unleaded 95 or super 98 octane?

[coldel]

Is it only 1p difference per litre between Shell and Tesco? Thought it was more like 4-5p. Shows how much I pay attention.

 

In any case, I usually stick in BP or Shell or some brand like that and occasionally put in supermarket fuel of the same RON never had any problems with any car I have had. Never saw any difference either when I ran a few tanks of Tesco either. I never put in lower RON fuel though into the cars that the manufacturer says not to either.

[Jeff E]

And so what discussions have you had with these OEMs ? In what context ?

[ilogikal1]

And so what discussions have you had with these OEMs ? In what context ?

 

I notice how you seem to avoid answering the question put to you. It was a genuine question by the way, so care to offer an answer at all?

[Jeff E]

Apologies for my in haste and unhelpful response. I was involved with research/ technical staff in getting approvals with OEMs for petroleum additives and keeping them abreast of developments. There was an on going programme with Mercedes. As a marketer/chemist I had a period trying to sell gasoline additives to companies often referred to as national /second tier oil companies such as Fina, Agip, Aral, Kuwait. Majors such as Shell are supplied by their own chemical companies. I was also involved in selling a range of petroleum products/ additives to lubricant blending companies such as Castrol (pre BP ownership ), Valvoline, Fuchs, Millers etc.

Later I moved into trading involving base oils, gas oil and gasoline. Now retired but I was involved at a time of significant change in the auto industry which required corresponding improvements in petroleum products.

[nowhereboy]

I've always ran my car on super but I can't help but wonder if the risks are exagerated.

 

Is it not likely that many of our cars have been ran on 95ron for weeks/months or even years before us owning them?

 

It's pretty rare an engine lets go on this forum, I kind of understand the OP's point of view in his original post.

 

Edit - Not disputing that it's harmfull to the engine but just questioning if it's as serious as people make it out to be.

Edited February 4, 2015 by nowhereboy

[Ricey]

I've always ran my car on super but I can't help but wonder if the risks are exagerated.

 

Is it not likely that many of our cars have been ran on 95ron for weeks/months or even years before us owning them?

 

It's pretty rare an engine lets go on this forum, I kind of understand the OP's point of view in his original post.

 

Edit - Not disputing that it's harmfull to the engine but just questioning if it's as serious as people make it out to be.

 

I'm trying to think of a good analogy but it's tough.

 

Ultimately you are without doubt running a 'risk' by putting a single tank in because it simply isn't rated to deal with the heat created by combustion and compression.

 

It's a cumulative effect though. Post combustion det is damaging but the engine usually can cope with an element of it hence the presence of a knock sensor to tweak things when it goes wrong. Can cause catastrophic mechanical failure in extreme conditions or just 'wear' that puts eroded (not sure that's really the right word in this context) particles into the oil which in turn cause further wear.

 

In the end that will affect the longevity of the engine.

 

More seriously it can just smash bits of the combustion chamber and piston to smithereens,......let's assume you need to be lapping on pretty hard and regularly for this to happen but it CAN happen.

 

Thirdly you can cause pre-ignition as a result of post det.......that's where the affects of post combustion det cause pre combustion det (red hot carbon deposits, superheated spark plug etc). That's where you get the big snapola......your piston is hurtling towards an expanding flame front - el cruncho.

 

So yes......long term post det will eventually murder the engine but it takes time for the effects to build up. That said a single tank of the wrong fuel can definitely cause some limited amount of damage or wear.

 

 

[brillomaster]

I think it depends how its driven - trackdays, drifting or driving enthusiastically, you need to run 98 since the car will be redlined a lot more often. of course nowadays the cars are getting cheaper to buy, the mileages on the engines are getting higher and higher, and the use of the car is shifting to the younger buyer who might take it on track occasionally.

 

I suspect we might start seeing a lot more engine failures in the future - after all, there will be several 1 careful owner cars with mileages approaching 100k that come up for sale and are bought by younger guys who do a trackday with it - and that hard use after years of driving around on 95 might trigger a failure.

Edited February 4, 2015 by brillomaster

[ilogikal1]

Apologies for my in haste and unhelpful response. I was involved with research/ technical staff in getting approvals with OEMs for petroleum additives and keeping them abreast of developments. There was an on going programme with Mercedes. As a marketer/chemist I had a period trying to sell gasoline additives to companies often referred to as national /second tier oil companies such as Fina, Agip, Aral, Kuwait. Majors such as Shell are supplied by their own chemical companies. I was also involved in selling a range of petroleum products/ additives to lubricant blending companies such as Castrol (pre BP ownership ), Valvoline, Fuchs, Millers etc.

Later I moved into trading involving base oils, gas oil and gasoline. Now retired but I was involved at a time of significant change in the auto industry which required corresponding improvements in petroleum products.

 

Thank you for that, it certainly gives more context and substance to your previous posts on this thread.

[Jeff E]

Need to get out in my Zed more and lighten up Jeff E alias Victor Meldrew !!!!!!!!!!!

[Suits]

I get para if I put anything other than Shell Optimax-V-Power-Dog-6+NOS whatever it's called.

 

There have been times I've had to put 95RON fuel in, when I do I put as much as I need to get to the next Shell garage.

 

When we go to Europe, we carry a box of the RON top up bottles just in case.

 

I'd go near a track with my 370 with a full tank of Shell Premium.

[choptop]

98 Ron or above. Its in the manual for a reason.