabilities / SF thru to SJ

[kiwifoz]

^ Thanks for that clarification and correction, Sim.

I have seen what the centre diff in a Subie looks like after it's failed - it's ugly ... .

What did it look like? Any pics?

 

[Ratbag]

^ have look at this thread, KF:

https://www.offroadsubarus.com/showthread.php?t=5450

This is what a plate pack looks like from another knackered centre vLSD:

That black crap leaking out of it is supposed to be semi-translucent, and should not flow at all!

 

[kiwifoz]

Jeez - that looks properly burnt out! If only Subaru built them from the factory with 4.44 gearing, long 5th, 1.59 low, LSD front, DCCD centre and a locker out back...

 

[Ratbag]

^ Too much maintenance, and too much potential for serious warranty damage in the hands of the ordinary car owner.

I would have liked my series II SG to have a 1.25~1.30:1 LR and a higher 4th gear, with a slightly higher 5th.

Having a 1.59:1 LR and 4.444:1 FD behind the EJ-253 would be (mostly) a recipe for disaster, IMHO. Too much torque at too low rpm for that sort of gearing. The series I SG has a torque curve shape much more akin to that of the SF (although more of it) than it is to the series II EJ-25.

 

[jf1sf5]

Jeez - that looks properly burnt out! If only Subaru built them from the factory with 4.44 gearing, long 5th, 1.59 low, LSD front, DCCD centre and a locker out back...

You're talking about Dedman's foz :iconwink:

 

[kiwifoz]

^ Too much maintenance, and too much potential for serious warranty damage in the hands of the ordinary car owner.

I would have liked my series II SG to have a 1.25~1.30:1 LR and a higher 4th gear, with a slightly higher 5th.

Having a 1.59:1 LR and 4.444:1 FD behind the EJ-253 would be (mostly) a recipe for disaster, IMHO. Too much torque at too low rpm for that sort of gearing. The series I SG has a torque curve shape much more akin to that of the SF (although more of it) than it is to the series II EJ-25.

Yes, the maintenance and build cost would reduce Subaru's profit margin significantly.

I agree, the gap between 4th and 5th is too high. 5th is geared a little low too, even with 215/65s, for extended highway cruising. It really needs a 6-speed.

You reckon? The EJ251 is completely different to drive compared to Dad's old 2008 Impreza with the EJ204. Although the fact that's a DOHC engine would explain the lack of low-end torque. The EJ251 is superior for my needs and suits the Forester better, as the torque off idle is fantastic. You can crawl up hills at 1250rpm in low 1st no problems. Which you have to do because the gearing is crap.

You're talking about Dedman's foz :iconwink:

I know right.

 

[NachaLuva]

If only Subaru built them from the factory with 4.44 gearing, long 5th, 1.59 low, LSD front, DCCD centre and a locker out back...

Plus bigger tyres & more suspension travel

^ Too much maintenance, and too much potential for serious warranty damage in the hands of the ordinary car owner.

I would have liked my series II SG to have a 1.25~1.30:1 LR and a higher 4th gear, with a slightly higher 5th.

Having a 1.59:1 LR and 4.444:1 FD behind the EJ-253 would be (mostly) a recipe for disaster, IMHO. Too much torque at too low rpm for that sort of gearing. The series I SG has a torque curve shape much more akin to that of the SF (although more of it) than it is to the series II EJ-25.

Nothing like that of a H6!

Venom has a 1.59 LR with 4.111 diffs behind a H6 with heaps more torque and no issues.

LR is NOT meant for normal driving despite anything a marketing booklet (aka owners handbook) might say nor for dropping the clutch. If you look after the gears they will look after you :iconwink:

If you're worried about too much torque at low rpm you def should NOT use LR for towing!!

 

[Ratbag]

Yes, the maintenance and build cost would reduce Subaru's profit margin significantly.

Fuji Heavy Industries are not exactly a huge player. They have to keep costs down and profit/unit up, or they are dead meat ...

I agree, the gap between 4th and 5th is too high. 5th is geared a little low too, even with 215/65s, for extended highway cruising. It really needs a 6-speed.

They did that, and dropped the LR ... Ugh.

A slightly better choice of ratios would have helped. But still far better than the ratios in the 5MT in my '93 Impreza. They were bad! Combined with a gutless 1.8L EJ-18 engine and a torque curve that went from about 3,600 - 6,500 rpm ...

You reckon? The EJ251 is completely different to drive compared to Dad's old 2008 Impreza with the EJ204. Although the fact that's a DOHC engine would explain the lack of low-end torque. The EJ251 is superior for my needs and suits the Forester better, as the torque off idle is fantastic. You can crawl up hills at 1250rpm in low 1st no problems. Which you have to do because the gearing is crap.

Don't get me wrong about the EJ-251. IMNSHO any one of the SOHC N/A EJ-25 series engines is the "natural" engine choice for the Forester. Should have been in it from 1997.

