Supermarket fuels

shifty_uk

shifty_uk

shifty_uk

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..Or specifically supermarket fuels in turbocharged engines...

What's the thoughts?

In my never ending quest to get to the bottom of an intermitted misfire I've noticed the car generally runs rough and hesitates on supermarket regular 95.

I normally use V Power Nitro as a preference(could explain the intermitted aspect...) and there's a Shell garage around the corner which helps but occasionally, on a trip, to avoid paying service station prices I'll nip off at the closest supermarket and stick a tank of 95 in - I've never rated supermarket premium so I'm none the wiser hence sticking regular unleaded in. I'm all for branded petrol...snobbishly.

Could this indicate fuel system clogging? Car gets long trips(in my ownership at least) on V Power but I've read a bottle of Redex etc can help in these matters?

Car has just had a full service because of this including gearbox fluids a week or so before it.
 
What car / engine is it? As above, check the fuel filler or manual for what octane rating. If the car has been remapped then that also may affect what octane is required.

Bear in mind it may be nothing to do with fueling though, when I had a cooper s I took it back to the dealer several times complaining of poor running/misfires which they put down to poor fuel - 3 months down the road they "discovered" the timing was slightly out due to defective chain tensioner.
 
pepsilol said:
Sounds like your car has an issue.

I've ran pretty much every fuel going in all sorts of cars and never had an issue in anything.
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Could be right, did the same in my old (previous gen) 2.0T and it ran okay.
Jokester said:
What RON fuel is your car's engine tuned for according to the manual?
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98 I believe. Seen a few reports online with other Audi owners stating the cars start to run quite rough on 95 but those are all B6/B7 Audis and not the current generation of cars, hence asking here.
 
Armageus said:
Bear in mind it may be nothing to do with fueling though, when I had a cooper s I took it back to the dealer several times complaining of poor running/misfires which they put down to poor fuel - 3 months down the road they "discovered" the timing was slightly out due to defective chain tensioner.
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Bugger! The amount of sensors running on this car, I'd assume something would go off if its mechanical/electrical, that's why it's a nightmare to get to the bottom of.
 
shifty_uk said:
98 I believe. Seen a few reports online with other Audi owners stating the cars start to run quite rough on 95 but those are all B6/B7 Audis and not the current generation of cars, hence asking here.
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In that case it might be fuel. Mine certainly prefers 98 over 95, though not to the point of misfiring on 95.
 
Is this at Idle or when on the move? Injectors can sometimes fail on the 2.0 TFSI engine.
 
chroniclard said:
Supermarket fuel is no different to shell/esso/whatever.
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Yes it is.

You always hear people saying how the lorries leave the same depots so must be delivering the same fuel. The reality is that the base fuel is the same but modern fuels also have a lot of different additives - this is where the difference is. In the same way that shell fuel and esso fuel are different.
 
My car definitely used to run a bit rougher the few times I filled it up with Asda unleaded, never noticed any issues with other fuel though.
 
TheVoice said:
My car definitely used to run a bit rougher the few times I filled it up with Asda unleaded, never noticed any issues with other fuel though.
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I noticed the exact same thing before, all other supermarket fuel has been fine though
 
Mine states 95-98 but in normal running there's very little difference using supermarket 95 to BP's Ultimate. That's not necessarily the case for everyone, but if the car is designed to run on 95 but is having problems, something is wrong.

For me personally, the difference in the fuel - supermarket vs. BP Ultimate - is that BP's fuel helps keep inside of the engine cleaner, it's 97 RON vs 95 and.. I get more pops and bangs with it. :D I'm expecting a small MPG difference using 95, but one that's barely noticeable.
 
Dogbreath said:
Wait, your car requires 98 octane fuel, but because you don't like supermarket fuel you'll only use their 95 octane? That makes as much sense as religion.
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My last car was a 2.0TFSI which was reccomended to run on 98 - it was fine on tesco momentum stuff but didn't run as smoothly on 95, regardless of whether it was supermarket or branded
 
95 RON fuel will only ever be 95 RON, whether its marketed as unicorn **** or standard boggo fuel. The difference is the additives in the fuel.
 
When I had the Seat, with the 2.0 TFSI engine, it definitely preferred the 98RON. It idled better, pulled harder and did get extra MPG (I can prove it).

95RON didn't make it misfire but it just wasn't as perky.
 
I've ran every type of fuel, but I would say VPower or whatever it is now, is all I run the RX8 on and my Supercharged car... I believe they give better MPG as well, but that's my opinion. They do run fine on 95 ron fuel and so should all straight from factory cars apart from some exotica, then again they'd still run fine. Highly tuned and you'll possibly have a problem.
 
I've run everything from supermarket 95 RON, momentum 99, branded 95 RON, V Power and BP ultimate in the M135i and frankly I couldn't tell the difference at all, either in performance or MPG.

I run a tank of higher RON through it when there's a good price, and in France over the 2500 miles I did it was exclusively on 97/98 RON because it's relatively so cheap it would be rude not to.
 
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