Ultimate fuel questions...

[barefoot]

I've been playing the fuelly.com thing with my cars since last October and appear to have achieved a degree of consistency.

 

I caught a comment on a thread on here the other day where someone claimed to get 10% better fuel economy for a 7% increase in cost.

So I thought I'd look into it a little.

Apparently Ultimate is 5p a litre dearer than ordinary which I calculate is 3.7% more.

If I can get an improvement of 3.7% mpg per tankful, surely that means I'm on to a winner.

Porsche is currently averaging 28.2mpg, so I need to see 29.3mpg.

Or the last tankful was 30.4, so I'd need 31.5.

 

It doesn't seem impossible does it?

 

As a further incentive, when all the extra Ethanol is introduced soon,I am led to believe that ordinary will become E10 whereas Ultimate will remain E5.

 

Am I working this out correctly?

Has anyone else read the E10 thing?

Am I talking from my anal tract?

Has anyone else sussed this previously?

[scooters]

there are other benefits to running 'ultimate' fuel especially diesel - detergents added to keep the fuel injection system clean

 

(disclaimer - the above may be pish suggest you contact fiatdaft to check)

[John F]

(disclaimer - the above may be pish suggest you contact fiatdaft to check)

 

[fiatdaft]

Maybe ultimate would help your rover 800 slay some moderns,oh wait a minute you fucked that aswell.

[Volksy]

Give it a rest FD & Scoots, or keep it in PM.

 

Thanks.

[skattrd]

I tried this sort of thing in my old Scirocco and found the best benefit was with Shell v-power type stuff, the others didn't give the same improvement in mpg. I do believe that different cars prefer different fuels, so reckon all are worth trying.

 

I tried v-power diesel in my boring and it made no difference to mpg at all, but I think thats because its an older type diesel engine. I do think it would be of benefit for more modern diesel engines (common rail, hdi etc)

[Spiny Norman]

I tried my own little amateur test with Shell Optimax a few years back when the firm was paying for the petrol for my Alfa 156.

On this slightly 'performance oriented' engine I noticed no difference whatsoever to the way the thing drove or the mpg, which stayed within the same range as it always previously had, although if it had increased from 30.4 to 31.5 I wouldn't have noticed.

 

Any improvement which cannot be felt and has to be measured isn't a real improvement IMO.

[HillmanImp]

I was actually talking to a workmate about this very thing yesterday when I was working out the 'Old Expensive Luxury vs Modern Diesel'. He has worked it all out on a spreadsheet which will send to me tomorrow and I will let you know what his results were.

[barefoot]

.... if it had increased from 30.4 to 31.5 I wouldn't have noticed.

Any improvement which cannot be felt and has to be measured isn't a real improvement IMO.

 

I appreciate that in the real world it makes bog all difference, it's just that I have taken to constantly monitoring mpg so I would be able to see it

& it may save me some money, I could perhaps save enough to start smoking again.

 

... He has worked it all out on a spreadsheet which will send to me tomorrow ....

 

Dull as it may seem, I'd be interested in that since I bought my new anorak.

[CreepingJesus]

Last time I tried a full tank of super in the V70, I thought it had caused a dip in the economy: 28.7mpg for the previous tank of regular, 27.8mpg for that one. The next week's tank went to 27.6mpg on regular, which did cause some headscratching.

By the next tankful, I'd had a wheelbearing replaced, and got back to 28.7mpg!

Once I get round to sorting the binding brakes out, I'll try it again. But subjectively he seemed to pull better on super, and run a bit smoother. Wasn't worth the money tho', as far as I can see.

[Pete-M]

The Impreza likes the posh 97 ron stuff. It runs like shit on the ordinary gear. I think it's actually meant to have 98 ron, but it can have what it's given. It does appear to back everything right off when run on cheap stuff, as if the knock sensor goes hyper at the thought of cheap fuel.

 

The XJR seems happier when run on a mix of super and normal unleaded even though Jag reckon it's fine on the cheap stuff. It does seem a bit better on the 97, but just as good on a mix, so that's what it gets.

 

My old 850 T5 liked Super as well.

 

Maybe whatever benefits Super has are more obvious with forced induction? It'd make sense as all a turbo does is effectively raise the compression ratio so the high octane would make a difference when boosting.

[Parky]

Mrs P's Leon seems to run much the same with similar economy on regular or super unleaded. It does idle more smoothly on super though, although that might just be my imagination. My Bini prefers super, I definitely get more out of a tank, something to do with knock sensors and ignition advance I expect. Throttle response is also a little sharper.

 

Ex GF's Pug 106 pinked like a mofo on regular unleaded but was fine on super. We bought it from new and it did that from the word go. It did like Total Super Unleaded more than others though. The biggest difference was on a 55 Picanto Mrs P had. That thing only had a small tank anyway but I used to get 30 more miles out of it on super unleaded and it was perkier as well - which was pretty useful as it had so little poke to start with.

[Cavcraft]

Have to admit I always thought it was just clever marketing when companies suggested better economy etc with expensive fuel. To be fair a lot of drivers do claim higher MPG figures and cleaner/faster/smoother driving, so maybe there is something in it.

 

Personally speaking being a mingebag I always try to avoid the dearer stuff, it's expensive enough for 'normal' petrol and diesel without paying a few more pence per litre. To counter that though I have recently experimented again with my favourite fuel addative-vegetable oil. Happy to report that the £19.99 for 20 litres stuff is just as good as the £20.99 per 20 litres stuff, so another quid saved there. The 306 has so far returned 252.1 miles for half a tank of fuel, next fill up I'll brim it, drive it round for a while then top it up to get 'real world' figures. I'd have done it last time but I thought my tank was full and it wasn't!

[DSdriver]

I have been advised to run the Citroens on Super because there is less ethanol and more cleaning agents. However being a cheapskate I have only put it in the fuel injected saloon. The Safari runs on LPG most the time and when it does run on Regular unleaded it has much better performance so I don't think it needs anything better.

There does appear to be a difference in brands of LPG as well. BP is crap so I try and buy Shell. Apparently, I have been told that in Germany and Poland people got so fed up with crap LPG that they kicked up a stink and standards have improved but we Brits don't like to complain, we just stop using it so it's on a downward spiral.

[Spiny Norman]

Since you're mentioning old cars I discovered my old twin carb Volvo Amazon used to run a lot better on whatever the highest octane brew was available. There wasn't a Tesco near me for their 99 octane stuff but it used to run well on Sainsbury's 97 octane.

[pompei]

My Fiat 500 runs better on Super but it has been enlarged to 700cc and tweaked. It pinks like buggery on the normal stuff. I also lob in a good lug of anti valve seat recession additive just for good measure.