The EJ-251 has a far better torque curve and output than the 2.0L engines. The EJ-253 is just that bit better again, with its torque coming in lower (about 80% of max from 1200 rpm) and running out further (about 90% of max at 6,300 rpm - red line). Witness the fact that the N/A EJ-253 is only very slightly slower 0-100 kmh than the turbo SF. I would wager that it would eat it for usable torque rev range as well.

That difference in the torque curves between the EJ-251 and EJ-253 is reflected in the fact that I can crawl up hills with the loaded trailer on behind and two adults on board at 1250 rpm in 2nd/LR. Different hills though ... :iconwink: :lol:.

It seems that the EJ-253 in our SH has some more slight modifications when compared with the one in our SG. Personally, I reckon that the EJ-253 is one of the best general purpose engines ever made by Subaru. I'm not a fan of the FB-25 engine ...

And yeah, the DOHC and 2.0L engine in your Dad's Impreza wouldn't help anything ...

 

[Ratbag]

Nothing like that of a H6!

Venom has a 1.59 LR with 4.111 diffs behind a H6 with heaps more torque and no issues.

I say yet again that Venom is hardly representative of the average driver - whether of Subarus or any other make.

That hypothetical "average driver" would wreck Venom's setup in about a week.

LR is NOT meant for normal driving despite anything a marketing booklet (aka owners handbook) might say nor for dropping the clutch. If you look after the gears they will look after you :iconwink:

I completely agree with that last premise.

However, one only has to look at the proportion of auto transmission to manual transmission cars made to realise that the chance of the "average driver" having much idea of how to look after the clutch and tranny in a manual transmission car is close to zero. Car makers cannot and do not make their cars for "expert drivers". They make them for (very) "average drivers".

If you're worried about too much torque at low rpm you def should NOT use LR for towing!!

Apart from sharing some common ratios, the gearbox in the series I SG is different from that in the SF. The one in the series II SG is different again. Subaru do play mix-n-match, but one has to be very careful generalising from one generation of car to another.

If one is stupid enough to do launches with a loaded trailer on behind in LR, one probably deserves what one gets (or in HR, FTM ... ).

I don't thrash my car much, other than giving it a good rev to keep the engine clean now and again. I sure don't belt the gearbox and clutch around.

I will continue to use LR where and when appropriate, and in an appropriate fashion. I do not expect any problems from this source.

Perhaps you need to drive one of these cars in the circumstances in which I drive mine? There will be problems if you drive it the way one has to drive a 2.0L SF. I discovered this very quickly when I moved from my Impreza to Roo2. That move completely changed the way I drive my car. One always needs to adjust one's driving to suit the car one is driving. There is no universal rule; no 'one size fits all'.

 

[kiwifoz]

I didn't realise the gearbox was different between SG5 and SG9 models, what are the changes? I do know the synchro on first is pretty shot on my gearbox, I usually double-clutch it and rev match to stop crunching (you pretty much can't select 1st unless stopped and even then you sometimes have to let the input shaft 'spin down' after having had it in neutral at the lights). Third and fourth are definitely on their way out too, it makes a little click when going into 3rd... But slowly, even dad's Impreza did this with only 140,000km on the clock. It does sometimes refuse to change down from 5th to 4th when doing ~60kph. If this gearbox goes I'll have to have a think about what to do. I'm tempted to grab an SF 1.47 box, whack on the DCCD and call it a day.

Venom's car is probably the best allrounder offroad Subie in the world, frankly.

 

[Ratbag]

I didn't realise the gearbox was different between SG5 and SG9 models, what are the changes?

AFAIK, there were changes to the synchro setup, with double synchro rings on some gears. Don't quote me on that ... :iconwink:.

The width of some gears is different between the SF and SG, with the gears pairs in the SG being significantly wider - therefore square law stronger, if all other things are equal in their making: i.e. if 25% wider, they will be approx. 56% stronger.

I do know the synchro on first is pretty shot on my gearbox, I usually double-clutch it and rev match to stop crunching (you pretty much can't select 1st unless stopped and even then you sometimes have to let the input shaft 'spin down' after having had it in neutral at the lights). Third and fourth are definitely on their way out too, it makes a little click when going into 3rd... But slowly, even dad's Impreza did this with only 140,000km on the clock.

My '93 Impreza was starting to do those sorts of things. Synchro on first was always 'slow', even from new and after running in. I was told that this was normal. All the other gear changes worked fine until around the 200K Kms mark, when they all started to get progressively slower, both up and down shifting.

I figured that if I were going to throw a poultice of dough at this, I would buy a Forester which suits what I do and want to do far better. And not its only problem at 236K Kms, either ...

It does sometimes refuse to change down from 5th to 4th when doing ~60kph. If this gearbox goes I'll have to have a think about what to do. I'm tempted to grab an SF 1.47 box, whack on the DCCD and call it a day.

