Good info and experiences. Thanks all.
I'd still think, at my altitude, I could go down to mid with no negative consequences, but for now, i'll stay premium.
I should note, premium here is 91, mid is 89 and regular is 85. That's what they provide at this altitude.

 

I'm not sure higher octane fuels burn cooler. I suppose it's possible, but I've never heard that. One distinguishing factor is that the higher the octane, the harder it is to ignite. So an engine that operates at a higher temperature requires a higher octane fuel to prevent the premature ignition of the fuel. Not counting other additives or detergents, the ease of ignition is the only difference. But it's an important one.

 

Just stay away from Costco, SAMS and grocery store chain gas at any octane and you will be fine.

 

I've been experimenting with regular and premium since last summer. I was commuting 50 miles a day so It was fairly easy to track mileage. I seemed to get about 12 mpg no matter which grade of fuel I was using and never noticed any knock or pinging,.........However, I WAS and still am buying my gas at the cheapest stations which are either Walmart/Murphy gas or a local Grocery chain (HEB),.....so now wondering if I started to use my old favorite Chevron again,....if I would see some improvements with premium. Think I will give it a try on my next tank while prices are low.

Brian in Cedar Park

 

I will be interested in seeing real numbers in the difference. I used the Costco a couple of times and I am not exaggerating, 8mpg. It's great to hear you are getting 12!

 

One of my prior Disco 2s got about 8,......so,....yeah, I consider myself fortunate

 

I'm averaging 16 in mixed highway/city driving using Chevron premium.

 

Dave, I've seen numbers like this before and they baffle me. My 6 cylinder 2003 Explorer and 6 cylinder 95 Montero both ran flawlessly and only got 15ish mpg,...and they were both considerably lighter vehicles with supposedly more fuel efficient engines and from what I have read on the internet,.....that was the norm for both........I did use to use Chevron in everything years ago,....mostly because of the Techron content,....and it was the closest station to my house. I'll give it a shot again.

BTW, is your Sig line "Not a Land Rover Master technician" designed to be a jab at someone who used to put "Land rover master Tech" in their sig line? Haven't seen that guy here in a while, can remember his name,.....but remember he could be a bit abusive from time too time.

 

Here's my data point, take it for what you will: I've owned my disco for almost 8 years. Only put premium in it one time; the rest of the time, it's regular grocery store gas. I haven't had any issues with the cheap gas (I did just put on a new head gasket, but that's not related to gas, it's just poor engineering). I get 17 on the road and 14.5 in town.

 

That's freakishly impressive. I bought a 2006 bmw 330i (the small sedan) with 6 speed manual to improve my commute fuel consumption,.....and it only got 19-21 when I was doing my daily commute....(gets 31 on the highway at 70MPH however)

BC