High Test Gas?

[copelals]

I just bought an RX330 yesterday and am a bit confused about what grade fuel to use. The manual says 87, but "using a higher grade may improve performance". I have heard that modern engines designed for regular unleaded may be damaged by using higher octanes. What does everybody use and have you noticed any performance problems, advantages or disadvantages of either? Thanks.

[wwest]

The only damage a higher grade fuel will do is to your wallet.

I picked up my C4 in Germany and was advised that basically any grade available anywhere in Europe, absent ones with lead, would work because of the adaptive nature of the engine ecu. Lexus has the same capability.

[SW03ES]

Not entirely true. Using higher octane gas in a car designed for lower can increase carbon deposits and buildup in the engines because they don't burn completely. Its two different schools of thought.

Not really a concern on the RX330, now Lexus gives you a choice on the new V6 models. I run 93, but if you can run 87 and get no pinging then go for it.

[tds]

Here is the reply I received from Lexus re Octane and the RX300.

I interpret this response to mean I should be able to get an additional approx 10 hp by using 94 Octane gasoline.

Here is the response:

There is more than one "octane rating". Research Octane Number (RON) is a

laboratory rating that manufacturers generally use.

Motor Octane Number (MON) is another laboratory method of measurement. Anti

Knock Index (AKI) is the number quoted at gas stations. It is an average

of these two: RON + MON / 2

87AKI is equal to 91RON. The engine in the RX300 produces 220 hp on this

"regular" fuel. If premium fuel is used (over 87AKI or 91RON), a slight

improvement in power output is likely.

The ignition system used on the RX300 continually monitors engine knock

(detonation), and tailors spark advance to operate at where its peak

performance can be obtained. Hence, the better the fuel, the better the

potential performance (within limits, of course).

[beachbum]

I've definitely noticed increased performance when I fill up with premium fuel. Frankly, it's somewhat surprising how dramatic the difference is...

[tds]

Your right! It is one of the best kept secrets.