Standard or Super unleaded?

lightning · Post by **lightning** » Tue 20 May, 2014 07:30

I see that the handbook recommends Super but says that Standard can be used, or even the poorer quality 91ron fuel that we don't have in the UK.
So it's obviously not going to harm the car, but do people use Standard or Super Unleaded in their Z3? Is there any noticeable difference in performance etc? Mine's a 2002 3.0.

Thanks.

('_')Z3 · Post by **('_')Z3** » Tue 20 May, 2014 07:36

Super in my 2.0ltr, not going to say it improves performance or anything but feels better some how. Sure it's in my head

TR4man · Post by **TR4man** » Tue 20 May, 2014 08:15

Bog standard normal unleaded from whichever supermarket has the best offer.

No problems since I bought the car nearly two years and 44,000 miles ago.

gIzzE · Post by **gIzzE** » Tue 20 May, 2014 08:48

Super.

These cars have maps on the DME for both fuels, 95 and 98, if you put 95 into your car it wil retard the timing slightly to cope with the lower octane fuel, I know when this was tested on a 530i a while back the difference was not much in regards to power, it was around 10bhp, so less than 5%, however, on the tests the retarded timing reduced mpg by around 8%, so there was no financial value in using the 95 ron that is 5% cheaper.
They did say you could notice the power difference though, more so going from 98 back down to 95.

The other thing worth noting was although it will retard the timing if you suddenly put 95 in after tanks of 98, if you do the other way round it can take hours to go back, so putting 98 in you won't notice it straight away, if you pull the battery the dme resets, so if you suddenly go with 98 maybe do that?

Obviously depends on the car, not all cars have maps on them for higher octane fuel, using 98 in those is a waste of money.

You then get into highly tuned cars and the difference can be staggering.
Thorney Motorsport ran tests on their M3 CSL using 95 and Tescos 99 and it lost over 11%, it lost over 40bhp. OK that is a 360bhp car but some owners were spending £10,000 to try and get another 20bhp out of the CSL at the time, so £6 a tank to keep 40bhp didn't seem too bad at all.

I remember having to put 95 in my M3 CSL in France as they were out of 98 and you could really feel it straight away that something was different, I was really worried at the time that I had got some water or some crap in from the pump, there were fuel strikes at the time and thought maybe I was filling from the dregs at the bottom of the tank. But we made it home fine and didn't get any worse, so must have just been the cheap 95 ron supermarket fuel.
That was the last time I used 95 ron in a car that says it takes 98 ron.

Mike Fishwick · Post by **Mike Fishwick** » Tue 20 May, 2014 10:54

I find that the best UK fuel - in terms of fuel consumption for a given type of driving - is Esso 97, with their 95 octabne still better than most 98 octane fuels. The worst was Tesco 95 bought in Ashford.

wonderloaf · Post by **wonderloaf** » Tue 20 May, 2014 11:26

I use Shell V-Power super unleaded in my 2.2i, I'm sure I can feel a difference the car seems more responsive and smoother to drive. Makes no difference to MPG as some of the advertising claims. Probably all in my head, but at only a couple of extra quid per tankful seems silly not to use it!

lightning · Post by **lightning** » Tue 20 May, 2014 13:57

OK l will use Super for the few pence extra per litre.

Post by **Robert T** » Tue 20 May, 2014 14:30

I did a bit of a test a good number of years ago and whatever the Shell superunleaded was then delivered about 3-4 mpg improvement, which just about offset its cost. The more noticeable difference was the willingness of the engine to pick up and pull. I have now been running on Shell V-Power and Nitro+ for a good few years and won't go back to standard unleaded - I've stuck with Shell as I have a loyalty car which gets me a few free litres of fuel every so often. I also run the frog on V-Power is it is closer to the old 4 star - without additives as it has an unleaded head.

Cheers R.

