Quote:
Originally Posted by ThomasG
Hmmm... Fully logical.
But.
After return, I started "experimenting" with different brands of fuel. My average mpg was climbing, two of best being Sainsbury's super and shell 99octane. Mpg went high, as for this car. Record shown by on board computer was 26.6 mpg.
Then.. I filled premium at station with green flower.
Almost instant drop to 23.6, and after using up that tank, I struggle to bring it over 25 no matter what I fill.
So.. apart from tarmac..
Is it at all possible that European petrol has additives that help engine, with effects lasting for about 3 weeks after return to UK.
Or is it more possible that something went wrong with my engine same time I filled that premium, not necessarily caused by fuel at all.. and now it burns more..
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Your fuel economy sounds really poor to me. My S60 has the same 2.5T B5254T2 - if I was only seeing 26.6 mpg on the trip computer after a long run I'd be worried.
Even your 32.5 mpg in Europe sounds a little low to me - I can see that on 60 mile trips around the Cotswolds, including some brief "spirited" moments, and up to 35 mpg on a steady motorway run. All my figures are from the onboard computer. I do mostly run light with only me in the car.
Last year after I bought the car, money was tight and I mostly ran on Asda petrol. I saw 28 mpg as my average, with 30-32 mpg on longer motorway runs or sticking to 50mph.
This year I've been mostly on BP standard 95. Easily 30+ on any trip, at least 32 and normally 35 on motorways. I also had a full alignment done which was needed and did help the improvement, and switched to Michelin Pilot Sport 4 tyres, which also seemed to help.
Now I've changed fuel again... E10 is here, and I've been saying to myself all year that although it's meant to be fine, I'm not going to use it. I bought BP Ultimate 97 for the first time last weekend. 55 litres added on tank 1, then 45 litres added on the way back from Exmoor on Monday night. I try to use BP wherever possible purely because they're the most convenient locally where I am in Oxfordshire.
My car used 45 litres of mixed 95/97 then, doing 320 miles of driving Saturday to Monday. First from Oxfordshire down the M5 to Exmoor, just me, then close to 200 miles over Exmoor, all fully loaded with three adult passengers and a dog. She went up Porlock hill twice, did the climb out of Lynmouth, ran flat out for an extended period on B-roads over the moors, then got me back to BP at Taunton (now just me in the car again) where I topped up. At that point the trip computer was estimating 150 miles but as there was still 25 litres left, that would have climbed pretty considerably as soon as I got back on the M5.
My overall fuel economy for the trip (Oxfordshire to Exmoor, working very hard for 200 miles over Exmoor, then back home again), was 30.6 mpg. The M5 south we were stuck in traffic for ages too which killed it, then Porlock hill was frustratingly slow both times, stuck in second with a lot of throttle and almost hearing petrol drain away. But I'm sure I could still have got over 450 miles, maybe even 500 miles, from that tank of fuel... Just wasn't safe to leave it and try though, in case I'd hit traffic on the M5 north coming home.
Result after driving 100 miles home from Taunton, at 70+ and flat out up the hill on the A417 back into the Cotswolds... the trip computer was estimating a range of 455 miles when back on the driveway.
This is very encouraging to me - back when I was on Asda petrol, I used to drive away from the forecourt being pleased to consistently see 440 miles estimated on a full tank.
I have no doubt at all that
my car with me as the driver would do 500 miles on a clear motorway, with good petrol, before I really needed to worry about refilling.