Question about Subaru legacy S-I Drive

[Rob4001]

I've been on this website a few times pondering what car to get well it crunch time now as old cars MOT & Tax runs out next month. I have 10K to spend and pretty much settled on Legacy I want an autobox because I driven an auto for past six years. I have been told on this forum though the autobox on the legacy is not good. I've been reading though the S-I drive has improved things greatly. I am taking one out on test drive on the weekend anyway. Has anyone got opinions on or used S-I drive? Other options I am considering are Golf VI GTI, Audi 2.0T S-line and BMW 330ci

Thanks

[cruiser647]

Many of the journos don't like the 4-speed Subaru auto boxes. But then again, drive it and see.

What do they know. . Can't say I agree with them a lot.

[steelwind101]

The SI drive is a 6 speed unit, more so the SI drive is a smilar to what you find on say some of the Mitsubishis.

Its more then a gearbox, its a computer that is in control of gearshift timings, engine managment, traction control/power application (where the power goes and where grip is), stability control and anything else that they have added.

When you twist the dial thats by the gear stick you acutally adjust the settings for whole car. I think in sports sharp, you get longer in gear time, valve timing tuned for power/fast pick up not economy etc etc. It hangs on nicely in the corners and found it gave positive, no fuss kick down to the correct gear and gives good exhaust note when doing so.

Intelligent is like most Jap cars, this will limit RPMs and sadly will make the box more picky about choosing gears. Like in my Auris in "E" you might find it frustrating that it chooses to the gears to soon.

Sport mode is different from sport sharp as its less full on, the torque curve is different and the valve timings altertered.

Maybe the beauty of the system is that you can have it set between Sports and sports sharp to your personal tastes. The dial moves in section and is not limited one mode or another.

I have driven it only on the 2.5 turbo in the USA. Sadly, on the UK spec Legacy (no turbo) it seems to be much slower then the manual version. However, i dont know what setting they had the dial turned to when they did the 0-60 calucation. I think you will need to test drive and see!

Its the kinda thing i personally like, but it isnt just an standard auto box.

As for the 4 speed Subaru gearbox, i do not have any complaints either!

Geoff

[cruiser647]

Oohhh, a right techno box then!

Sounds good.

[Teacake]

Until the launch of the current Legacy in 2003, all Subaru autoboxes were 4-speed. None of these will have SI-drive. From the 2003-model onwards all automatic Legacies will be 5-speed with steering wheel tiptronic-style buttons. There are no 6-speed autos on any Subarus.

SI-drive was introduced, I think, in 2007. I've not driven a car with it fitted, but I have driven the earlier 5-speed auto, and found it quite annoying. The car needed to use more revs than I would like to make brisk progress, and frequent down-changes, accompanied by a fair amount of jerkiness, if pressing on. Despite being an H6 with 240bhp, it felt like it needed about another 40bhp and a lot more torque to be happy with the ratios it had. The 6-speed manual I drove later was much, much better.

For completeness, I've also driven a 5-speed automatic twin-scroll turbo, which was epic, but much lower-geared than the UK autos, several older 4-speed autos, which were plodding donkey 'boxes but not without their charm, a 4-speed automatic twin turbo, which was frenetic, and several five-speed manuals with a variety of no, single or twin turbos, which all had very good gearboxes.

[steelwind101]

I dont think the H6 got alot of love, it wasnt that much more a zoomer then the 2.5. A shame in the UK they dont like to give us the Turbo models. Ok, maybe we only get the 5 speed auto in the Uk too.

[Mort]

I have Si Drive on my 6 speed manual Legacy (2007) - it has bugger all to do with the gear box I can tell you that.

Basically it controls turbo boost and throttle response.

• i-mode is an economy mode with moderate boost and less throttle action. Its good for round town and cruising. Its saves about 1.5 litres per 100 km.
  
• sport mode has much more boost and throttle action. Its a much more practical mode and its where I drive most of the time.
  
• sport sharp has full boost capability and throttle action. You have to select it manually and only when the engine is warmed up (it wont select other wise). It gives the full 280BHP with excellent throttle reponse and very little lag. Very good for sporty driving, heavy loads or towing.
  

