Apologies if this is a stupid question but I have just been told by a mechanic that fuel with a higher Octane rating wont necessarily make your car faster.

I currently own a UK MY96 and have been using Super Unleaded (97 Ron?). A friend of mine then pointed out to me that Shell Optimax is 98 Ron and a better fuel. I just assumed that the higher the Octane rating the better the performance of my car, but apparently it won't make any difference.

The car will be a little more responsive and the Mpg will improve but the performance wont. This is down to the fact that a UK car will be set up to use normal Unleaded rated at 95 Ron, and not anything higher.

Is this true or is this mechanic talking out of his @rse?

 

Using Optimax will just optimise (no pun) the power available to the car.

 

all i know is that on my my99 scoob inside the petrol filer door there is a label that says 'super unleaded only', i think the higher octane fuel reduces the chance of det and is on the whole better for your engine, could be wrong though

James

 

As your car has a knock senser the car will adjust the fueling to suit a higher octane rating, so you will benefit.

 

It will need an ECU reset to benefit fully from the new fuel though.

 

If nothing else, it will go a long way to protecting your engine from the killer detonation if you really wind it up often enough. As also stated, it will prevent the standard knock sensor from retarding the ignition and thus will keep power levels up.

Les

 

Optimax will not make it any faster but it will reduce the possibility of det.

 

it made my car Go 100 mph faster. And it made it handle better. And you won't believe this, but it also made me a better driver. This fuel is unbelievable, it also made my car shinier, and the interior smell is better than it used to be, and you want to see the birds I pull now they used to be quite largely but now they're very slim and I put it down to the fuel I'm using not the car I'm driving incidentally. This fuel debate gets very boring I drive a Ford Maxi along with my Cortina mark 4 .its personal preference each to the own stop going on about it

 

I use 1 tank of optimax to about every 3-4 tanks of Super in the Evo and Civic type R. I have done many tests and both cars are alot more responsive on Optimax. But hey its up to you.

 

Ive got an my93wrx....and my car doesnt like optimax..... i reckon i lose around 3 mpg with it...no, its not alot but its over 10% when i can return around 25 mpg with NUL....and i dont think it really helps the performance that much.

So as pointed out, i think its down to personal preference and your car set-up..


Frank

 

Does disconnecting the battery reset your ECU?

Is all super unleaded the same and is it OK to mix it with super from other suppliers if your usual garage is closed?

 

Disconnecting the battery will reset the ECU on an older shape car, providing it's left off long enough. However, the best and fastest way of doing it is detailed here.
There's no similar way to reset the ECU on the new age cars without using some sort of external device, but there's no need to reset on fuel grounds anyway as the new age ECU's adapt extremely quickly to changing fuel grades.

Mixing different brands of super unleaded is obviously better than running out of fuel, but there's plenty of evidence to suggest that all brands of Super are not the same (and indeed one fill of Optimax may not be quite the same as the next).

In these cases a KnockLink is always extremely useful in giving you a real-time visual indication of how your car is coping