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Hi All,

Have been looking at the relatively new Forester (2008+) and have noticed that all the diesel models only come with a manual gearbox ie no autos. Was wondering why this is the case? Surely a decent diesel/auto combo would be very fuel efficient?

Cheers,
Dave.

They didn't engineer one in the first place. It's not "prioritised", in spite of there being a CVT Outback diesel. One's not due until 2015 . Subaru do their own thing and are a small company, so don't possess the resources or large 'parts bin' of the big companies (article here too). Their engines and, as far as I can tell, their AWD drivetrains are Subaru-specific. Diesels also apparently cause particular stresses related to their characteristics that require engineering around ( like large torque at relatively low revs and the impulse from each detonation through the drivetrain). Still, Mazda ain't huge and managed it for a diesel auto...

It can't come fast enough. Subaru will be bleeding sales to the RAV4/ CX-5 auto diesels. I'm eyeing off a CX-5. As you say, these diesels should mate well to auto trannies which can keep the engines in their happy zone.

Coming from a petrol, they're quite limiting, wanting to rev a bit but redlining around 4750rpm. Coming from an old school diesel, they're unusable, completely lacking torque under 1500rpm, won't tolerate any load at idle (will stall) and with light-switch torque cut-in from 1600rpm. Driving a manual diesel requires adept use of the gears. Add on peculiar gearing and all the DPF / emission control compromises especially in urban driving, touchy on fuel quality and frankly, a VAG turbo petrol type of engine looks a winner.

But with a 50:50 front:rear manual drivetrain torque split ( the auto/CVT are something like 90:10 or 80:20 I believe) and up to 350Nm of torque (limited to less in 1st) you can make other vehicles look quite silly in the wet. I haven't managed to spin the wheels (or trip the traction control) from a standing start, dry or wet. And 3rd gear is brilliant, from ~40 - 100km/h. Economy good for a big, blocky vehicle but not to quoted figures.

pitrack_1 wrote:Still, Mazda ain't huge and managed it for a diesel auto...

Mazda might be small but they make/sell almost double what Subaru achieves each year.

As you have noted Subaru's gearboxes are 'Subaru specific' due to the flat, longitudinally mounted engines. Mazda on the other hand are transverse or 'east-west'. It's quite simple for Mazda to source a gearbox from Jatco or Ford, not so simple for Subaru. Thus the production prioritising done by Fuji.

There is indeed a diesel + cvt auto combo in the outback. I think the reason they did this is because the outback/liberty are the upper market models and so cost significantly more than the forester. Diesel engines and cvt transmissions are very expensive, especially as subarus are unique to them, so having both in a forester would have driven the cost up past the market they are trying to target the forester, or eat into their margins.

Thats my theory anyway.