The auto legacys (2.0l Turbo GTB) are lower in power than the manual. They have about 240BHP I think. They also have traction and stability control fitted where the manual does not (nor does it need it). The 3.0 flat 6 legacy with an auto box is very good. Smooth and powerful. If you want more practicality - have a look at the Outback - its a cracking car too.

The 2.0 litre GTB really is a superb car. Bilstein suspension, uprated brakes. Good seats and equipment. It is genuinely fast and has brilliant handling. It can do daya to day stuff like drive to work and take the family out etc but it can also be a proper sports car. Not many cars can pull that trick.

[Teacake]

Mort's absolutely right about the six-speed manual turbo. This is the pick of the bunch, and an absolute corker of a car. Can't overstate how jealous I am of his motor.

Some confusion perhaps arises in the discussion here because differences between the manual and auto cars run deeper than just the 'box itself, some of which Mort has already mentioned.

The manual cars always have mechanical diffs, with a permanent 50:50 split between front and rear wheels. One or more of these diffs will be viscous couplings, giving a limited slip effect. All cars have a centre coupling limiting the slip between front and rear wheels. Turbo cars have a second viscous coupling between the rear wheels, controlling the flow of power there. I've not yet seen a Legacy with a front coupling, although I understand some Imprezas have one.

The automatic cars have electronic diffs, with an 80:20 power split between front and rear wheels in normal use. This is one of the reasons why the automatic H6 can claim better fuel economy than the manual - it's not putting all its effort through all four wheels all the time. If I understand correctly, it's actually possible (though not advisable) to turn an automatic Legacy into a front-wheel drive car by pulling one of the fuses. This is done for towing.

The automatic Legacy therefore has electronic traction control and stability control because it's part of the drive-train, whereas the manual has a far simpler mechanical arrangement, which simply works. I always used to boast that normal cars need traction control, the Legacy just has traction.

Mort is right that the auto turbo cars have less power - 260bhp to 280bhp. The non-turbo cars have the same power regardless of transmission.

Back to SI-Drive, I think I read somewhere that SI-Drive does affect the shift map, which seems entirely in keeping with its purpose, but this would of course only be applicable with autos not manuals, as Mort rightly states.

[Mort]

I could add a further word about the handling (which my favourite bit - I love it )

They seem to have found that perfect point between firm controlled suspension which is bang on perfect for fast road driving and yet isn't harsh at all otherwise. It performs and is totally practical without pissing you off when yer not in the mood. Its not hard-core like an impreza. Its comfy and practical.

Turn in - This must be something to do with the flat 4 engine with low CofG. It is really quick and east to turn - you can really fling it in to a turn. It does it without any form of lurch to the outside of the turn or seemed transfer of weight. It Allows you get on the gas really early and carry far more corner speed.... or even with the family on board there's no roll in the turn. Dead Flat. Compared to a normal inline 4, v6 whatever it feels so balanced. No understeer or oversteer at all. Total balance front to read and transversely. It raises the speed at which you can take a turn with confidence by a massive margin. Grip is fantastic in the turn and on the power. It can really use the power it has unlike all FWD and some RWD cars. It can do 0-62 in something like 5.5 secs but thats all b ollocks... the special bit is how it hangs on round a turn and lays down the power down early out of the turn. As TC says above Traction control is not needed because it has TRACTION.... Its a riot in the wet too. Nothing can keep up. :D (Except perhaps an Impreza or an evo)

All up it gives great confidence I've not found in other cars. Its limits are very very high indeed (well Ok it aint a Ferrari). I often compare it to riding a fast bike where the only real limit is yourself...how well you drive not the limit of the car.

Not bad for a cheap(ish) 5 seat practical family estate.

Edited April 30, 2009 by Mort

[Teacake]

^ This. All of it. Bang on.

With the Legacy, even the older models, Subaru seemed to get the balance between compliant ride and sharp handling dead right. Even in my sister's bog-standard non-turbo two-litre, I'm kissing apexes and carrying more momentum, more safely, than in my current 9-5 Aero, within a couple of minutes of getting into it.

[steelwind101]

So after all of that did you get the test drive and what did you think?!