Cal1000 · Post by **Cal1000** » Tue 20 May, 2014 16:08

I've been using V Power in my 2.8 for the last couple of months, it definetly feels smoother and pulls harder compared to what I used to get at asda.

sirius-c · Post by **sirius-c** » Tue 20 May, 2014 16:46

Shell v power for me too, now I know this may make a few of you laugh but I'm convinced it changes the exhaust note too.
I have to agree with Mike regarding esso fuels....I tried all brands back in the day and the one that always made a noticeable difference was esso 95 & 98. It always made my old bangers run smoother and I always gained a few more mpg's without fail, but it was the most expensive.
The fact that I used to work for esso designing their petrol stations has nothing to do with it

A friend of mine swears by 98 from BP, he claims it's the only fuel out there with the lowest ethanol content and the other things they mix in with it (forgot what he told me, I just remembered the ethanol part)

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gIzzE · Post by **gIzzE** » Tue 20 May, 2014 16:59

Shell for me, their Nitro stuff is great.

I love the way people think it is snake oil. Makes me chuckle.

These cars have knock sensors on them, they can tell what octane the fuel is and the higher the octane the more advanced the timing is, increasing both power and economy, or I should say, move away from the recommended 98 ron which the car is set up for and you will loose power and economy.

Davejue1 · Post by **Davejue1** » Tue 20 May, 2014 17:18

I'm persuaded! I'll give it a whirl! Bye bye asda bogo hello v-power!

gIzzE · Post by **gIzzE** » Tue 20 May, 2014 17:26

You need to give it around half a tankful at least.
You could pull the battery and it 'should' reset the DME. However, drive it quite hard for the first 30 minutes or so if you can, as the DME will be learning your driving style again.

Davejue1 · Post by **Davejue1** » Tue 20 May, 2014 17:37

I've got half a tank now, if I mix it will it start to work or am I best to run it low first?

gIzzE · Post by **gIzzE** » Tue 20 May, 2014 17:49

Run it low.

And put 3 or 4 tanks in, then if you go back you will notice it more.

Mugs · Post by **Mugs** » Tue 20 May, 2014 19:24

the company that mapped my Impreza has done some tests and found v power nitro + and tesco 99 to be the best and on a mapped Impreza can give up to 25bhp difference on the rollers.

akirk · Post by **akirk** » Tue 20 May, 2014 19:56

So who here is on comission for Shell?!

will be interesting to try - my nearest petrol station is a Shell garage...

Alasdair

bentley-boy · Post by **bentley-boy** » Tue 20 May, 2014 20:18

Hi all, Shell Nitro V Power (which is claimed to be 100 octane if you believe their leaflet) is what I run too. Two reasons: a) I use diesel for most of my mileage so am used to paying £1.36 litre and b) although not definite, the tests I did gave an mpg improvement it seemed of 2 - 2.5 miles per gallon so about pays for itself. As for performance I can't say as I do not drive spiritely, I only run a 1.9 eight valver. But for you guys with your 3 litre jobbies I am sure a 100 octane has got to be good news!!
Regards BB

Woody1000 · Post by **Woody1000** » Tue 20 May, 2014 21:09

I use BP 97 octane and would never put 95 in mine and I have the same 3.0 engine, why because when I use the premium fuel my car produces 380 Bhp and does 0-60 in 3.2 seconds when I use cheap supermarket fuel I only get 210 Bhp and 0-60 in 8 seconds. Well in my head that's what happens !!!!

fish · Post by **fish** » Wed 21 May, 2014 07:55

Shell V Power for me…I actually work in the industry and have seen the engines sawn in half as they use 2 fuel tanks during tests etc….the uprated fuels always come though perfect…

Shell is moving to gas to liquid (GTL) technology - I am not 100% sure whether UK V Power is formulated with that yet…, whereby the fuel is made from Gas…its so pure the flame burns clean etc….its certainly in diesel and aviation products (fuel) have been developed too…..I'll do some digging around to see about the UK V Power….have a feeling the Audi Le Mans car was recently powered by GTL (diesel) from Qatar too….

