I have a 13B n/a in my car, I've always put in 94 octane and sometimes the octane boost additive to bump it to 102 octanes. I was recently told that N/A cars run best with low octane. Apprently mazda N/A race cars would use 80 octane which I've never heard of b4. Some places I've seen sell 86. I've noticed the car drive smoother with the ultra high octane. So whats the deal extactly. I always bought the best for my car, but maybe the most expensive isn't necessarily the best for my car.

www.portugesethug.homestead.com/jim.html

 

Any car will make the most power with the lowest octane it can *safely* use. This goes for turbos too, but you can run higher boost with a higher octane, and therefore make even more power. Lower octane gas burns quicker, which makes more hp, but also makes it more prone to detonation. On n/a's that isnt a problem unless you have your timing advanced.

 

I found on my 87 Sport, 91-92 octane worked the best. I got the best mileage and best accelleration.

However for my 91 Coupe; 87 octane seems to work just fine and it doesn't seem to make much if any differance using 91-92 octane (other than the higher cost of gas).

On my 88 GTU I have the timing slightly advanced and it runs crappy on 87, better on 89, and best on 91 octane, but again the timing is advanced and the intake/exhaust is more open than stock.

The only other advantage (which may or may not be an advantage depending on where you get your gas) is that in Califonia many of the premium grades have more detergents, and anti-oxidents than the lower(and cheaper) grades have.

 

ARRGGGHH!!!! not another one of these posts!

The answer is simple 87

If you want the reasoning do a seach for "NA octane" I'm sure you'll find PLENTY