I am experimenting with MPG and different makes of gas. (all 91-93 octane) and this is what I've come up with so far....

-Chevron: 380!! miles/tank
-Exxon: 340 miles/tank
-Mobil: 346 miles/tank
-Valero (Diamond Shamrock):335 miles/tank

I drive mostly highway commuter miles with small amount of city, granny style. I've also got a GAB with K&N, but that's it for mods.

Anybody else have any particular gas they use that gets em good mileage?

I'm shooting for 400 mi/tank

 

Just a bit more information if you don't mind. Do you fill when the idiot gas light comes on or do you drive for 30-40 more miles after it comes on? How many gallons is your typical fill up? It has been my experience that unless I am driving completely city miles I always get 400+ miles per tank unless I am trying to make it from Charlotte to Florida in record time.

 

magdocjr makes a good point... you can't really go by when the light comes on as your "stopping point". I think the better way to do it is using average MPG.


1. Fill it up to full.

2. Reset the odometer.

3. Drive it till empty or whenever.

4. Note mileage driven since fill up.

5. Fill it up to full again and see how many gallons filled.

6. Mileage/gallons filled = MPG.

7. Repeat a few times and take the average MPG.

 

Gotta love this kind of results from experiments...


Good instructions Puppet and Mag...

 

Not to : but doing it by how many miles to the tank is not too great. Remember pysics? Different temp will let you have more or less gas in the tank. No it may not be that much more, but fill your tank druning the winter at night, and then wait about 6 months and do it in the heat of the day. Yes I understand that you have not been doing this for a year or so, but all Im saying that that using the trip will be much better for your results.

 

If you want to get picky,

8. Load (did you have to drive the 300 lb. mother-in-law to the airport with all her luggage sharing space with the 15,000 Watt system in the in the trunk and the back seat?)

9. Tire pressures (Huh?!? I trust the guy at Iffy Lube does that...)

10. Weather conditions (was it 20 below on snow/slush, or 65 deg w/ 20 mph tail winds?)

11. Accessories (was A/C or the 15,000 Watt system on most of the time?)

12. Jackrabbit starts (I pwnd that stang GT at the light...)

 

I don't go by the gas light coming on, I go until it is on the empty line, then fill up. typical fill up is a little over 16 gallons. I always reset the trip sitting at the pump, and I have a sub box in the trunk (50-60x-tra lbs or so). My SES light is on b/c of my rear O2 sensor being gone completely (long story) and I know that it makes a small diff in the avg. MPG I get. I also live around Dallas, and the weather is pretty much unpredictable. Seems like after a half a tank mark, it goes fast from there.
I check/refill tire pressure religiously as well. No jack rabbit starts...

 

I was assuming all those and other factors were approx. constant/similar... didn't wanna get bogged down with the details...

 

Your rear O2s will not affect MPG (assuming all your primaries are working)... only the primaries affect AF.

 

Good to know...