Just wondering as I only just got my 03 Disco with 87,000 miles on it.

Is High Octane gas really a must? What will happen if I use 87-88 oct. ? Will it just decrease engine efficiency or will it damage anything.


I currently pay anywhere from $2.73-2.85 for regular and about 10-15 cent more per gallon for the highest octane level.

Thanks

Chris

 

I have never used anything other than 93. All I have read in thses forums strongly urges only hogh octane. And low octane causing poor running rough idle and throwing the SES light.

 

I have been told several times that the high octane gas is a must especially on the ones that say premium on the gas door. In the summer months I ran lower octane gas didn't have any problems but when winter came, I kept popping the service engine soon light on (mis fire cylinder 3, and all sorts of different codes each time it came on) until I used premium gas and now have had no problems. Be thank full your premium is just at $3 a gallon, I pay $3.35 to $3.39and our regular unleaded is the price of your premium. I have not seen any better fuel economy with the premium, but she seems to run smoother. I have also found that the grades or brands of gas even premium are even different.

 

I'm curious about this too, as I'll be picking up my first Disco soon, a 2004 G4 Edition.

I intend on using the truck up north in Quebec, and high octane isn't available up there regularly. I'm frankly stunned, if a Land Rover couldn't make due with low octane. What the hell do they do in Africa where they have REALLY bad gas? You can't get premium in lots of places there, and sometimes can't even get 87!

Several years ago, I talked to a guy who had done an around the world trip in his Disco, and he had to have the computer flashed with a new program so it could run on 85. So, I know the engine can take it.

It sounds like from the discussions I've read, the trucks *will* run on 87, but most people claim they don't run as well and/or don't get as good milage.

From an engineering standpoint, it makes no sense whatsoever. At 217hp from 4.6L, the engine is only making 47hp/L. That's a quite low "power density", and there should be no need for premium at those power levels.

For example, most new Fords only make 66 hp/L, whether you're talking the 4 bangers in Focuses, or the big V8's, that's the standard power density (and it's pretty much the worst in the industry) but they do it on 87 octane.

Typically an engine won't need premium until you're up around 100 hp/L.

So, I don't understand why this engine needs premium. It must have a terrible combustion chamber design that's very prone to detonation or something.

You guys are lucky in the US where 91 is only about 5% more than regular. In Canada, premium is 10-20% more expensive.

 

I've read that carbon build up in the valve train is the major concern.
I wonder, if 93 is not accessable, if one could toss in a little bottle of that octane booster they sell at the parts stores and fuel stops?

 

If you guys can afford to buy your new Rovers then what is another $3.00 or $4.00 a tank full to get better MPG, Performance and even more importantly keep your Rover engine from carboning up, which is very common and expensive when you take out a valve or two.
What next, retread tires and reconstitued engine oil.



"Several years ago, I talked to a guy who had done an around the world trip in his Disco, and he had to have the computer flashed with a new program so it could run on 85. So, I know the engine can take it. " That is so far from the truth, there is no way this will maintain the same performace and more importantly stop the engine from carboning up.

If you disbelievers have a problem, sell your Rovers and by a Ford Escort, you'll love it.

Mike

 

The octane boosters are found to be completely useless. Nothing in a little bottle like that can boost octane meaningfully. There used to be some chemicals that did work in low concentrations, but they have pretty much all been banned. MTBE was one of them.

One trick that race car guys use is you can throw in a gallon of Tolluene bought from a paint supply store. It is a very effective octane booster, since it has an octane rating IIRC of around 110. So, one gallon added to say, 10 gallons of 87 would give you... 89. So, you'd need 2 gallons per 10 gallons of regular to get to 91.

You can see it gets pretty impractical to use on a truck, unless you had a jerry can filled with it to carry around.

Those little bottles have pretty much been disproven as snake oil. The issue is they typically quote raising the octane by "Points". What's a point? Most would think, a full point 87 to 88 or 89 or however many points they say. But they don't. They actually increase it by points as in... .2 or .3 or whatever. That's how they get away without false-advertising lawsuits. You'll notice the bottles don't say "Add this to ten gallons of 87 octane and you'll have 89." That would be very clear. No, instead they say it adds "two points", and the definition of a point is ambiguous.

I've read numerous magazine reviews of these additives. Some are better than others, but none is as cost effective as a jug of Toluene from the paint store (they're used as thinners).

Here's some great info:

http://en.wikipedia.org/wiki/Octane_rating

 

Mike the difference in price can really add up in Canada because our premium is so much more expensive. I also didn't buy a brand new truck at $50k, these things used ARE the price of Escorts (ok, Focuses). So, it is a consideration.

That being said, I'm not saying I plan on running 87 regularly. I'd like to know, that if I actually use the truck for what it is INTENDED, that is, to get away from civilization, that it will run on 87 if needed.

It would be kind of stupid if Land Rovers must use high octane, they are restricted to remaining within the bounds of civilization where... an Escort could take me. That's my concern.

What's far from the truth about my story? You think the whole thing is a fabrication? It's not. This truck was part of some official trip, can't remember who the sponsor was. I saw it and talked to the guy for a long time at the Woodward Dream Cruise, I think in 2004 or 2005. It was a white Disco, highly modified.

If you don't believe engine computers can be reflashed to run on lower octane, you got another thing coming. I was a Ford Powertrain Engineer for 4 years. The only issue which would remain is the carbon problem. And again, that's an extremely rare problem on modern engines, and must be a result of Byzantium combustion chamber design.

Again, not even Ford's engines are this bad, and they are the far and away the worst engines for power density and specific fuel consumption of any major manufacturer.

 

Don't mean to butt in an argument in which my knowledge is somewhat limited, but the Land rover V8 engines date from the 1960s and are by no means modern engines.

 

Stay away from the paint shops, too many people over the years have tried this stuff, end result, bad 02 sensors, bad seals and valve issues.

This item has been beat to death for years, bottom line, if you drive a Rover and you want to keep your cost of driving as low as possible then do what Rover says, cause there are few times when they are right and this is one of them.