Better gasoline

[Shannara]

My 454's run much better on the mid-grade gasoline which is sold in most, if not all marinas in British Columbia. Is mid-grade available at any marinas in Washington state? Is there a reasonably inexpensive additive I can put in the tank to increase octane?

[SomeSailor]

I'd imagine your 454's are running better on mid-grade gasoline more for it's cleanliness and quality rather than it's octane.

Unless your motors are actually detonating, you're probably not needing more octane in and of itself. You can however, buy many brands of octane-boosters, but in most cases they are a waste of money for the reasons above.

Additionally, since the EPA is so tight on fuel additives, most are alcohol-based, which are bad for fuel systems.

Just watched a very informative television show on the History Channel called "The History of Gasoline". They told all the secrets and really explained many of the less known facts. A great show to watch if you can catch it.

[heymagic]

Many EFI engines run better on mid-grade, my truck gets about 1.5 mpg better consistently on mid-grade. You need to have computer controlled timing and a knock sensor to do so. Normal carb motors with stock compression generally don't see an increase worth talking about. The only additive that actually works is toluene. Mix it 10% and you gain about 2 pts or so. I have a chart somewhere. It adds nearly $2.00 per gallon though....ouch. Most products avaiable in parts stores are too wimpy, achohol and even more costly. I used to like Shell gas and dislike Texaco. Nowadays you don't know what you're getting or whose storage tanks it came out of.