First post here. We recently bought a 1.4tsi DSG. It is a joy to drive, as widely described, and definitely not underpowered. But I have been disappointed in the fuel consumption. Anyone else have any experience?
Background is we live in the country and I regularly match or exceed the extra urban figure in my car. We were way off that with the Skoda, but I figured it was stop-start winter motoring and we needed a run to form a true impression. Xmas brought trips to Bournemouth and North Wales. Long runs on A roads, few traffic lights, average speed between 40 and 50. Result - 43 mpg. Not bad in itself, but the claimed extra-urban is around 55.
Golf drivers who have had the same engine for longer appear to be reporting similar figures. Anyone differ?
Jon
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Is the car brand new? If so it may improve as the engine runs in.
What is concerning is that I am starting to hear of lots of complaints of drivers of high mpg cars not being able to get remotely near the stated mpg figures.
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What fuel you using 95 or 98 RON ?
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Was your last car something with a bigger capacity engine, so that you were able to use a gentler right foot to maiuntain decent progress?
I agree that it should improve with more mileage, but I'm still sceptical about small-capacity engines in biggish cars. If there's anyone out there driving a car with the VAG 1.8 TSI engine, it would be interesting to know how economical that is.
I think 55 mpg is unrealistic for any petrol-engined car pulling a medium-sized car like an Octavia. As you say, 43 mpg is not bad.
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I'd be interested to know too Jon what car you've managed to achieve the extra urban figure in.
That figure is for a pre-warmed engine, running at an average of 39mph mostly at steady speeds.... a pretty easy time for the engine.
I'd say for mixed use the combined figure is more of a realistic target. I've just started running a small engined big car (1.6Hdi C5) and am happy with a fuel consumption in this weather of 50mpg which is near enough to the combined of 53mpg. I would never expect to get the 59mpg extra urban figure unless travelling on a deserted level motorway at 55mph in 5th.
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Thanks for the feedback.
My car (the new Skoda is my partners, and now our family car) is a MB C-class estate 2.7cdi (so yes a diesel) auto. With 120k on the clock it is still getting over 45mpg.
We live 5 miles from the nearest traffic light, which has to help. If on the long runs I had got half way between the mixed and extra urban figures I would hot have queried the figure. It was the fact that under these optimal conditions I just managed the combined figure. For reference, on the same runs in my car I would have expected to see close to 50mpg.
I shall keep watching as the engine runs in, but it looks like it will be a disappointment, which is a shame as I am otherwise very happy with the car.
Jon
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My 2008 Octavia 1.8 TSi averaged around 28 mpg in mostly urban use and just over 40 mpg on the motorway. My older (Mk 1) Octavia vRS managed largely similar figures, despite an extra 20 BHP.
I'm currently considering a Yeti 1.2 TSi to replace our current 1.6 Qashqai, but am slightly concerned about reported poor fuel consumption. Small engine vs big car ??
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engines in biggish cars. If there's anyone out there driving a car with the VAG 1.8 TSI engine it would be interesting to know how economical that is.
I'm getting about 37mpg out of my Octavia according to the computer, not yet calculated manually for comparision.
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The fact that you've presumably only driven it when the ambient temperature is cold will not help fuel economy - especially with the super/turbocharged engine which will exacerbate the problem.
The TSI is a torquey little monster and its fun to use the punch to drive along short shifting, actually they will use quite a lot of fuel driven like that because the turbo will be spooling up when the engine is under heavy load. If you use less throttle and let the engine rev more freely on light throttle openings it'll actually be more economical driven like that as you'll be generating less turbo boost on light throttle openings - less boost = less fuel being chucked in.
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If you use less throttle and let the engine rev more freely on light throttle openings it'll actually be more economical driven like that as you'll be generating less turbo boost on light throttle openings - less boost = less fuel being chucked in.
You've absolutelly lost me there :o/
Its an assisted 1400cc engine, if you drive it off boost it will drive like an unassisted 1400cc car with a heavy body = use losts of fuel
If you drive the car on boost with light throttle I think you'll find you'll make good progress and use less fuel
Holding the car in 6th gear off boost with lots of throttle will use lots of fuel IMO
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You've absolutelly lost me there :o/ Its an assisted 1400cc engine if you drive it off boost it will drive like an unassisted 1400cc car with a heavy body = use losts of fuel
The TSI engine is (centrifugally)supercharged and turbocharged so it's never an unassisted 1.4 lugging a heavy body - there's always a degree of forced induction throughout the rev range.
If you drive the car on boost with light throttle I think you'll find you'll make good progress and use less fuel
That's my point, on light throttle there will not be much boost. What you'd be doing by driving it on light throttle openings is driving with the boost provided by the supercharger only. Turbo chargers only spool up when the engine is under load, that's why you can rev the crap out of a turbo car standing still and it will not provide boost. If you use light throttle openings the lack of volume of air through the engine stops the turbo spooling up and therefore saves fuel. In other words drive gently but without lugging the engine which would cause the turbo to chirp in.
Holding the car in 6th gear off boost with lots of throttle will use lots of fuel IMO
If you're using lots of throttle at anything much above tickover with a modern turbo it will be on boost - that how a turbocharger works and yes you'll be burning lots of fuel.
