So I find myself here quite often reading over various threads learning as much as possible and have recently thought about various fuel conversations I see. I know this is only loosely tech related but I do have a fuel related question...

My Indy 500 has a sticker on the dashboard saying 92 Octane minimum required. Here in the UK our standard fuel is 95 Octane however I run nothing but 99 Octane and have done for about 7 years now.

I know that you guys in the US have much lower octane fuels but often discuss the advantages of 92 Octane to reduce pinging. I am curious whether the (relatively) higher octane fuel I am using is going to have any affect on my engine in the long term (whether its better or worse)??

 

There should be no adverse affects from running higher octane fuel through your engine. Your engine should live a long and trouble-free life, as long as oil+filter changes are done at reasonable intervals. BTW, isn't the engine in your vehicle turbo-charged?

Octane in generally available US gasoline has been lowered over the years due to the removal of lead as an additive and reformulation to reduce emissions, in conjunction with automotive engineering changes (catalytic converters, EGR valves, charcoal canisters, smog pumps, etc.).

 

Indys are NA but have different computer tuning from the factory.

 

Many thanks for the re-assurances on the fuel, it was just a thought but I'm pleased to hear it won't be doing any harm (but also getting a few extra hp's :P).

I keep up to date with the oil and filters (every 4k) but finding the parts in the UK can be a nightmare, especially something as simple as 10w-30 oil, that stuff is rare over here. I tend to run it on 10w-40 and haven't had a problem yet!

Also, as dodgedude said it is indeed NA.

 

You are fine using the 10w-40.

 

Wasn't there a 'special edition' Indy pace truck that had a turbo charged 5.9 Magnum in it? I vaguely recall seeing one documented some time ago during one of my Web search sessions.

 

Turbo?

Detroit never associated big cubes with turbo power until lately.

Supercharged is more likely, but even that is doubtful.

 

I did see an Indy at JTE (Jeep/Truck Engineering) with a Paxton supercharger, but I don't know if that was production or just a prototype.

 

On the octane thing the US, Canada and a few others compute octane differently than the rest of the world. Most of the world uses Research Octane Number RON. The US uses an average of the RON and Motor Octane Number MON. This is called Anti Knock Index. The easy conversion is to subtract 4 to 5 from the RON as used in most of the world to get The US AKI. So the UK 99 octane is about a 94 US AKI and the 95 is about 90.

 

Caripple, thanks a lot for the insight I had no idea that this was the case. It does probably mean that this truck had been run on the wrong fuel for a few years before I got it! It was imported in 2007 and I have had it 2 years so it's probably had a good 4 years on 90 octane! It's in safe hands now though :P