Premium ULP for Lexus LX470?

Most late modle petrol engines will benafit from using a premium fuel and the 100 series would be one of them.

If they advertised the 100 series needing premium fuel no one would buy them as at the time they were competing with others that requried standard unleaded...... But at the same time the others would of benafited from a premium fuel as well.

Nothing sinister.... Just marketing to their core customer base.

Yes the LX470 will happaly run on standard unleaded.

Greg - No, the 4.7L 2UZ-FE engines vary in tune according to the application. The Japs play with design and tuning changes like you and I change our shirts.
I think you'll find the 2UZ-FE in the LX470 has a slightly higher level of tune with a slightly increased compression ratio over the 2UZ-FE fitted to the 100 series.

It's all about tuning the engine/vehicle to the intended use. The 100 series would have been expected to be worked in poorer conditions than the LX470, so a slightly lower level of tune was selected, and standard ULP (91RON) was selected as the fuel.

In the case of the LX470, it would have been deemed that as a luxury vehicle, it would be used in urban environments and as a high speed tourer on good roads, so the state of tune was raised a little, and premium ULP was selected as the recommended fuel.

I can't find the figures at present, but I seem to recall the 100 series 2UZ-FE was 9.6:1 compression ratio, and the LX470 2UZ-FE was at or over 10.0:1 CR.
At 10.0:1 CR or more, standard 91 RON ULP is struggling to avoid detonation when the engine is working hard - although the ECU and anti-knock sensor will retard the timing and inject more fuel to reduce the likelihood of detonation occurring (a rich mixture reduces combustion temperatures and therefore helps to lessen the chances of detonation occurring).

You probably could run an LX470 on regular ULP, if you weren't operating at high speed on hot days or towing a decent load.
Engine wear will also reduce compression ratios, with valves being the first component to wear in an engine - and they will start to leak combustion gases at as little as 80,000kms from new.
With a slightly lowered compression ratio due to engine wear, you would probably find the LX470 would cope with regular ULP in nearly all conditions.
However, the manufacturer recommends premium ULP as the fuel for the LX470, so the car dealers have to stick with that.

Cheers, Ron.

Any idea what the manual for a LX470 says?
Everywhere I looked (carsales, redbook and other sites) the Lexus LX470 and the Landcruiser UZJ100 both use 91RON fuel. And torque, power, consumption and compression ratios (9.6:1) are the same.
And the 200series with upgraded VVTi motor still uses 91 RON.
It's possible that those sites are wrong, but I doubt it.

The later Lexus RX570 and 200series(1UR-FE) had higher compression and needed 95RON.

Greg,
My nephew used to own a Falcon XR6 Turbo and he reckoned that he got 40 kilometres more out of a tank full of 98 RON compared to 91 RON. He would never use 91 after that.

If his figures are correct, I have no reason to doubt them, then any saving using 91 RON would vaporise I imagine.

I am running a 2UZ FE and always use 95 around town and 98 or premium when towing.


Cheers, Bruce.