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To Ron 98 or not to Ron98

Fulled up my Cup TWICE yesterday with ordinary unleaded but as i closed the flap the second time i noticed a sticker stating Ron98 fuel recommended, obviously this is just a recommendation and ordinary unleaded will not do anything detrimental to the engine. But should i use Ron 98 from now on and will it benefit me or the car.???

Any opinions greatly received.

Still cant stop :):):):):) after driving the car.
  Audi S3

id just use the 98 i mean its only 3 - 4 pence more y risk any chance that it may hurt it, it can only be better! well thats my opinion anyway

  ICE'dberg MK2 172

Optimax only!!!!!!!!!!!!!

I could tell the difference with 95. it felt sluggish and unresponsive using it

I find BP Super unleaded 97 RON to make my 172 the most responsive. Optimax just seems to make it feel sluggish and tight. Its very strange considering its a higher octane rating but Ive experimented with different fuels and the only thing in common is that it goes though a slow phase when filled with Optimax - although the economy is a few MPG higher on Optimax. Very strange!

i found the the exaxt oposite, i filled up with BP SUL the car felt fast then I filled up with Optimax and I was like a new car.Find a garage with a hight turnover of fuel as i think Optimax deteriates faster than SUL

1.higher octane rating means less calories per litre.

2.higher octane enables greater cylinder pressure without pinking. = so You can advance ignition further, get higher comp.ratio, give more boost, and be safer with NO2

You should use in general lower RON rating, that Your ECU is mapped for.
As it cant advance the ignition beyond preset point (usually it only retards)

You wont see power gains using fuel with higher RON rating than your ecu is factory mapped to, without remapping the ignition (at least ignition).

If recommendation is 95 - as per valver/will try 1/2 tank 95 and 1/2 98 ... this should give nice result.

Hmm some differing opinions about make of petrol. But am i right in saying that i should go for Ron 98, in whichever make optimax or other. Thanks in advance.:)
  Clio 1.6 16V

The average CR on most family saloon engines out there is 10:1 running on mild economy cam profiles. The 16V run wilder cams and the 172/Cup have wilder cams and a CR of 11:1. Hence why Reno probably recommend 98 octane fuel on the 172 over the average 95 RON. If they recommend this then Im sure the optimum ECU mapping is based on 98 RON. The car will run on 95 RON but will compensate, the results being higher fuel consumption and reduced performance. Im sure running a 172 long-term on 95 RON wont do the engine any favours. Correct me if wrong, when the 16V was in production old ***** star was dead and buried and Super Unleaded was becoming the rare new boy on the forecourts. Im not surprised that the performance engine in the 16V/Willy will thrive on the modern Optimax/98 RONs out there.

Good thats what i wanted to hear i will blast the 95 ron out on some B roads and fill the cup up with 98 ron .

Cheers Guys I just cant stop :)ing
  Clio 1.6 16V

Reth, glad youre enjoying you new Cup. These engines seem to get better and better the more miles you get on the clock. Have you run it in yet or have you decided to cane it from day one?

No not really run it in yet i have been taking it easy i did get 42.1mpg out of it yesterday and it hasnt been below 38mpg. Wait till she has been run in, i am goint to get a tow bar fitted so i can put jerry cans on a trailer top fill her up.:)
  Clio 1.6 16V

Bad news mate ... apparently towbars cant be fitted to the 172!! Blown that idea :). Once you get down to high twentys/low thirties mpg things will start to get a bit more interesting! Afraid I was a nancy during running in. Kept to the book till 650 miles then built up the red line 0.5K every 100 miles after that. Then changed my oil/filter at 1500 miles.

Real world performance is no different whether you use 95 or 98 ron(optimax only real advantage on a 172 is cleaning agents)as long as the 95 ron is not supermarket fuel and you get better mpg on 95 because you put in more fuel for the same amount of money obviously!

Im sure most people with clio sports will attest that their cars have good and bad days in performance terms(much like the human body), no matter what grade of fuel is in the tank, some days the car just seems to go better. At the end of the day there is no substitute for 15-20k miles to bring the engine to full potential and lets forget about this pointless ron debate for 172s. Many 172s do not generate stated power(<165 bhp@flywheel) for fuel to make any difference.

Bye Bye