a budget offroad gearbox build and BIG tyres.

Have you seen a 0-100 video of one... my push bike is faster than the sad 16 seconds it takes it! :raspberry:
I also don't see how fuel economy could be much better. My mothers XV fb20 CVT with the tune returns about 4l per 100km on the highway. Thats over 1000km to the standard tank(60l) which most of us have.
 
Gidday Andrew

AndrewT said:
Isnt the Impreza of that era only like 150kg lighter anyway? Forester with the same motor would theoretically drive like the Imp with two extra passengers?
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I don't know about the 1997 Impreza, but my '93 1.8L 5MT hatchback weighed 1,075 kgs tare weight. Power to weight ratio (tare) = 1075/76 = 14.15 Kgs/KW; torque to weight ratio (tare) = 1075/147 = 7.31 Kgs/Nm.

My 2006 Forester (alloy wheels and aluminium bonnet) weighs 1,380 kgs tare. Power to weight ratio (tare) = 1380/121 = 11.4. Kgs/KW; torque to weight ratio (tare) = 1380/226 = 6.11 Kgs/Nm.

Looked at another way, my model Forester weighs 28.4% more (26.4% more with an 80 Kg driver in each car), but has 59% more power and 53.8% more torque.

Then there is the comparison between the shape of the torque/power curves between the two vehicles' engines. The EJ-18's looked like an inverted ski jump in both cases; the EJ-253's is flat like a clay pan ... :iconwink:.

Throw the suitability of the gearing into the mix, and it is easy to see why the Impreza got better fuel economy around town but not on the open road, and the Forester is much faster at everything, and gets (comparatively) rotten economy around town but is brilliant on the open road.

Moving 1.5 tonnes (with driver) off the mark is always going to use more fuel than moving 1.3 tonnes off the mark.

Loved my Impreza. Love my Forester more ... :biggrin:.
 
yeah naturally there are many factors, gearing is a huge one. I find the biggest factor in economy is driving style / technique - I remember Clarkson demonstrated this by getting better fuel economy around a racetrack in a BMW M3 than a Prius lol.
 
Everyone severely underestimates gearing.

Comparing a foz and an impreza is like comparing chalk and cheese - no two ways about it!

The impreza definitely has different gearing - and in the research I've done I believe it changes with the engine size too. *Most* subaru first gears are 3.545:1. The front wheel drive imprezas got 3.6-something:1 and the SGs got 1.454:1. That's just first gear to look at - then there's second gear which seems to have even more variation.

3rd and 4th look like they're about the same across the board with only two variations from memory.

Then add to all of this is the final drive ratio where Subaru have a selection of 4 in total to choose from - 3.7:1 3.9:1 4.111:1 and 4.44:1. The final drive can change so much in the performance characteristic department of EVERY drive gear it's just not funny and therefore different models should not be compared in this manner without very careful consideration of their different setups.

As for engine size - you could have a 1.6 litre on a 40 tonne truck and it'd still go to a point. You'd need 50 more gears to get it moving at speed but it's possible.
And Taza, I know you have it in for the EJ20, but they're a decent engine. You just need to know/learn how to drive them accordingly! Just because it's a subaru doesn't mean it's got WRX performance no matter how hard you stomp on the go faster pedal!

Cheers

Bennie
 
El_Freddo said:
Everyone severely underestimates gearing.
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Couldn't agree more! Since I changed to 4.44 final drive with stock 1-4 gears and taller 5th so rpm on the freeway is matched I love my car with its little ej20. Sure its not fast but it get there and off the line it does very well with the very short 1st gear. Offroad is absolutely brilliant 1st high range is now the do almost everything gear except for the very steep or rough (and probably sand but I haven't tried that yet).

In conclusion if you are building an offroad box 1.59LR and 4.44FD is worth every dollar IMO and I personally would not go to the effort of doing just one without the other.
 
^ Agreed.

The problem with the Impreza ('93, AWD, 5MT, EJ-18) was that the engine was seriously underpowered for the weight of the car; the tune was quite inappropriate for a general purpose vehicle (it was tuned to go like the clappers from about 4,000 to 6,500 rpm ... ); and the gearing was all wrong.

Much the same can be said for the first model Foresters. However, the tune was better in the Forester (I have driven a very early model SF when it was relatively new), and the gearing was far more appropriate (even forgetting the dual range box completely).

IMHO, both would have benefited from having the EJ-22 from day one. That wouldn't have fixed the gearing in the Impreza, however. Having said that, the Impreza was a wonderful touring car.

Even the EJ-251 N/A Forester lacked the performance of the EJ-253 over anything like the rev range. The EJ-253 SG is about 0.5s slower 0-100 kmh than the SF Forester GT. I suspect that the series II SG is a far more tractable car to drive from looking at the shape of the torque curves for both cars (I haven't driven an SF turbo).

Many, many factors go into a car's performance. Appropriate gearing is at or close to the top of that list, but it is not the only thing, not by a long chalk.

