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Automatic Gearboxes

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Aictos

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Don't vehicles with a automatic transmission use up more fuel?

I ask that as I've driven a auto before and the fuel consumption wasn't that good.
 

Ediswan

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Don't vehicles with a automatic transmission use up more fuel?

I ask that as I've driven a auto before and the fuel consumption wasn't that good.
It depends on the type of transmission. With a hydraulic torque converter, yes. Dual clutch mechanical, no. Other transmissions exist, but I don't recall how they fare.
 

Aictos

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It depends on the type of transmission. With a hydraulic torque converter, yes. Dual clutch mechanical, no. Other transmissions exist, but I don't recall how they fare.
How do you find out what the type of transmission it is for any vehicle?
 

ac6000cw

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We've run a Suzuki Vitara (1.4L 'BoosterJet' engine) with a 6-speed auto box for the last few years. AFAIK it uses a torque converter (it certainly drives like it has one, including 'creeping' at idle) - and it returns pretty much the same MPG figures as the 6-speed manual version (based on manufacturer and road test report MPG), Certainly we've got no complaints about the fuel economy of it.

We test drove both the manual and auto versions of the same model, and decided that the auto was the nicer/better drive (and not just because it changes gear for you!).

How do you find out what the type of transmission it is for any vehicle?
Googling for specs and road test reports?
 

Ediswan

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How do you find out what the type of transmission it is for any vehicle?
As ac600cw said, use Google. I do not know of any simple consistent way to tell for sure.

Vehicles using DCT (dual clutch) or CVT (continuously variable) automatic transmission tend to advertise the fact. So if a model says simply 'automatic', then it probably uses a torque converter, but no guarantee.
 

Snow1964

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Don't vehicles with a automatic transmission use up more fuel?

I ask that as I've driven a auto before and the fuel consumption wasn't that good.

Some modern ones, like dual clutch (which are effectively motorised manual gearboxes) often have more gears than fully manual ones.
6 or 7 gears are common, some have 8 or 9 gears.

More gears means engine more likely to be in sweet spot, using less fuel. And some have an economy setting that automatically coasts.

Some small 3 cylinder engines provide little engine braking so holding in low gear which it will do using a topodyne (incline detector) doesn’t actually hold speed when going steeply downhill, so brakes need using as well. (But modern cars have ventilated discs on front that are tested on some very long downhills in Alps) so unlikely to overheat in UK)
 

AM9

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Don't vehicles with a automatic transmission use up more fuel?

I ask that as I've driven a auto before and the fuel consumption wasn't that good.
It used to be the case with the old 'Borg-Warner' type of 3-speed auto transmission that the torque converter and simple speed vs torque gear selection criteria were sources of higher fuel consumption. Modern auto transmissions (even the automatically selected manual types) have far greater integration with the engine management system. Thus changes can be chosen for lowest fuel consumption, best engine loading and/or highest acceleration. The result is that there is rarely a performance penalty with modern types especially when compared with any driver other than an expert at the controls of a manual transmission. Indeed, most auto transmissions can give higher performance, and certainly more consistent results than somebody claiming to be an expert at 'stirring porridge'. :)
 

delticdave

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We've run a Suzuki Vitara (1.4L 'BoosterJet' engine) with a 6-speed auto box for the last few years. AFAIK it uses a torque converter (it certainly drives like it has one, including 'creeping' at idle) - and it returns pretty much the same MPG figures as the 6-speed manual version (based on manufacturer and road test report MPG), Certainly we've got no complaints about the fuel economy of it.

We test drove both the manual and auto versions of the same model, and decided that the auto was the nicer/better drive (and not just because it changes gear for you!).


Googling for specs and road test reports?
I think that your Vitara has a 6-speed DCT, according to Suzuki literature, possibly depends on age?

Contact Suzuki UK or a UK dealer for confirmation??

As for creeping at idle or slow speeds a modern DCT is designed to "feel" similar to a torque converter transmission.

I'm no expert but we have owned 5 6-speed DSG cars, (still have 3 of them) & I've no desire to return to slushboxes....
 