Mike Fishwick · Post by **Mike Fishwick** » Wed 21 May, 2014 10:01

Most peole think high-octane fuel is not worth using because that drive a small Japanese car of a Ford etc which does not have knock sensors, and has a restricted advance curve. This means that it is set up to run on 91.95 octane, so a higher cotane fuel will not be able to make any difference.

Here in France 98 octane costs about 3% more than 95, so for the usual 10% improvment in MPG it is well worth using - although on Monday's drive frm Salais to the Dordogne I was averaging a colculated 33.7 mpg cruisng at 80 mph - until my half-way refuelling stop, after which it plunged to 28 mpg! Perhaps total are starting to adulterate their usually good fuel with extra ethanol. I'll excperiment with our local supermaket 98 and see what happens.

Flight · Post by **Flight** » Wed 21 May, 2014 10:17

Hi, interesting subject. I run three cars my 3.0i, my Lotus Elan and my MG ZTT Diesel. All of them run better on branded fuel over supermarket fuels. The reason I have been quoted, is that branded fuels contain 5% ethanol, whereas the supermarket fuels contain 7% which is why it is cheaper. I haven't noticed any difference between the super and standard grades, even my 40 year old Lotus runs equally well on either, but can be difficult to start after standing idle for some time, this is due to fuel degradation, as ethanol fuel only has a shelf life of around 3 weeks. I also fly a light aircraft with a Rotax flat four engine, I always use branded fuel, and it runs well on either grade, but doesn't like the 7% ethanol supermarket fuel. The ethanol fuels have a greater propensity to create water which can cause carb icing, therefore the less ethanol the less water, and fuel samples are taken frequently. What really made a huge difference to the Rotax was Total UL91 ethanol free fuel. It felt smoother, produced the same engine revs for a less throttle opening, and on a two hour flight saved 2 litres of fuel. There is no doubt we are being sold inferior fuel at the forecourts. At the moment UL91 is only available for aviation use, and only made by Total but I believe that BP are to produce a similar ethanol free fuel. Perhaps the fuel pressure groups can persuade the garages to offer it. Incidentally the UL91 grade equates to around 98 ron.
Flight

Davejue1 · Post by **Davejue1** » Wed 21 May, 2014 10:18

Be interesting to see the result Mike. I ran to Newby hall on Sunday on 95 and returned 32mpg. I am going to switch to 98 after I've finished this tank and moniter from there. We have a shell station 2 mins away so v-power will be the trial fuel.

TR4man · Post by **TR4man** » Wed 21 May, 2014 10:53

Very interesting.

I'm tempted to give it a try too.

I'll use super for the next month and see how she goes.

frog farmer · Post by **frog farmer** » Wed 21 May, 2014 11:25

As an aside, my fuel dial stuck a few weeks back and after reading about the problem on here I changed to the better fuel and the problem cured itself..

Madmonkeyfish · Post by **Madmonkeyfish** » Wed 21 May, 2014 13:38

I use V power or tesco 99RON in both my M44 and my FJR bike. Better performance definitely and on the bike, over 10% better fuel economy. It also seems to run much smoother in both cases. Proven benefits for no overall extra cost. I never bother with 97 RON stuff as the benefits are not so pronounced and the return on my investment is therefore lower

Cheers

PJ

Rafolian · Post by **Rafolian** » Wed 28 May, 2014 09:59

Let the tank run right down and thought I would try Shell V-power. Put 50 euros worth in on Saturday and apart from costing €1.58 per litre as opposed to €1.40 per litre for normal unleaded I have yet to determine any difference.
So will be going back to 2 star!

gIzzE · Post by **gIzzE** » Wed 28 May, 2014 10:27

Rafolian wrote:Let the tank run right down and thought I would try Shell V-power. Put 50 euros worth in on Saturday and apart from costing €1.58 per litre as opposed to €1.40 per litre for normal unleaded I have yet to determine any difference.
So will be going back to 2 star!

I doubt 50 litres will make a difference, it normally takes around 2 tanksful for the ECU to get back to proper timing.
Plus I bet you still have 5 litres of 95 in there.

