[grodenglaive]

Quote: Originally Posted by Japper (original)

Our std. Unleaded is 95 ron and costs £1.02 per litre ( £4.63 per gallon )

Super unleaded runs from 97-99 ron and costs £1.08 per litre ( £4.90 per gallon )

OR 3 times what you lucky guys pay in the US.

OUCH

[spiney]

I don't know about you but as I see it there's a conspiracy going in in the petrol companies over here in the US (I'm a Brit so it's called petrol, not gas...).

The MINI (and my previous Audi A4) all recommend 91 octane, but I can't buy it anywhere! You get 87, 89, then they skip 91 and go right to 93 for a premium. I keep thinking about doing half a tank of 89 and half a tank of 93, but in the end I just can't be bothered with two credit card swipes, and just get stiffed for the 93.

[TheBigNewt]

We get 91 octane in AZ, but not 93. It varies by state. In NM and CO they can get 86, we can't.

[mason storm]

after two weeks of driving with Tesco 99 I haven't noticed any obvious increase in performance, the exhaust just sounds a bit louder.

I think I'll switch back to 95 premium to see if I notice any loss in performance

[*Jason*]

Mason, you won't notice any appreciable gains in power although you may see a slight decrease in fuel consumption. Unfortunately, unless the ECU has been specifically re-mapped for super unleaded and differences are due to the placebo effect.

[Boro Boy]

My thoughts exactly, Jason. Has anyone had their ECU mapped specifically for super unleaded I wonder? Would it be something MINI would endorse and so not affect the warranty?

[*Jason*]

Boro Boy, its unlikely that MINI would notice provided the re-map wasn't too aggressive although if they found out it would invalidate your warranty, which is why they only endorse the JCW re-maps.

I went down this route with my Impreza even having it serviced at a main dealer for the first year after having a re-map producing 260bhp - engineer on test drive didn't notice.

Was a different matter when it eventually produced 333bhp in that it was specifically re-mapped for Optimax as it would run like a dog who's swallowed a wasp - rough or what.

[mason storm]

Quote: Originally Posted by *Jason* (original)

Mason, you won't notice any appreciable gains in power although you may see a slight decrease in fuel consumption. Unfortunately, unless the ECU has been specifically re-mapped for super unleaded and differences are due to the placebo effect.

That's what I was thinking but some on here seem to think they are getting more power from 99 fuel. Is the VW Golf GTI mapped for super unleaded as Evo got a significant increase when comparing super vs premium? if so then their test was a bit of a farce as the car should be running on 99 anyway.

[adam_Randell]

I used 'Super Unleaded' the other day, and was very dissapionted. It lasted me 40 miles LESS than regular unleadded and cost 10p per litre more!

[Tunster]

Quote: Originally Posted by adam_Randell (original)

I used 'Super Unleaded' the other day, and was very dissapionted. It lasted me 40 miles LESS than regular unleadded and cost 10p per litre more!

You may of not noticed any performance increase but the higher RON fuel is better for the engine with better stuff inside it from what I've heard that will clean out the muck inside and make it breathe easier.

I know my current car (to be replaced when the MCS arives in Mid-April ) an MG ZR doesn't know how to deal with higher RON fuel because of a lack of a knock sensor. However, I do top it up with the super unleaded stuff every 4/5 top-ups to give the engine a good clean out of the muck and it does seem smoother afterwards.

[adam_Randell]

Im not really too fussed about better performance, im only 18 and the 120bhp it produces on normal fuel is enough for me (at the moment). Im more on about the MPG. BP say it should last 30 miles MORE than regular but i used it and it lasted 40 miles LESS than regular

[Fizzoid]

Quote: Originally Posted by Tunster (original)

You may of not noticed any performance increase but the higher RON fuel is better for the engine with better stuff inside it from what I've heard that will clean out the muck inside and make it breathe easier.

