[Dave Elliott]

Hi All,

I know there are heaps of threads relating to fuel, but mainly it's with regards economy.

I just thought I'd share some recent experiences I've had with regards two fuels available here in Perth, Australia.

Since buying my 2002 MCS just over a year ago, I've always filled up with BP Ultimate (98 octane). I get roughly 550km from a tank of this fuel. Point to note is that since buying it, I have had the "cold start" problem (where it only starts after the second turn of the key) and it also sometimes exhibits a slight "yoyo" effect or surging.

Occasionally my wife drives the car and on a couple of occasions she has filled up with Shell Premium (95 octane). When I get back into the MINI after the fill with Shell Premium it seemed different; more responsive and also easier to start. The first time this happened I thought I was imagining it; however after the second time I think there is a definite difference.

In other words, I think my MCS runs better on Shell Premium than BP Ultimate. As I said, it's easier to start ("Cold start" issue almost non existent), it' seems to have got more low end torque, probably a result of it not surging (yo-yo-ing) as much. Only downside is that I don't get as much out of a tank (only just over 500kms).

I know that the manual recommends 95 octane fuels, however I would expect that the ECU should be able to adjust the engine management so that the supercharger can run at a higher boost. Perhaps this is not the case and I've been wasting my money. What is probably worse is the additives in the Ultimate seem to be giving the MINI the "cold start" and "yoyo" symptoms.

I think I'll stick to Shell Premium for a while.

Can anyone else relate to my experiences? What do others run their early MCSs on (note that mine is still bog standard).


Cheers,

Dave

[Mike Clarke]

Hi Dave,

I usually use Premium, on odd occaisions i've used Ultimate and really haven't noticed any difference. Tend to get 500km from a tank of Premium around the city.

[Razorlite]

It's a bit pointless using SUL or higher for a STD MCS considering the car isn't mapped for that sort of thing. If the car was tuned (mapped) to within a few clicks of det then you would definitely need SUL (or better) to avoid 'knock'/detonation but you are better sticking to fuels that have a higher calorific value as opposed to octane levels (they dont necessarily always go hand in hand).

MB

[dlpruk]

Quote: Originally Posted by Razorlite (original)

It's a bit pointless using SUL or higher for a STD MCS considering the car isn't mapped for that sort of thing. If the car was tuned (mapped) to within a few clicks of det then you would definitely need SUL (or better) to avoid 'knock'/detonation but you are better sticking to fuels that have a higher calorific value as opposed to octane levels (they dont necessarily always go hand in hand).

MB

Are you sure? Most modern cars adjust automatically to whatever quality of fuel they're being fed. Thus I'd always use Shell V-Power in an S, if I had one (!), and expect the same performance benefits that my Jaguar gave before I moved up a class.

(Dunno what the equivalent might be in Aussieland!)

[Razorlite]

Quote: Originally Posted by dlpruk (original)

Are you sure? Most modern cars adjust automatically to whatever quality of fuel they're being fed. Thus I'd always use Shell V-Power in an S, if I had one (!), and expect the same performance benefits that my Jaguar gave before I moved up a class.

(Dunno what the equivalent might be in Aussieland!)

To be fair I dont know of any normal/warm performance car that advances the ignition timing due to detected octane levels unless its been mapped to do so. I could be wrong of course but I'd be surprised if BMW would do so due to warranty constraints - for example, ECU detects SUL: ECU advances ignition and then a batch of dodgy fuel hits the engine and you have detonation. However, I'm new to mini's (fancied a small total fun car for the weekend) but having owned several performance cars that were heavily modified - dynamic advance/retard of ignition timing depending on octane levels has normally been the domain of high end ECU's such as Pectel, Autronics and Motec etc etc.

Tell you what, I can ask one of the franchised dealerships as we've done a lot of business with them and will try and get a straight answer (without marketing bull ) from one of the friendly mechs this weekend.

Unless someone on the forum has the ECU map for the BMW Mini?

edited to add:

Oh forgot to mention, most cars are equipped with a 'knock'* sensor so they will retard ignition if knock is detected. Some ECU's actually put it into 'limp' mode.

* Knock = detonation

[MINI-Morgan]

I think you will find that the MINI is always bound by same set of rules no matter what fuel you put in. It will not advance more than 50degrees and will retard at the slightest knock/ping. The only benefit of using higher octane fuels on a standard car is usually that you get a more complete and stable burn and in most cases more engine cleaner lol.

