Quote from S14 DRIFT :

Honestly, if you're whinging about the fuel costs, how it's hard to afford etc, just stick with the cheap and cheerful fuel.. :doh:

Naah, Jack is obsessed with his mileage like a geek is on maximizing performance on his computer. It will get too complicated quickly.

Just concentrate on your driving, leave out the "the occasional crazy bits" you mentioned, unnecessary overtaking, stopping for lights and slow granny accelerations from stand still.

The whole point is that expensive petrol MAY cost less in the long run - that's what i'm finding out.

Quote from S14 DRIFT :

Yeah I remember this, IIRC they used a Golf GTI or something, mainly to measure extra power.:

Yer that's the one, and a new M5 I think, not sure how much they dwelled on fuel consumption but I'm sure there's a bit about it.

I'm being serious Jack....

(Slight spinoff here)

My Dad had a PETROL 2.2 Vectra, 2003/04 model. It was every car you ever wanted, he claimed it was nimble, hung on well (I can vouch for that) and was quick enough for overtaking, and pulled well enough to be left in 5th gear at 30mph.

It had a 60L ish fuel tank. On a long, gently cruise at around 60-65mph we could get over 500 miles from it's tank..

By the time he came to get rid of it (Now he has his little chav Corsa :razz, the onboard trip computer was showing an AVERAGE of 38.7mpg. FROM A 2.2 CAR WEIGHING 1.5 TONS. It was the norm to be getting 45mpg on motorway journeys, middle lane speeds 70-75 and the like.

Obviously engine technology has moved on in the 5 or 6 years between the cars, but I fail to see how a 1.5 can possibly give less MPG than a car which not only has a bigger engine, but weighs more and can make faster progress and still achieve more MPG.

(/spinoff)

If it DOES save you money, it will be neglible and only be an effective way of saving money if you do alot of big mileages (reps in petrol cars tend to use it), as if you're cruising, you're naturally doing more MPG anyway, so the advantage is more noticeable.

During town work it's a pointless waste of money (and I talk from experience). Nice way to show off to your friends down at the pub (Eeh I got that nuu hi octane petrol I have, it's what Michael Schoooomacher uses!), but as a money saving excerise, stick to petrol unless you do motorway miles.

Quote from Jakg :

The whole point is that expensive petrol MAY cost less in the long run - that's what i'm finding out.

The difference and possible advantage is probably so tiny it's not even worth finding out.

Personally I think 36,1 MPG (7,8 liter/100km) isn't that bad for an old engine from 1992.

Quote from S14 DRIFT :

By the time he came to get rid of it (Now he has his little chav Corsa :razz, the onboard trip computer was showing an AVERAGE of 38.7mpg. FROM A 2.2 CAR WEIGHING 1.5 TONS. It was the norm to be getting 45mpg on motorway journeys, middle lane speeds 70-75 and the like.

My cars engine was designed in 1993 for a Mitsubishi Colt - Engine hasn't been changed since then from when it was fitted in my car (2002) - Proton say my car should get 32MPG, so if i'm getting 36 out of it it can't really be my driving...

Quote from Blackout :

The difference and possible advantage is probably so tiny it's not even worth finding out.

On the way to work I can fill up at any of the petrol stations I mentioned - If "performance" petrol gives me the same or better MPG than i'm getting now - why not use it? Even if it's got no benefit for performance or the car, saving maybe 1p per mile all adds up - plus the expensive stuff usually gives better rewards (i.e. Shell give me double the points which all adds up).

Quote from S14 DRIFT :

If it DOES save you money, it will be neglible and only be an effective way of saving money if you do alot of big mileages (reps in petrol cars tend to use it), as if you're cruising, you're naturally doing more MPG anyway, so the advantage is more noticeable.

During town work it's a pointless waste of money (and I talk from experience). Nice way to show off to your friends down at the pub (Eeh I got that nuu hi octane petrol I have, it's what Michael Schoooomacher uses!), but as a money saving excerise, stick to petrol unless you do motorway miles.

