fuel

[robgt3]

I'm quite sure that this question has been raised already but here goes. Is there any advantage to fuelling a 991 GT3 with higher or premium octane fuel? Now that the price has come down a bit I feel that I can go the extra few quid.

[sidicks]

robgt3 said:

I'm quite sure that this question has been raised already but here goes. Is there any advantage to fuelling a 991 GT3 with higher or premium octane fuel? Now that the price has come down a bit I feel that I can go the extra few quid.

I'd question why you would fill the car with anything other than Super unleaded, given that is what is recommended by the manufacturer...

Do you mean special fuels i.e. 100 RON or do you simply mean Shell V-power, BT-Ultimate etc as opposed to normal 95 Octane?

Personally, I'd only ever use anything other than Shell V-power as a last resort - e.g. when in the Hebrides with no other options...!

[jakesmith]

Waste of money unless you have a turbo where it does give more powe.
If you knew how crap 91/93 RON fuel is that these cars are designed to run on around the world, 95 is already a treat.

[Trev450]

As already stated, Porsche recommends a minimum of 98ron - why use lower? And before the naysayers chip in, it does make a difference to performance as if a lower octane is used the anti-knock sensors will retard the ignition to prevent damage.

[jakesmith]

how can they recomend 98 when that's unavailable in half their markets?

[Magic919]

They recommend it as that's what the car works best on.

[sidicks]

jakesmith said:

Waste of money unless you have a turbo where it does give more powe.
If you knew how crap 91/93 RON fuel is that these cars are designed to run on around the world, 95 is already a treat.

Wrong!

[PTT]

jakesmith said:

Waste of money unless you have a turbo where it does give more powe.
If you knew how crap 91/93 RON fuel is that these cars are designed to run on around the world, 95 is already a treat.

Can you explain why it has a benefit for turbo engines.
I can acquire RON 102 at a normal gasstation.(Holland)
Thanks

[Trev450]

jakesmith said:

how can they recomend 98 when that's unavailable in half their markets?

I'm sure its available in Hereford which is where the OP hails from.

[chrisABP]

Always run Shell V-Power in my 997.2 GTS as did the previous owners.

Can't see the point on skimping on fuel for your pride and joy.

Besides it helped get these for the boys!

[sidicks]

<End of thread>

[GT3andy]

No question rob, always use the highest octane rating you can get admittedly only 98 Ron in the UK. A friend who has just retired from a large oil company, and knows, put me straight some time ago about the differences between the supermarket fuels which lack many of the additives found in the premium fuels. Then there are the Shell power fuels, and his opinion was they were in a higher league than even most of the other premium fuels due the protection they give to engine and fuel line components. As well as the slightly higher octane rating. He didn't work for Shell by the way. Albeit the octane rating is not always the ultimate arbiter of burn limits, it was explained.

Expensive car rob. Give it the best you can get hold of.

[Trev450]

GT3andy said:

always use the highest octane rating you can get admittedly only 98 Ron in the UK.

Actually, Tesco Momentum is 99.

[V8KSN]

Rob, shell v power all the way every time.

Grab yourself a shell drivers club card next time you fill up and you can accumulate points and then exchange them for shopping vouchers for Molly - everyone wins

[robgt3]

Thanks Guys. The best it is from now on then! Car has now done 900 miles and never ceases to amaze. Inadvertently took it to 8000 rpm in second, I can only liken the engines ability and desire to rev being akin to that of a motorcycle. Still treating it to lots of respect.

[Magic919]

Shell is 99 too.

[GT3andy]

Actually, Tesco Momentum is 99. 

Well how about that. I stand corrected. Didn't know as don't go to the filling station there. Still wouldn't use it in my car though.

[LukeS]

When I picked my car up from OPC Reading the salesman said every 4th fill up use shell otherwise it would be fine on supermarket petrol. Then again he has no vested interest in long term reliability!

Edited by LukeS on Tuesday 30th December 20:02

[sidicks]

LukeS said:

When I picked my car up from OPC Reading the salesman said every 4th fill up use shell otherwise it would be fine on supermarket petrol. Then again he has no vested interest in long term reliability!

95 RON will be 'fine' and won't give you any reliability problems. It will just mean your car doesn't perform as well as it could do and you aren't do my what Porsch recommend.

No point in spending that much on a GT3 and then trying to save a few pence on fuel, particularly when people often find they get improved mpg with Superunleaded.

Edited by sidicks on Tuesday 30th December 20:25

[Pat Cash]

jakesmith said:

If you knew how crap 91/93 RON fuel is that these cars are designed to run on around the world, 95 is already a treat.

Indeed - For example, somewhere close to a third of all Porsche cars built Worldwide in 2014 will end up in China, where 91/93 are the norm, you sometimes see 89. Anything above 97RON is unheard of and the quality of the pump fuel is dubious at best in almost all cities, due to the supply chain regularly tampering with the fuel before it gets to the pumps.

Whilst in itself this is not a critial issue as manufacturers do a significant amount of testing for this.
Cars will run no problem, but rough running and antiknock retardation is often a factor, as well as occasionally buildup of nasty deposits, such as manganese on exhaust valves sometimes experienced in higher temperature/compression engines.

A number of manufacturers, BMW for example, sometimes produce specific engine variants for such markets, usually with different mapping and lower compression ratios.

All interesting stuff but completely irrelevant to the OP, I know...