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Steve Lee is right. You won't be able to drive the car on boost with a light throttle. If you put your foot down i.e heavy throttle, the turbo will spin and produce boost.
If you don't put your foot down i.e light throttle, the engine will be cruising with no/ light boost.
If you use light throttle with a gear lower than normal to maintain enough revs to keep the engine under light load when cruising, you will get better economy.
Some people try to get into top gear as quickly as possible, because thats what they've been told in order to improve economy. But thats no good if the revs are too low or you are climbing a steep hill. The engine will be under heavy load i.e poor economy because you are putting your foot down more to maintain forward progress.
I hope thats clear!
(That engine is supercharged too isn't it? The supercharger cuts in at low revs, the turbo at high revs).
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The road test I read never mentioned supercharger, only turbo.
Superchargers being crank driven sap power and use fuel, if it were my car I'd find the point where the turbo takes over and drive on light throttle turbo assisted with the electromechanical clutch of the supercharger disengaged.
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Old fashioned rotax-like displacement superchargers create quite an amount of mechanical drag, as well as excessively heating the inlet charge - not particularly efficient but they work. Most modern superchargers are the centrifugal type - think of the compression impeller of a turbocharger but belt drive it instead of driving it via an exhaust impeller. These are pretty efficient - as a bonus they allow air to bypass them easily so the old problem of displacement superchargers creating enormous negative pressure between them and a closed throttle has gone without the need for bypass valves.
In automotive applications, centrifugal super chargers are geared to effectively produce no boast around tickover so unlike the old displacement type you're not burning fuel/creating excessive heat trickling along in traffic.
Edited by Pugugly on 09/01/2010 at 17:50
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I've seen plenty of before / after rolling road graphs for the fitment of aftermarket centrifugal superchargers and everyone sapped power below around 4000RPM.
You can't get around the physics, drive off the crank and you'll sap power, be it an alternator, PAS pump, air con pump or supercharger.
Turbos have been the way forward for charging the inlet for years because they are more efficient, the supercharger in this instance is used to plug a hole in the rev range because the turbo is larger that the what has become the light pressure standard issue, without the supercharger this heavy car would be a laggy off boost pig to drive...............
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I don't think that the 1.4TSI engine in the Octavia has a supercharger
Edited by harib on 09/01/2010 at 18:06
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I don't think that the 1.4TSI engine in the Octavia has a supercharger
The A### E###### article online I read never mentioned one..........................
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You're right, its just the 122 bhp turbocharged engine. I was thinking of the 178bhp engine as used in the Seat Ibiza FR e.t.c. Both called 1.4 TSI.
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I don't think that the 1.4TSI engine in the Octavia has a supercharger
I'm no Skoda expert but I believe that is the case for the 1.8, I thought the 1.4 was like the VW motor. Anyhow the concept is the same if you use light throttle openings on a turbocharged car you save fuel by limiting boost.
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I have the new MK6 Golf 1.4TSI SE 122PS and since late July and despite now being run-in have never returned the combined 45.5mpg as stated by VW. Admittedly now, the weather isn't helping and I'm doing short cold journeys and so would not expect to. However until recently was averaging per tankful about 42 to 43 mpg. This contrasts with my old MK5 golf 1.6FSI which easily returned the VW combined fuel figure. So far both cars have similar average mpg's. I must admit to having expected a little better fuel consumption from this small turbocharged engine and slighlty lighter car.
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You're within 5% of the manufacturers figure with more to come.
How do you drive it, off boost or on?
Light throttle on boost would be my way, but others want to put the turbo in the bin for a more sedate pace
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I had an 09 Audi A3 with the 1.8 TFSI petrol engine for 6,000 miles. The computer was very accurate and showed 39.4 MPG over the 6,000 miles.
Individual journeys were interesting. I drove 25 miles to Peterborough and got 52.9 MPG driving at 60 MPH and being uber economical. I got 49 driving from North Wales to Cambridge where I got 39 going (the difference was careful driving in terrible rain versus blasting it in sunshine).
The Mrs got 5 MPG less from the car than I did in identical situations - this is the same in every car - Saab, Subaru and i10. Driving style, reading the road ahead and accurate gear changes make a huge difference.
I also believe that in the real world you get a better MPG from a bigger output engine driven properly (as in economically) - so I got far better MPG from the Saab 150 BHP diesel than the 120 loaners.
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Just a quick thank you for all the responses. It seems to be true that a big engine driven carefully can return better mileage (in relation to published figures) than a smaller one, which is ironic given taxation is forcing us away from them.
Thanks again
Jon
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I have noticed a significant drop in economy this winter. Far more than previously. Must be due to very low temps at start up and worse traffic.
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Yers a big drop in economy in yaris diesel.. From 57mpg to c 45mpg..
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I have noticed a significant drop in economy this winter. Far more than previously. Must be due to very low temps at start up and worse traffic.
Not just startup, atmospheric air becomes more dense the colder it gets, the fuel injection system senses this via a ambient pressure sensor and adds duration to the injectors (fuel to compensate for the denser air) in order to maintain the correct fuel/air ratio. You will also notice your car will perform more eagerly in colder weather as it will be making more power for the above reason.
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