Petrol Question for 2004 Boxster

[HalesOwen]

Hi everyone,
We currently use local fuels for all of our petrol and diesel needs and our cars run really well on this fuel. The petrol is ethanol free (hence why we use it) and 95 RON. We could put in Shell petrol with a higher RON, BUT is the higher octane really worth it, especially as its mixed with ethanol? What do people think?

 

[dpoynton]

Alun

You really do not know what you've started by asking that question.
Relevant question; though it will have been covered many times before on here somewhere.

David

 

[HalesOwen]

Will search for related threads thanks

 

[richardjjs1]

V Power is awesome and so is the price
Morrisons is 1.13.9 at Shrewsbury Nearest V power 1.29.9 that's 16 p per litre. at its 25 miles away
So I try and do a fill about every 4th or 5th tank full Boxster 2.7 2007

If I was driving a higher spec Porsche I would only use V Power it has incredible engine cleaning properties

 

[Motorhead]

Alun,

As David says, this is a well-covered topic on these forums.

As you're aware, your car will run perfectly happily on 95 RON fuel - the engine's knock sensors will take care of that whether or not ethanol is included; and most fuels nowadays have a minimum of 5% ethanol. The inclusion of ethanol shouldn't be a problem with your 2004 Boxster; it's only the older air-cooled cars which can be affected adversely. You'll only get the benefit of a higher octane fuel if you use the performance of your car to the full as it will release a few extra horsepower.

By "local fuels" I presume you mean unbranded fuels and the fundamental difference between those and the major branded fuels such as Shell, BP, etc., will be the additives included, the potential benefits of which are advertised extensively. Whether or not you choose to believe the hype is a personal preference but I'm sure that they do provide some benefits over cheaper brands.

If you look carefully at the additional cost of using a high octane premium fuel when taking into account overall annual running costs (depreciation, servicing, tyres, general maintenance and vehicle tax) I'm sure that you'll find that's it's minimal, depending of course upon your annal mileage.

Jeff

 

[DrSimon]

A well covered topic indeed! I rather dangerously entered into a discussion on this on Pistonheads a while ago. I just about managed to escape unscathed but the upshot seemed to be the following:

1) Lower RON fuel won't harm your engine (as has been stated above, your sensors will adjust accordingly)
2) Higher price/RON fuel from the bigger brands MAY contain additives that MAY help keep your motor in finer fettle
3) Higher RON fuel won't increase your overall BHP but you MAY notice a slight increase in throttle response. I did some research on this and found a paper that provided some evidence to back up this statement. Unfortunately I don't have the reference but might be able to dig it out given time.

The way I look at it is these engines were designed to be run on higher RON fuel so I blindly follow their advice. I know many don't and have had no adverse affect whatsoever. If you go on the motoring forums you'll be inundated with horror stories from drivers about how supermarket fuel 'destroyed' their cars but with zero evidence to back this up - apart from "Geoff at my local garage told me". The choice is yours...

Simon

 

[911hillclimber]

Killer question to ask, and there will be a huge amount of responses, mostly all un proven, just gut reactions.
My 2 p here is little more than that too...

I have a humble 2.9 987.2, nothing fancy and I don't drive it like I've stolen it, I have a race car for that.
I seem to be surrounded by Shell stations, BUT this is not the case everywhere.
I got caught out in Wales once and filled with Total 95 RON. Car just drove like it did with the then 97 RON Shell V Power.
When 1/2 empty, filled with V Power so a mix of octanes, no perceptible difference, car ran great, but I was not thrashing it. (wife on board)

Always try to use Shell 97 RON, just think it is a the best fuel, maybe I'm a sucker for the adverts?
Last year in France in the car and filled many times with French motorway brand fuels, some 99 RON, no difference, just price.

A Porsche friend works in QA for Bentley. He said when those cars go performance testing over the world, the fuels they are forced to use can be near any RON and all is well.
The car have to tolerate the variations, why modern cars can self-adjust, and do, to what you pour in.

In general I believe Shell V Power is a very consistent fuel so I take the price hit knowing the best (in my opinion) is in the car.
I use it in my 1973 911 and it feels to make quite a difference to that cars 'feel' compared to Shell 95, and I use it in the Porsche air cooled race car too that is always thrashed as hard as possible!

I think just use good 'names' fuel, 95 ron minimum and enjoy the drive. If you are going racing? V Power every time.

All imho of course.