-   Introductions (
-   -   Premium vs %10 blend regular (

IsaacCarlson 07-16-2009 03:05 PM

Premium vs %10 blend regular
i have been using premium because when i use the blend my mileage drops by about 5 mpg. how many of you use premium vs blend?

Frank Lee 07-16-2009 03:26 PM

Do you have enough data to draw that conclusion?

20% change seems awful high for that variable.

Common practice is to burn the lowest grade fuel that still runs decent. On many if not most vehicles, higher grades don't bring any benefits at all so it is just money out the window.

wagonman76 07-17-2009 12:13 PM

Only time premium ever made a noticeable difference for me is when I would tow with my 200k+ mile Pontiac 6000 wagon, it gave me some of my lost power back and was worth it. Other than that, it never made a noticeable difference in anything.

micondie 07-17-2009 05:07 PM

The only time using premium makes sense is if you can advance your timing on premium and get better mileage. I have a Trans Am that calls for premium but it will run on regular. The computer just backs off the timing to compensate. This loss of power is noticeable when you drive it. I haven't done any mileage checks one vs the other but I would assume the mileage also drops. I remember reading a new car test back in lthe 80's when no-lead gas was first introduced, and they tested two Oldsmobiles, one needed high test, the other has it's compression reduced to run on regular unleaded. The high compression one got better mileage, more than enough to compensate for the extra cost of the high test.

superchow 07-17-2009 05:17 PM

Even though my Civic is designed to run on regular gas (87 octane), I use premium (91-93) regularly. It just gives me better low-end torque - probably because of the advanced timing, right?

The thing is this (and this was also true for my previous car, a 1993 3.3L Oldsmobile Ciera): I get better mileage total AND per dollar. I.e. more miles per dollar assuming premium is only 20 cents more expensive than regular. And the higher the price of gas goes, the less of an improvement I need to get to justify premium. When gas was back down to $2 it was almost a tossup which one I used.

This is something I encourage everyone to do: Figure out how far a dollar of regular will take you compared to premium. (This of course assumes that there is an actual improvement.) :thumbup:

Frank Lee 07-17-2009 05:40 PM

You'd be the first person I ever heard of to get better enough fe for it to pay.

tasdrouille 07-17-2009 06:44 PM

Here's some food for thoughts. For diesel fuel, you usually want the lowest grade fuel you can find. Diesel fuel is generally rated by the cetane number. Higher cetane is higher grade and has a lower ignition delay. Lower cetane fuel on the other hand is generally denser and has an higher btu content, but you can still compensate for the longer ignition delay by advancing timing. That's what I've been told by truckers lately, and it's interesting enough my best tank so far has been on the cheapest fuel.

superchow 07-18-2009 04:05 AM


Originally Posted by Frank Lee (Post 116268)
You'd be the first person I ever heard of to get better enough fe for it to pay.

I'm sensing a hint of disbelief... :p I am scientific enough to put my word where my mouth is and will fuel with regular gas for the next few weeks. I fill up every 6 days on average, so this will not be resolved quickly. However, maybe the gains I think I am experiencing are really not there - maybe it was the break-in period when we bought this car - who knows. My goal to have my lifetime average over 37 mpg this year may have to wait, but at least it's a worthy cause, no? (For the record: I will try to not change my driving habits in an attempt to be as objective as possible. Let's see if my wife will notice.)

2000mc 07-19-2009 06:06 PM

i don't think the gains are from premium or octane number, just the fact that you're getting away from the blend. i believe ethanol has about 2/3 the BTU per gallon compared to gasoline. so a 10% blend of ethanol only has about 97% of the energy of regular gas.

All times are GMT -4. The time now is 04:39 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2022, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright