Ever since I've owned my Camaro, I've noticed it runs better on a full tank of gas compared to a 1/4 tank. It seems to have slightly more pep. Everything minus the injections and fuel rails has been replaced over the years (fuel pump, sending unit, regular, filter, etc). It's not a major power loss by any means but the car just feels slightly smoother with a full tank.

The other thing I have noticed over the years my car feels peppier with ethanol free gas. Our cars are port fuel injected so using the E10 isn't as big of a deal to us as our carburetored cousins. That being said, when I have ran several tanks of ethanol free gas my car does feel more alive and my engine sounds a bit quieter.

Has anyone else noticed similar findings?

 

Might be a certain amount of pressure or vacuum in the tank when it's lower that's effecting the fuel pressure.

As for ethanol free.... It surely affects some of the air fuel ratios but it's a very small difference. Ethanol is a far superior fuel to gasoline and so it's not entirely unwelcome if the engine is properly tuned for it. It tunes like it has 114 octane. Makes more power than C16 and runs cooler. It's a fabulous fuel and it's presence, when properly calibrated for, is almost all benefit.

We LOVE E85. It's literally $3 a gallon race fuel.

GD

 

Believe me, I've seen first hand what E85 can do with those Outlaw 10.5, X275 tire cars and Pro Mods. It is the better fuel. Just your engine needs to be built for it. In an ideal world we would be switching to ethanol instead of electric.