Personally I dont use BP Ultimate as i have heard that in tests it goes off so to speak really fast. Great when you have a full tank but in a couple of days its rubbish! I'll stick to my Tesco 99....

[dlpruk]

Quote: Originally Posted by MINI-Morgan (original)

I think you will find that the MINI is always bound by same set of rules no matter what fuel you put in. It will not advance more than 50degrees and will retard at the slightest knock/ping. The only benefit of using higher octane fuels on a standard car is usually that you get a more complete and stable burn and in most cases more engine cleaner lol.

Personally I dont use BP Ultimate as i have heard that in tests it goes off so to speak really fast. Great when you have a full tank but in a couple of days its rubbish! I'll stick to my Tesco 99....

So it's not pointless to run an S on good stuff?

I've never used Ultimate petrol as V-Power has a higher spec and I avoid all supermarket fuels on principle. But Ultimate Diesel seems good stuff and with better Cetane numbers than V-Power Diesel I'll stick with that!

[Razorlite]

A lot of the 'premium' branded fuels such as v-power include a superior blend of additives offering increased engine protection. There used to be some talk of supermarkets using near raw fuel = very bad for consumer car engines but I don't think thats been proven or disproven to be honest. As for me I just use shell vpower for the norm but for the mini I may just stick to std shell - as long as I'm getting the additive (no pun intended) protection thats good enough for me.

[steve11]

I have always used Shell Vpower & will continue to do so.
It's makes sense that a 98 octane fuel will burn better than a 95 octane thus the car will not pre ignite as readily in extreme conditions resulting in the ECU retarding the ignition.
My MCS is fairly well modified so to me it's a no brainer.

[Dave Elliott]

Quote: Originally Posted by Razorlite (original)

It's a bit pointless using SUL or higher for a STD MCS considering the car isn't mapped for that sort of thing. If the car was tuned (mapped) to within a few clicks of det then you would definitely need SUL (or better) to avoid 'knock'/detonation but you are better sticking to fuels that have a higher calorific value as opposed to octane levels (they dont necessarily always go hand in hand).

MB

I reckon this is a good point, and seems to match what I've experienced on my own MCS.

Now I'm thinking it might be a good idea to get the re-map after all.


Cheers,

Dave

[Silent1]

Sorry to bump this thread, but there's a lot of misinformation in here.

Inside the filler cap it states the car MUST be run on 98 RON or greater;

Standard unleaded does not meet this as it is 95 RON
Super unleaded is what the car is designed to run on, it's mapped for this, running it on anything lower will potentially cause long term damage to the engine, at the least you'll see worse fuel economy and poor engine performance.

If you ask anyone involved in fuel production or car tuning they'll tell you V-Power is light years ahead of the next best super unleaded (BP Ultimate)

Tesco 99 has a higher octane due to the high amount of bio-ethanol in the fuel.
Bio-ethanol has a similar effect to cars not designed to run on it as putting unleaded in a 4-Star car

[MINI-Morgan]

Well I hope thats your opinion only as there are no facts that I can see to be correct.

by the way the MINI was mapped for even poorer grade fuel than 95RON so dont believe everything you read! Was your MINI second hand and someones put a sticker on?

Superunleaded in 2002 was also pretty much 97RON except for Optimax. I'm even suprised JCW recommended 98RON.

[r1_kde]

just checked my car and it says run on 95ron or higer, its a 2004 pre facelift model, though my JCW certificate says to use 98ron or above. I would check your cap agian, I have looked in at the 2007 model too and that says 95ron, would be different if you have a JCW factory build

[Dave Elliott]

Quote: Originally Posted by Silent1 (original)

Inside the filler cap it states the car MUST be run on 98 RON or greater;

My 2002 MCS which was bought in Australia has a label on the filler cap stating that the petrol can range from ROZ/RON 91 to 98.

Perhaps MINIs are set up (different maps) for different regions, because according to my filler cap MINI says 91RON is OK.

As I mentioned beefore, I have found my MCS runs smoother and is more responsive when I use 95RON. When I use 98RON it develops a hesitation about 3000rpm

[Razorlite]

Quote: Originally Posted by Silent1 (original)

Sorry to bump this thread, but there's a lot of misinformation in here.

Inside the filler cap it states the car MUST be run on 98 RON or greater;

Standard unleaded does not meet this as it is 95 RON
Super unleaded is what the car is designed to run on, it's mapped for this, running it on anything lower will potentially cause long term damage to the engine, at the least you'll see worse fuel economy and poor engine performance.

