What Fuel Should I Use?
We asked owner of The Figaro Shop, Toby Brooks to comment on one of the hottest subjects when owners buy the car; What octane number should I put in my Figaro?
The argument on fuel types for Japanese cars has rolled on for years. There probably isn’t any extensive testing, or at least I’ve not seen any specific or relevant data for the Figaros.
In my opinion and having asked hundreds of owners what they use I think it’s not that important, but each owner needs to make their own decision.
There are so many other variables to fail and take into account that its impossible to pin down any faults to fuel type alone.
In Japan they do have a higher octane or faster burning fuel, up to 100 ron. In the UK you can get up to 99. This would effect the way an engine burns its fuel and could in theory cause a problem. Its just very hard to measure timing and other key factors on 27 year old cars that have usually been apart a few times.
In theory you can adjust this out by changing the timing. Doing this stops the engine running with an issue known ‘pinging’ which in simple terms is the timing of the spark and the bang being slightly out of time.
My opinion is that with the Figaros the engines are of a certain age and are worn. Have usually had loads of mechanical work over the years and also often have quite a bit of old fuel knocking around the system. They are generally not being driven like race cars either. They also have quite dated devices for setting timing and fuel mixture so its likely that wear and tear will mean that timing is not as accurate as it once was.
When setting up a car here we always start with the base timing setting and then tune cars to suit, we do that by ear and by how crisp they rev up. That’s it, nothing relating to the fuel.
The problem you get is the variables, engines with bigger or new pistons always perform better with the timing set slightly differently so that can contradict the textbook usage.
So in summery putting the best fuel in is always going to be good for the car, any car in fact but especially a Japanese import.
My overall opinion is that it won’t necessarily damage it if they don’t though.
I think its good practice but not life changing
Manager The Figaro Shop