HI OK TAIN PETRUL

[scooters]

Those of us of a certain vintage will recall the old 'star' system and most of us have owned chod that was built to run on leaded 4 star.

 

There's a lot of resources out there on the content of petrol...Typically what you pay for you get.

 

I was brought sharply down to earth with a bump when I had the audacity to put 20 quid of Tesco cooking petrol into the 244.

 

How the car hated it. It's been running like a dog since and only started to behave one the Shell V max I put in and which would have been floating on top of the cheap stuff started to get sooked in.

 

The 244 needs at least 97 Ron or ideally 98.

Supermarket cooking petrol is 3 star at best.

[dollywobbler]

I can't recall ever having an issue with any brand of petrol in any car. Just by way of contrast. Tell the Volvo to man up.

[Station]

I was always aware there is no difference between the RON as this only affects the combustion compression/temperature (higher RON resists combustion better - hence why high compression/turbo engines need it to avoid pre detonation).

I always 'lol' when people say 98 RON made a difference to their 1.2 engined car.

 

BTW fuel is stringently checked by Trading Standards - it's always up to spec.

[lisbon_road]

A modern car should advance a bit more with the higher octane petrol, so the 1.2 litre might go a bit better (a bit).

 

I think I have seen worse fuel consumption from supermarket petrol, and have read that elsewhere, probably to do with the additives.  Very hard to prove though - so many variables that it is hard to get a consistent result.

[Mr Lobster]

My SEAT seems to do slightly better on V Max than Tesco petrol but theres not much in it. Other stuff doesn't seem to make any difference at all. 

 

That said with Tesco doing the upto 20p off a litre thing at the moment, everything is getting a diet of Tesco with no ill effects.

[saucedoctor]

Tesco are moneygrabbing bastards. I wouldn't be a bit surprised if they diluted petrol.

 

What cannot be disputed is the fact that my W221 S350 ran like SHIT on Tesco diesel. Pissed out smoke too. I brimmed it with BP diesel, and it behaved again.

[barefoot]

I got 28 mpg from the 944 on ordinary, I put in super unleaded for about six months.

mpg instantly increased to 29 and a bit and then slowly, over the course of the six months tailed off to the point where I was wasting my money - I can't explain that at all.

[beko1987]

My friend says his octy vrs runs better on esso expensive rather than asda boggo, proved it with an increase in MPG and everything. The Meriva had a tank of Shell £££ during the fuel issue a few years ago as our local had run out of normal, and it did a few more miles but nothing astonishing enough to bother with again.

 

I've read on forums that the XUD in mine will run better on expensive Derv, I'm not convinced personally!

[scooters]

Don't forget the 244 is a carburettor. Non efi systems can't automatically compensate for fuel quality. Further research has informed me that you should on no account use fuel with an octane rating of less than 97 in the B21 carburettor engine.

 

Of course in later 240 s with efi this is not an issue

[scooters]

Diesel is totally different. Price essentially is a matter of how much detergent is added.

 

If you are doing mixed driving with a modern common rail diesel engine then you should put some quality diesel in every 3rd tankful. Or add injector cleaner to cooking diesel. Unless you are doing most of your driving at speed and for longer than 40 mins at a time.

If you don't do this and combine short journeys and pov spec diesel your intake and injection systems will tar up pretty quickly and the aged diesel in the tank will start to be eaten by bacteria which shots water. Snot in the fuel filter will conform this.

 

This isn't necessary in indirect injection engines like the xud btw.

 

Especially important with Ford tdci and hdi engines

[scooters]

This from volvo in the engine in my car:

of these engines have a high compression ratio and need a high octane fuel, and the only way to get them to run on 95 octane unleaded petrol is to fit 2 head gaskets. As mentioned above, this is not a very good idea.

[scooters]

As described running the car on 95 is not a good idea and virtually impossible to get smooth running

[fordperv]

The saph gets better mpg on petrol from our local sainsburys than it does on fuel from tesco and it gets slightly better mpg when it's run on super unleaded

[Lacquer Peel]

My injected 1985 Audi coupe HATTED 95RON.

[Disco Fever]

Yeah, all of the above really. As I've just got my first diesel after 26 years of pez, the comments around sticking some good stuff in regularly sound good and I'll adopt that.

There was a similar thread to this a while back where differences between premium and supermarket brands were discussed and I still think there's a difference ever since Tesco had too much silicone in the mix a few years ago and killed loads of engines.

On a side question - was old school 5 star unleaded and who used it?

[steve_earwig]

I'm sure it must have been leaded as there wasn't any unleaded then. Reading this, I'm sure I remember seeing "use 5 star only" on P6s.

[Noel Tidybeard]

5* was 100 ron

4* -98

3* -95

2* -92 iirc

super u/l is 97

tescos momentum is 99

[jonny69]

The old Ford Pop I had only had about 6:1 compression to run on 2-star, so one of the first things I did was whip the head off and get it skimmed to death for around 9:1. Free horsepower!

[Conrad D. Conelrad]

I'm sure it must have been leaded as there wasn't any unleaded then. Reading this, I'm sure I remember seeing "use 5 star only" on P6s.

Only for the awesome high compression ones.

 

Untitled by cdconelrad, on Flickr

[Spiny Norman]

The RON rating is nothing to do with whether it's 'cheap supermarket petrol' or not, Tesco do a lovely 99 octane brew that my old Amazon loved. I was able to tweak the timing a bit when I was using it too, but if I had to run it on normal 95 octane unleaded it felt like knocked a good 20bhp off the engine.

