What gas to run

[sking]

1973 stock motor & carb (not sure which carb).

What should i be running in it?

Thanks all!

Shenton

[tjones02]

It really depends on what you set your timing to and how much power you want on a regular basis. Yow can dial the timing to stock or even back a bit so that it doesn't ping on regular 87. Or dial it up and run only premium 91.

So, let's say 30 deg max advance (vacuum disconnected) for 87 and up to 36 deg max advance for 91. That's just a ballpark, as your motor/compression will dictate when it wants to ping on a given timing spec.

It's your choice.

[roadhog0]

With timing out of Haynes I can run 87 all day long on a stock motor. (1500 RPM on the ball with vac advance disconnected.)

[Mike Self]

is very happy with midgrade gas (89 Octane here in OH).

I started out with all premium, the went to half premium and half midgrade, then all midgrade. Doesn't ping at all even with the dizzy set spot on per the dizzy rebuilder's specs.

Your stock engine should have 8:1 pistons and should be perfectly happy on 87 (regular) octane gas.

cheers

mike

[adawil2002]

The Bimmers get 91-93

Pre-war cars 89.

[fourtii]

1973 stock motor & carb (not sure which carb).

What should i be running in it?

Thanks all!

Shenton

You could be at 7000 ft elevation like me where it doesn't matter at all.

There's more fuel than air....

[2thosd2]

Just to complicate things...

Now don't be looking at older fuel octane suggestions and get confused. There have been several octane rating systems. We currently Use the "AKI" system(Anti Knock Index). Back when these bimmers were new, the fuel was being rated under a different system, like the "RON" octane rating system. FYI, RON rates the octane higher than current AKI (91 RON is Not 91 AKI).

bottom line, like previously suggested, use whatever your car is happy with. Fill 1/4 tank with oh say...87 and see how she likes it. And work you way up, if needed, from there. Back in high school (im 23 )when I drove my VW bug I put 91 in it, because the gas filler flap had a 91RON sticker on it. Wasted $$$

[c.d.iesel]

http://www.toptiergas.com/

really .