~DrEaM~

hi everone

just want to know are the tesco's 99ron fuel really 99ron? i fillled up my 1st tank of tescos and feels the same as Optimax?? is there any proves that they are really 99ron?? cos from my experience i should be able to feel the difference??

jpmason33

DeEaM

What were you expecting? Optimax is 98.2 on average, so you are only gaining 0.8 RON. It MAY protect the engine from Det to a greater extent but I very much doubt you will FEEL any difference. Its not Nitrous Oxide!

nik52wrx

Depending on what model impreza you drive i challenge you to spot the difference between optimax, Tesco 99999999ron and Tesco premium unleaded.
I drive a uk WRX and can't tell the diff between £1+ litre stuff and regular.

In conclusion who cares if its 99, 98 ,97, 96 or help me god 95!!!!

Sorry to not be much help but this fuel thing does my head in

highlander68k

The octane rating is only important to those who use it to it's full potential.

Dream, your car will NOT perform noticably better if you put higher octane in than it has been set up for. If it's been set up for 100 RON (ie. a JDM car), the higher the RON, the better it will perform (in theory).

A UK WRX set up for 95 RON (and in perfect working order) will not start running better with higher octane fuel. However, using a higher octane will reduce the amount of detonation (or inhibit it) should conditions (heat-soaked TMIC etc.) cause a problems.

Now, I'm told that it should be possible to gain a fair amount (10% on a 280bhp approx.) of power if a car is mapped for and using 98 RON rather than mapped for 95 RON and using 98 RON.

Sorry for all the stuff in parenthesis (brackets) I've got to get on with some work, so don't have time to write things out fully

marcymarc555

Actually Optimax is 98.4 ron , thats why it gets rounded down to 98
Tescos is 98.6 ron , thats why it gets rouned up to 99

As you can see there is 0.2 difference not 0.8 difference as someone said earlier.

mgcvk

I thought optimax was 98.6?? Either way can't believe you are going to feel much difference, apart from in your wallet.

warrenm2

Why do people always ask this question - of course its f%$*&g 99 RON!

And where the hell did you get that 98.6 figure from? what crap. try looking here.

A quick look at the spec sheet will show you are talking out of your ar$e.

highlander68k

TBH, over a year I would/do save £300-350 by using 95 RON from a reasonably priced petrol station. I could save another £1500 by using an economical diesel/petrol car.

I enjoy driving a Subaru, so I don't care.

ben44

I've been running the Tesco 99RON. I used to use Optimax. I've found the car feels better and does a bit more to the tank (all be it 10 - 15 miles)

Defo a thumbs up IMO.

mgcvk

Yep, I mean if Tesco 99 ron is a bit cheaper than Optimax you might save. I'm not suggesting running on 95.