 

I tried believing the 'ALLSUPERMARKETPEZIZSHIT' nonsense but after extensive tests on an Alfa 156 using petrol the company was paying for, I couldn't tell the difference between Asda's cheap stuff and Shell Optimax.

 

Other scientific results may vary.

[Richard]

I only use supermarket petrol stations as an absolute last resort. There is a Tesco round the corner from me but I will make a round trip of 20 miles or more to avoid using it.

 

Supermarkets even water meat down so I think it's a foregone conclusion that they water fuel down. Even if they don't there's still the matter of supermarkets being rammed full of fuckwits who will do everything in their power to spoil your day. Even if supermarket forecourts were cheaper, which they aren't, and the fuel was of an acceptable standard, which it isn't, it wouldn't be worth the aggravation to use them.

[Micrashed]

Micrashed runs the same no matter what shit pez I lob in the tank.

[Rusty_Rocket]

Didn't Top Gear/ Fifth Gear/ someone else test supermarket petrol vs the expensive stuff? I seem to remember it made NO BLUMIN DIFFERENCE to anything other than a highly-tuned tossmobile  and even then the difference was minimal.

Certainly I'd say if your carburettor'd car starts, idles and revs - that's the best you can hope for 

[Pillock]

I ran the Focus on mostly Sainsburys diesel - because Nectar points - and it was fine over 54,000 miles.

I put one tankful of Ultimate in (because I pulled up at the wrong pump, and fuel card says I couldn't be arsed to move) and it started with all the random faults a week later. Coincidence? YOU DECIDE.

My G40 Polo liked superplusOMGYO stuff, but that's quite a highly strung engine. It has specific spark plugs too and quite high compression. There was definitely a performance boost to putting it in, I used to alternate so the tank would be swilling around with a mix.

[Asimo]

A long time ago I had an E28 BMW 518. Carb. model. During that time unleaded was introduced and I was surprised to note that the 93 octane unleaded worked much better than the 97 octane leaded, smoother, better mpg and much LESS prone to pinking.

 

40 years ago I was working in a BP station, pumping petrol: we had a special seperate pump for the 101 octane five star which came from it's own special tank. The other pumps did 91, 93 (2*), 95 (3*), 97 & 99 (4*) octane by blending different ratios of 2 and 4 star. Diesel? Just one diesel car in all the time I worked there (Austin Cambridge) 37.5pence per gallon for 2*, 40 or 41pence per gallon for the five star. Diesel was MUCH cheaper.

[mercrocker]

Local Morrisons always has a fuel offer.  Its really not worth the light-up price display as the forecourt is full of mummy vans and knobs in 4wds.   People drive bloody miles to fill up  there - it cant possibly be worth it.   Apart from that I have tried my chod on both regular and 98.  I have only ever used Optimax in the Merc as I have done with all my Mercs, just an expensive habit probably but I never get any emission problems from year to year on MOTs.  Quite prepared to believe it makes no difference but equally unprepared to change to save a few pence.   T25 doesnae care, nor does the Minor but the Oxford gets/got very upset unless it had 98.   Made a bit of difference to MPG I reckon, too but again its not scientific and never cared enough to prove either way.   Cowley is running so rich at the moment its getting the cheap stuff and like it but when the shiny new SU comes it will be on the Optimax too.   There was also the benefit of less ethanol but I think that's no longer the case.   Having seen some of the goons who run fuel stations these days (branded and supermarket) I am surprised there are not more contamination issues but none of my stuff is hyper-sensitive.   We get LOADS of problems at work with bio diesel....

[Squire_Dawson]

Another trouble is the number of filling stations has declined sharply since the 1950s, whilst the number of cars has increased, plus there is little profit margin in selling fuel alone, so the old-school filling station-cum-garage is a thing of the past (along with the service).

[Skoze]

Capri gets treated to v-power or whatever Shell calls it now, absolutely loves it. Returned 28mpg over 400 miles at generally 70+ plus a bit of 'round town with the 4-speed.

 

The TDI in the Landy isn't fussed by anything that goes into it - didn't like bio in winter though. 

Carb stuff would appear to appreciate being spoiled a bit. 

[rml2345]

I tend to fuel up wherever is closest/most convenient. Typically it's Asda or Morrisons standard unleaded. Since road fuel has to meet pretty stringent standards I can't say I've had any bother with it, although they've all been cars with EFI. BP etc. Add extra things to their fuel to improve combustion and reduce crap in the system and that shows up in the price. From highly unscientific comparison I'd say the current Volvo likes high octane a bit more than 95, and runs a bit better on "posh" 95 as opposed to supermarket stuff. The difference has never been enough for me to switch from one to the other.

[PhilA]

I was always aware there is no difference between the RON as this only affects the combustion compression/temperature (higher RON resists combustion better - hence why high compression/turbo engines need it to avoid pre detonation).

I always 'lol' when people say 98 RON made a difference to their 1.2 engined car.

 

BTW fuel is stringently checked by Trading Standards - it's always up to spec.

 

You say that about Trading Standards but the same is meant to happen here. We had a spate of issues locally whereby the base fuel (meant to be 87 (R+M)/2 ) that gets blended with whatever esters if you push the 91 or 93 button was actually coming out of the nozzle at about 68 (R+M)/2 and people's modern wondermobiles were lunching piston crowns and exhaust valves. By the time the check-engine lights had been paid attention to, things were pretty far gone.

 

I can feel the difference between fuels in my truck, especially when it's running at light throttle because it'll drop to 4 cylinders, run rough as anything then drop back to 8, loop and cycle like crazy. That and the fuel economy drops to about 16mpg instead of 22.

 

--Phil