99 RON fuel

[Windymiller]

Hi All,

 

As a recently new owner I'm 'feeding' my car on a diet of 99 RON premium fuel. 

 

I note that that the owners manual recommends 98 RON, but states the car is also ok on 95 RON. 

 

My question is - will the higher (99) RON fuel have any detrimental effect - e.g., 'hotter' burn when combusted?

 

i have noticed in the past 1-2 weeks an ever so slight 'judder' at low revs from cold, which I didn't notice within the first 2-3 weeks of ownership (when it was actually colder in the mornings). It's not as pronounced as an obvious misfire, but there's definitely some sort of 'shimmy' in the engine. 

 

Its a gen 2 S. 

 

Thanks in in advance for any opinions / thoughts. 

 

Jason

[Windymiller]

Replying to my own post, having given this some further thought - might 99 RON produce a different detonation 'pattern' / flame front (or something similarly pseudo-scientific sounding), which might expand in the cylinder differently to 98/95, I.e, out of time?

 

Is what I'm experiencing just 'pinking'?

 

Perhaps I'll try a tank of 98/95 and see if there's a difference. (Now an excuse to drive off the remaining 3rd of a tank of 99!!! ????). 

[Porker]

1 hour ago, Windymiller said:

Replying to my own post, having given this some further thought - might 99 RON produce a different detonation 'pattern' / flame front (or something similarly pseudo-scientific sounding), which might expand in the cylinder differently to 98/95, I.e, out of time?

 

Is what I'm experiencing just 'pinking'?

 

Perhaps I'll try a tank of 98/95 and see if there's a difference. (Now an excuse to drive off the remaining 3rd of a tank of 99!!! ????). 

Your engine management will take care of it, it will not have a detrimental effect at all. 95 is fine but will loose some HP, doubt youlll notice on the road, may notice on track.

[Windymiller]

Thanks Porker, apologies for late response / acknowledgement of your reply. 

 

 

[Mk1]

Where do you buy the 99 fuel  ... Tesco ?

Perhaps you have had a bad batch ... 

 

Info ... https://www.pistonheads.com/gassing/topic.asp?t=302977

 

 

[Windymiller]

Hi Mk1,

 

yes i I have been buying the 99juice from Tesco in Aylesbury. 

 

I topped up with shell v power 'nitro' (also 99 RON) on Saturday and I do think the 'lumpiness' at low revs is diminished. Perhaps you're right, just a 'bad batch'...

[beeby11]

I always run my cars on Shell or Bp (if i can't get to a shell garage)

 

My current car is mapped on Nitro V and i certainly can tell the difference if it doesn't have it in.

 

As others have said, i would expect running on 95 you will lose some bhp and maybe responsiveness. My cars feel a bit lethargic on cheaper petrol

[Kai]

I would stay away from Tesco 99 if possible and just stick with Shell V power. 

 

I do do this for many reasons but mostly:

1) the car feels and goes better on Shell

2) I have been told by people in the racing world that Tesco is sh1t and they do not use the same system to rate their fuel meaning 99 ton fur Tesco might be nowhere near 99 for Shell etc. 

 

Stick to the good stuff, my friend ?

[beeby11]

if you do go shell, get one of their rewards cards, get some half decent offers come through the door like ££ off per litre of fuel

[Windymiller]

Thanks all for the various replies. 

 

Definitely this morning the 'lumpiness' at low revs was absent, and it was a cold morning (half a degree - in May!?), so I think the shell v power has worked its way through and has flushed out the Tesco 99, which must be of a 'lesser' quality. 

 

Although, Tesco gets its fuel from the same supplier as Esso (green energy). 

 

Its a shame, because Tescos is closer than nearest shell / BP and their 99 RON is quite a bit cheaper than the others' premium fuel. 

[Equinox]

Always drive out of my way every week to fill up on Shell V-Power. Means I get a longer, windy, country road drive back from work on a Friday too which is a bonus!!!

 

If I ever get caught out and have to use standard fuel, I only ever chuck the minimum in to get me to the next Shell or BP to fill back up on the good stuff

[MJ]

the cheap supermarket fuel doesn't contain all the good additives that you get with a premium fuel like VNitro, excellium etc.  I used to work alongside a petro chem team of specialists and they all said to stay clear of supermarket fuels because of its poor quality. How do you think they manage to sell it so cheaply? 

