Copper Nine Eight

Why do people say there is no difference in gas grades when cars (my car lol) runs totally different when I pump regular and when I pump premium? ! Orrrrrrr is it just classic cars where gas makes a difference? This was just a random thought I had

MDchanic

Who says there's no difference between gas grades?

- Eric

chip-powell

ditto!

Octania

You don't appreciate or use the difference... if your ordinary driver car engine is low compression and needs only 87 Octane. If you have a 10.5:1 engine, you very much use and appreciate the 93, 94, or higher octane fuels.

joe_padavano

^^^THIS. You should run the lowest grade, cheapest gas your car will run on. If your car runs fine on regular, you're wasting money to run something more expensive. If your car pings on lower grade, then you do want a higher grade. New cars with knock sensors will advance the timing (and thus make more power) if there is higher octane gas in the tank.

Railguy

I don't know if this has anything to do with this but. Back in the "70s?" indy cars used toluene which was basically lacquer thinner at that time.
Railguy

joe_padavano

Unfortunately, it doesn't.

Different engines, designed to run different fuels. The last time gasoline was used at Indianapolis was 1964, when a fiery crash resulted. USAC switched to methanol (not toluene) in 1965 and ran that until the more politically correct (and agri-lobby supported) ethanol was mandated in 2007.

Railguy

It was used in F1 cars in the 80's at 86%. Sorry I could have sworn it was indy and a higher %.
Railguy

Copper Nine Eight

A lot of people say premium gas is a waste of money but from my experience my car runs horrible on regular. It shakes! But when I run premium it's fine

joe_padavano

If you mean it shakes at idle, I'd find out why. That has nothing to do with the grade of the gasoline. It MAY have something to do with a particular gas station having water in their tank.

Allan R

Is your car designed to run on Premium? That could be part of the problem when you run regular through it, but not enough to make the engine shake. Then again, as JP mentioned you might have bad gas. Do you fuel up at the same location all the time?

btw

I'm a fan of race gas - 107. Get it all the time at the Marathon station. So I pay a little more? Who cares!

88 Cutty Classic

my cars have always got better gas mileage on 93, especially on the highway.. enough so that its offsets the cost difference. over the course of the year i mean we might have been talking about a couple hundred dollars if that. thats peanuts when talking about cars I love and care for. with that said my current daily driver calls from premium fuel only, i dont even think about it. its the cost to drive something with guts instead of some commuter POS.

Allan R

You'd be surprised how many cars nowadays have guts running on regular gas. The program "Market Place" did a review on whether premium works better than regular on modern cars. The result was based on lab tests and actual performance showing that IF your car needs premium, use that. IF on the other hand it's designed for regular (or, shudder, e-85) using premium is just a waste of hard earned $$.

FYI - I'm not disagreeing with your choices in cars or fuels, just stating something that most consumers are ignorant of.

Copper Nine Eight

I drive a 85 Olds delta 88. Owners manual say it's meant to drive on regular! I usually pump gas at chevron. That's where my grandpa got his gas so that's where I go.

Allan R

Basically the same 307 as the one in my old 83 Ninety Eight. It didn't like specific brands of fuel and I had to shop around to find one that it got along with. It never ran rough though, just lacked a lot of power and with inferior gas it pinged. For some weird reason, it liked methanol/ethanol blended gas.

76olds

I run 91 in my low compression Olds 350. Simply because it sits all week. I used 87 a few years ago and found the fuel to turn a brownish color in my pre-pump clear view filter with the week of sitting. Since I just use 91 the fuel stays clear and clean even sitting a month between fill ups.

Railguy

I run 93 or 92 in my omega. Everything gets 87. I'm the kinda guy that checks the milage every fill up. I've never noticed any difference in milage or profomance worth speaking of. We like "the Omega and I " Sunoco . I use it when I can. If not sheetz.
Railguy