Shell V-Power test

[n0rt0npr0]

I have tested higher-than-required octane and logged the results off-site with my 1989 Chevy v6 mpfi, and the higher (89) octane was ALWAYS cheaper to run ONLY in the winter. In the summer it always was 4% under baseline.
I'll be performing the same testing in a couple months on my 96' Monte.

IIRC - 3.5% more than 87octane, and I got an average of 5.9% more gas mileage.

Originally Posted by Rick Rae

Agreed. I'm only running the premium for this test because it's the sole grade with 4x detergent that Shell touts as "gunk-removing" versus "gunk-preventing." I didn't expect a performance improvement (at least, not an immediate one) since my engine shouldn't be knock-limited.

Personally, I'd tweak your statement to say "that doesn't benefit from it." If I could get better-enough gas mileage from higher octane to more than offset the additional cost, it'd effectively be less expensive, and I wouldn't hesitate to use it whether it was required or not. But that's almost semantics, as I doubt any engine that doesn't require high-octane fuel will show any significant improvement when using it.

Nope, if there's really a FE bump here I think it's from something other than the octane rating.

Rick