I know we got a few on here so maybe I can get an answer.

Gasoline

What options for older blocks particularly higher compression.

What I'm contemplating is a mid 80s four banger jap motor with around a 10:1.

Pump gas w/corn, premium pump or rec 90?

But I'm probably overthinking things.

I would just run highest octane pump gas, stay away from ethanol.

It's what I do why my classics.

91 octane no corn.

Thanks, that was what I was figuring. Shame we have so few choices.

Always A fuel that’s 100 some guys used it for racing fuel years back. Not sure if it’s different now.

I run Premium in my Goat...10-1 compression..no problem

Folks running higher than 10:1 static comp on pump gas.
Also depends on your cam specs, as far as what you can get away with.

Bigger question is WHY a Japanese 4 cyl, lol???

I've got a good one sitting on a pallet out back.
Replaced it with a SBC...

Thinking I just might pull the trigger on a suzuki samurai.

LOL, one of my brothers, who.has over a dozen trucks, and a PILE of engines, told me last week:

" I noticed a Samurai sitting in someone's yard on the way home from work a couple months ago.
And everyday, I look at it a little bit longer...'

One thing we used to do was cut 93 octane premium pump fuel with some 100 octane av gas , say a couple gallons per tankful than to buy Cam II racing fuel (114 octane). Much cheaper than running straight Cam II race gas. Rarely do you need the full 114 octane unless it is a full all out race engine.

Unless you get overnight parts from Japan.......

A guy would probably have to have oil wells or a trust fund to afford running a big compression engine nowadays.


Last car I built was a 13:1 396 (.030" over actually, so 402) that required straight Turbo Blue 115 octane. Made 5.5 mpg on the highway and that's when Turbo Blue was $2.65/gal 25 years ago. I have no idea what it costs now. But it's gotta be $8 - $10 I'd think.

10:1 should be just fine with premium pump gas. There's a lot of factory engine out there running 11:1 and higher. The newest Z06 corvette has 12.5:1 and runs on premium pump gas. It'll all depend on engine design. Things like aluminum cylinder heads, a good combustion chamber design with no sharp edges, fuel injection with a good tune , and cam timing all help to prevent pinging. A cam with a lot of overlap acts to reduce compression. Calculated compression is different than running compression. The air/fuel charge doesn't start getting compressed until the intake valve closes, so adding intake duration and/or retarding the cam will close the intake valve later when the piston is further up the cylinder, reducing actual compression.

If you're feeling crazy, you could run E85. It's around 105-110 octane and cheap.

Fastest car I've been in was a Mitsubishi Evo that ran on e85. Turbo 4 cyl tuned DOWN to run 700 hp on e85 after being retired as a drag car. It was a major hazard on the street and got about 6 mpg.

It's incredible, and 4banger to boot

Ah come on just run Sunoco 110 lead, you don’t need O2 sensors anyway.