95 or 98 RON?

Z

Z4 COUPSTER

Active member
 Bridgend South Wales
Just a,quick one. Anyone notice a marked difference in the 3.0si with super, on performance and economy? Or do most do as I do which is give a boost of 98 every couple of tankfulls. Not done on the Coupe yet, hence is it worth the extra bucks.
D
 
Z4 COUPSTER said:
Just a,quick one. Anyone notice a marked difference in the 3.0si with super, on performance and economy? Or do most do as I do which is give a boost of 98 every couple of tankfulls. Not done on the Coupe yet, hence is it worth the extra bucks.
D
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You won’t see a noticeable improvement increase on a normally aspirated engine but it’s the engine cleaning detergent properties of super unleaded which are worth having-lots on here about this topic :thumbsup:
Rob
 
Thanks bud. Tbh I normally throw a tank full in once in a while. It never hurts that's for sure. I'll search nxt time.
 
It really depends on the engine management system, if it can tune the fueling and timing based on the lambda and anti-knock sensors then you will see a difference in performance and economy. The question is how intelligent are the BMW ECU's :D
 
EXTRA! EXTRA!... read all about it... https://z4-forum.com/forum/viewtopic.php?f=2&t=102010&hilit=octane
 
Shell V Power for me. There's a Shell garage on the way out of my village, so it's very convenient, and the extra cost is negligible when my annual mileage of <3000 is taken into consideration. So a no-brainer for me and my circumstances.

Plus when pedal goes to metal I like to think that I didn't leave any of the horses in the stable!
 
I always put Shell V Power or BP Ultimate in the Zed and the Cooper S. The Discovery makes do with normal diesel.

With 98 grade you get the pops in the exhaust on over run, but not with 95 grade. :)
 
RickRob said:
With 98 grade you get the pops in the exhaust on over run, but not with 95 grade
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Interesting observation...I've got 95 RON in at the moment so I will see if mine is same.
 
RickRob said:
With 98 grade you get the pops in the exhaust on over run, but not with 95 grade. :)
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I'm on my second tank since collecting my 2.5 and so far I have just used standard 95. I will probably put a tank of 98 through it once in a while. With the exhaust back-box mod on mine with boggo 95 it pops and crackles like a good-un anyway. Maybe with the 98 it'll go one step further and spit flames! :lol:
 
I don’t notice a difference in power but I do in economy.

The exhaust note is also louder with V Power.
 
I have run my 2.8 on both, and definitely get better MPG on 98 RON, cant say I notice any power difference,
 
RustyZ4 said:
I have run my 2.8 on both, and definitely get better MPG on 98 RON, cant say I notice any power difference,
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This is,what I was thinking. Noticed a lot on previous cars with economy and a little more punch.
 
It would be very hard to differentiate between noticing a power increase and the placebo effect. You’d need test conditions to know for sure. I would imagine it would give a very slight increase in performance though.

As said above the main reason people tend to go for the expensive stuff is because it has better cleaners - that’s why I only use v power (tesco’s Momentum is 2nd choice).

A tank every now and then won’t give you extra power as the car won’t ‘realise’ it’s sipping better fuel until the tank is half gone and it would have been diluted when you filled up anyway.

Better miles per gallon and being able to drive at slightly lower revs should cover the cost of the good stuff.
 
Silverzedtom said:
It would be very hard to differentiate between noticing a power increase and the placebo effect. You’d need test conditions to know for sure. I would imagine it would give a very slight increase in performance though.

As said above the main reason people tend to go for the expensive stuff is because it has better cleaners - that’s why I only use v power (tesco’s Momentum is 2nd choice).

A tank every now and then won’t give you extra power as the car won’t ‘realise’ it’s sipping better fuel until the tank is half gone and it would have been diluted when you filled up anyway.

Better miles per gallon and being able to drive at slightly lower revs should cover the cost of the good stuff.
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Surely driving at the same road speed would mean the revs were exactly the same no matter which fuel was used? :?
Rob
 
Smartbear said:
Surely driving at the same road speed would mean the revs were exactly the same no matter which fuel was used? :?
Rob
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Sorry, I should have said drive in a higher gear and utilise the lower range of the Rev counter.
 
Silverzedtom said:
Smartbear said:
Surely driving at the same road speed would mean the revs were exactly the same no matter which fuel was used? :?
Rob
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Sorry, I should have said drive in a higher gear and utilise the lower range of the Rev counter.
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Ah, I getcha! :thumbsup:
Rob
 
Costco 99 for me, for two reasons. There's one round the corner from work, therefore very convenient, and their 99 is cheaper than the "standard" fuel from places like Shell etc, and only a couple of pence more than a supermarket 95 octane.

Their own 95 is 4-5p cheaper than the 99 usually, but 4p over 50 litres isn't exactly worth scrimping in my mind. Whereas the local Shell charging 139.9p for V-Power can sod right off!
 
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