Difference between an auto and semi auto?

[Sim667]

I’m starting to keep an eye out for a LWB Kombi Auto, to buy potentially in march if everything falls into place.

On Autotrader I’m seeing some listed as DSG and some as Semi Auto - is there actually a difference or is “Semi auto” just DSG but with flappy paddles and can be driven fully auto?

My wife is auto license holder, and I’ve never bout a manual before (except her Honda Jazz)

 

[Bav]

DSG is semi-auto. It has a manual mode, but is usually driven in auto mode.

You can't order flappy paddles from factory, but they can be retro fitted. Flappy paddles simply provide another method of using manual mode.

 

[Sackmycook]

At the risk of being wrong, an auto-licence like your wife has, only bars her from vehicles with a physical clutch pedal arrangement? So she will be OK with DSG

 

[Sasquatch]

Legally it comes down to what's written on the V5. I suspect DSGs will say auto for the reason SMC suggests, but worth checking prior to buying.

 

[Sim667]

Cheers all, just as I thought!

 

[Ali-G]

I could be wrong but my understanding is auto is your traditional torque converter box, and semi-auto is the dual clutch system as in DSG.
I think they call it semi because it's essentially a manual box that changes gear itself.
As I said though, I could be wrong.

 

[Skyliner33]

I could be wrong but my understanding is auto is your traditional torque converter box, and semi-auto is the dual clutch system as in DSG.
I think they call it semi because it's essentially a manual box that changes gear itself.
As I said though, I could be wrong.

That's spot on.

 

[Sasquatch]

Mechanically thats pretty much spot on. A DSG is an MMT unit - mechaniseed manual transmision - or a robotised transmission rather than a true auto that untilises a fluid coupling.

Legislatively though its down to the intervention required from the driver to change gears. Back when I was in the job tiptronic or geartronic type systems, that could self change, or change "manually" with the flick of a lever or paddle, were almost always auto on the V5. DSG behaves in much the same manner so would presumably be also an auto for driver licensing purposes, but do double check.

 

[Ali-G]

According to Google AI.

"Semi-automatic (semi-auto) and automatic (fully automatic) cars both lack a clutch pedal, but differ in control: semi-autos allow manual gear selection (via paddles/stick) alongside automatic mode, whereas fully automatic cars handle all gear changes without driver input. Semi-autos are often more fuel-efficient but can have slower shifts compared to modern automatic"

 

[Skyliner33]

According to Google AI.

"Semi-automatic (semi-auto) and automatic (fully automatic) cars both lack a clutch pedal, but differ in control: semi-autos allow manual gear selection (via paddles/stick) alongside automatic mode, whereas fully automatic cars handle all gear changes without driver input. Semi-autos are often more fuel-efficient but can have slower shifts compared to modern automatic"

I’m not convinced by the slower shifts bit. I’m pretty sure that the DSG box is faster due to the dual clutch. So the next gear is already selected so it’s just a case of engaging the gear.

 

[Ali-G]

I’m not convinced by the slower shifts bit. I’m pretty sure that the DSG box is faster due to the dual clutch. So the next gear is already selected so it’s just a case of engaging the gear.

I agree, l think they've got that wrong, DSG is really quick.

 

[dubber36]

Let's not forget CVT, which also has 2 pedals. Horrible things tho'. We had a Corolla with one as a hire car on holiday. Then there's EVs that has a fixed single speed transmission. Both can also be driven on an auto only license.

How about heavy haul trucks? Autos with clutch on demand to aid setting off. I know we are talking about a different license class, but my autisticness wouldn't let that one go.

As for gear change speeds between dual clutch and torque converter, with modern boxes I don't think there's much in it nowadays. We've got a DSG Tiguan and a ZF8 Auto in the BMW. Both have manual paddles, kickdown etc. Whilst the difference may be measurable, it sure as hell can't be felt.

 

[Sackmycook]

I used to ride a Yamaha Tmax 500 in London to commute. It had a CVT and was great fun, reliable and could be ridden on my auto- bike licence. I never got on with geared bikes as a learner

 

[StratosFearXX]

I used to ride a Yamaha Tmax 500 in London to commute. It had a CVT and was great fun, reliable and could be ridden on my auto- bike licence. I never got on with geared bikes as a learner

Didn't know there was an auto bike licence ...

 

[Bav]

I’m not convinced by the slower shifts bit. I’m pretty sure that the DSG box is faster due to the dual clutch. So the next gear is already selected so it’s just a case of engaging the gear.

DSG is quicker, but only if the gear anticipated and readied for the 2nd clutch is actually the gear you need. If that selection is wrong - e.g. you're in 4th and you need 3rd, but 5th has been selected - then the change will be much slower than in a torque-converter auto.

 

[Salty Spuds]

DSG is quicker, but only if the gear anticipated and readied for the 2nd clutch is actually the gear you need. If that selection is wrong - e.g. you're in 4th and you need 3rd, but 5th has been selected - then the change will be much slower than in a torque-converter auto.

Very true. You can catch the DSG out now & then when it’s poised with the wrong gear and fluffs the gear change.