High Altitude Octane

[jamescrane9609]

Regular gasoline at almost all higher elevations is 86 octane. Manufacturers of most new cars — including our 2004 Lexus ES 330 — recommend regular gas, only 87 octane.

I haven't found any clear explanation of why gasoline distributors sell regular at 86 here, and at 87 at sea level.

Also, I'd like confirmation that my car will perform properly with 86 octane at 5000 feet — our altitude here in Albuquerque.

[monarch]

Yes, 85 or 86 octane is OK for altitudes around 5,000 feet or above.

And 87 is OK for altitudes below 5,000 feet

But your owners manual says 87 octane is the MINIMUM allowable octane.

High octane premium gas will deliver noticable better power and slightly better gas mileage, plus

it will virtually eliminate the hesistation upon acceleration problem some late model ES owners complain about.

[gserep1]

Hello,

Above 5000 feet, the engine requires lower octane fuel because there is less internal cylinder pressure due to elevation, and less chance of detonation, or pinging. Less oxygen means the 0/2 sensors will have to compensate for the loss, and in turn, cause the computer to reduce the amount of fuel in the mixture. This will result in better gas mileage, even though overall power will be reduced. In most cases, higher octane fuel is not needed, and may be a waste of money.

GSEREP1

[Lexusfreak]

What does your owners manual state for octane recommendations? & does it mention anything specifically about high altitudes? Best advice is to stick to what Lexus says is best for your car. B)