Millbrook Report: Tesco petrol vs Premium

mcpitman

AdrianC wrote: »

Simple question: Will it run perfectly well, with no damage (and no major driveability compromises), on a given fuel?

No? It requires a different fuel.
Yes? It does not require a different fuel.

Can you define "perfectly well" in your unbelievably pedantic debate?


If you mean as the manufacturer intended, then no the car in question will not run "perfectly well", it will be down on power due to retardation of the ignition system, reducing power to prevent pre-ignition or pinking.


If you mean will it get me from A to B? Then the answer is yes, but not as well as it was designed to.

almillar

Simple question: Will it run perfectly well, with no damage (and no major driveability compromises), on a given fuel?

No? It requires a different fuel.
Yes? It does not require a different fuel.

That IS a simple question. The answer isn't simple.

Example - Nissan 350z - UK car, not an import. Asks for 98 (maybe 97) RON fuel. 95 is only to get you to the next petrol station that sells super, and you're not to drive hard or rev above 4000 odd RPM.

Just like the question on the thread, the answer is 'it depends on your engine'. Attempts to generalise is what starts the arguments over the specifics.

...despite the fact the answer is clearly "yes".

Argue over the A45 if you like, but not for the 370Z. Stop. Generalising.

mcpitman

motorguy wrote: »

Agreed.

The basic fuel is the same - comparing Tesco 95RON to any "premium" brand 95RON. Its whether or not you buy in to the additives / cleaning agents being worth the premium.

If i've a car that can run on 95RON unleaded then yes i'll cheerfully run it on supermarket fuel. My Volvo 2.5 T5 for example gets almost exclusively ASDA fuel.

Diesel fuel too. When i was doing 30K pa in a 1.6TDI golf i was getting at least as much MPG from supermarket fuel as i did from premium brands. And that was brim to brim calculations, stored in a spreadsheet over the lifetime of my ownership so not back of a fag packet one offs.

I personally stick a cleaning agent in to the diesel fuel if its an older diesel - something like Millers - and then just use supermarket diesel. That way i'm getting the cleaning agents, but for a fraction of the price of the extra cost of premium diesel.

Usually this stuff..

https://www.amazon.co.uk/Millers-Oils-Diesel-Power-500ml/dp/B002WCAISS/ref=sr_1_1?ie=UTF8&qid=1491295534&sr=8-1&keywords=millers+diesel

Havent needed to run a diesel in a couple of years though

Agree with this speaking from 90k miles of logged brim to brim calcs using ASDA fuel and Millers.


Ambient temperature makes a bigger difference than where I buy fuel from or what it claims to do.

AdrianC

almillar wrote: »

Example - Nissan 350z - UK car, not an import. Asks for 98 (maybe 97) RON fuel. 95 is only to get you to the next petrol station that sells super, and you're not to drive hard or rev above 4000 odd RPM.

If that's really the case, then that's one of the rare examples where the answer is "no".

motorguy

almillar wrote: »

Argue over the A45 if you like, but not for the 370Z. Stop. Generalising.

Theres no real world argument to be had about an A45 either.

It "can" run on 95RON if it has to, but you will lose power and economy by doing so.

To suggest running it on 95RON is banal.

motorguy

AdrianC wrote: »

If that's really the case, then that's one of the rare examples where the answer is "no".

So answer my question then - WHY would you be happy to lose power and lose economy running on a fuel thats against the manufacturers recommendations just to what - save a few pence? :eek:

Maybe running a performance car isnt for you?

motorguy

mcpitman wrote: »

Agree with this speaking from 90k miles of logged brim to brim calcs using ASDA fuel and Millers.


Ambient temperature makes a bigger difference than where I buy fuel from or what it claims to do.

Also, from memory isnt there a winter diesel and summer diesel?

One gives better economy than the other - the summer one i think.

AdrianC

motorguy wrote: »

So answer my question then - WHY would you be happy to lose power and lose economy running on a fuel thats against the manufacturers recommendations just to what - save a few pence? :eek:

Maybe running a performance car isnt for you?

My ol' Saab 900 was more than quick enough to be thoroughly antisocial, even with the boost knocked back ever so slightly on 95, thanks. With half the power of your Merc.

Mind you, it was less than 2/3 the weight...

mcpitman

motorguy wrote: »

Also, from memory isnt there a winter diesel and summer diesel?

One gives better economy than the other - the summer one i think.

You are possibly correct (I am unsure). I though the "winter" diesel was a thing of the past.


I believe my car does "worse" in winter due to the warm up cycle effectively taking longer and a product of throwing more fuel in to act as a "choke", along with more strain on battery from heaters, lights etc.

motorguy

AdrianC wrote: »

My ol' Saab 900 was more than quick enough to be thoroughly antisocial, even with the boost knocked back ever so slightly on 95, thanks. With half the power of your Merc.

Mind you, it was less than 2/3 the weight...

So you're basing your wild assumptions on your experiences of a car made 30 years ago?

:rotfl:

Brilliant.

I cant think why anyone would think "well, the manufacturer of the car (Mercedes) recommends 98RON, the engine builder (AMG) recommends 98RON, i am being told by both of them to only use 95RON if i am forced to because of no other choice, and that if i do it will impact performance, power output and economy, but i know best, i'm going to run it on 95RON anyway to save a few
pence per litre"?

Are you really saying the above and "i would force my car to run on the lower RON fuel" particularly given any perceived "saving" in the fuel cost would most likely be easily offset by the extra fuel used?