What octane fuel do you prefer for your Delorean?

[DMCVegas]

I heard a story from a guy the other day about gasoline. Don't know how true it is, but was interesting anyhow. He said that years ago, Shell bought oil rights in New Mexico. Turned out that the crude wasn't sweet, but had a VERY high content of sulfur in it. So much in fact that it began to be corrosive because of the sulfuric acid content. Shell though didn't want to let their investment go, so they installed an additional machine to refine the sulfuric acid out. However every once in a while that machine breaks down. But Shell doesn't shut down the wells or refinery; they just let the stuff pump through the pipelines. No one knows when this machine goes down, but it does cause lots of problems with the fuel systems in old cars when they get this stuff in their tanks. He said he knew this because he was a retired chemist from Shell after 30 years, and since then he never bought a single drop of shell gas.

Don't know how true it is, but it was an interesting story.

[nullset]

I heard a story from a guy the other day about gasoline. Don't know how true it is, but was interesting anyhow. He said that years ago, Shell bought oil rights in New Mexico. Turned out that the crude wasn't sweet, but had a VERY high content of sulfur in it. So much in fact that it began to be corrosive because of the sulfuric acid content. Shell though didn't want to let their investment go, so they installed an additional machine to refine the sulfuric acid out. However every once in a while that machine breaks down. But Shell doesn't shut down the wells or refinery; they just let the stuff pump through the pipelines. No one knows when this machine goes down, but it does cause lots of problems with the fuel systems in old cars when they get this stuff in their tanks. He said he knew this because he was a retired chemist from Shell after 30 years, and since then he never bought a single drop of shell gas.

Don't know how true it is, but it was an interesting story.

The problem with that argument is that all the gas goes into the same pipeline, and comes out and goes to the various companies.

Shell puts X gallons in, and gets X gallons out, but those gallons are not the same ones.

It's all blended together. The only difference between the major stations is whatever extra additives they dump into it in the tankers or in the tanks at the station.

--buddy

[Marty]

I'm confused. Why does everyone say use 87, and "use what the manufacturer recommends" and that sort of thing, when it clearly states in the manual that the DeLorean requires 91 octane. 87 may work for some, but my engine pings heavily with 87.
http://www.dmcnews.com/Techsection/pdfs/ownmanr1.pdf p.39

[nullset]

I'm confused. Why does everyone say use 87, and "use what the manufacturer recommends" and that sort of thing, when it clearly states in the manual that the DeLorean requires 91 octane. 87 may work for some, but my engine pings heavily with 87.
http://www.dmcnews.com/Techsection/pdfs/ownmanr1.pdf p.39

It actually says 87 (R+M)/2 method, 91 "research octane".

87 Octane is the correct octane for the engine. If your engine is pinging that badly on 87 octane, there may be something wrong with it.

[thirdmanj]

I use the strongest stuff the bar tender's got.

[Marty]

It actually says 87 (R+M)/2 method, 91 "research octane".

87 Octane is the correct octane for the engine. If your engine is pinging that badly on 87 octane, there may be something wrong with it.

Did you look at your manual or my link to the PDF? I can't imagine someone modified the text of that PFD, but it does not say 87 (R+M)/2 method, 91 "research octane". I'm not say you're wrong, but the EXACT wording of the manual is "Fuel tank 13.2 gallons (91 octane unleaded only)"

[Marty]

Ah, I found the other octane quote you are talking about. I can understand my own confusion now.

[nullset]

Yeah, the 91 in page 29 is considered to be a misprint, or intended for the European market. The information on page 30 is correct.

That also is similar to other cars with the same engine, they all use 87 octane.

Higher octane is only necessary in higher compression or boosted applications. My 93 benz (soon to be lemons racer) requires 91 minimum, because of the 11:1 compression ratio.

--buddy

[Marty]

Yeah, the 91 in page 29 is considered to be a misprint, or intended for the European market. The information on page 30 is correct.

That also is similar to other cars with the same engine, they all use 87 octane.

Higher octane is only necessary in higher compression or boosted applications. My 93 benz (soon to be lemons racer) requires 91 minimum, because of the 11:1 compression ratio.

--buddy

misprint - ah, I wasn't aware. Okay. So, I guess I'll have my timing checked if the knock/ping worsens.
higher octane - yes, I'm very familiar with octane in regards to boost. I run 20 psi in my Talon on 8.5:1 pistons.

[dmc6960]

Just noticed I never voted in this poll. I chose 93 (though sometimes I'm stuck with 91 or 92 depending on the station) because of my 10.8:1 compression. Before my engine rebuild I always ran regular 87.