So I know my landy ('00 Disco II) says premium gas only, but these times are tough and sometimes opting for the cheaper alternative is just too darn tempting.



Of the three (for discussion purposes - base, medium, premium), I find myself going for medium. It gets the job done while saving some extra coin.

Base: Always makes my disco jumpy, anyone else get the same result here?
Medium: Best for me, not jumpy at all. Should I be concerned here though?
Premium: The old-time favorite

Brands
76: OK
Shell: OK
Mobil: thick
Chevron: Is Techron really worth the extra coinage?
Arco: Champagne of beers
Costco: Bottom Suzy

Fuel Additives: If you're like me and opt for a lower grade gasoline, do you supplement your fuel tank with additives to curb any negatives? If so, please list them.

 

I never put cheap gas in my disco. Regular will cause your engine to carbon up so thats a BIG no. And premium gives me the best MPG. You really should use premium, I mean, its only a few bucks more and if you consider the damage you could cause by not using premium its really worth those extra few bucks.

All that being said, I always use Shell premium gas and I put in shell's V-power additive at every oil change. I also run a can of seafoam through the gas tank twice a year (right before a long drive).

My advise to you, forget saving a few bucks and just run premium. It will pay off for you in the long run.

 

It is HIGHLY recomended to run premium fuel in these rigs. Many other members will say the same.

I usually only run Chevron or Shell. I have made big bucks replacing fuel injectors on Nissan / Infiniti vehilces that have ran ARCO, so I never buy fuel there.

I'm not sure about the 76 stations around my parts and will rarely get fuel at Costco.

Fuel additive is not neccesary if you use premium.

 

The engine in your Disco is a high-compression V8. If you run regular fuel in it you will have predetonation that will damage the valve train. Octane level equals burn temperature - the higher the octane, the higher the burn temperature. It has nothing to do with fuel "quality." The premium fuel requirement for this vehicle is not considered an option by the manufacturer - they don't recommend premium, they require it. If fuel costs are a concern, you should probably check into a different vehicle before you damage the engine in the one you have. As Camdisco said, it's just a few dollars more at fillup to use the correct fuel. Have you looked at the cost of replacing your engine?

 

I use Shell Premium, but what really pisses me off is that I live in Oklahoma, a gas and oil state, yet the premium octane fuel is only 91 Octane... When I took a trip to Arkansas recently the premium was 93 Octane, and I saw no appreciable price diffrence.

 

Ok, here we go...
Your truck REQUIRES premium gas, 91 octane MINIMUM, not 89, not 87, 91 or higher.
Here is why, our engines do not have a EGR (exhaust gas recirculation) valve.
The EGR routes exhaust gas back into the engine to get burned.
This does 2 things, 1: it lowers the combustion temps, 2: it lowers emissions.
87 octane gas burns hotter than premium gas BUT premium gas has more power per gallon.
Premium also does not ignite as easily as regular so it will not burn until the spark plug sets it off.
Regular gas will ignite before the spark plug sets it off and so it is not only wasted because it is burning before it is supposed to but it does not burn completely so it will carbon up your exhaust valves.
To compensate for the pre-detonation of the wrong grade of fuel the ECU retards engine timing and by doing so reduces engine power and fuel economy.
So the $3 that you are saving at the pump is costing you $5 because you are getting LESS mpg.
Now lets talk about that excessive combustion temps, all of this extra heat builds up inside the cylinder heads and will shorten the life of your headgaskets and it will bake your motor oil and cause excessive sludge build up inside the engine and eventually clog your oil passages.
Look at it this way...
95% of all gas station use the "ten cent spread"
That means that each grade of fuel is ten cents higher than the one before it.
So if regular is $2.45 per gallon and you buy 20 gallons that will set you back $49.
Mid grade will be $2.55 per gallon, thats $51 for the same 20 gal.
Now premium will be $2.65 per gallon, thats $53 for 20 gal.
So you saved $4 if you used regular, $2 if you used mid grade.
Now add up the higher maintenance costs, repair costs and the 10% reduction in mpg, what have you saved?
Nothing.
You are costing yourself money.
Stick with the name brand gas stations, try and always go to a high volume gas station because a low volume gas station, like Costco, (who buys premium at a discount rip you off store?)will actually have stale gas in the tank in the ground.
Discount gas has no additives most of the time.
No additives means more deposits inside your engine which also means less mpg, high maintenance.
If you want to cut back on the sting of buying gas, buy it when you reach a 1/4 tank, then it will only cost you $20.
I buy gas at the Shell station in my area every Tuesday, they have $.06 Tuesdays.
Save $.06 on every gallon of premium, so its like buying gas that is on sale.
As for additives...dont bother as long as you use good gas because the good gas brands use additives in their gas already.
The owners manual says that premium gas is required for a reason.
Who knows your truck better than the people who designed it?

 

Wow, looks like it's octane 91 or higher for me from now on out!

@gilder - seriously, thanks for breaking that down for me. i was clueless about the octane levels. 91 or higher for me now!
@spike555 - i'm jealous, premium is like $3.29 here in Los Angeles.

Is there a specific premium gas brand (Shell, 76, etc.) that you notice you get better gas mileage on?

 

I get better mpg when I use Shell, BP or Marathon (a MI company)
But like I said I use Shell because of it being on sale every week.
If I have to get gas elsewhere I try and use a name brand.
EDIT:I just paid $2.61 today.
Now ask Urban Panzer how much he pays for fuel. (hint, over $100 to fill his truck)

 

Cheap gas (like those discount gas stations) makes my engine ping. I notice immediately it's rougher in starting and just is no good. So I stick with Chevron, Texaco, or Shell. And I'd never consider putting anything less than premium. Why the bloody heck would I want to risk having costly repairs down the road because I wanted to save 5 bucks on a whole tank of gas? Naw...no thanks.

 

Mobil 93 octane usually.