Well here's a case where I need to eat my own words. It appears I'm the idiot here for saying the above without thinking! According to the fuel sticker on our GLK's (inside the filler door) our GLK's can run on 91RON minimum through 95RON recommended. The conversion of these RON ratings to the AKI (Antiknock Index) (which is the same as the USA/Canada (R+M/2) rating) would be the equivalent of 87 through 91 pump octane (R+M/2) here in the States. (And Canada)

LINK:
https://mbworld.org/forums/glk-class...y-new-glk.html



The above pix is the octane rating (in RON) as noted on the car.

RON is the same as ROZ but not the same as the AKI or R+M/2 pump octane here on this side of the pond..


FUEL TYPE ...............RON (Research Octane Number)(Europe)........................MON(Motor Octane Number)............AKI or (R+M/2) USA Canada
hexadecane ...............................................< -30
n-octane............................................ .......-10
n-heptane........................................... ......0........................................... ..........................0....................... .............................0
diesel fuel.............................................. ..15–25
2-methylheptane..................................... ...23
n-hexane............................................ ......25.......................................... .........................26....................... ............................26
1-pentene........................................... ......34
2-methylhexane...................................... ...44
1-heptene........................................... ......60
n-pentane........................................... ......62
requirement typical 2stroke engine...............69........................... .........................................65....... ............................................67
Pertamina "Premium" gasoline Indonesia.......88
n-butanol........................................... ......92.......................................... ...........................71..................... ..............................83
n-butane............................................ ......91
"Regular" gasoline in Australia,
New Zealand, Canada and the USA...............91–92........................... ...................................82–83.......... .....................................87
Pertamina "Pertamax" gasoline Indonesia......92
Shell "Super" in Indonesia...........................92
"Pertamax Plus" gasoline in Indonesia...........95
Shell "Super Extra" in Indonesia...................95
Shell "FuelSave " in Malaysia.......................95
ExxonMobil Avgas 100................................99.5 (min)
"EuroSuper" or "EuroPremium" or
"Regular unleaded" in Europe.......................95................... ................................................85 –86.............................................90 –91
Shell "V-Power 97" in Malaysia.......................97
"SuperPlus" in Germany, Great Britain,
Slovenia and Spain, "SP98" in France............98.............................. ......................................89–90....... .......................................93–94
Shell "V-Power Racing" in
Australia - discontinued July 2008................100
iso-octane (RON and MON 100 by definition)..100.................................. ..................................100............. ..................................100
benzene........................................... ........101
"BP Ultimate 102 - now discontinued"............102...................... .............................................93–94 ...........................................97–98
t-butanol........................................... .......103........................................ .............................91................... .............................97
ethane............................................ .........108
propane........................................... ........110
toluene........................................... .........111...................................... ...............................95................. ...............................103
E85 gasoline.......................................... ...100–5
xylene............................................ .........117
isopropanol....................................... .......118........................................ ..............................98.................. ..............................108
ethanol........................................... ........108,6..................................... ..............................89,7
methanol.......................................... .......133........................................ .............................105.................. .............................119
methane........................................... ......135......................................... .............................122.................. .............................129

 

MBRedux, this is why I pay attention to your posts.

Everyone makes mistakes; it's what they do next that defines their character.

 

Thanks rmfnla! That means a lot! But there's even an newer update to this post! Please read it! Link: https://mbworld.org/forums/glk-class...ate-alert.html

My Mom & Dad taught me this virtue. I believe in correcting my mistakes because no one has a monopoly on the truth. If I'm wrong, then so be it. I rather stand corrected than stand at fault.

 

Yeah, but all along the way you may have burned a few bridges insulting people calling them stupid and other demeaning terms. That kind of stuf is hard to correct.

 

Yes, at times some people do say stupid things, like me, so I agree, (but it's not that often at all and it's not meant to hurt, it's all in jest! We are all adults here, aren't we?) but unlike others here, I do apologize directly to them if I indeed made a mistake. I cannot help it if they are unwilling to accept that.

 

Not to start 87 vs. 91 wars again but here are interesting results:
Dyno test of GTI with 87 and 91 and less than 10% effect on power. Very surprising considering GTI has turbo engine, and I would expect boosted engine suffer most from lower octane.

http://blogs.insideline.com/roadtest...its-power.html

 

not surprising.

 

probably the turbo is not high compression enough to take a hit from 91 to 87

 

There is an option to adjust the car computer to use 87 gas in MB DAS. It comes with cost, your car performance. It changes the top dead center timing. However, if you are a light driver, go for it. You will need to find a private shop with DAS to do it for you. Dealerships will never do it for you whatsoever.

 

Cars that require higher octane gas actually need that higher priced gas because the engines compress the fuel more before it ignites it. If you put regular gas in a car that requires premium, the gas will prematurely ignite when it’s being compressed and the engine will give you a knocking sound. This is bad for your car.

 

Cars that require higher octane gas actually need that higher priced gas because the engines compress the fuel more before it ignites it. If you put regular gas in a car that requires premium, the gas will prematurely ignite when it’s being compressed and the engine will give you a knocking sound. This is bad for your car.

 

Not really, for those that choose to put anything other than premium in their car will probably only see an effect on gas mileage and performance. Today's cars have computers that will regulate engine combustion and timing so as not to create engine "knock".

 

I think this works for fuel injection. But the trouble of direct injection is gum buildup, etc and using a low grade fuel can aggravate this.