You need to be very careful about doing that. Far better served by putting the 1.447:1 LR into an SG box, then a helical front LSD and plated rear LSD along with a DCCD - just IMHO. Maybe even forget the 1.447:1, just do the front, rear and centre diffs ...

Venom's car is probably the best allrounder offroad Subie in the world, frankly.

It is very well set up ... Sounds like a high quality sewing machine going flat chat, if you know what I mean. Lovely note. Probably even better after all his recent work. I haven't heard it since then.

 

[taza]

Turbo wins over n/a motor any day.
I challenge you to a race Ratbag against my GT!

 

[taza]

Gearing before LSD's. Power before gearing.
my 2.5 in my forester made the SF gearing epot on for on and offroad except for the **** 5th gear. The biggest problem like that was then diagnal slip which a rear LSD would help and probably be enough for my needs.
However I will be going 1.59 low range with a front and rear lsd just to help save the clutch and habe plenty of general all round traction.

 

[simxs]

I do know the synchro on first is pretty shot on my gearbox, I usually double-clutch it and rev match to stop crunching.

This has gone quite OT but thought I'd mention...

On the recommendation of people in the know, I switched to Redline Lightweight Shockproof gearbox oil some years back. No more crunching into first! (It 'baulks' a bit now instead - not ideal but preferable.) The main benefit though is the improved shift action generally. It's expensive stuff, but worth it.

 

[Ratbag]

Gidday Taza

Turbo wins over n/a motor any day.
I challenge you to a race Ratbag against my GT!

The SF 2.0L turbo is about 0.4s faster 0-100 kmh than the N/A EJ-253. Hardly earth-shattering ... :rotfl:.

There would be more difference between individual drivers than that.

Besides, I gave up doing that sort of stuff at about 21 y.o.
Good fun, and we had a quarter mile measured out on the Qld Uni circuit road for the purpose ...

My Morris 1100 was nearly as fast as a stock 1800cc MGB over that 1/4 mile.
Not too bad, considering.

Nah, what I was really talking about was the tractability of the car. How pleasant it is to drive in everyday life, no matter what you are doing. For that, the EJ-25 engines win hands down, even if a bit slower.

Besides, turbo engines can end up costing a motza (or two ... ) in maintenance and fuel bills.

We won't even talk about how long my driver's licence would last! Even at my age, there is still some of the screaming wheelie, milk bar hoon boy left ... :lol: . Best not to put temptation in my own way!

One of the benefits of towing the trailer around the country is that I am somewhat more likely to be (relatively ... ) law abiding.

 

[ALMOSTunseen]

One of the benefits of towing the trailer around the country is that I am somewhat more likely to be (relatively ... ) law abiding.

Yeah launching our ute uphill with a trailer didn't leave the clutch too happy after a while!

 

[Kevin]

This has gone quite OT but thought I'd mention.

Really.....I hadn't noticed! :lol:

 

[Ratbag]

^ Wouldn't life be boring if we didn't occasionally take the road less travelled?

One of the main reasons I traded the Impreza in on the Forester is so that I can swerve off in a different direction with some degree of safety ... :iconwink: :ebiggrin:. I will also try to do more of this when driving ... :rotfl:.

 

[kiwifoz]

AFAIK, there were changes to the synchro setup, with double synchro rings on some gears. Don't quote me on that ... :iconwink:.

The width of some gears is different between the SF and SG, with the gears pairs in the SG being significantly wider - therefore square law stronger, if all other things are equal in their making: i.e. if 25% wider, they will be approx. 56% stronger.



My '93 Impreza was starting to do those sorts of things. Synchro on first was always 'slow', even from new and after running in. I was told that this was normal. All the other gear changes worked fine until around the 200K Kms mark, when they all started to get progressively slower, both up and down shifting.

I figured that if I were going to throw a poultice of dough at this, I would buy a Forester which suits what I do and want to do far better. And not its only problem at 236K Kms, either ...



You need to be very careful about doing that. Far better served by putting the 1.447:1 LR into an SG box, then a helical front LSD and plated rear LSD along with a DCCD - just IMHO. Maybe even forget the 1.447:1, just do the front, rear and centre diffs ...



It is very well set up ... Sounds like a high quality sewing machine going flat chat, if you know what I mean. Lovely note. Probably even better after all his recent work. I haven't heard it since then.

I'd like at least the 1.47. Here in NZ our 4wd tracks are VERY steep compared to what you guys have in Aus, as far as I've seen, and so the lower the gearing the better IMO.

I have already heard about the differences in 1st 2nd and R SF-SG.

Yes, there's enough 98-03 Outbacks in NZ that SG strength gearboxes aren't too expensive, If I was going to build an offroad box from an SG I'd go with the 1.59DR, and probably the helical front diff from a DCCD STi box.

 

[taza]

Haha Ratbag... I just got the GT modded to a wrx turbo and a tune on 16psi boost... there would be no comparison I'll be giving some v8's a run for their money.