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[PaulMarshall]

After reading my owners manual I noticed it said to use at least 95 RON in my 1.3 . So this tells me no less than 95 Ron but higher would be ok. I have put 98 RON in the other day and I noticed improvement in performance and fuel economy. Is it ok to continue to use 98 RON or will it do damage?

[CrazyG]

The only thing that 98RON will damage is the amount of cash in your wallet,
or hat your bit of plastic will pay for.. (aka your bank account).
The manual is correct....the minimum is 95RON.  We would say that 98RON
is perhaps the better one to use... if you can afford it, specifically for the
'beneficial' reasons that you have mentioned.

[Alex]

Only damage it can do is to your wallet.  Our engines use quite high compression, 10:5:1, so they may benefit from the higher octane, but mostly it's placebo.

Higher octane petrol doesn't have more calories, so it doesn't produce more power when burned, but because it can be compressed more it can make a bit more torque this way, but of course only if the engine senses the better petrol and advances ignition, or if ignition was retarded on 95ron petrol.

I see Graham has posted while I was typing 

[PaulMarshall]

If I may I would like to add that this fuel has 10% ethanol, would this do damage?

[Unknown]

98RON is cleaner too, it is more refined so burns better plus it has added additives to keep the engine cleaner.

I used to run my forfour on 98RON (when I could afford it), it takes a couple of tanks to get in the system fully and does feel like it improves throttle response and mpg however you would be better off buying an additive, like Reddex, to keep the engine clean.

[Alex]

Ethanol has a lower caloric value, so MPG should normally drop a bit, but if it burns cleaner and develops a bit more power than maybe this offsets the lower MPG.

Under 10% ethanol there should be no issues, most cars nowadays can even run on E20 because the hoses and seals have all been designed to take ethanol as well (it corrodes and eats up hoses and seals on older cars).

I think there's a list online of all the cars that can handle different ethanol-gasoline mixes.

[basilbrush]

98 Ron will produce a slower more controlled burn and allow the ignition to be advanced to take advantage of it to produce more power. As the 1.3 engine cannot adjust the ignition range using 98 Ron and paying the extra money is a sheer waste. There are enough additives in 95 Ron to keep engines clean.

http://www.youtube.com/watch?v=gQghB4asSnI

[Problemchild]

think mr singh in his 1.1 (and a lot of the fortwo owners) use v-power in their cars and they get better mpg overall.

if you do decide to go for a higher octane then shell is your best bet (its not actually any more expensive than the supermarket stuff)

JJ

[Unknown]

I currently find a good branded 95RON fuel (like ESSO or Shell) is of a similar quality of a supermarket 98RON fuel.

My Corsa runs better and attains a better mpg using ESSO 95RON fuel, if I run a supermarket fuel (typically Tesco) I can see a 10 to 15% drop in economy compared to ESSO.

The secret to great mpg is simple; a regularly well serviced/maintained vehicle, no unnecessary weight, reduced drag, use fuel efficient tyres (low rolling resistance). This should improve mpg and improve acceleration too (in theory).

[mr singh]

think mr singh in his 1.1 (and a lot of the fortwo owners) use v-power in their cars and they get better mpg overall.

if you do decide to go for a higher octane then shell is your best bet (its not actually any more expensive than the supermarket stuff)

JJ

you are correct JJ.... my 1.1 has run on V-Power since i bought it with the odd fill of normal fuel and overall it works out cheaper than the normal stuff.
1)Shell V-Power Nitro+ is only 8p more than Shell Fuel Saver
2)you get double points of you use V-Power
3)you go further on a tank if filled with V-Power
4)the power delivery is MUCH smoother e.g. at 4000 rpm in 1st there is a noticable step when the VVT changes on normal fuel and its hardly noticable when running on V-Power (a hire car isnt the fastest car in the world if you drive like me).
5)if you opt for money off fuel vouchers then it works out even cheaper.

[PaulMarshall]

Thanks everyone I think I will continue to use 98 for now because fuel economy has definitely improved. Performance not to sure about yet as it may be a placebo effect. Car pulls great on both 95 and 98. 

[mr singh]

try the 98 ron for about 3 months and then switch to 95 ron and see how it feels.

[PaulMarshall]

Will do 

[airSnake]

Or better yet, get someone else to fuel your car up and guess which fuel they put in. If they don't come back at all, they've put diesel in.

[mr singh]

Or better yet, get someone else to fuel your car up and guess which fuel they put in. If they don't come back at all, they've put diesel in.

PMSL!!!