Best fuel octane level?
Thread Starter
Registered User
Joined: Feb 2002
Posts: 97
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From: Ontario, Canada
2010 E550 / 2012 ML 550
Best fuel octane level?
On the new supercharged 5.5 litre engines for the S, E, & CL55 AMG models, are there any advantages in using the 94 Octane fuel, rather than the 'normal' 92 octane premium gasoline?
Super Member
Joined: Dec 2001
Posts: 581
Likes: 4
From: Dallas
C32 AMG
higher premium fuel will allow better/more combustion which leads to higher hp ratings
Mercedes sets up their engines for 91 RON. If you switch to a different supercharger pulley (increasing boost, hence increasing effective compression) you might need higher octane.
That said, I run 93 in my C32 "just to make sure"
Member
Joined: Nov 2002
Posts: 88
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From: Southern Cali
2000 Honda Accord EX V6
OHHHH.... thanks for the clarification jswedberg..... i just always thought the consistancy of the fuel would lead to better hp numbers... but now.... its only if the engine in knocking. gotcha!
Super Member
Joined: Dec 2001
Posts: 581
Likes: 4
From: Dallas
C32 AMG
Higher octane means (in a simplistic way) slower burn, so if an engine has such high compression that it "pings" or "knocks" (premature detonation of the fuel-air mix), higher octane will "burn slower" and not allow the knock. So high compression engines need high octane.
Higher octane fuel does not have any more "energy" - it just is harder to ignite.
Higher octane fuel does not have any more "energy" - it just is harder to ignite.
