The Under the Hood Show
Hey Motor Medics, I’m a mechanic and my co-workers battle over fuel. Our pump octane is 88 to 93 and that’s ethanol free for the 93.
The guys say they get better fuel mileage using 93 octane fuel in their older 1990s trucks versus using the 88-90. I think they are nuts.
These are stock trucks with only air filters and exhaust upgrades. I just don’t think it’s possible.
I drive a modified 2000 Chevy truck with a higher compression 454 and it requires using the high-octane fuel to prevent damage. I have to pay more for it, but it is worth the protection for my engine. I only use the cheaper 88 in my 2020 Suburban.
What are your thoughts?
Thanks, Dave in Diana, Texas Dear Dave, It’s all about octane if we are talking about regular fuel with no ethanol in it so let’s start with that. For the sake of this conversation let’s talk about a 1998 Chevy truck with a 350 engine and we can throw a 2005 Buick LeSabre into the mix because they are basically the same for this conversation.
If you burn 87 octane in these, your mileage may be slightly less than using 89-91 but if you compare 89-91 to using the high priced 93 it usually makes no difference. That’s because you have more octane than needed. The cars computers can only make use of so much octane and then they max out.
The bottom line is use the most your car can but no more to save the most cash.
Take care, The Motor Medics
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