It is not instant going back, but if you put 95 back in it will drop down straight away.

Rafolian · Post by **Rafolian** » Wed 28 May, 2014 10:45

Will give it another tankful then to give it a chance and see if I notice any difference!

gIzzE · Post by **gIzzE** » Wed 28 May, 2014 10:50

That does seem like a big price hike, going from 1,40 to 1,58.
I think it is about 6p over here, so a complete no brainer.

akirk · Post by **akirk** » Wed 28 May, 2014 15:21

Turned up at my local Shell to fill up and they have a promotion with Super Unleaded at the same price as Standard - hurrah! long may it last...

Alasdair

gIzzE · Post by **gIzzE** » Wed 28 May, 2014 15:27

akirk wrote:Turned up at my local Shell to fill up and they have a promotion with Super Unleaded at the same price as Standard - hurrah! long may it last...

Alasdair

Normally around 250 miles for me.

akirk · Post by **akirk** » Wed 28 May, 2014 16:52

gIzzE wrote:
akirk wrote:Turned up at my local Shell to fill up and they have a promotion with Super Unleaded at the same price as Standard - hurrah! long may it last...

Alasdair

Normally around 250 miles for me.

That would be nice - not likely unfortunately, too many short trips meaning MPG is lower...

Alasdair

gIzzE · Post by **gIzzE** » Wed 28 May, 2014 17:34

I got 341 miles out of my last tank, I was just sat in 5th most of the time going back and forth to the coast, which is a steady 95 miles there and back. But had to do the run 3 times and the other 50 odd miles was pottering about too.

35mpg. Beats the usual 28, I was seriously impressed.

sirius-c · Post by **sirius-c** » Wed 28 May, 2014 17:47

I recently fitted an OBC, for the first 50 miles driving after installing and resetting it, it was reporting 46.6mpg....if only!
Its now settled at 33.3 which I consider pretty good as I have a very heavy right foot. Obviously I'll have to compare that to my own calculations then I'll probably have to adjust the KVBR ratio on the OBC to bring it together.
I have always filled up with v-power and the Max mpg I have obtained on my 2.8 auto is 28, the lowest is 17mpg.
Probably not a true reflection of actual mpg as I'm always disconnecting the battery and working on it.

Rig sparky · Post by **Rig sparky** » Thu 29 May, 2014 20:13

ok guys some background then results
My only car at present is a 1998 1.9 that has always run smoothly and pulled superbly above 1000rpm but ticked over like the usual bag of spanners at around 750rpm
since Feb this year it has had two oil changes with mobile 0 30 fully synthetic oil and genuine Bmw filters , Maf changed out , new Bosch top end spark plugs fitted new plug leads new hoses etc etc to try and fix the rough idle to no avail

Now my two previous BMW's a 520ise and a 523 and the current z3 have all been run on bog standard super market unleaded for as long as I can remember
the weeks im not offshore playing around with the electrics on drilling rigs . I commute from inverness down to the office and back in Aberdeen two or three days per week, a round trip of 196 miles obviously a regular route for me and the z
so same driver, same route, same car !!!!!!!!!! all fast A road driving anything from thirty mph if stuck behind a lorry to seventy -eighty mph on the dual sections.
I am in the habit of brimming my petrol tank the evening before my morning commute ( 5am start doesn't fit a morning fill up) then brimming the tank again at the same station in Inverness upon my return ready for the next run down to Aberdeen
at recent prices 95 unleaded has cost me between £31.50 and £32.00 per return trip or just under half a tank in the Z paying £127.50 per litre
but after reading this post earlier this week if decided to fill up with Tesco's super unleaded for the first time at £133.50 ( six pence a litre more)
after the first hundred miles down to Aberdeen I noticed a distinct increase in power for overtaking and an improvement in the idle for the first time ever !!!!!!!!!!
first return run cost me 30.00 so a saving of 1.50 over normal unleaded and the second run today only cost me £29.00 to brim the tank just now
and the idle has settled down to a nice steady tick over at around 800 rpm for the first time ever
what have I been missing all these years
think the above speaks for itself
I shall be keeping a eye on the mpg over the next couple of weeks to see if it stays like this
but my advice would be put some quality stuff in the tank !!!!!!!!!!!!!!!!!!! can the timing have been that retarded running on normal unleaded ???????????????????????????????????????????????????????????????????????????????????????????????