It's not just the higher octane stuff that has cleaning agents in though

[*Jason*]

True. Most modern fuels contain detergents that have a cleansing effect on the engine although I'd steer well clear of supermarket fuels.

[Tunster]

Quote: Originally Posted by *Jason* (original)

True. Most modern fuels contain detergents that have a cleansing effect on the engine although I'd steer well clear of supermarket fuels.

Very true. Although, my boss' best mate works for a fuel storage depot near the QE2. He says that all the petrol stations in the area get the same fuel. Even from the supermarkets to Shell/BP etc.

However, I still only use the main petrol stations rather than supermarket ones....

[caesar]

5th Gear did an article on this last year and using 99 octane fuel was a definite advantage for high performance engines. A surprising fact was that 99 octane fuel deteriorated the longer it was stored in the garage fuel tanks. They reckoned that buying petrol from stations with a high turnover i.e. supermarkets meant that the fuel would be fresher.

[Mark84]

Well im on my third tank of v-power and as expected the engine is alot pepier and the flat spots at lower revs have cleared up mostly!! Not saying that there is any HP increase but i would say that the torque has been increased a little as i say giving more power through the range!

Don't think that i'll be going back to standard ever and despite what anybody says i am definately getting more MPG!!

Just my opinions guys but all i can say try it for a few tankfuls and tell me i'm wrong! but get Shell v-power its definatley the best (again in my opinion!)

[*Jason*]

Quote: Originally Posted by Tunster (original)

Very true. Although, my boss' best mate works for a fuel storage depot near the QE2. He says that all the petrol stations in the area get the same fuel. Even from the supermarkets to Shell/BP etc.

However, I still only use the main petrol stations rather than supermarket ones....

And he's absolutely correct regarding the feedstock i.e. the basic fuel/petrol component, however its the various detergents and additives and ratios of toluene/ethane etc that differentiate a fuel such as V-Max from the muck you get at Tescos. These are mixed in when the road tanker is loaded.

Although, turnover obviously has an effect I still wouldn't touch supermarket fuels particularly when you consider the problems they encountered last year in the London area

[*Jason*]

Quote: Originally Posted by Mark84 (original)

Well im on my third tank of v-power and as expected the engine is alot pepier and the flat spots at lower revs have cleared up mostly!! Not saying that there is any HP increase but i would say that the torque has been increased a little as i say giving more power through the range!

Don't think that i'll be going back to standard ever and despite what anybody says i am definately getting more MPG!!

Just my opinions guys but all i can say try it for a few tankfuls and tell me i'm wrong! but get Shell v-power its definatley the best (again in my opinion!)

Mark, this is the placebo effect which their marketing departments rely on - free power increase when you use our fuel. You may find a slight increase in MPG but as I've said, the reality is that your engine won't really notice the difference. Might do on a more performance orientated engine but not on a standard MCS.

[caesar]

Prior to owning my July 07 MCS I had a Civic Type-R . During the the 3-years I owned it I kept a record of the grade of petrol and the MPG.

Using Shell V Power or Tesco 99 the engine ran smoother, more responsive to throttle and gave a better mpg than standard unleaded. The cost per mile was less despite the extra cost.

As a result been running the MCS on Tesco 99 from new, therefore can comment on how it would run on standard unleaded. It's now done 4.7K miles and has averaged 35.0 mpg compared to approx 24.0 mpg with the Type-R

[Razorlite]

Difference in RON makes absolutely no difference to the performance of the Mini Cooper S - also makes no difference to the 'cleanliness' of the fuel as that factor is completely down to the quality of the additives in the petrol.

BMW would never endorse a policy of dynamically mapping the car a few degrees/clicks closer to det just to gain a few BHP because of a higher RON level otherwise you risk of knock/pinking if a bad bit of fuel hit the engine.

Fact is, a car is either specifically mapped for higher RON values or is it isnt unless you are lucky to own a high end ECU such as pectel/motec etc that can be configured to dynamically change click values based on detected RON (RON is also only half the story).