[Healeys] octane needs for 2006 Mini Cooper S

[Earl Kagna]

Jack:

If the engine has a spark knock sensor on it, you will do no harm with the 
lower octane fuel - even if premium is specified.  The engine's management 
computer will instantaneously alter ignition and fuel injection maps if 
knock is detected to avoid harm.  The downside is that if the manufacturer 
recommends premium and you elect to use regular, when knock is detected, the 
engine will immediately feel down on power - boils down to your call.

I have an '03 car with a knock detector that is supposed to run premium and 
have used regular all along - I don't particularly care about the power in 
that car.

Check the owners manual for the recommended fuel, and possibly check with a 
dealer's service people to confirm that the knock detector is present on 
your car.

Earl Kagna
Victoria, B.C.
BT7 tri-carb
BJ8

----- Original Message ----- 
From: "Brashear, Jack, N" <JNBrashear at garverengineers.com>
To: "Spridgets" <spridgets at autox.team.net>; "HealeyMail List" 
<healeys at autox.team.net>
Sent: Monday, June 23, 2008 11:12 AM
Subject: [Healeys] octane needs for 2006 Mini Cooper S


Hi All.  I bought a 2006 MC S automatic when it had 10,300 miles on it.
Now it has nearly 20 grand.  The PO said she had always used 87 octane
with no problems.  Soooo, I have continued using 87 octane with no
apparent problems.  Recently I've had folks tell me to use 91+ octane.
Why??  Am I damaging anything by using the lower (and cheaper) 87
octane??  Thanks for your feedback.

Jack Brashear, PE
Project Manager /  Water

Garver Engineers
Office: 501-376-3633 Ext. 402
Mobile: 501-352-8890
E-mail: jnbrashear at garverengineers.com