I love the way your preaching to me when you don't even know what engine my car uses - it seems the benefits of each fuel depends on the car, and as there is nothing I can find about my car on the internet related to this I thought I may as well do the tests myself.

If you can show me what fuel (in the UK) works best on a Mitsubishi 4G15 engine then please, do - If you don't actually have anything factual to add then please stop with the pointless shit.

Quote from Jakg :

On the way to work I can fill up at any of the petrol stations I mentioned - If "performance" petrol gives me the same or better MPG than i'm getting now - why not use it? Even if it's got no benefit for performance or the car, saving maybe 1p per mile all adds up - plus the expensive stuff usually gives better rewards (i.e. Shell give me double the points which all adds up).

What I said can also be turned upside down, it's no use finding out if the cheaper petrol gives you poorer performance and just stick with the more performancely you like.

I can't find the screenie atm, but I did similar a few years ago.

I found that I did get improved MPG using Shell Optimax/VPower over standard Shell 95RON.
Average on VPower was about 35, average on 95RON was about 30.
The one time I had to use BP Ultimate, I got a shocking 28MPG.
I never tried supermarket fuel, I never pass any to fill up in.

Obviously not all tankfulls were used the same way, but as I only really use my car to get to/from work it would have been a fair-ish test.

The idea that "more expensive fuels cost less in the long run" is a load of crap. Just buy the cheapest fuel you can get with the recommended octane rating for your engine and you'll be fine.

I use 87 AKI (equivalent to 95RON) in my bike (now a 2006 SV650, previously a 1990 EX500/GPZ500). At best, a higher rating will do absolutely nothing if your engine does not require it. At worst, it'll reduce power and reduce fuel efficiency.

Quote from Forbin :

The idea that "more expensive fuels cost less in the long run" is a load of crap. Just buy the cheapest fuel you can get with the recommended octane rating for your engine and you'll be fine.

I use 87 AKI (equivalent to 95RON) in my bike (now a 2006 SV650, previously a 1990 EX500/GPZ500). At best, a higher rating will do absolutely nothing if your engine does not require it. At worst, it'll reduce power and reduce fuel efficiency.

Must agree with forbin here, in my experiance, it makes little difference what fuel you use, either in MPG or (percieved) performance.

Where do you think supermarkets get their fuel from?, it all comes from the same place, the only difference is the "additives" that some companies (say they) put in, but I am sceptical about it.

Rubbish

Regardless of "rubbish" (care to expand?), any data you get from checking your mpg in non-lab conditions is "rubbish" too.

After weeks and weeks of doing the same route, driving the same way, with the same fuel, and getting wildly different results, quickly proved that any data gain this way was worthless.

There are much cheaper and easier ways of improving your fuel ecomony than using pricy fuel

No, I don't really care to expand. I could, but it's not worth it. I'll keep the good fuel for myself, and get to where I want to go for less money in the long term. If you get wildly different results then I suggest you get your car serviced.

Quote from Jakg :

I love the way your preaching to me when you don't even know what engine my car uses - it seems the benefits of each fuel depends on the car, and as there is nothing I can find about my car on the internet related to this I thought I may as well do the tests myself.

If you can show me what fuel (in the UK) works best on a Mitsubishi 4G15 engine then please, do - If you don't actually have anything factual to add then please stop with the pointless shit.

Sorry what? Pointless shit? Irony alert!

Ok, here are some facts.

Hi octane fuel gives more performance in engines that can take advantage of it. High performance engines generally have higher compression ratios and can take advantage of the increased power that could be possible.

You may gain a few miles extra per tank but you will get a neglible power increase since your car is so ****ing old it can't make the most of it, such as what is possible with a newer car or a bike (because of the high performance nature of the engine).

The best fuel for you is regular 95. Now stop making a big deal of nothing, go back to scamming your insurance company or something.

Who cares exactly what engine your car has? I'm sure you simply got the engine code from Wikipedia anyway. It's a very old engine in a shit car, what's to know?

