Recommended Fuel
Discussion
The manual states the recommended fuel for the Chimaera is 98 RON (Super Unleaded) Unfortunately my local garage has not had any for a couple of days so have ran car on 97 RON - one of the "Premium" Unleaded brands. Could there be any dowsides to running car on other than the recommended RON grade? Is ordinary unleaded (95 RON I believe) out of the question?
I don't think the octane rating is that accurate. Periodic sampling at the refinery will be used to adjust additives but what you get at the pumps could vary. For me I wouldn't use anything but V Power. That choice is partly because of the octane rating but mostly because the detergents in V Power are very good at maintaining a clean stepper motor. Unlike many on here I have covered over 15k miles since I last cleaned the stepper and it's still running fine. When using BP (Super) I needed to clean the stepper every couple of months.
Just read a review where Tesco (99 octane) has won out on best value high performance fuel, compared againt Shell V Power (99 octance) and BP ultimate (102 octane)
The results showed the BP gave the highest performance (obviously!!) but at £2.42 p/l, but Tesco won out overall, with V Power coming 3rd.
Interestingly the test showed the Tesco fuel gave higher power and torgue at low revs than even the BP fuel.
Test conducted using a M3 CSL in this months Classic Car Magazine.
The results showed the BP gave the highest performance (obviously!!) but at £2.42 p/l, but Tesco won out overall, with V Power coming 3rd.
Interestingly the test showed the Tesco fuel gave higher power and torgue at low revs than even the BP fuel.
Test conducted using a M3 CSL in this months Classic Car Magazine.
Would have thought the best fuel is the one that matches how your timing is set.
A higher octane allows more advance without pinking. On modern cars the ECU uses a knock detector to adjust the timing advance to obtain the best from the fuel. Unless you have some very clever mods the timing is fixed on the Chim and Griff so using the fuel that it was set to use will give best results, using a higher octane than it was set for will gain nothing, use a lower octane and it may burn holes in the pistons.
A higher octane allows more advance without pinking. On modern cars the ECU uses a knock detector to adjust the timing advance to obtain the best from the fuel. Unless you have some very clever mods the timing is fixed on the Chim and Griff so using the fuel that it was set to use will give best results, using a higher octane than it was set for will gain nothing, use a lower octane and it may burn holes in the pistons.
I understood that you specifically shouldn't use regular (95 RON) unleaded as it will cause pinking and foobar the engine if prolonged.
I also understand that Tesco fuel has a higher amount of Ethanol in it (meaning a greater proportion of the fuel is from a renewable sources). A greater proportion of ethanol has been shown to provide greater performance, which I'm guessing is why the Tesco fuel came out tops for performance.
Personally, I used to like the pops and bangs the Tesco fuel gives and my Chim 500 ran very smoothly on it, but I prefer the peace of mind that comes with putting a fuel in my car that has additives to care for the engine. Not heard of any fuel that can touch V-Power in that respect - though I'm no expert...
Cheers,
James
I also understand that Tesco fuel has a higher amount of Ethanol in it (meaning a greater proportion of the fuel is from a renewable sources). A greater proportion of ethanol has been shown to provide greater performance, which I'm guessing is why the Tesco fuel came out tops for performance.
Personally, I used to like the pops and bangs the Tesco fuel gives and my Chim 500 ran very smoothly on it, but I prefer the peace of mind that comes with putting a fuel in my car that has additives to care for the engine. Not heard of any fuel that can touch V-Power in that respect - though I'm no expert...
Cheers,
James
[quote=jdharris]I understood that you specifically shouldn't use regular (95 RON) unleaded as it will cause pinking and foobar the engine if prolonged.
Dont know as I always but 97/98 RON in mine, but the main dealer I bought it from told me it was a waste of money and to use standard 95. Personally as its a 2nd car, it doesn't really bother me to pay 7-8p per litre more as Im not doing that many miles.
Dont know as I always but 97/98 RON in mine, but the main dealer I bought it from told me it was a waste of money and to use standard 95. Personally as its a 2nd car, it doesn't really bother me to pay 7-8p per litre more as Im not doing that many miles.
The point is if the timing is set for normal fuel then it will be fine, and using higher octane will gain nothing. If it is set for the higher octane fuel ( timing more advanced ) and you run normal fuel it will probably cause problems. You can generally bung whatever in modern cars and they will optimise the settings to match, extracting the best available performance.
We dont have any of those flash high octane fuels around here. I've run on BP ultimate 97 for 2.5 years now, never had any problems. My local tesco recently started doing Super 97 at 6p/litre less than BP so I fill up with that every now and then. Chim runs smoothly on both but for some reason the tesco stuff makes one hell of a lot of pops and bangs, BP ultimate is a lot quieter.
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