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95 or 98 RON?

2003 - 2009, roadster, coupe, facelift
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ph001
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95 or 98 RON?

Post by ph001 » Thu May 17, 2018 12:45 pm

Generally speaking ALL fuels come from the same UK refineries and ALL meet the same quality standards (EN228 for petrol & EN590 for diesel). The only difference is the additives which may boost octane and help prevent gumming up of fuel lines / injectors etc. There have been rumours in the past that some supermarkets have on occasion imported 'excess production' from outside Europe but I suspect the administrative complexities of doing so are a pretty big deterrent as they would still be legally obliged to meet EN2228 and EN590 if they wanted to sell it in the UK.

That said, Ethanol content does have an impact. Ethanol is added by almost all manufacturers as it's a cheap easy way to boost octane rating and because it's an oxygenator it results in less harmful emissions (the primary reason for government legislation for it's use). The vast majority of fuels in this country are UPTO 5% ethanol but 10% has been rumoured for a long time and is undoubtedly on it's way. It's supposed to be clearly identified on the pump in terms of an E no. e.g. E5, E10 etc.

Ethanol has a lower calorie value than petrol so inevitably mpg suffers (about 3-5% for E10) BUT it has good anti-knock properties so may allow more ignition advance and hence power output. It's very hygroscopic unfortunately meaning it absorbs moisture. This can be a problem if you leave fuel sat in a tank for prolonged periods as you can get quite a lot of water forming at the bottom of the fuel tank and cause starting problems / rough running. Finally it can react quite badly with certain plastics, rubbers and seals, but any car manufactured after 2002 is likely to be fine and EVERY car manufactured after 2011 HAS to be compatible by law.
2007 E85 Z4 3.0Si manual :driving:
19" CSL's | Eibach Springs | Aeroskirts | Z4M front bumper | Clear brake light | ZHP | RCH+| Stubby

2004 E46 M3 coupe manual - gone but not forgotten.

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srhutch
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95 or 98 RON?

Post by srhutch » Thu May 17, 2018 1:51 pm

I always use 98 unless I have no choice. The reason being the Z4's are prone to O2 sensor issues and changing fuel grade can trigger them easily.

I had it when I did the NC500 and had no chce bu to use 95 and within 10 mile the light had come on.

Likewise when I was in France and TAZ filled up with 98 instead of his usual 95 his light came on.

Both times I managed to reset both cars though.

So I'm not advocating 98, but suggesting your car will adapt to one and where possible stick to the same grade and brand of fuel.
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95 or 98 RON?

Post by kis » Thu May 17, 2018 1:53 pm

srhutch wrote: Thu May 17, 2018 1:51 pm
Both times I managed to reset both cars though.
How can you do this, incase it is triggered?
My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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95 or 98 RON?

Post by Zulu59 » Thu May 17, 2018 3:45 pm

Smartbear wrote: Thu May 17, 2018 10:14 am
Zulu59 wrote: Thu May 17, 2018 7:52 am Before having the Z4 I had an MGF and this subject was debated on many occasions , I think the concenus of opinion amongst MGF owners at the the time was that apart from the cleaning properties of 98 there was no noticeable improvement in performance , I've run the Z on 98 and can't say I've noticed any difference , as much as I've tried to convince myself to the contrary :)
At least there should be less carbon to clean off when changing the head gasket :)
Rob
the dreaded MG head gasket :rofl:

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95 or 98 RON?

Post by Smartbear » Thu May 17, 2018 6:24 pm

kis wrote: Thu May 17, 2018 1:53 pm
srhutch wrote: Thu May 17, 2018 1:51 pm
Both times I managed to reset both cars though.
How can you do this, incase it is triggered?
I think most code readers/apps allow you to reset warning lights :thumbsup:
Rob
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e89 Sdrive 20i, plenty of mumbo & good economy-the thinking bears z4
e89 Sdrive 30i, this ones busted, pass me another...
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95 or 98 RON?

Post by kis » Thu May 17, 2018 6:30 pm

Smartbear wrote: Thu May 17, 2018 6:24 pm
kis wrote: Thu May 17, 2018 1:53 pm
srhutch wrote: Thu May 17, 2018 1:51 pm
Both times I managed to reset both cars though.

How can you do this, incase it is triggered?
I think most code readers/apps allow you to reset warning lights :thumbsup:
Rob
Oh right, didn’t realise I’d get a flat out dash error. Should be a simple enough Carly jobbie then :thumbsup:
My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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95 or 98 RON?

Post by Z4 COUPSTER » Thu May 17, 2018 6:49 pm

Wow thread going great guns.
On a personal level I noticed massive difference in my old turbo cars (850 t5 back in the day, and more recently an RS6) regarding supermarkets I don't use Tesco..for some reason none of my cars like it, but Sainsbury's seems fine. The highest bang for the buck I have ever noticed was Agip Super when we lived in Spain, my e36 compact was a totally different animal and id wait until we passed an Agip station to fill up.
On the Zeds.. We'll only a few hard driven tank fulls will tell I suppose...WHAT A SHAME!!!
Anyone else fancy burning up some super in the name of science?
D
:thumbsup: Z in da Head.
3.0i Z3 sport,sapphire black,3.0i Z4 roadster Sterling grey,auto,Z4 3.0si Coupe Titanium silver,Stubby &B06 Plus some other German beauties!!

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95 or 98 RON?

