Which is the best Octane? 91 or 94?

bmw07 · 04-20-2011, 09:57 PM

Which Octane is best? I have been using 94 ( Major Mac and Mc Cowon Petro) but just curious of what others think or uses?

CRS · 04-20-2011, 10:04 PM

Use whatever your owner manual suggests.

shonuff · 04-21-2011, 07:32 AM

Personal preference really (butt dyno). I'd go with which ever one has a better rewards program (in your opinion) as the difference is minimal (imo). The only exception is if you are tuned, in which case 94 to maximize potential gains.

/thread

2kaccordocoupe · 04-21-2011, 08:26 AM

Quote:

Originally Posted by shonuff

Personal preference really (butt dyno). I'd go with which ever one has a better rewards program (in your opinion) as the difference is minimal (imo). The only exception is if you are tuned, in which case 94 to maximize potential gains.

/thread

RickG · 04-21-2011, 04:11 PM

higher octane= higher performance
correct me if im wrong.

also have a question not sure if its still the case but last summer shell had a whole bunch of commercials and publicity about the premium having hydrogen (i think) in it and saying it runs the motor more cleanly is that true or just BS?

ericlol · 04-21-2011, 04:38 PM

i heard shell 91 has the least amount of ethanol in it...

sgmpw · 04-21-2011, 04:41 PM

Quote:

Originally Posted by ericlol

i heard shell 91 has the least amount of ethanol in it...

+1. Other stations list up to 10% even for OCT91. Shell states no ethanol.

farbmw · 04-21-2011, 04:52 PM

So the question is or should be "Is ethanol good for your car?"

RickG · 04-21-2011, 05:14 PM

sorry looks like its nitrogen I meant this
http://www.shell.ca/home/content/can.../shell_vpower/
is that true or just bs... and also the ethanol is also a good question.

michaelthepsycho · 04-21-2011, 05:19 PM

The minimum before knocking ; the maximum that your ECU will adapt to.

Tune = potential for higher octane.

This subject has been asked a gajillion times.

CdnE90 · 04-21-2011, 05:39 PM

Quote:

Originally Posted by farbmw

So the question is or should be "Is ethanol good for your car?"

It depends on what you are after.

Ethanol improves the octane rating of the fuel, which (in very simple terms) means less tendency to knock.

But ethanol has less energy per unit than gasoline, so if you burn ethanol you need to burn more of it to produce the same amount of power.

My suggestion is to use Shell. More power while still having the same octane rating that the owners manual recommends.

One more point: Petro-Can produces their 94 octane fuel by adding ethanol since it has an octane rating of over 100. But as I've stated here, better octane rating isn't always better performance.

Volasko · 04-21-2011, 08:58 PM

The octane rating in fuel is just the fuels resistance to detonate. Detonation is when the fuel combusts on it's own (no spark) due to a combination of high pressure and heat. What you don't want is the fuel to combust before the piston reaches top-dead-center (engine pinging) as you cause large amounts of stress to the connecting rods and possibly throw a piston.

People often get high octane fuel confused with more performance because high performance engines have higher compression ratios. High compression ratio engines (BMW, Ferrari, etc) require higher octane fuels to prevent the fuel from early combustion.

I am pretty sure stock ECU's don't adjust for more octane, so you are just wasting money. I know ECU flashes like AA tune can have different mappings that take advantage of higher octane fuel, but not stick.

04-20-2011, 09:57 PM	#1
bmw07 BMW BLUE Silence 5 Rep 31 Posts Drives: BMW Join Date: Oct 2010 Location: Markham iTrader: (0)	Which is the best Octane? 91 or 94? Which Octane is best? I have been using 94 ( Major Mac and Mc Cowon Petro) but just curious of what others think or uses?
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04-20-2011, 10:04 PM	#2
CRS First Lieutenant 20 Rep 324 Posts Drives: 2009 323i Join Date: Dec 2009 Location: Vancouver iTrader: (3)	Use whatever your owner manual suggests.
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04-21-2011, 07:32 AM	#3
shonuff Second Lieutenant 16 Rep 225 Posts Drives: E92 335xi Join Date: Jul 2010 Location: Thornhill iTrader: (7) Garage List 2008 BMW 335xi [10.00]	Personal preference really (butt dyno). I'd go with which ever one has a better rewards program (in your opinion) as the difference is minimal (imo). The only exception is if you are tuned, in which case 94 to maximize potential gains. /thread
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04-21-2011, 04:11 PM	#5
RickG Youngster 5 Rep 127 Posts Drives: f25 diesel Join Date: Apr 2011 Location: Ontario, Canada/ Portugal iTrader: (0)	higher octane= higher performance correct me if im wrong. also have a question not sure if its still the case but last summer shell had a whole bunch of commercials and publicity about the premium having hydrogen (i think) in it and saying it runs the motor more cleanly is that true or just BS?
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04-21-2011, 04:38 PM	#6
ericlol BMW Amature 7 Rep 297 Posts Drives: 2011 AW 335i xDrive Join Date: Apr 2011 Location: Toronto, Canada iTrader: (1) Garage List 2011 BMW 335i [0.00]	i heard shell 91 has the least amount of ethanol in it...
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04-21-2011, 04:52 PM	#8
farbmw Brigadier General 422 Rep 4,499 Posts Drives: 2015 M4 6SPD MANUAL! Join Date: Aug 2009 Location: Toronto iTrader: (11)	So the question is or should be "Is ethanol good for your car?" __________________ Have BT Tool professional, will scan and clear codes on your BMW. And now I am able to code my 2011 335is and M4 Link to my M4 euro delivery! http://f80.bimmerpost.com/forums/sho....php?t=1006526
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04-21-2011, 05:14 PM	#9
RickG Youngster 5 Rep 127 Posts Drives: f25 diesel Join Date: Apr 2011 Location: Ontario, Canada/ Portugal iTrader: (0)	sorry looks like its nitrogen I meant this http://www.shell.ca/home/content/can.../shell_vpower/ is that true or just bs... and also the ethanol is also a good question.
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04-21-2011, 05:19 PM	#10
michaelthepsycho Lieutenant Colonel 76 Rep 1,644 Posts Drives: 11 Montego Blue E90 335i Step Join Date: May 2009 Location: CA iTrader: (4)	The minimum before knocking ; the maximum that your ECU will adapt to. Tune = potential for higher octane. This subject has been asked a gajillion times. __________________ Former car 2011 BMW 335i Step - Montego Blue / Chestnut Brown
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04-21-2011, 08:58 PM	#12
Volasko Colonel 705 Rep 2,605 Posts Drives: 06 330i E90, 18 530xe G30 Join Date: Dec 2010 Location: Toronto iTrader: (2) Garage List 2018 BMW 530e M Sport [9.00] 2006 BMW E90 330i [8.28]	The octane rating in fuel is just the fuels resistance to detonate. Detonation is when the fuel combusts on it's own (no spark) due to a combination of high pressure and heat. What you don't want is the fuel to combust before the piston reaches top-dead-center (engine pinging) as you cause large amounts of stress to the connecting rods and possibly throw a piston. People often get high octane fuel confused with more performance because high performance engines have higher compression ratios. High compression ratio engines (BMW, Ferrari, etc) require higher octane fuels to prevent the fuel from early combustion. I am pretty sure stock ECU's don't adjust for more octane, so you are just wasting money. I know ECU flashes like AA tune can have different mappings that take advantage of higher octane fuel, but not stick.
	Appreciate 0 Quote