What grade of gas does your large gas engine require
With the big V-8 and V-10 engines do you have to burn a higher octane than regular unleaded? Back in the days of muscle cars you had to burn premium. Does that apply to big blocks in RVs?
Forum Discussion
I got this off the internet about 85 octane.
Q:
I live in Arizona and use 87-octane regular. In Utah, Idaho and Nevada, stations were selling 85-octane as regular gas. This forced me to pay more for midgrade 87-octane. Is this the latest petroleum-industry scam to get more of our money? Will my car run okay on this bogus 85-octane regular?
A:
Octane is the ability of a fuel to resist knock, and high-compression engines tend to knock more. The obverse of that is that lower-compression engines can run on lower-octane gas. Air is thinner the higher above sea level you go. Less air going into the cylinders means less pressure at top dead center when things go bang. It's a lot like lowering the compression ratio in the engine, reducing the need for high octane. Cars will run just fine on lower-octane fuel when they're well above sea level--and all of those states are. Hopefully, by the time you get back down to denser air, you've burned off most of the low-octane stuff, and can refill the tank with higher-grade fuel.
Q:
I live in Arizona and use 87-octane regular. In Utah, Idaho and Nevada, stations were selling 85-octane as regular gas. This forced me to pay more for midgrade 87-octane. Is this the latest petroleum-industry scam to get more of our money? Will my car run okay on this bogus 85-octane regular?
A:
Octane is the ability of a fuel to resist knock, and high-compression engines tend to knock more. The obverse of that is that lower-compression engines can run on lower-octane gas. Air is thinner the higher above sea level you go. Less air going into the cylinders means less pressure at top dead center when things go bang. It's a lot like lowering the compression ratio in the engine, reducing the need for high octane. Cars will run just fine on lower-octane fuel when they're well above sea level--and all of those states are. Hopefully, by the time you get back down to denser air, you've burned off most of the low-octane stuff, and can refill the tank with higher-grade fuel.
