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MG MGF Technical - Octane?

What octane level does the F perform best on? Is optimax worth the extra? And finally do octane boosters work?

jon
Panthro

A 95
B yes for Shell in any way.
C yes, at last for those who sell them.

Seriously, the MGF or TF has no knock sensor. So advantages can't be found with any Octane improvements.
Dieter K.

Cool, so cheapest is best!

Thanks Dieter

jon
Panthro

Cheapest ?? ; (LOL)

95 - 98 leadfree, though.
And what is _cheap_ with fuel ?? ;)
Dieter K.

Hi Panthro,

I don't do many miles in my F, so I have used Shell Optimax since buying the car.

My theory is that if it keeps the engine clean, it may avoid expensive repair work in the future.

Also never seen garage run out of it!

Sam
Sam Murray

In New Zealand we 91 and 96 so I have been using 96 but when I need to just top up I use 91.Both are unleaded.

How will the MGF run on 91???

Price here is NZ$1.22 for 91 and NZ$1.27 for 96 a lt. Thats about 1.91 pond a gal.

Mac

In Australia I use a high octane fuel , the car needs it. As mine is a VVC I take it to 7000rpm a fair bit without problems the only time I had to refuel with standard the car would not pull as well through the high range. Fuel is GBP2.8 per litre at the moment!
Andrew Regens

You should use 95 or above (unless the OZ versions have been detuned to work with crap fuel) Occasional use of 91 as a get you home fuel should work, but I wouldn't want to push the engine with it.
Will Munns

There are two standards used to calculate the octane rating of petrol, which are RON and MON. MON figures are lower than RON. In the UK we use the RON standard.

Ralph
Ralph

Andrew,

Their is something wrong with your conversion calculations or something terrible has happen to petrol price since we were there in November last year.

I remember your petrol was dirt cheap. You are suggesting it is now over 340% more expensive than ours - naaaaaaa
Patrick Beet

Andrew did the conversion from dollars to pounds the wrong way round!
d mottram

My mistake , GBP 0.40 per litre ,after five weeks in the U.K doing the conversion the other way it stuck.
Andrew Regens

Actually, in NZ we also have 98 RON available from some service stations - it is sold at the same price as 96 - it replaces 96 RON at these service stations. 91 is not enough for the F; it would not be a good idea to run an F on anything less than 96.

Recently drove my VVC from Wellington to Bulls, deliberately trying to squeeze maxiumum economy out of it, and managed an impressive 51 mpg - a good way to minimise the effect of higher petrol prices.
Karl Woodhead

Karl, where do you find 98 for the same price as 96? BP and Mobil generally charges a premium of several cents for their 98 octane. Not worth the extra IMHO.
Neil Courtney

the difference where i live between 98 RON and 95 RON is £0.05 (thats 5 of your english pence) per litre!

Unleaded (95 RON)
81.9p

Optimax
86.9p (98 RON)

John

Neil,

To be honest, I haven't actually made the price comparison for a while, as I always buy fuel from the most convenient station for me, which is BP on Lake Rd between Devonport and Takapuna...I do know that when they first started selling 98, it was at the same price as 96, but as I say, I haven't checked for a while. Interestingly, most service staions don't now display the higher octane price (96 or 98)on the large roadside signs, just the 91 RON, so comparisons can only be made at the pump, by which time......

You are right, if there is a premium, then it wouldn't be worth it, given that the state of tune isn't adjusted to take advantage of the higher RON.
Karl Woodhead

Shell Optimax or BP Ultimate are well worth using, cleaner engine with less buildup of carbon and more miles per litre, tried and tested .
Robert
R J Hemphill

Dieter is correct (again). Optimax seems to work well with some older engines (my Mini loved it), but is wasted on a K series.
Dot

Alway fill up with 95 @ Tesco (club points), Sainsbury (nectar points) or BP (nectar points). Whichever is teh cheapest, Tesco and Sainsbury at the moment 80p(79.9)/litre while the BP in Bo'ness road straight across from Grangemouth's BP refeinery is 82p(81.9)/litre. as is the Earls Gate station at he roundabout on Earls Gate @ junction 6 on the M9. When I was working in Adlington (England) earlier this year Tesco (Chorley) was 78.5 and BP Shevington was 2p cheaper than BP Grangemouth. When I wrote to BP regarding this decrepancy I was reliably informed that prices were set according to supply and demand and actual transportation costs played very little part in price adjustment. Market monopoly obviously does as there are no petrol stations in Grangemouth except the BP. As for consumption figures, I recoeded my best since owning my F (jan 04) when going to Newport (South Wales) from Grangemouth and back one weekend recently, a round trip of some 780 miles, of +/- 43mpg.
John Dickson


Optimax etc. can only ever make a difference due to the "cleaning" additives and stuff. The K series, as others have said, can not take advantage of the higher octane rating of these fuels. Period.

Anyone noticed that you can clean the engine out by going for a long blat down a motorway in 4th at high revs? Cheaper than Optimax et al. <grin>

John, dunno if it helps, but the BP on Bo'ness road has *always* been stupidly priced since it opened. :-( I know scores of people who have compalined... and all got the same answer as yourself. It sucks. My relatives have always traveled to Falkirk or Stirling for petrol. Stupid isn't it.

P.
Paul Nothard

Gull in New Zealand have a 97 octane and their 91 is actually higher than 91, about 93 I think
mac

This thread was discussed between 16/08/2004 and 30/08/2004

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