What Octane do you guys feed your Delorean?

[SIMid]

I know you guys have pretty average fuel in the US. Here in OZ, we can get 3 grades of fuel. Unleaded 91 - 95 - 98 Some have Ethernol and a few places you can come across 100 Octane fuel.

Currently I'm just feeding her 91. Not sure if there is any benefit to run 98. I know Shell V-Power fuel
http://www.shell.com.au/home/content/aus/products_services/on_the_road/fuels/v_power_2011_tpkg/
is meant to clean the engine and run slighter warmer. But being a 30 year old block, I'm thinking I could do more damage than good to her.

Opinions?

[Alex Brooks]

I always thought it ran better on lower octane I ran unleaded 87 in her Simon

[Farrar]

If you're using the same Octane measurement system in Australia as they do in the UK, then you're going to confuse the Americans. ;-)

Unless you're running with boost, use the lowest octane fuel you can find at the pump. The engine was designed to burn it. If you hear knocking, then go up a grade.

[Jimmyvonviggle]

I run the highest octane I can get here in Canada. The highest octane also contains no ethanol here. Why wait for your engine to knock?

[DMCMW Dave]

I run the highest octane I can get here in Canada. The highest octane also contains no ethanol here. Why wait for your engine to knock?

Because if it doesn't knock on low grade gas you are wasting your money. Although given the choice I'd "waste my money" on gas with no ethanol in it. It definitely ages better.

[DeLorean]

on a very hot day with the AC on, I can occasionally hear audible pinging when running regular fuel. I will run 92 when I know it's going to be real hot. Under all other conditions, it runs just fine on regular.

[SIMid]

Is it worth running a full tank of 98 to clean the injectors as they say it does? Of will it dislodge too much crap and may cause an issue down the tack?

[jawn101]

I don't think the "cleaning" characteristic of any of these enriched fuels is meant to be a single shot deal, if it actually does anything in the first place. I think it's more of a cumulative "run nothing but this gas and over time your engine will be cleaner" sort of thing.

[SIMid]

I don't think the "cleaning" characteristic of any of these enriched fuels is meant to be a single shot deal, if it actually does anything in the first place. I think it's more of a cumulative "run nothing but this gas and over time your engine will be cleaner" sort of thing.

I've had debates with a few mechanics and they recommend to run a tank of Premium Unleaded once every 3 tanks to keep things "clean".

[RIUM+]

SIMid, I did the conversion a few months ago & I found that the values represented in the owner's manual matches best to our cheap Aussie 91-octane, unleaded, ethanol-free petrol available today (which actually wasn't readily available here back in 1981!). Burning anything higher than that is basically a waste of money (obviously this changes if you're not running the stock engine setup).

Only go for the premium Ethanol-blended cleaning fuels if you've replaced or at least cleaned your fuel system. It'll clean the system but in the process it'll probably cause a blockage somewhere as 30 years of crud comes loose. Plus you'll probably need a new filter when you're done!

Try to avoid Ethanol fuels for general use if you're not planning to go through the whole tank in under a fortnight. The Ethanol will absorb water from the air, creating all manner of problems. But if you use the fuel before that happens it shouldn't be a problem!

[SIMid]

Mike, I'm going to stick with 91 for a while and maybe switch up to 95 during the colder weather to allow the engine to burn slightly hotter.

I seriously don't want to have any fuel problems down the track.

[David T]

In the US all fuels are basically the same, brand names mean very little except for advertising and pricing. They do have different octanes but the higher octanes are just less volatile so they will not ignite prematurely and cause knocking or pinging. There is no more Winter/Summer blend and they all clean the fuel systems. When a refinery puts a gallon of gas into the pipeline what comes out at the other end is not the gallon they put in but a similar gallon which is then branded by the particular outlet. There is no benefit using a higher octane fuel than is required for the motor. In fact, most modern cars will adjust to lower octane fuels by retarding the timing when the knock sensor detects preignition. It does reduce performance but you won't hurt the motor. The Delorean can't do that but it doesn't have to. If you are pinging something is wrong. Check your timing, vacuum and mechanical advance. Also make sure you are not overheating.
David Teitelbaum