A bit OT: car fuel consumption.

[charles]

It's actually quite surprising how many hills there are in London

[Michael Chare]

Not like my VW then!

[Steve Walker]

Any for those that do contain ethanol, the quoted figure is usually an overestimate, plus it varies depending upon time of year.

[ARW]

Agreed.

I get around 50MPG out of my car most of the time. The gf used it to get to work and back for three days with a range of 400 miles showing when she first took the car.

After three days of her driving the car and doing about 120 miles the display showed a range of 330 miles.

Her work place is pretty close to the places I visit when using the car.

When I next used the car the range went down to

275 miles a few minutes after joining the motorway.

[Andy Burns]

Many cars lack the sensors to know they're running on "super" fuel, so without a re-map won't really benefit from it. It's always difficult to be objective about whether there's any improvement in performance or economy, since you

*know* what's in the tank and start driving to get the results you're hoping to see ...

[Steve Walker]

Quite a lot of cars have a knock sensor and will tweak the timing for the optimum while avoiding knock.

[newshound]

That's why I said "upper bound". I assume that, over the whole of the supply industry, companies will try to approach the mandated value while never exceeding it in individual batches.

[Dave Plowman (News]

This part of London is built on a series of hills. But I've yet to find a filling station that isn't level here.

The tanks are normally underground. That amount of excavation makes it simple to provide a level surface afterwards.

Do the floors of a house built on a hill slope too?

[Dave Plowman (News]

ISTR being told S London was built on 7 hills same as Rome.

However, easy enough to find data about possible flooding if the barrier failed.

[Dave Plowman (News]

If you do very similar driving every day, I'd guess it could be fairly close. I tend to look at my average MPG over a tankful and reset when I fill up. With Covid and not really going on decent long journeys, that stayed pretty consistent.

[Dave Plowman (News]

Are their any new petrol cars that don't have knock sensors? Thought everything had since about the 90s.

[Dave Plowman (News]

I'd say all these days. And a knock sensor reacts (near) instantly. Never quite understood why so many say your car needs to 'learn' the fuel over several tanks. That makes no sense to me.

[Andy Burns]

I thought knock was about too low octane, rather than too high?

[Andy Burns]

Probably, but the audi forums say that only the engines fitted in S and RS models can "spot" 97-99 octane fuel and make proper use of it.

Depending on your area of the country, super vs regular can be 0% vs 10% ethanol now, which is noticeable per tank, rather than 0% vs 5% before.

Before the petrol panic, I had been 'treating' mine to super, mainly because it had new plugs and I'd switched back to thinner oil, so it was running nicely.

[Andrew]

I put £40 worth of Esso synergy 99 octane in my car last time and it definitely seems to make the engine run more smoothly and seems to be quite nippier accelerating away from low speeds.

I have done 50 miles so far and the fuel gauge has barely moved.

Because I do such a low annual mileage, avoiding ethanol seems to be a good idea and the extra cost is not really an issue.

[JNugent]

No answer. Perhaps you don't know what you were talking about.

I hadn't realised that nobody was allowed to have different experiences of the real world and that yours - however limited and unrealistic - trumped all others.

What are you talking about?

Have you really never seen a house with a sloping garden?

[Dave Plowman (News]

Yes. There is more to getting the benefit of higher octane petrol than simply adjusting the ignition timing. Although one designed for high octane will retard it for low.

Plenty countries have been using higher than 10% ethanol for years.

[Dave Plowman (News]

So you are saying, in your experience, that the majority of filling stations have the forecourt - the bit a car is on when being filled up - on a slope?

That must be the case, otherwise you'd not have mentioned it.

You also talk about 'kerbside' filling. I thought that had been illegal for years.

[JNugent]

No.

I hadn't said - and will not say - that.

I did and will say that I know of two garages near here with sloping forecourts. One slopes in one direction only (away from the adjacent road); the other slopes away from the road and with the adjacent road, which is on a hill.

I did not.

Your imagination is working overtime.

So it might well be. But it doesn't matter because I didn't mention it.

[Kemle]

Didn't happen with one of ours which has just recently been completely rebuilt with all new tanks in a massive hole when being installed. Presumably because it would make the bits going back onto the existing roads unviable.

Those dont have car access,