Premium vs. Regular - Fuel Economy, Hypermiling, EcoModding News and Forum

thebluelightbulb · 04-13-2009, 04:09 PM

Anyone have any gains using premium vs. regular gasoline? I've been using Shell V-Power and i seem to get a 10% gain in efficiency.

cfg83 · 04-13-2009, 05:02 PM

thebluelightbulb -

I use (mostly) Chevron 91 Octane. However, I have a Hot-Air-Intake, so the premium fuel is insurance HAI (hot-air-intake => lean-burn => higher octane is better to avoid knocking/pinging). Here are threads on same :

Regular vs. Premium
Fuel Grades

CarloSW2

Johnny Mullet · 04-13-2009, 09:14 PM

I use premium fuel and get better performance/mileage from it.

MetroMPG · 04-13-2009, 10:25 PM

Call me skeptical, but I'd like to see a controlled test.

some_other_dave · 04-13-2009, 10:35 PM

I think this is another one of those areas where "it depends" on a lot of factors. Engine design, engine management system (e.g. how exactly it reacts to pinging), driving style (P&G puts my car into the regime where it may knock/ping depending on other conditions), ambient temps, and on and on and on.

One thing is for sure: Over the long term, pinging is very bad for your engine.

The best way to tell if premium fuel helps is to do an instrumented test. Or, rather, a whole lot of instrumented testing. If it does help, then you get to figure out if the MPG difference makes up for the $$ difference or not.

BTW, in my car it doesn't seem to make any difference for MPG. But it does keep the car from pinging in the "worst" of circumstances--where it will with regular-grade. (And the tendency to ping appears to vary from fill to fill as well, even when using the same grade of fuel from the same station.)

-soD

Christ · 04-13-2009, 10:39 PM

Put some more E85 in your diet.

thebluelightbulb · 04-14-2009, 09:56 AM

morning,

it seems there is a wide variety of critisism regarding this. i'll go through another tank and see if there are any gains. chances are that i will to back to #87 just because a 10% gain in efficiency cancels out the cost of premium which is 10 to 15% higher than #87 in my neighbourhood. i have found that different brands of premium give me different results. Shell V-Power gives me the greatest gain while Crappy Tire #91 must be full of ethanol, not giving me the required boost for my test. too bad i don't have a dyno and a fuel monitor. that would give me the best test.

...thebluelightbulb...

MetroMPG · 04-14-2009, 11:08 AM

Unfortunately, tank to tank testing of anything is an exercise in futility for the vast majority of drivers (whose normal variation, absent any changes at all, is large). Far too many variables to possibly isolate just one as the cause of any change.

wagonman76 · 04-14-2009, 01:30 PM

Only time I noticed a difference with premium was with the old 6000 wagon when towing a trailer. With over 200k on the engine, the premium stopped the pinging and restored some of the lost power when climbing hills, so I would make it a point to use premium when towing. If I didn't have it, I could really tell the difference. Other than that, never noticed a difference. Tried it for a couple tanks in the Celeb once but never noticed a difference in performance or mpg.

thebluelightbulb · 04-14-2009, 04:12 PM

since there is a marginal or no increase in efficency compared to cost, i'll just use good ol' #87. i'll use premium only if i really need to do so.

thanks for the advice everyone!
...thebluelightbulb...