SMG e46 m3

SMG e46 m3

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Discussion

Toady1

Original Poster:

1,618 posts

231 months

Thursday 24th May 2007
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I am warming to the idea of getting the SMG version as its more like a manual with paddle shifters than a conventional auto.....but if thats the case, how do you do a standing start if you know what i mean? I dont like the way an auto (when your stopped) pulls away in 1st if you want to give it some beans to pull out because they slowly build up the power, or go mad if they have a lot of power (volvo t5 springs to my mind) and wheel spin out of junctions etc.

What Im trying to say is, how does the SMG system work, pulling away in 1st gear? can you build up the revs and allow the clutch to engage or does it work slowly like a normal auto box? thanks for reading such a messed up question! lol!

Andrew D

968 posts

247 months

Thursday 24th May 2007
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In my experience it pulls away just like a manual. The computer can interpret the position of the accelerator, and effectively makes the clutch movements that the driver would otherwise make in a conventional manual.

For instance, if you just feather the throttle to pull away slowly, the computer slips the clutch uses it to control the car speed, waiting until you're moving before fully engaging the drive. Alternatively, if you mash the throttle it just dumps the clutch and lights up the tyres, as you would if you were wanting a quick/expensive getaway in a manual.

Toady1

Original Poster:

1,618 posts

231 months

Thursday 24th May 2007
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ah, brilliant stuff! I think SMG is the way to go then! sounds like the best of both worlds!

english68

166 posts

212 months

Thursday 24th May 2007
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Not that I have completely mashed the throttle from a standing start, but I would say that your comments are spot on except that the tyres never light up because the traction control kicks-in, preventing it. Assume not true if it is switched off though.

Clutch does seem to 'slip' a bit to give smoother (relatively) departures, especially when you have slowed, it's still in 2nd and you want to pull away again - it is VERY clever!

Always preferred a manual, but having had SMG for a bit I am getting used to it and can't imagine going back - even with the bunny-hops it sometimes provides!

Toady1

Original Poster:

1,618 posts

231 months

Thursday 24th May 2007
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bunny hops???

Toady1

Original Poster:

1,618 posts

231 months

Thursday 24th May 2007
quotequote all
Also what is the life expectancy of the clutche/gearboxes? as it sounds like it is quite aggressive on them?

Andrew D

968 posts

247 months

Friday 25th May 2007
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"Bunny hopping" is the only major negative feature of SMG. Opinion is divided on the exact cause, but in my experience it's due to the computer fully engaging the clutch slightly earlier than you would with a manual. As a result the engine speed has a bigger effect on vehicle speed than you would normally expect. And as most cars with SMG have large torquey engines with light flywheels and low vehicle weight, small movements on the accelerator produce large changes in vehicle movement. The way it normally works is that you prod the accelerator to move off, but as the transmission is fully engaged it goes quicker than you expect, so you back off and it slows quicker than you expect, so you press on again and the cycle repeats.

However, it's only a problem when you're not familiar with SMG, as it can be easily solved by maintaining a constant throttle position. Either feather the throttle and pull away slowly, or else mash it and keep it in for a quick launch.

As regards clutch and gearbox consumption, if you used SMG in the same manner as a manual there wouldn't be much in it. However most people don't bother backing off the gas when they change with SMG (which would shag a manual), so there's a degree of clutch slipping or quickly letting in the clutch that will wear it quicker than normal. Also, the sport shift settings result in fairly savage shifts that, again, you wouldn't do very often in a manual. So I suppose the rule is that technically there's not much difference, but that SMG promotes a clutch-consuming style of driving.

darreni

3,999 posts

277 months

Friday 25th May 2007
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[quote=Andrew D So I suppose the rule is that technically there's not much difference, but that SMG promotes a clutch-consuming style of driving.
[/quote]

I disagree, the shift action is controlled by the cars electronics & protects the clutch etc.
You cannot over rev the car, & if you are sat in traffic in gear, the car will drop the car out of gear untill you press the throttle again.
The launch control & burnout mode will wear the clutch more quickly though.

Toady1

Original Poster:

1,618 posts

231 months

Friday 25th May 2007
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is there an actual button for launch control then? im going to have to get myself out in an SMG to decide for myself! ;-)

english68

166 posts

212 months

Friday 25th May 2007
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It's better than that, not just a button but a whole sequence to go through.

Never been brave enough myself, haven't even tried it with DSC off!

Andrew D

968 posts

247 months

Friday 25th May 2007
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Yeah, at £250+VAT a corner for the tyres power sliding loses some of it's appeal.

u02dtd

11 posts

212 months

Friday 25th May 2007
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The launch control is the business. I have driven both manual and SMG and although I am not sure which I prefer the SMG for country roads does have the edge. If you want smooth driving through town though the manual is a bit easier.

I spent a while reading the manual before I knew how to use the launch control. Which my brother didn't really appreciate as its his car!!!

english68

166 posts

212 months

Friday 25th May 2007
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Rear tyres are £177 + VAT from Micheldever tyres near Winchester.

Andrew D

968 posts

247 months

Friday 25th May 2007
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english68 said:
Rear tyres are £177 + VAT from Micheldever tyres near Winchester.
The cruel irony is that the tyres on my Z4 cost more than those on an M3, by virtue of them being runflats. God I hate them.

Don't want thraping by the dealer for a new set of boots when I trade it though, so I stick with them.

Toady1

Original Poster:

1,618 posts

231 months

Monday 28th May 2007
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mmm, thats not cheap! I take it those prices are for the 19's tho?

Andrew D

968 posts

247 months

Tuesday 29th May 2007
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You'd think so, but unfortunately not! That was the main stealers quote for 18" rear Bridgestones. Apparently they're in short supply, no doubt by virtue of them being on every E46 Sport, so they seem to be doing a spot of Gordon Gecko-style profiteering.

Thankfully Kwikfit sorted me out for 20% less. I'm sure I could get them cheaper elsewhere, but it was a short-notice thing; two-inch bolt through the middle of the passenger-side rear. Nice.

Toady1

Original Poster:

1,618 posts

231 months

Friday 8th June 2007
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what is the profile of the 18 and 19" tyres?

Also the SMG, does that mean you can do full throttle gear changes? or do you still have to come off the gas pedal when shifting up?

english68

166 posts

212 months

Friday 8th June 2007
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You don't have to lift at all, but if you're just cruising around it feels more 'sympathetic' to lift a little.

Accelerating hard, it sounds really nice as it changes (very quickly) up through the gears (because I am childish, I always try to time the changes for just as I am passing another car too!)