sobemike

I noticed the gas cap on my E63 requires 98 octane or minimum of 93 octane...I wonder if this has anything to do with lower dynoed Hps on the car. I am planning on a dyno run on my car with 91 octane and also mix it with 100 octane (maybe I'll get 95 octane) and see if it records different numbers on the dyno. I spoke to the shop tech at dealer and he did mention that the new e63 engine is alot more tuned (racing) than other engines and requires much higher octane gas to run to its potential. His exact words were "imagine a formula/cart car running on 91 gas, it will not post the same hp numbers as it would with the required gas"....

I thought it was interesting since some E63 owners is concerned with lower dynoed hps as manfacturer has published.

AMG_55

it would take a little while for the ecu to get used to the "new" gas, ive heard it takes a tank.
however when i put 100octane and octane adder in the tank and went to the track i was .2 sec. faster through the 1/4. (ive been there numerous times before).

there are obviously many variables involved (weather...) but thats my experience

sobemike

I just think the e63 is not posting its potential due to the high octane requirements.

ChicagoX

Those are most likely RON numbers. In the USA, we generally use R+M/2 numbers (research octane + motor octane divided by 2.)

The RON numbers are generally 5-7 points higher than R+M/2 numbers for the same fuel.

wolverine

That sounds very similar to the M5 requirements. These engines respond very well to higher octane - there is a 15 Hp difference between 91 and 94 octane. I'll bet the E63 engine is similar.

Sunoco sells 94 octane gas, but only in selected stations. You can sign onto their website and use the station locator to find the nearest 94 octane Sunoco station.

http://www.sunoco.navisite.com/

You'll have to call to find out which ones have 94. Here it is about 1 in 5 stations.