Only true if compression is high enough to start selfcombusting (pinging) on 95. If compression is low enough for 95 there's no advantage in using 97 (or 98 or even 102.
gr J
Technical Supermarket fuel
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Technical Supermarket fuel
gr J
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Not sure that's 100% the case - you can advance timing to introduce knock on lower compression engines, too - if you recall the phasing out of 4* leaded fuel, the 'fix' for lead replacement fuel was to retard the timing on the distributor.
If a car has a knock sensor and the ECU allows it, you can advance the timing until you get knock, then bring it back until it goes away.
Our Toyota V6 has knock sensors on both cylinder banks and is much happier on super grades.
Look on youtube for the 5th gear test.
gr J
gr J
Good point for normally aspirated perhaps? But chuck a turbo (or supercharger) into the mix and the parameters are rather changed? - especially when it really gets on boost. I got quite involved with "bolt on" (Shorrock) superchargers back in the '60's/early '70's. It was quite usual to fit 2 head gaskets or (more reliably) a steel spacer to lower the standard compression ratio as the compressed air charge would increase compression pressures to such an extent detonation was almost garanteed!
I too remember retarding timing on BL "A" and "B" series engines to allow them to run without pinking - it made something like an MGB rather sluggish but at least they ran. Until the exhaust valves and seats burnt anyway!
Back to Shell V Power last night. Yikes it goes, and that's despite the weight of a full tank. Asda 95 Unleaded doesn't appear to be any different to start with, but in 2nd at 10mph you get a clunk trying to get it to pick up. Which is first thing that returns. 30-50 through 2nd and 3rd gets slower by noticeable amount too. Also 3rd at 20mph there's a throttle delay. Had to put back in 2nd. Car great fun with V Power, rubbish otherwise.
Well I'm a bit of a cynic when it comes to premium fuels. I normally run the 1.9 16V mJTD Croma on Tesco standard diesel due to it being local. Every so often I'd use an additive (Millers). However following some apparently fuel system related issues I put BP premium in it and it is a noticable difference in drivability and the fuel consumption is improved especially in the A14 roadworks 40MPH limt that I'm doing most of my driving in these days. I'd try the Shell but the only one near my local routes is a services so prices are a bit inflated.
Robert G8RPI.
Robert G8RPI.
One of the difficulties with these sorts of comparisons is that there is considerable variation from batch to batch of what is nominally the same fuel. You could find a fuel today which works well, then come back next week to the same pump at the same filling station and find the next tanker delivery has been blended differently. Refineries vary the blend for all kinds of reasons, not least of which is the feedstock availability on the day.
Subjectively I've noticed some tankfuls do noticeably better than others, but making any kind of proper sense of it would require far more sophisticated metrics than are available to most drivers.
For those with petrol engines, finding an ethanol free blend will get you a 5% economy improvement without changing anything else. Most premium petrol is still ethanol free, but not in the west country or Scotland.
For anyone who absolutely must have ethanol free fuel, it's a nightmare.
Subjectively I've noticed some tankfuls do noticeably better than others, but making any kind of proper sense of it would require far more sophisticated metrics than are available to most drivers.
For those with petrol engines, finding an ethanol free blend will get you a 5% economy improvement without changing anything else. Most premium petrol is still ethanol free, but not in the west country or Scotland.
For anyone who absolutely must have ethanol free fuel, it's a nightmare.
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What did you add to unleaded that will keep it good for months?
I know UK fuel is reasonably stable.. but you will still be losing
'The light.side' through evaporation..
Briggs and Stratton "Fuel Fit". Supposed to be able to keep fuel "fresh" for up to 3 years? More importantly to us it (is supposed to) protect against the effects on fuel lines etc of ethanol and prevent gumming up of carbs etc. I came across it when I started looking after horticultural machinery (which I subsequently did professionally for the last 15 years of my working life). The man I replaced had been using it and, as the boss was buying it anyway, I just kept using it. Whenever a machine was to be laid up for more than about 8 weeks (lawn mowers, brush cutters etc over winter) I would add the recommended dose and run it for a few minutes. I have to say I never had blocked jets due to "gunge" and the engines always started easily at the start of the season too (mind you I would be servicing them over the winter period anyway so they shouldn't have problems related to air filter, spark plugs, fuel filter etc.) Now retired, I just drain my machines if they are not to be used for the winter. - Too tight fisted to buy stuff like this!
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You're more likely to get consistency in blend by buying from a branded site, as they will consistently pull stock from the same place
Some of the supermarkets are buying 'spot market', so could deliver from one of several terminals to the same site.
One of the big exceptions to blend differences is VPower as it is specifically made to a specification at a single refinery (Stanlow), then sent out to regional terminals by pipeline, rail or road tanker.
Some of the supermarkets are buying 'spot market', so could deliver from one of several terminals to the same site.
One of the big exceptions to blend differences is VPower as it is specifically made to a specification at a single refinery (Stanlow), then sent out to regional terminals by pipeline, rail or road tanker.
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I see that Shell V-Power fuels have a new improved formula. Anyone tried it yet and seen any difference over the original V-Power
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That was launched ages ago! - probably the best part of 2 years since it hit the market now.
Octane stayed the same, but the cleaning and lubricating properties were further enhanced.
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Formula Piranha maybe ?
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??Motorcyclist Colin
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Jock
Just tell Mrs Jock it runs better, goes farther and the engine will last longer with less maintenence and all in all it really saves a lot of money. Do you think she will be happy with that? If so do you think she will check up on everthing to see if you are correct? No! Then you are both on to a Win Win situation
Chriselectrics
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I run my 2014 pop on ASDA basic petrol/ Tesco sometimes. Asda is the cheapest round here. Car runs fine never had any issues. But supermarket fuel played havoc with my ZX7R motorbike. killing all the seals. The other issue was you cannot store this fuel for any period of time. As it sucks water out of the atmosphere and collects it in your tank.
So if your planning on parking for any period fill up at BP or shell and only use the top quality stuff.
So if your planning on parking for any period fill up at BP or shell and only use the top quality stuff.
Putty John
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I ran company cars for over 30 years covering over 35k miles per year, never had a problem with supermarket fuel just collected the vouchers.
Now retired always put Shell / BP in Panda 1.2ltr because they are closest, again no problems.
Now retired always put Shell / BP in Panda 1.2ltr because they are closest, again no problems.
Killing seals and not being able to store has nothing to do with coming from a supermarket. It has everything to do with the Bio-Ethanol that's mixed to all of the 95 fuels. Not even all 98 RON is Ethanolfree.
gr J
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You can’t buy 98 in the UK...
