Very Low MPG...is this because my car has a auto gearbox ??

chaparral

chaparral

chaparral

Caporegime
Joined
27 Nov 2005
Posts
25,492
Location
Guernsey
My Vauxhall calibra "2.0L 8valve auto" only gives me between 18 to 20mpg (even with driving like a granny:o)

Is this low MPG because it has an auto gearbox ???:confused:
 
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I don't think Auto-Boxes do you any favors, do you do lots of short journeys? Town Driving?

More info :)
 
I'm getting about 25 gallon out of my automatic 2.5 V6 MX6 and I don't hang about so you should be getting more than that !
Try changing the oil and air filter if they look dirty and check your tyre presure !
 
West said:
I don't think Auto-Boxes do you any favors, do you do lots of short journeys? Town Driving?

More info :)
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I do many small journeys with living on an small island....But other manaul gearbox cars i have owned have been noway near as bad as this car mpg.....

(My manual gearbox 2.0l calibra 16v i have a few years ago,,always gave me much better mpg figures with the same type of driving )



(i replaced Thermostat & airfilter which made my MPG increase by about 1mpg)
 
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6thElement said:
You're driving on Guernsey, the engine doesn't even get warm before you reach your destination.
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Your right there...with most my destinations being only about a 3mile drive...(5 to 8min)

But this still does not explain why the MPG is so bad with this car compared to the many other manual cars i have owned....
This is why it leads to me to thinking it because of the auto gearbox...

(But then why would about 90% of taxi drivers over here use an auto car if auto cars burn much more fuel:confused:)
 
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To be honest, its probably mostly the short journeys - they will do two things:

your engine wont heat up fully, and will burn more fuel.

The auto box wont hit operating temperature , and will cause you to burn more fuel.
 
Jonny69 said:
42mpg out of her 10 year old 2 litre auto Scenic on the motorway. Slightly less than 30mpg around town.
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There is simply no way you are getting 'slightly less' than 30mpg around town (Assuming town means that - town, cold starts, short trips etc) from a 2 litre automatic Renault scenic. I was a good 3-4mpg adrift of that in a MANUAL 2 litre Mondeo, even driving in an economical fashion.

Town driving kills economy - your fuel computer lies to you or you've perhaps got a slightly different idea to 'town' driving than the rest of us.
 
I get about 26MPG in Jersey on my manual 93 1.4 Astra L. (I'm not sure I worked it out right though :/)
Although I don't drive to work, it's used for getting around outside of; sometimes I will only take a 5min journey and sometimes I do just go for long drives.

But I love driving so I take the long routes if I have the time :D

I usually miss the get home rush after work trying to go places, but you can still get stuck in slow moving traffic for 30mins on such a small island ://
 
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Slightly off topic, but can anyone explain why auto boxes give worse fuel economy? I would have thought modern auto boxes and their computers would know the optimum gearing to keep a car in to increase fuel economy when not driving in a spirited fashion.
 
Older boxes only had 3-4 gears and a rather inefficient torque converter.

Modern auto's are far more efficient with computers, 5-6 gears and better torque converters. Nowadays the difference between the auto and manual in a model range should only be marginal.
 
BigT said:
Slightly off topic, but can anyone explain why auto boxes give worse fuel economy? I would have thought modern auto boxes and their computers would know the optimum gearing to keep a car in to increase fuel economy when not driving in a spirited fashion.
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The modern DSG style boxes such as the one in this Passat seem to offer up very good fuel economy, as good as the manual in most area's.

Full auto's its the torque converter, while it is not locked through these are rather innefficient at transferring power.

http://auto.howstuffworks.com/torque-converter2.htm

Just 2 fans in a bath of oil effectively, not suprising really that it saps economy.
 
I used to average about 28mpg in my automatic 1970's 1.9 litre saloon, doing mixed driving.......On a run, it was possible to get it to sit quite happily at the high 30's. Peaked it just over 40 once cruising at 60 with a tailwind!

Good box the ol' Borg Warner in that :)

Anyway, I'd give it an extremely thorough service, clean and going through, including tyre pressures and things like this........and see where you stand then :)
 
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