Jamie, it's not just the octane that differs in expensive fuels. Also, you are confused about how octane and compression ratios work to produce power. You don't know enough to state what fuel is 'best', and you seem incapable of working out what he wants - low cost per mile rather than power.

Low cost per mile would surely be the cheapest fuel, as I've said if he uses his car for school (commuting), the possible extra mileage he could get would be neglible because he's doing low-mpg work anyway.

If he had a 60 mile drive down a motorway, you'd be doing more MPG and any difference that using hi-octane fuel would give would be noticable more, since it would not "add 2mpg all the time", it would, say, increase by 1 or 2 in town, and maybe 3 or 4 on the motorways, if you see what I mean.

As I've said, I've been using V-Power for years doing daily commutes, motorway blasts, country driving and fooling about. Every so often, usually because I'm urgently looking for fuel or need the 24hr self-service that Tesco provides I have to fill up with cheap fuel. And that week ALWAYS increases my cost per mile.

I save about £10 per month using expensive fuel, and I've got a shitty 1.6 litre engine based on a twenty-something year old design producing only 115hp.

And I've been sort of checking this, informally, for about 4 years now via receipts and a calculator. I've not got an iPhone app that works it all out, but I've not done enough miles to make a meaningful judgement based on that data alone.

But if you think only 'modern' engines or high performance engines are the only cars to benefit from decent fuel then you really need to study IC engines a bit more.

Well, I still don't believe that it'll make any difference in Jacks case.. but we can wait and see in a couple of months.

I've tried it and I'm not any better off for it.. not economy wise at least, I notice a performance increase..

I guess it's all down to your circumstances and the like Tristan. - May be beneficial to some but not to others.

That's the thing you won't notice - a performance increase. It'll be so marginal that you won't feel it, hear it or anything. That's the placebo effect of marketing working on your mind.

Well i have a 1998 rover 200. It is the 1.6 16v K-Series engine. The engine it has now was fitted to the car in summer 2006, which equates to 14'000 miles ago and it was a completely reconditioned replacement unit, not just block and pistons, the whole thing, head, cams, valves,crank, etc...

I usually use tesco petrol, because the garage is about 10 yards from where i work.

Bearing in mind that i do not drive it hard very often, usually 3k to 4k max revs in any gear, and i get about 34 to 35 mpg.

When i do give it a blow out, up in the 6-7k region, Exhaust rawing, induction kit howling, etc, i can expect to get around 30-32mpg.

Considering my engine was built in 2006, and is only 100cc bigger than yours, then 36mpg for your older, probably more worn engine, isnt at all bad, plus i would guess that a wira is margionally heavier than a 200.

Using 'expensive' fuel, depends if your ECU can advance or retard the ignition with the changing octane level

Quote from tristancliffe :

I save about £10 per month using expensive fuel, and I've got a shitty 1.6 litre engine based on a twenty-something year old design producing only 115hp.

£10? A MONTH? jesus man, your calculator must be up the duff!!!

@ OP take a look at this site:

http://www.fuelsaving.info/fuels.htm

If you google a bit you will find at least a couple videos on the 'tube with RL tests for standard vs premium fuel. The bottom line is that only turbo engines will be able to make use of the extra octane.

I can't talk for other countries but in mine the only difference is some gas stations do better maintenance and thus the fuel has less junk in it. It can be hard to find out which ones though as long as I don't have to change my fuel filter every other day I tend to assume the fuel is clean enough

Depending on the car you're driving, technique might make a difference on the mpg you're getting.

http://metrompg.com/

offers a handy guide detailing what works, what doesn't, and how much difference there is. I've put pulse and glide and drafting to good use.

You "can't" measure fuel's effect on mpg in real life conditions, you need to do it in lab conditions to get accurate measurements. Too many variables in real life.

For instance: Toyota Prius 2008 model is rated for 46 MPG (Imp. combined)
Hypermilers do 136 MPG (us?) in the prius. Clarkson did 17 MPG (imp?) versus the M3 (19MPG) on the Top Gear track. Nearly 10 fold difference on driving style alone.