It's why I keep banging on about balance in all these things.
A GTHO Falcon or WRX might be faster than an old 3.8/4.2L E-Type Jag, but neither is anything like the car either for the sheer pleasure of driving it, nor for the overall balance ...
 
Dedman said:
In conclusion if you are building an offroad box 1.59LR and 4.44FD is worth every dollar IMO and I personally would not go to the effort of doing just one without the other.
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Sure is, but I wouldn't want such a shaved crown. Time will tell if its reliable.
 
jf1sf5 said:
Sure is, but I wouldn't want such a shaved crown. Time will tell if its reliable.
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It'll be reliable - Dedman is not the first to do it! There's a EJ turbo'd brumby running 1.59:1 low range and 4.44 diff's - I've not heard of this unit having an issue yet it's been operational for a number of years now.

If I didn't have to modify my pinion shaft to get 4.44s with my setup I'd be going that way too!

Cheers

Bennie
 
jf1sf5 said:
Sure is, but I wouldn't want such a shaved crown. Time will tell if its reliable.
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I don't believe the shaved crown wheel would be a problem, it was not quite into the contact region. If it does fail it will be hard to tell if its a result of the shaving or as a result of not being set up correctly as I don't really know what im doing...

That being said, if I were to do it again I would spend the extra $$ and go with the All drive Subaru low range kit, simpler and doesn't require machining on the low range parts to install and the 4.44 gear doesn't need much taken off. You could do that conversion well without a lathe where as the L series one is much much more difficult to do without a lathe although so far mine seems to be working.
 
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Well my foz has hit the 400.000km. And the same day the reverse gear died.
not happy with that, the offroad box isn't ready and living nearby Amsterdam you do need reverse daily.

speeded up the offroad tranny. At this moment the box is at the gearbox guru. The diff will be a 4.444 from a 98 wrx-sti. And the lowgearing from a impreza <94 1.6 LX. With a 1.59 ratio. The same ratio is used in the first legacy's 1.8 .
I went from a phase 2 to a phase 1 tranny otherwise the low gearing wouldn't fit. The parts are ordered and the are not in stock in Europe. They have to come from japan and that will take 3 weeks. So 3 weeks of carefully parking my foz or using my wifes fozzy.

The part numbers of the lowgear parts are:

35202AA050 shaft input h/l
35215AA020 gear counter
35206AA060 gear input low

price ( not sure if it is the same order)

€ 162.97
€ 124.71
€ 98.92

Exclu. Tax and i get 10% discount on them
 
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I skip the dccd for this moment. Because i opted to also change the engine for one with much less kilometers and i want to keep a budget for going to Marocco with this foz in oktober.
Maybe in the future
 
That is very bad luck for your reverse to die now!
 
Sorry to hear about your reverse gear stripping, Casper.

That's a real bugger! :( :cry:
 
So thats the low range gearset you're buying new?

Why wont it fit in a phase 2, I thought the idea of the EJ LR is that its a straight swap?

One more question, what is a phase1/2 gearbox? lol
 
NachaLuva said:
Why wont it fit in a phase 2, I thought the idea of the EJ LR is that its a straight swap?

One more question, what is a phase1/2 gearbox? lol
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Yes, thats what I thought too…

But there is a difference between a phase 1/2 SF gearbox but not in the box itself, more in the center differential, the phase 1 is tougher :iconwink:
 
As I understood from the gearbox guru the H/L from a phase 1 is bigger then from a phase 2.
it is possible to machine them to fit in a phase2.

I had a spare phase 1 lying around and i could buy for not too much money a 4.444 front (and rear diff) for a phase 1. So that's wy I went for phase 1
 
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Not having ever taken apart a phase 1 dual range box I could be completely wrong about these details but from what Ive read;

Phase 1 EJ AWD Trans
4 bolt (confirmed)
Larger diameter input bearing (not confirmed)
Longer splines for dual range syncro hub (not confirmed)
Return to centre spring for 1st/2nd gear side is outside gearbox (confirmed)
Phase 1 centre diff and transfer gears (see image below) (confirmed)
Has 4 bolt port on top of transfer case similar to old pt 4wd gearboxes (confirmed)

Phase 2 EJ AWD Trans
8 bolt (confirmed)
Smaller diameter input bearing (not confirmed)
Shorter splines for dual range syncro hub (not confirmed)
All return to centre springs are internal (confirmed)
Phase 2 centre diff and transfer gears (see image below) (confirmed)

decsuby008fx7.jpg


Again don't hold me to any of this, the items that are (confirmed) I have seen examples of comparing a phase 1 and 2 tranny but that does not mean that it is the case for every one. There are most likely other differences I have missed as well.
 
Another little difference is the speedo "thing" fixed on the gearbox. 4 bolt is made of metal, 8 bolt is made of plastic.

As I don't know how a 8 bolts inside looks like, I can not compare either...
 
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