If you ask anyone involved in fuel production or car tuning they'll tell you V-Power is light years ahead of the next best super unleaded (BP Ultimate)

Tesco 99 has a higher octane due to the high amount of bio-ethanol in the fuel.
Bio-ethanol has a similar effect to cars not designed to run on it as putting unleaded in a 4-Star car

Sorry to bump this thread again but the cap on my car quite clearly states 95 Ron or higher. Seriously, you are wasting money if you are looking to gain performance by using a higher SUL petrol - however the additive blend in higher SUL fuels can enhance the protection of the engine (apparently). With regards to misinformation maybe you can state what misinfo is being stated - cars will only make use of higher octane levels if the car has been mapped to do so. Period.

[Fen]

Yes cars will vary their base fuel requirement depending where they are sold. Here in NZ and (I guess Aussie also) the "ordinary" fuel is 91RON and "Premium" is 95. In the UK the basic fuel is 95RON and premium is 97, 98 or 99 RON. My Mini is a UK car but I imagine the locally supplied ones demand lower fuel rating. Is there anything actually different in their engine or ECU map - probably not is my guess.

I'm afraid I have to disagree with you, Razorlite. Even if the car is mapped to use 95RON (minimum) if you get a bad batch of 95RON, or even if you run high boost for a long time or thrash the car in warm weather so it gets very hot under the bonnet (specifically round the exhaust ports) you might find that the knock sensors retard ignition because they pick up detonation whereas with better fuel there would be no det, hence more aggressive ignition timing. Now round town and taking it easy I agree you might not see an improvement, but what performance modification do you see improving that sort of situation?

Then again what's so say it isn't set up such that it will always run on the knock sensors using 95RON? Knock detection is good enough these days that it can be used to save the engine and what the minimum fuel requirement may in fact mean is "don't put any worse fuel in the tank than the figure as the car will not be able to retard ignition far enough to prevent damage". Think about it; why have a minimum at all if the car can cope with anything you put in it? The point of the range is that the engine is set up to get the benefit of the upper quality stated and can run safely on the lower end. Anything higher than the upper end is wasted and lower than the lower end is dangerous is how I understand it.

Many years ago I had an Impreza RB5 which had a standard ECU and was a UK model, hence not a Jap spec built for 100RON. In that thing if you put 95 in it you could feel it reign in the power the first time you floored it compared to Optimax as it was back then. That power only came back gradually over time after putting good fuel back in it.

Many cars run better on quality fuel, I agree not necessarily because they will advance timing until they "see" knock, but because if they detect knock they retard timing back from their optimum setting and usually they take some time to advance again. They do that precisely to avoid damage - it doesn't take much detonation to damage or even destroy an engine so you need to stop it instantly when it happens, but there is no risk in taking a while to gradually put back the advance. Some cars need over a tank of decent fuel to make a noticeable difference and if you run 95RON the chances are you might well see better performance only if you switch to V-Power etc. and stick with it for some time. Cars have been able to do that for years, in fact I have one which was designed in the ealy 80's that used to dynamically retard timing. Ironically it now runs an Autronic ECU which does not even measure knock, far less dynamically adjust ignition as suggested above!

Lastly even if you don't get better performance out of 98 or 99RON fuel in a standard MCS you probably do get better mpg - assuming you don't drive flat out everywhere - as the fuel burns more smoothly and gives consequent smoother power delivery. I was literally astounded by the difference improving the ignition system made on the car I mention above, and that difference was everywhere - idle, throttle response, top end, even mpg. Better ignition only changed the spark, nothing else, and that spark made all the difference by improving the burn, and better fuel has a better burn.

To answer the OP and reference this back to the MCS mine is not standard, but neither is it remapped. In NZ it goes significantly better on Mobil Synergy 8000 than BP Ultimate. Nothing else higher than 95RON is available here so that's all I've tried. BP Ultimate has never had a good review as I recall and I consequently never used it in the UK - it's probably the same story down here.

[Silent1]

Quote: Originally Posted by Razorlite (original)

Sorry to bump this thread again but the cap on my car quite clearly states 95 Ron or higher. Seriously, you are wasting money if you are looking to gain performance by using a higher SUL petrol - however the additive blend in higher SUL fuels can enhance the protection of the engine (apparently). With regards to misinformation maybe you can state what misinfo is being stated - cars will only make use of higher octane levels if the car has been mapped to do so. Period.

Don't be silly, all modern cars have adaptive mapping, anything run on SUL all the time will use the petrols higher resistance to detonation to increase the performance.