AM9

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... More gears means engine more likely to be in sweet spot, using less fuel. ...
CVTs even more so.
... And some have an economy setting that automatically coasts. Some small 3 cylinder engines provide little engine braking so holding in low gear which it will do using a topodyne (incline detector) doesn’t actually hold speed when going steeply downhill, so brakes need using as well. ...
My last car, (Mercedes A180 CD) with it's 2L diesel engine had no problem keeping speed to within 2mph on normal inclines, and even on a very steep one it was no worse than +5. That was very useful when in cruise as well. That certainly showed up those who didn't keep to speed limits downhill.
 

ac6000cw

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I think that your Vitara has a 6-speed DCT, according to Suzuki literature, possibly depends on age?

Contact Suzuki UK or a UK dealer for confirmation??

As for creeping at idle or slow speeds a modern DCT is designed to "feel" similar to a torque converter transmission.

I'm no expert but we have owned 5 6-speed DSG cars, (still have 3 of them) & I've no desire to return to slushboxes....
Based on the descriptions in the car user guide of the driving controls for the different transmissions, and some researching I did before posting here, I'm pretty sure it's a 6-speed conventional auto box.

Sukuki refer to their automated manual transmission as TCSS (Twin Clutch System by Suzuki) in the user guide, and the gear selector control for that is different. The one in my car matches the 'automatic transaxle' control (it's very much an 'international English' document....)
 

jfollows

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Some modern ones, like dual clutch (which are effectively motorised manual gearboxes) often have more gears than fully manual ones.
6 or 7 gears are common, some have 8 or 9 gears.

More gears means engine more likely to be in sweet spot, using less fuel. And some have an economy setting that automatically coasts.

Some small 3 cylinder engines provide little engine braking so holding in low gear which it will do using a topodyne (incline detector) doesn’t actually hold speed when going steeply downhill, so brakes need using as well. (But modern cars have ventilated discs on front that are tested on some very long downhills in Alps) so unlikely to overheat in UK)
I don't disagree with you fundamentally, but my last car had a 5L engine and a 6-speed automatic gearbox, which was a good combination. Jaguar switched more recently to an 8-speed automatic, which definitely will have been a better choice for the majority of their cars with relatively small diesel engines, but it won't have been as good a match for the 5L petrol engine because it will spend too much of its time changing gear unnecessarily. Be that as it may, the 8-speed gearbox is certainly a vast improvement over my only other car (my first car) with an automatic gearbox - a rather basic 3-speed one coupled to a 2L engine back a long time ago.
 

thejuggler

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I've driven autos for decades, from torque converters on Jaguars and Mercs, to auto clutch on smarts, to DSG and CVT on Audis, planetary CVT on Toyota hybrids.

I currently drive a Subaru with their latest 7 step CVT and for me it provides the perfiect combination of smooth pick up, seemless 'changes', ability to lock up if required and excellent mpg.

Coupled with the Eyesight cruise control system driving can be reduced to just steering as accelerating, gearchanges and braking are all automated.
 

Jamesrob637

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I've just gone back to a torque converter having had DSG for years. I thought the DSG 'boxes were a masterpiece, though there is definitely something "soothing" about a slushmatic! It is an early incarnation of the 6 speed VW by Aisin and it definitely shifts well without the "thump" you often experience from DSG 'boxes.

To the poster whose stepmom had a Nissan PUKE and got rid of it, GOOD! Worst thing on the road. The new one is fine but I guess she had a pre-2019 model.
 

AM9

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I've just gone back to a torque converter having had DSG for years. I thought the DSG 'boxes were a masterpiece, though there is definitely something "soothing" about a slushmatic! It is an early incarnation of the 6 speed VW by Aisin and it definitely shifts well without the "thump" you often experience from DSG 'boxes.

To the poster whose stepmom had a Nissan PUKE and got rid of it, GOOD! Worst thing on the road. The new one is fine but I guess she had a pre-2019 model.
I always though of that as a Nissan Joke. :)
 
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