Post by srhutch » Thu May 17, 2018 7:02 pm

kis wrote: Thu May 17, 2018 6:30 pm
Smartbear wrote: Thu May 17, 2018 6:24 pm
kis wrote: Thu May 17, 2018 1:53 pm
How can you do this, incase it is triggered?
I think most code readers/apps allow you to reset warning lights :thumbsup:
Rob
Oh right, didn’t realise I’d get a flat out dash error. Should be a simple enough Carly jobbie then :thumbsup:
I used torque on Android with an elm327 Bluetooth dongle. Under a tenner for both in total.
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95 or 98 RON?

Post by kis » Thu May 17, 2018 7:16 pm

Z4 COUPSTER wrote: Thu May 17, 2018 6:49 pm
Anyone else fancy burning up some super in the name of science?
TBH I wouldn't mind, but then like someone said driving style plays a big factor. As does the types of road. As well as how frequently you actually fill up. So me running a certain type of fuel, and someone else running another... wouldn't really work. I guess what would work is if a few people wanted to fuel up "for science" and perhaps take data for the same set of fuels. For example both fill up with Momentum99 and standard 95 and see the results.
My E85 Z4 3.0i SMG

BMW Family History (past and present):
1 Series - E87
3 Series - E46 Coupe, E46 M3, E90 (x3)
4 Series - F36, F82 M4
5 Series - E34 (x2), E39
7 Series - E32
X5 - E53, E70
X6 - E71

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95 or 98 RON?

Post by Z4 COUPSTER » Thu May 17, 2018 7:27 pm

kis wrote: Thu May 17, 2018 7:16 pm
Z4 COUPSTER wrote: Thu May 17, 2018 6:49 pm
Anyone else fancy burning up some super in the name of science?
TBH I wouldn't mind, but then like someone said driving style plays a big factor. As does the types of road. As well as how frequently you actually fill up. So me running a certain type of fuel, and someone else running another... wouldn't really work. I guess what would work is if a few people wanted to fuel up "for science" and perhaps take data for the same set of fuels. For example both fill up with Momentum99 and standard 95 and see the results.
I agree if the right foot is heavy, hell breaks loose.
Nice though.
:thumbsup: Z in da Head.
3.0i Z3 sport,sapphire black,3.0i Z4 roadster Sterling grey,auto,Z4 3.0si Coupe Titanium silver,Stubby &B06 Plus some other German beauties!!

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95 or 98 RON?

Post by Z4 COUPSTER » Sun May 20, 2018 9:28 pm

ph001 wrote: Thu May 17, 2018 12:45 pm Generally speaking ALL fuels come from the same UK refineries and ALL meet the same quality standards (EN228 for petrol & EN590 for diesel). The only difference is the additives which may boost octane and help prevent gumming up of fuel lines / injectors etc. There have been rumours in the past that some supermarkets have on occasion imported 'excess production' from outside Europe but I suspect the administrative complexities of doing so are a pretty big deterrent as they would still be legally obliged to meet EN2228 and EN590 if they wanted to sell it in the UK.

That said, Ethanol content does have an impact. Ethanol is added by almost all manufacturers as it's a cheap easy way to boost octane rating and because it's an oxygenator it results in less harmful emissions (the primary reason for government legislation for it's use). The vast majority of fuels in this country are UPTO 5% ethanol but 10% has been rumoured for a long time and is undoubtedly on it's way. It's supposed to be clearly identified on the pump in terms of an E no. e.g. E5, E10 etc.

Ethanol has a lower calorie value than petrol so inevitably mpg suffers (about 3-5% for E10) BUT it has good anti-knock properties so may allow more ignition advance and hence power output. It's very hygroscopic unfortunately meaning it absorbs moisture. This can be a problem if you leave fuel sat in a tank for prolonged periods as you can get quite a lot of water forming at the bottom of the fuel tank and cause starting problems / rough running. Finally it can react quite badly with certain plastics, rubbers and seals, but any car manufactured after 2002 is likely to be fine and EVERY car manufactured after 2011 HAS to be compatible by law.
Interesting thing happened yesterday/today. Filled £20..00 in Tesco yesterday and used it all by late today......weather has been fab....so called in to my regular Sainsbury's and put in another £20.00the difference is amazing. So I'm going to check these ethanol levels.
:thumbsup: Z in da Head.
3.0i Z3 sport,sapphire black,3.0i Z4 roadster Sterling grey,auto,Z4 3.0si Coupe Titanium silver,Stubby &B06 Plus some other German beauties!!

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95 or 98 RON?

Post by Ewazix » Mon May 21, 2018 6:55 am

Ambient air temperature (cold is better), damp/humidity (more water in the air is better) air pressure (high is better) and altitude (lower the better) makes more difference than the fuel grade TBH, like a natural intercooler. But V. Power for me anyway :driving:
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95 or 98 RON?

Post by allanhelen » Mon May 21, 2018 9:00 am

I tend to use Shell Vpower (or whatever they call it this week) and Tesco 99. I do so few miles in the Z4 each year that cost is not really a factor. if i can't get these i just tend to put a splash and dash of 95 in. To be honest there is no noticeable difference to me when using the different fuels.

I had an e91 330i in the past and on anything other than super unleaded it ran like a dog it was hesitant, thirsty and the engine just felt flat. As soon as the super was back in it was a different animal, i asked BMW to check it out a few times and they could newer find a problem so guess it just liked the finer things in life.

I also had a 4.8i V8 X5 and again there was no noticeable difference in performance between fuels and given the size of the fuel tank and the speed it gulped fuel it ran on regular unleaded most of the time

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95 or 98 RON?

Post by PRMG » Mon May 21, 2018 12:39 pm

I always run 98 RON, I found that in my last car (MX-5 NC), if I bought £10 95 RON and £10 98 RON, the car would go just as far.
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