[11891952]

What this man ^ said.  Same supplier and base stock does not mean same additive and lubricant package.  And while they may have been the same RON rating to start with, they will deteriorate faster, who knows what it might be by the time it's in your tank!

 

As far as the original question Porker is spot on, the ECU will listen to the knock sensor and adjust the ignition timing accordingly, so no danger to engine from running 95RON.  But as he quite rightly says, there may not be the same amount of fun attached to the loud pedal. :-)

[DJMC]

Shell V-Power for me 99% of the time. Get a Shell driver's club card and present it each time when you pay. Then you'll get money off fuel coupons and other freebies every so often.

 

[Idlewild]

Tesco 99 usually because it's cheaper than V Power but exactly the same.

 

Never buy BP Ultimate because:

1. It's much more expensive than the others
2. It is a lower octance rating (97 iirc) which isn't high enough for a Cayman
3. It has loads of nonsense about 'cleaning your engine'. As if the millions of cars that use regular fuel are constantly braking down due to having dirty engines.

[MJ]

but its not exactly the same because it lacks all the exotic additives.  Bit like buying cheap aftershaves or expensive ones...you can definitely tell the difference ;-)

You don't even get good mpg out of cheap fuel so its a bit ironic to buy it to save a few pence per litre.

 

There was an article in the Porsche press this month about the number of cars with DFI now suffering injector issues from using poor fuel and carbon buildups. That'll be all the supermarket fuel buyers then.

[Idlewild]

On 5/22/2017 at 13:18, MJ said:

but its not exactly the same because it lacks all the exotic additives.  Bit like buying cheap aftershaves or expensive ones...you can definitely tell the difference ;-)

You don't even get good mpg out of cheap fuel so its a bit ironic to buy it to save a few pence per litre.

 

There was an article in the Porsche press this month about the number of cars with DFI now suffering injector issues from using poor fuel and carbon buildups. That'll be all the supermarket fuel buyers then.

 

What 'exotic additives' are these? Snake oil and confirmation bias?

 

MPG is going to be the same.

 

Poorer fuel causes injector issues does it? And you think that's supermarket fuel? Please show me a peer reviewed study that shows that supermarket fuel is at fault here.

 

If you can't, please stop spouting nonsense. Unless you are a shill for the likes of BP?

[Porker]

1 hour ago, Idlewild said:

 

What 'exotic additives' are these? Snake oil and confirmation bias?

 

MPG is going to be the same.

 

Poorer fuel causes injector issues does it? And you think that's supermarket fuel? Please show me a peer reviewed study that shows that supermarket fuel is at fault here.

 

If you can't, please stop spouting nonsense. Unless you are a shill for the likes of BP?

I tend to agree, fuels will be made to strict standards and independently tested for octane ratings. There may be some marginal benfits but you won't feel it in your right foot, that's why the science guys have all sorts of exotic equipment. 

 

On on a side note, I've filled up close to blyton park before a track day tommorow. Drove up from London and staying locally, bit weird up here outside the m25. Anyhoo, the local Tesco doesn't do ultimate so I've got to make do with 95RON. I shall blame this when I'm overtaken by MX5s

[DJMC]

This seems a good article: https://www.petrolprices.com/blog/supermarket-fuel-and-premium-petrol-the-lowdown.html

 

Where I can't find Shell, I seem to only use Tesco 99RON. Can't think of another supermarket which has 99. Plus I get my club card points too.

 

 

[MJ]

On ‎27‎/‎05‎/‎2017 at 19:38, Idlewild said:

 

What 'exotic additives' are these? Snake oil and confirmation bias?

 

MPG is going to be the same.

 

Poorer fuel causes injector issues does it? And you think that's supermarket fuel? Please show me a peer reviewed study that shows that supermarket fuel is at fault here.

 

If you can't, please stop spouting nonsense. Unless you are a shill for the likes of BP?

I do not pretend to know the answers but I certainly trusted the words of the 'specialist' petro chem team I used to work alongside, most of whom had been in the business for 40 years...guess they don't know what they are talking about eh? They gave me lengthy explainations at the time but that was over 5 years ago.

But upto you if you want to put cheap fuel in your premium car, i'll stick to the good stuff, each to their own.

I hear Chinese wiper blades are just as good as Bosch ;-)