95 or 98 RON Fuel

[Wipeout]

Hi,

I was wondering if anybody had tried 98 RON instead on 95 on there Cooper S and had noticed any difference in performance or economy.

The manual says "You can also run the engine on : Super Plus 98 RON in order to increase engine output slightly."

Regards WipeOut

[jamski]

I was wondering this with my MC this afternoon. With all the petrol talk on the news it got us talking in the office. We've a MCS and a Cleo Sport who always fill up with 98 and I was questioning if it does make a difference?! Also if I go from 95 to 98 will it take a couple of fills to notice the difference as the petrol will be mixed slightly, so it would be more like 97!

[JAMIE1131]

Part of my job is designing engine management systems for a british manufacturer. I always fill up with 98RON (shell V-power) in my Cooper S. If you run 95 RON the ECU will retard the ignition and hence decrease max power output.
And yes, it will take a couple of tankfulls to notice the difference, we mix fuels at work to change the octane ratings!!

[Restyle]

Quote: Originally Posted by JAMIE1131 (original)

I always fill up with 98RON (shell V-power) in my Cooper S.

You may like to know that Shell V-Power is 99RON ... hope you dont lose your job

I use it all the time, as its the cheapest performance upgrade you can do to your car without affecting insuance, & reliability etc for around an extra £2- a tankfull. Ive noticed I get slightly more mpg as well.

[Cooper S Dan]

I use Tesco 99RON and have found the car to run smoother, and who knows if it's a bit more responsive, but for an extra couple of quid it's worth it for the extra cleaning additives you get with their 99RON as opposed to the 95RON!

[jamski]

Ok well you've convinced me! V power it is next time!

[Cooper S Dan]

Quote: Originally Posted by jamski (original)

Ok well you've convinced me! V power it is next time!

from what i've read on the net Tesco 99RON is even supposed to be better than Shell!

There's someone on the forum who has commented on previous similar posts on this and has a signature for Tesco's fuel!!

It's not as expensive neither!!

[jamski]

I said v power but it'll any 98/99RON tbh. I'm actually looking forward to having to fill up with petrol now!

[ScottyBoy]

Quote: Originally Posted by Cooper S Dan (original)

It's not as expensive neither!!

until it creeps up again by another 5p the goes down by 2p and then people will same the same thing that its not expensive then the same again!

anyway i always use tesco 99Ron fuel! Clubcard points 2 "Bonus"

[tiger333888]

BBC NEWS | UK | Inquiry into 'contaminated' fuel

guys, heads up on the tesco fuel story if you don't know by now!! - current news

[ScottyBoy]

Hmmm Glad im a northener! suppose tho they havent found any problems with the tests at the moment!

[wheyaye2]

I always run on V-Power, it was Optimax before that.

The car does run a lot smoother, with noticeable performance gains over 95RON.

[South Shore Lad]

I'm confused a bit!

The sticker on the fuel cap of my R56 Cooper (not an S) states to use 91 to 98.

Does this exclude all the fancy Optimax/V Power/Tesco 99 etc then?

SSL

[JAMIE1131]

Quote: Originally Posted by Restyle (original)

You may like to know that Shell V-Power is 99RON ... hope you dont lose your job

I use it all the time, as its the cheapest performance upgrade you can do to your car without affecting insuance, & reliability etc for around an extra £2- a tankfull. Ive noticed I get slightly more mpg as well.

Doh! I meant 99RON for filling up, thanks for correction! we mostly use 98 and 95 at work so its gets confusing keeping up! Tesco 99RON is achieved using ethanol which boost the octane rating. It also oxygenates the fuel meaning you need more of it as the stoichiometric air/fuel ratio drops from 14.7:1 . With the current news at the mo I would steer well clear of supermarket fuel!

[popey]

I filled up with Tesco 99 last night. First ever time is not had V-Power and it only saved me about £2.30 on a full tank!

Not effected my car, and as far as I know its unleaded thats effected not the "Super Unleaded" 99. Could anyone confirm this.