91 vs 93 octane cars
08-18-2004, 10:27 PM
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C280
91 vs 93 octane cars
I think all mercedes' need 91 octane, but I remember in the 80 a lot of cars needed (and I think some of today's pure sport cars need) 93 octane.
My basic question is:
One average how much power is lost by "de-tuning" our engines for 91 octane?
(Or one can think of it this way "How much power would be gained if engines were tuned for 93?")
Maybe there was a car that; one year was tuned for 93, then the next (like around 1996 when OBDII came out) year the same car/engine was tuned for 91. and lost like 5 hp or so.
I've read the if we switch our computers to 93 mode, it advances the timing and we get a small boost in HP. I'm guessing it's something like 2-3 percent more power...it would be a "free" upgrade thought.
It sucks the most of us pump 93 octane and don't even use it...
My basic question is:
One average how much power is lost by "de-tuning" our engines for 91 octane?
(Or one can think of it this way "How much power would be gained if engines were tuned for 93?")
Maybe there was a car that; one year was tuned for 93, then the next (like around 1996 when OBDII came out) year the same car/engine was tuned for 91. and lost like 5 hp or so.
I've read the if we switch our computers to 93 mode, it advances the timing and we get a small boost in HP. I'm guessing it's something like 2-3 percent more power...it would be a "free" upgrade thought.
It sucks the most of us pump 93 octane and don't even use it...
08-19-2004, 09:24 AM
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C280
Originally Posted by CLKVegas
where do you fnid 93. I have never seen it here in Vegas
If I "chipped" my car I would run 94 just to be on the safe side...you know you can't trust those gas companies!
08-19-2004, 12:28 PM
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a Black
No way......
Boy, do I feel ripped off! I need all of you to road trip to Vegas, gamble all your money (in the gas station slots), and buy a ton of gas so that my stations will have a huge influx of cash and upgrade their offerings to 93. 
08-19-2004, 01:06 PM
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95 E320 Cabriolet, 108K
Originally Posted by CLKVegas
where do you fnid 93. I have never seen it here in Vegas
My car is specified for 91 minimum. I know the engine will adjust for octane lower than 91. Does anybody know if my car takes advantage of the extra octane over 91, or is it wasted?
08-19-2004, 01:34 PM
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a Black
My Powerchip is set for 91. I would sure love to find a station with 93 and have Travis and the boys reprogram my CPU to take advantage of it.
I am not sure how much, if any, your car will respond to 93, without a CPU change, but I can surely tell the difference from 87 (our reg) and 91.
I am not sure how much, if any, your car will respond to 93, without a CPU change, but I can surely tell the difference from 87 (our reg) and 91.
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08-19-2004, 06:11 PM
#8
I feel qualified!!!
Drove my ML500 across a good deal of the U.S. and back last week. We have 93 octane locally, the farther west I would go, the worse the fuel got. 92, 91, and in one case 90 was the best grade offered.
I lost 1-1.5 MPG using 91 vs. 93 octane.
Also I found previously that setting the octane rating in the control unit to anything other than "base" was detrimental to power and economy.
I lost 1-1.5 MPG using 91 vs. 93 octane.
Also I found previously that setting the octane rating in the control unit to anything other than "base" was detrimental to power and economy.