gIzzE · Post by **gIzzE** » Thu 29 May, 2014 21:41

It can make a huge difference, this is worth a read, it is about adjusting the timing to get the most from the fuel you are using.
It helps explain how much the timing needs to adjust between a 95 and 100 ron fuel.
The only difference on our cars, and most modern cars, is we have an ecu that monitors the fuel and adjusts the timing for you.

http://classicmechanic.blogspot.co.uk/2 ... fuels.html

gIzzE · Post by **gIzzE** » Thu 29 May, 2014 21:42

The last line of that says a lot....

If you are running super unleaded and wish to change to standard, the timing MUST be retarded to avoid damaging pinking.

Rig sparky · Post by **Rig sparky** » Thu 29 May, 2014 21:45

yeah just read it

ARoosterinaRoadster · Post by **ARoosterinaRoadster** » Thu 29 May, 2014 23:05

Hi to you all out there. I am a newcomer to this forum having only found it by recommendation from another forum and a request for help/advice that had been on for more than 3weeks with nothing coming back other than the heads-up for this forum.
I asked the same question just recently on yet another forum and before finding this dedicated Z Roadster forum.
I started with my 63,000 miles 2000(W) Z3 2.0 Auto on the basis of regular unleaded as suggested by the sales guy that I bought it from and currently I am averaging 27mpg (physically work out using calculation of 4.5461litres per gallon). I have covered 620+miles since picking it up on the 8th May. I am not a boy racer and at nearly 69yrs young I respect the car for what it is (along-time desire) and the fact that I am retired and skint with a modest pension over and above my state pension.
Now that I have a better understanding of the DME works I will fill up with the Shell V power product tomorrow and check it out again after another 600 miles are covered. I will post my finding as and when.

johnz3 · Post by **johnz3** » Fri 30 May, 2014 05:49

Hi and welcome. Look forward to seeing the results.

sirius-c · Post by **sirius-c** » Fri 30 May, 2014 09:02

Greetings and salutations....I too look forward to seeing your results

Sent from my HTC One mini using Tapatalk

DC · Post by DC » Fri 30 May, 2014 13:16

Rig sparky wrote:ok guys some background then results
My only car at present is a 1998 1.9 that has always run smoothly and pulled superbly above 1000rpm but ticked over like the usual bag of spanners at around 750rpm
since Feb this year it has had two oil changes with mobile 0 30 fully synthetic oil and genuine Bmw filters , Maf changed out , new Bosch top end spark plugs fitted new plug leads new hoses etc etc to try and fix the rough idle to no avail

Now my two previous BMW's a 5201se and a 523 and the current z3 have all been run on bog standard super market unleaded for as long as I can remember
the weeks im not offshore playing around with the electrics on drilling rigs . I commute from inverness down to the office and back in Aberdeen two or three days per week, a round trip of 196 miles obviously a regular route for me and the z
so same driver, same route, same car !!!!!!!!!! all fast A road driving anything from thirty mph if stuck behind a lorry to seventy -eighty mph on the dual sections.
I am in the habit of brimming my petrol tank the evening before my morning commute ( 5am start doesn't fit a morning fill up) then brimming the tank again at the same station in Inverness upon my return ready for the next run down to Aberdeen
at recent prices 95 unleaded has cost me between £31.50 and £32.00 per return trip or just under half a tank in the Z paying £127.50 per litre
but after reading this post earlier this week if decided to fill up with Tesco's super unleaded for the first time at £133.50 ( six pence a litre more)
after the first hundred miles down to Aberdeen I noticed a distinct increase in power for overtaking and an improvement in the idle for the first time ever !!!!!!!!!!
first return run cost me 30.00 so a saving of 1.50 over normal unleaded and the second run today only cost me £29.00 to brim the tank just now
and the idle has settled down to a nice steady tix over at around 800 rpm for the first time ever
what have I been missing all these years
think the above speaks for itself
I shall be keeping a eye on the mpg over the next couple of weeks to see if it stays like this
but my advice would be put some quality stuff in the tank !!!!!!!!!!!!!!!!!!! can the timing have been that retarded running on normal unleaded ???????????????????????????????????????????????????????????????????????????????????????????????

