What kind of gas do you use in your M5?

[M54ccibo]

Originally Posted by mindlessmark07

I'm lucky enough to have a 76 Station right by my office that carries 100 Octane race gas. I have been running 100 octane pretty regularly and whenever I have filled up with 91 octane, I definitely notice a drop in performance.

Just me 2 cents!

(For those in the OC, its the Bonita/MacAurther 76 Station)

^ This. Just down the road from my office/home. I do 1/4 tank 100, 3/4 tank 91, should be right around 95 when combined. Definitely notice a difference. Just a butt dyno though

[URBAN LEGEND]

Originally Posted by M54ccibo

^ This. Just down the road from my office/home. I do 1/4 tank 100, 3/4 tank 91, should be right around 95 when combined. Definitely notice a difference. Just a butt dyno though

My calculations say 93.25.

[mwlmd]

$9.99/gal is about what I paid in Germany. Market rate!

[M54ccibo]

Originally Posted by URBAN LEGEND

My calculations say 93.25.

You are correct. My math was off.

[URBAN LEGEND]

Originally Posted by M54ccibo

You are correct. My math was off.

Do you have 93 oct out there?

[M54ccibo]

Originally Posted by URBAN LEGEND

Do you have 93 oct out there?

I've never seen it in my neck of the woods, just 91 and this station with 100. What's 93 run per gallon?

[py0413]

So far it has been chevron 94 I used, but they close quite early in the area where I live. I am guessing one day or the other, I will be using shell 91(nothing higher grade than this here) at some point.

[URBAN LEGEND]

Originally Posted by M54ccibo

I've never seen it in my neck of the woods, just 91 and this station with 100. What's 93 run per gallon?

in TX ABOUT 3.94.

[nybimmerfan]

The Octane number shown in the U.S. is usually not the same as that shown in Europe. Europe uses the Research Octane Number (RON) whereas almost all U.S. and I believe Canada gas stations use the Anti-Knock Index (AKI) which is the average of the RON and the MON (Motor Octane Number). Octane number 98 or 100 in Europe is equivalent to the U.S. Octane number 93. If a gas station in the U.S. shows a sign saying 100 Octane then that station is stating the RON -- marketing tactic to entice consumer into believing it is a higher/better octane rating.

[mdosu]

Originally Posted by nybimmerfan

The Octane number shown in the U.S. is usually not the same as that shown in Europe. Europe uses the Research Octane Number (RON) whereas almost all U.S. and I believe Canada gas stations use the Anti-Knock Index (AKI) which is the average of the RON and the MON (Motor Octane Number). Octane number 98 or 100 in Europe is equivalent to the U.S. Octane number 93. If a gas station in the U.S. shows a sign saying 100 Octane then that station is stating the RON -- marketing tactic to entice consumer into believing it is a higher/better octane rating.

yes, correct. 100 RON is unleaded "race gas" here in the US.

[Protious]

Stuck with a maximum of Chevron 91 here.

[nybimmerfan]

Originally Posted by Protious

Stuck with a maximum of Chevron 91 here.

If I were in your shoes, I'd first note if the M5 engine knocks when using Chervon 91 (which is already considered high octane) and if does not, then I would continue to use it as it is the only one available in my area. If it does knock then I will have to look for gas with an Octane rating of 93 -- my mechanic tells me that the U.S. gas with rating of 93 is the recommended octane for turbo-charged engines.

[mcvaughan]

Shell 93 whenever possible!

[M54ccibo]

Originally Posted by nybimmerfan

The Octane number shown in the U.S. is usually not the same as that shown in Europe. Europe uses the Research Octane Number (RON) whereas almost all U.S. and I believe Canada gas stations use the Anti-Knock Index (AKI) which is the average of the RON and the MON (Motor Octane Number). Octane number 98 or 100 in Europe is equivalent to the U.S. Octane number 93. If a gas station in the U.S. shows a sign saying 100 Octane then that station is stating the RON -- marketing tactic to entice consumer into believing it is a higher/better octane rating.

According to VP Racing Fuels VP-100 (which is what mindlessmark07 and myself use here in SoCal) is 96 MON, 104 RON. So it is 100 AKI (R+M/2).

[Netwon]

Wiki Fuel Octane Rating Good chart in article which shows the different ratings, RON vs AKI.

[stealth.pilot]

I don't use gas. I use high octane petrol - usually Shell VPower 93. I think gas is intended for the kitchen stove or the fireplace.

[nybimmerfan]

Originally Posted by M54ccibo

According to VP Racing Fuels VP-100 (which is what mindlessmark07 and myself use here in SoCal) is 96 MON, 104 RON. So it is 100 AKI (R+M/2).

Good for you then. I guess you have to pay premium price for that. Although I would be very wary of claims by the vendor even with them showing 100 AKI in the spec sheets -- if the fuel contains ethanol then the mere fact that it has ethanol degrades the octane rating -- 100 AKI with ethanol would be no better than 93 AKI with ethanol. The 100 AKI may give you a slight boost in Dyno tests but in actual use you will not notice the difference ("in a blind test"). Also, in the long run, you still run the risk of water contamination if the 100 AKI fuel contains ethanol. Ideal fuel would be ethanol free.

[M54ccibo]

Originally Posted by nybimmerfan

Good for you then. I guess you have to pay premium price for that. Although I would be very wary of claims by the vendor even with them showing 100 AKI in the spec sheets -- if the fuel contains ethanol then the mere fact that it has ethanol degrades the octane rating -- 100 AKI with ethanol would be no better than 93 AKI with ethanol. The 100 AKI may give you a slight boost in Dyno tests but in actual use you will not notice the difference ("in a blind test"). Also, in the long run, you still run the risk of water contamination if the 100 AKI fuel contains ethanol. Ideal fuel would be ethanol free.

Those are good points to know. I'm not even close to an expert on this stuff and haven't spent much time (actually any) researching this, thanks!

[nybimmerfan]

Originally Posted by M54ccibo

Those are good points to know. I'm not even close to an expert on this stuff and haven't spent much time (actually any) researching this, thanks!

Only reason I have info on these things is that my girlfriend is a Chemical Engineer working for one of the major U.S. petroleum companies and has told me about gasoline processing and additivies. I also get info from my car mechanic who is more on the practical side of things.

[johntomferg]

The economical way:

http://www.summitracing.com/parts/luc-10026-1/overview/

[nybimmerfan]

Originally Posted by johntomferg

The economical way:
http://www.summitracing.com/parts/luc-10026-1/overview/

Am not familiar with the product. The M5 turbo charged engine can yield substantial performance and fuel consumption improvements with high octane fuel including boosters. The way boosters work is that the additives in the boosters prevent the onset of detonation or pre-ignition. You have to check the active chemical ingredient as described in the label. The only true additive that is effective and is used by petroleum refineries to raise the octane of fuel is the chemical Methylcyclopentadienyl Manganese Tricarbonyl or MMT for short. Be careful of additives which also boosts the octane, whose active ingredient is Tetra-ethyl Pb which as the name implies contains Pb or plumbum, the scientific name for lead.

[johntomferg]

Originally Posted by nybimmerfan

The only true additive that is effective and is used by petroleum refineries to raise the octane of fuel is the chemical Methylcyclopentadienyl Manganese Tricarbonyl or MMT for short. Be careful of additives which also boosts the octane, whose active ingredient is Tetra-ethyl Pb which as the name implies contains Pb or plumbum, the scientific name for lead.

Oh yeah "that stuff"...it's got it. Here is the datasheet:
http://www.lucasoil.com/images/media.../MSDS10026.pdf