Car: Mondial t Cab - same engine as 348 The closest gas station only has 91 fuel. About 2 or 3 miles away is a station that has 93 fuel. Is there any performance difference between the two fuels? Will the 91 fuel hurt the engine in any way? Any other advantages or disadvantages?
From what I was told, the cleansest burning fuel is always the best. As for performance, I don't believe (and this is purely my opinion) you will notice a difference between 93 and 91.
No, your OM specifies 95 RON fuel minimum which is about equivalent to 90 AKI fuel minimum (on US fuel pumps the octane rating is given in AKI units). 91 AKI meets the specification just fine (there is no performance advantage to 93 AKI vs 91 AKI fuel -- just a higher octane rating for higher cost ).
this is sill an area of confusion? For "odern multi valve engines", with catalysts(most posters on this site) "Oxctane, per se," is a measure of the fuels anti detonant capacity with respect to standardized compression ratios, and as such has, essentially,NO, NONE, ZERO, factor in the area of performance!! NONE! You have a pizeo-electric sensor on the block to sense "pinging"-which is detonation-a force 30x times more violent in the combustion chamber than the forces exerted by the FLAME FRONT which is being propogated during the burning/regular combustion in your ottocyle. Octane has NO MEASURE with respect to the latent energy in the fuel-the BTU's as it were... NONE
The Mondi has no knock sensor. Thus it is best to run 91 octane especially in hot weather and the engine under load. You don't need 93 octane unless you've increased the spark advance, the compression, or both.
Bosch 2.7 Motronic-you say-has NO pizeoeletric sensor located on the blocks top? Are you cetrtain? I've been rong before-and will be again(its what I get for regressing to carb comp cars!) 2.5 doesn not, I am almost willing to bet my set of 42DCNs that 5.2 has it as well! Kindly e-mail a scan of the WS manual/PB detailing fuel injection-anyone-I am vexed .... thanks-CIAO!
While I agree that 91 meets the factory recommended octane level, I have found that 100 helps prevent high gear/heavy load detonation in my BB512i in Georgia's 90-100 summer heat
Why is this a surprise? 91 AKI doesn't meet the spec for an unmodified BB512i (98-100 RON -- which would be about 93 AKI minimum) -- and with cats (adding even more underhood heat then when tested by F), you might need to push that up a tad.
I normally use 93, but on occasion will fill her up with 100 in the summer...my ole Fiat has no cats or dogs...never had them from what I can tell.