I've reached exactly the same conclusion, well worth using the good stuff for better performance and ultimately economy.
Mines an automatic and the difference is very apparent, even the passenger would notice as the gear changes are also better.
Good to have your experience backing up my own, I often fill up at Tesco Inverness and find the super unleaded is fine.
Dave.

ARoosterinaRoadster · Post by **ARoosterinaRoadster** » Fri 30 May, 2014 17:03

Hi to you all again. Having gone back into this topic I am beginning to think that a great many have been seriously missing out by using the regular grade unleaded fuel. I have not yet filled up but it will happen Saturday or Sunday regardless.
I carry out and record an interim fuel check each time I fuel up and that could simply be a half tank to brimming and then I will carry out a check after the mileage and total fuel bought reaches a worthwhile figure.
I will post on my findings in about 2 or 3weeks.

Rocketbike · Post by **Rocketbike** » Fri 30 May, 2014 18:20

I've not used supermarket fuel for years, but recently started using V power and other higher octane fuels, and with my 98, 1.9 I'm getting more power/better response, better economy (which I've checked), and like another post, I think the exhaust note sounds better too! I'm spending the same on fuel, as in the extra dstance balances out the additional cost pretty well exactly, so no saving, but better running

Rafolian · Post by **Rafolian** » Sat 31 May, 2014 09:43

As I stated earlier in this post, I put 40 euros of V-power in my 1998 64k mile 2.8 earlier in the week and couldn't detect any difference in performance. Well I still can't, but I noticed that the fuel gauge seemed to be dropping slightly slower than usual so I checked the mpg on the obc. Virtually all of my driving is light traffic and booting it on along the great twisty roads where I live, with no motorway driving so the mpg isn't great, normally reading about 24-25 mpg.
Now it's showing over 28 mpg which has really surprised me, so despite being about 18 cents a litre dearer than normal unleaded I am going to continue using it!

Rafolian · Post by **Rafolian** » Sat 31 May, 2014 09:45

Should read 50 euros, oops!

DC · Post by DC » Sat 31 May, 2014 10:25

I wonder if super unleaded has more effect or perhaps is more noticeable on smaller engines?
Dave.

Mike Fishwick · Post by **Mike Fishwick** » Sat 31 May, 2014 12:30

As it states in the Owner's Handbook (which of course no-one ever reads!) the 1.9 engine will produce its rated output on 95 octane, but will produce a higher output with lower fuel consumption on 98 octane. This means that the engine will run better on higher-octane fuels.

The larger engines are designed to run on 98 octane, but will tolerate 95 octane, while producing a lower output and using more fuel.

You get what you pay for.

Del · Post by **Del** » Sat 31 May, 2014 13:08

Based on my own experiences and numerous conversations with BMW technicians, the 1.9 not only responds well to higher octane petrol but also to occasional periods of "blowing away the cobwebs" with longer motorway type runs. These engines do not seem to like prolonged periods of short runs during which the engine and its oil does not get up to proper temperature long enough to clean up the engine internally i.e. around the hydraulic valve lifters etc.

I notice Rig sparky above also did some longer runs in the car which would have been a contributory factor to regaining a bit of smoothness and performance.

This phenomenon is also experienced with the modern "direct injection" BMW engines - cars with a prolonged history of short runs often needing major "decarbonising work".