Looking at a new 2012 LR4

[baja5337]

regarding 87 vs 91, you can always stock up on and carry some octane booster prior to heading somewhere where you think the higher octane won't be available and for whatever reason you have a requirement for the maximum stated hp numbers by the manufacturer (read into this unless you're racing your LR3, there is no need).

The reality is any modern electronic fuel injection will make the proper timing & fuel adjustments, regardless of whether the motor has high compression or not, to ensure there won't be any knocking or denotation....though there will be a loss in hp. The talk above of carbon build up and plug fouling is nonsense unless you're running carburetors, old mechanical FI (i.e. Bosch CIS), or very old EFI (which had very limited fuel/timing maps). With the adaptive and learning ECUs in the modern EFI systems, some might argue that it will take some time for the ECU to recalibrate itself from 91 fuel down to 87 and that you should be easy on the gas pedal for 100 miles or so. While this may have "some" merit, you can simply disconnect the battery to clear all of the adaptive/learned sensor data....this will have the ECU start learning/adapting immediately to the new fuel. If you have an OBD2 tool, it can be used to reset the senor data as well without having to disconnect the battery.

The net is the "required" octane value on modern EFI cars is only there allow them to claim their maximum hp performs numbers.

I'm sure there are some Land Rover FSE's that would disagree with your statement about carbon build up being nonsense. There are multiple SSM's regarding this topic for the 5.0 motor and even the old Buick v8 motor was susceptible to valve stick from continued use of poor quality fuel

[LtFuzz]

So where exactly is the OP going to take an LR4 that octane is something to be worried about...?

[Antichrist]

So where exactly is the OP going to take an LR4 that octane is something to be worried about...?

That sort of goes along with post #10.

[perkj]

Poor quality/dirty fuel does cause carbon build up. Octane level does not equate to the quality or how dirty gas is...dirty gas is a factor of the refinery, the additives, the tanker its transported in, the tank at the station, etc.

[perkj]

Not the case on GEMS equipped vehicles (not sure about Bosch and later trucks). The adaptive values cannot be cleared with a battery disconnect (earlier 14CUX trucks can) or an OBD II Scan tool. It requires a proprietary computer to clear.

Also remember these are European vehicles designed (initially at least) to run on Euro Fuel with much higher octane ratings even than US premium. The newer models are most likely equipped with fuel maps that go as low as US regular gas but I wouldn't be so sure all the older ones do. My 98 D1 for instance will soon let you know not just if you run on regular gas but also if the brand of gas (additives mix?) is something it doesn't like.

So a blanket statement that all modern (LR) vehicles with EFi will adapt for and run on lower octane fuels I would say is something to be cautious of if you have no personal experience that it is the case in the LR world at least.

Cost is not a stated factor for the OP but since we're discussing this from an Expo standpoint, range should be considered. These are big, heavy, un-aerodynamic vehicles and are not over powered to begin with, any reduction in power is going to cause more gas to be used and more gas to need to be carried when away from civilization. I have seen differences of up to 20% or more in loss of fuel consumption on long trips when running gas the trucks don’t like.

You won’t hurt it to run the odd tank of lower octane fuel but you are not doing yourself any favors really. If you have to head into the boonies and your concerned at the availability of higher octane gas, carry some Octane booster as has been mentioned. You can get quite far if you add a bottle every other tank or so and it doesn’t take up much room. But I wouldn’t try and drive around some parts of the world in anything other than a diesel anyway.

YMMV

Ian

My 2008 lr3 adaptive sensors are cleared after a battery disconnect. I know this because my obd2 scan tool has an obd2 test readiness feature that ensures all the values are populated so you will pass that check in a CA smog test. When I disconnect the battery and run the readiness it failed and shows n/a for all the values. After 100 miles or so and I rerun the test passes and all the values are present. I will point out when I disconnect the battery I touch the pos and neg cables together for a hard rest. I can also clear the sensors with my obd2 tool...verified with same method stated above.

[ipgregory]

Not sure your test is really proving what you think it is. I don't know the ECU set up of the more recent trucks so I cannot say for sure but from what you have said you only know it is clearing a flash memory containing test report values used for emissions testing. That does not mean that it is clearing the long term adaptive values that are used to modify ECU operation. Maybe it is, maybe it isn't. My point is that your original statement came across as a very blanket one that applied to all modern trucks and that is certainly not the case.

The OP posted about a 2012 truck of course but this thread has moved a little to discussing running lower grade gas in general. Others reading the thread who might be considering the question would be working from bad info if the believed they could clear their trucks with a simple battery disconnect or that their trucks will run just as well and there are are no downsides to using lower octane fuel.

[Daryl]

Also remember these are European vehicles designed (initially at least) to run on Euro Fuel with much higher octane ratings even than US premium.

I believe you are confusing rating systems. Europe is RON, the US is AKI ((R+M)/2). 95 RON is only 90 AKI.

[ipgregory]

I probably am, but 95 RON is regular gas in Europe (or was 10yrs ago when I left). What is 98 RON (Super Unleaded in Euro Terms) in US terms?

[KyleT]

YES, run high grade if possible. the direct injection system does not like low grade. and even still, buy from reputable gas stations. QT and racetrack are NOT the place to buy from.

Change the oil at 7500. NOT 15k.

not all adaptions are cleared by simply disconnecting the battery on any newer land rover. IDS/SDD is needed to fully reset them. yes it will adapt to low grade/quality fuel, but the effects include it running rough and idle fluctuations. as well as the other things mentioned above (ie injectors clogging ect...)

the LR4 is MUCH improved over LR3. and absolutely buy the 100K warranty.

[MattScott]

Just buy the damn thing already and go travel