Unleaded vs Super-Unleaded

j.wallace · 08-15-2012, 08:24 AM

Does it make a difference?

I've had my 04" Z4 3.0 for a couple weeks now. The guy I bought it from always used to fill her up with super-unleaded but since I've had her I've putting in the regular stuff and she seems a lot more reluctant to go lately.

I can't tell if I've just got used to the power (previous car was 1.2!) or if it's the fuel.

Any ideas?

Shipkiller · 08-15-2012, 01:32 PM

Its the fuel.

If you look at the owners manual (if you have it) the recommend fuel is 91 octane (US). The car will run with 87 but less performance and is not recommended for long term usage.

j.wallace · 08-15-2012, 03:17 PM

Do you know what the average octane is of standard unleaded here in the UK? I think the shell v-power stuff is 98 but I didn't think it went any lower than 90?

Rated M Roadster · 08-15-2012, 03:39 PM

Quote:

Originally Posted by j.wallace

Do you know what the average octane is of standard unleaded here in the UK? I think the shell v-power stuff is 98 but I didn't think it went any lower than 90?

98 octane in Europe is equal to 93 octane in the US I believe.

j.wallace · 08-15-2012, 05:10 PM

Ok, so I need to be putting super-unleaded in then. Do you get better MPG with higher octane?

seank · 08-15-2012, 05:17 PM

Quote:

Originally Posted by j.wallace

Ok, so I need to be putting super-unleaded in then. Do you get better MPG with higher octane?

YES

3point0 · 08-15-2012, 08:58 PM

AFAIK Europe uses the RON octane rating system and in North America we use the AKI system. If my memory serves me right from when I used to live in the UK regular is 95 RON which is the equivalent to premium (91 AKI) over here.

just looked it up on wiki and it seems to be as I remembered:

http://en.wikipedia.org/wiki/Octane_rating

j.wallace · 08-16-2012, 12:58 PM

Great info here guys, thanks a lot!

08-15-2012, 08:24 AM	#1
j.wallace New Member Drives: 04' Z4 3.0i SE Join Date: Aug 2012 Location: Guildford, UK Posts: 13 iTrader: (0)	Unleaded vs Super-Unleaded Does it make a difference? I've had my 04" Z4 3.0 for a couple weeks now. The guy I bought it from always used to fill her up with super-unleaded but since I've had her I've putting in the regular stuff and she seems a lot more reluctant to go lately. I can't tell if I've just got used to the power (previous car was 1.2!) or if it's the fuel. Any ideas?
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08-15-2012, 01:32 PM	#2
Shipkiller Lieutenant Colonel Drives: 2008 Z4MC & 2003 Z4 Roadster Join Date: Oct 2007 Location: Virginia Beach Posts: 1,631 iTrader: (3) Garage List 2008 BMW Z4M Coupe [4.13] 2003 BMW Z4 Roadster [5.00]	Its the fuel. If you look at the owners manual (if you have it) the recommend fuel is 91 octane (US). The car will run with 87 but less performance and is not recommended for long term usage.

08-15-2012, 03:17 PM	#3
j.wallace New Member Drives: 04' Z4 3.0i SE Join Date: Aug 2012 Location: Guildford, UK Posts: 13 iTrader: (0)	Do you know what the average octane is of standard unleaded here in the UK? I think the shell v-power stuff is 98 but I didn't think it went any lower than 90?

08-15-2012, 05:10 PM	#5
j.wallace New Member Drives: 04' Z4 3.0i SE Join Date: Aug 2012 Location: Guildford, UK Posts: 13 iTrader: (0)	Ok, so I need to be putting super-unleaded in then. Do you get better MPG with higher octane?

08-15-2012, 08:58 PM	#7
3point0 First Lieutenant Drives: 2005 z4 3.0 Join Date: Jun 2012 Location: Vancouver Posts: 329 iTrader: (2) Garage List 2005 BMW Z4 [2.00]	AFAIK Europe uses the RON octane rating system and in North America we use the AKI system. If my memory serves me right from when I used to live in the UK regular is 95 RON which is the equivalent to premium (91 AKI) over here. just looked it up on wiki and it seems to be as I remembered: http://en.wikipedia.org/wiki/Octane_rating

08-16-2012, 12:58 PM	#8
j.wallace New Member Drives: 04' Z4 3.0i SE Join Date: Aug 2012 Location: Guildford, UK Posts: 13 iTrader: (0)	Great info here guys, thanks a lot!