Leaded or unleaded - That's the question, Need advice on which type of fuel to use.. Options

[reineg]

Hi there, Laymen and Experts alike!

I have recently acquired a 914/4-70 with a newly built engine. Up to 2.2litre and some extra horses to boot. But now to the question:
The car has got new cylinders and pistons from Pelican Parts, but I do not know much more about the engine. So do you guys (and gals) reckon it would be safer to use modern fuel and add lead, or shall I just go for modern fuel and not add lead?

What is most detrimental to the engine; to add lead to an engine that doesn't need it, or not to add lead to an engine that requires it?

Appreciate any and all thoughts on this..

[bkrantz]

But the challenge the OP has with a modified 2.2 liter four is what compression ratio he has. Lead additive, no, but he might need to use higher octane to run that motor hard.

[wonkipop]

But the challenge the OP has with a modified 2.2 liter four is what compression ratio he has. Lead additive, no, but he might need to use higher octane to run that motor hard.

very good point.

probably needs highest octane unleaded available.
be 98 RON in aus.
i think you guys in USA rate your octane slightly lower.

i can run my 1.8 on 91 RON here which is i think equal to 89RON usa.
i sometimes run a tank of 95 RON through it.
i don't notice any difference in performance. ha. (IMG:style_emoticons/default/biggrin.gif)
not at its low CR. (IMG:style_emoticons/default/biggrin.gif)
but i tend to do it for a highway run. figure its kinder on the engine then.
but be buggered if i ever detect any real difference.
maybe marginal fuel economy but its pretty slim difference.

i know the factory 2.0 in the USA and i think ROW ran on 95 RON.
but the european 1.8 with twin carb needed 98 RON and had that sticker.
it ran a higher compression ratio than even the 2.0 D jets.

i'd be running the OP's car on the highest octane i could get.