Premium Gasoline

[puddlestomper]

I noticed that the LR3 is supposed to use premium gas\petrol. Does anybody know the true octane requirements and what type of gas is really required?

Thanks

 

[racingdc9]

I would think that 91 octane is the minimum. I live in Houston, TX and our premium(super unleaded) gas is 93 octane, but most other states, i've seen, their premium gas(super unleaded) is 91 octane.


Hope this helps.

 

[mwillems]

That's (R+M)/2; in Europe they use RON. I think 98 RON is about 93 (R+M)/2... avoid confusion!

 

[madtownrover]

I believe the recomended "premium" fuel in the U.S. is 90 octane. I've been running 89 octane in the cold winter weather, will run 91 or 93 in the summer depending on heat and humidity levels. There is a big difference in octane needs depending on air intake temps.

 

[toddjb123]

Just curious - with high gas prices and the low gas mileage, any harm in using regular fuel (87) all the time? Won't the engine adjust to the fuel and drive fine for most people.

I admitedly don't know how the engine design makes it demand one octane or another. Thanks for any info,
-todd

 

[madtownrover]

The only danger in running lower octane fuel is detonation (pinging). As a general rule, most companies recommend a higher grade fuel to be on the safe side.

That said, utilizing higher octane fuel is generally a waste of money...engines don't perform any better unless specifically programmed for that fuel grade (running advanced timing, etc.) However, running less octane than required will reduce performance...most modern vehicles will pull timing, hence reducing performance.

It really depends on how aggressively LR has mapped the fueling on the Jag V8. If you decide to run 87, especially in hot weather, pay attention to your engine under load. If it's pinging, get some better fuel.

 

[grommet]

The engine is designed/optimized for 91 octane (the normal "Premium" gas sold in most areas). It runs with a higher compression ratio, which is common in this class of vehicle. After buying a $50K vehicle, do you really want to run non-recommended fuel to save ~20 cents per gallon?

 

[madtownrover]

The engine is designed/optimized for 91 octane

Well, sort of. 91 Octane is expected to be sufficient for most conditions the LR3 may encounter, that is hardly "optimized". I'm not suggesting anyone run cheap fuel, but you can bet that the LR3s fuel "requirement" has a safety margin built in to protect Land Rovers warranty experience.

However, in other circumstances 91 octane may not be high enough. Heavy loads in high temperatures may still result in detonation, the Owner's manual addresses that topic.

If $0.20 per gallon isn't enough reward to offset the risks, by all means follow LRs recommendations.

 

[zdas04]

I live in the Rockies and my understanding was that with the air density above 5,000 ft, premium fuel is a waste of money. I've tried this theory on several high-end cars and it has always worked -- until now. My LR3 was running beautifully on 91 octane for the first 1,000 miles. Then I put in 1/2 tank of 87 octane and significantly lost power, the engine noise increased, I started to see some hesitation. I ran that tank down to 1/8 and filled up with 87 octane. The problems got more noticable. I ran that down to 1/8 and filled up with 91 octane and the problems went away.

Another "rule of thumb" in the toilet.

 

[disco1]

I agree with Grommet.