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[Diamond Black Geezer]

Which has been raised as an issue (as you're no doubt aware, of course) with regard to Tesco Ultimatum. I have found it can contain as much as 5% ethanol, as little as 0%. It's mixed in the tanker/tank, not at the refinery. BP Vanden Plas+, or whatever it's called apparently does not use ethanol, instead adding detergents as well as a 'lubricant' to help the pistons slide up and down easier. there is argument that Tesco's Superfuel with ethanol is in itself a cleaning agent. But as you say, strangely, for a 'superfuel' it may in fact be 'watered down' 

[Doctor Gollum]

Whereabouts is the knock sensor on the the V6?

One either side, about a third of the way back from front and halfway between head and sump. Bank 1 is down from cable tray to ecu loom and Bank 2 is just behind the alternator iirc

[Diamond Black Geezer]

  Good to know 

[Doctor Gollum]

Whereabouts is the knock sensor on the the V6?

One either side, about a third of the way back from front and halfway between head and sump. Bank 2is down from cable tray to ecu loom and Bank 1is just behind the alternator iirc

Corrected due to Left/Right confuddlement

[Shackeng]

Whereabouts is the knock sensor on the the V6?

One either side, about a third of the way back from front and halfway between head and sump. Bank 2is down from cable tray to ecu loom and Bank 1is just behind the alternator iirc

Corrected due to Left/Right confuddlement

Thanks Al.

[omega2018]

tesco say the max ethanol in their fuels is 4.8% (law allows 5%).  https://www.tescopfs.com/our-stations/faqs
their independent report (millbrook) shows up to 3.95% better fuel consumption with their super unleaded over their normal fuel.

back to the original question, doesn't that mean that using normal unleaded will require up to 4% more mass of fuel to be fed into the engine? perhaps not if the fuel mass is the same its just power output that is down but if yes then wouldn't the trim figures be different on superunleaded?

anyway doesn't ignition timing data show up on a cheap scanner?  i'd expect it to be advanced under super unleaded compared to normal (if not then there would be no increased mpg).

[Diamond Black Geezer]

That raises an interesting question, yes. 

Thoughts, gentlemen? 

[Mr Gav]

tesco say the max ethanol in their fuels is 4.8% (law allows 5%).  https://www.tescopfs.com/our-stations/faqs
their independent report (millbrook) shows up to 3.95% better fuel consumption with their super unleaded over their normal fuel.

back to the original question, doesn't that mean that using normal unleaded will require up to 4% more mass of fuel to be fed into the engine? perhaps not if the fuel mass is the same its just power output that is down but if yes then wouldn't the trim figures be different on superunleaded?

anyway doesn't ignition timing data show up on a cheap scanner?  i'd expect it to be advanced under super unleaded compared to normal (if not then there would be no increased mpg).

I`m not sure the Omega ECU has the capability to advance the ignition depending on fuel.

I remember reading an article years ago when the V10 M5 first came out and this was when the 98 and 99 ron fuels were coming more readily available.
EVO magazine did some dyno testing using five cars but only the new M5 and Golf GTi could take advantage of the higher ron rating.
I`m pretty sure the Omega falls into the category that can`t take advantage of it, only way to be sure is to get it on the dyno.

[Diamond Black Geezer]

Thanks  SO if we play the odds and say the Omega is just too old to make full/any advantage of newer octane fuels ...

I know it's been both said yes, and no, but I still would like to know what a remap could / would do? Surely it would make a difference? I fully appreciate what's been said in that because of the combustion chamber design there wouldnt be knock and 'within margin', but nevertheless surely moving that said margin along a bit, to the new optimum point (using the different fuel) would help? In essence do on a rolling road/etc what a newer engine with better knock sensors does by design automatically.

I mean a remap was always on the cards anyway, irrespective of whether superfuels even existed; but the old 'chip' company which was recommended doesn't seem to be around any more, and I know that there are good and bad remaps out there, and it's best to go recommended.

Suppose I'm looking at a little more into the science of 'electronic' engine fettling, really. 

[omega2018]

I`m not sure the Omega ECU has the capability to advance the ignition depending on fuel.

I remember reading an article years ago when the V10 M5 first came out and this was when the 98 and 99 ron fuels were coming more readily available.
EVO magazine did some dyno testing using five cars but only the new M5 and Golf GTi could take advantage of the higher ron rating.
I`m pretty sure the Omega falls into the category that can`t take advantage of it, only way to be sure is to get it on the dyno.

page 216 of the manual

"Octane requirement (RON)
95
98 <sup>(2)

(2)</sup> Knock control system automatically adjusts ignition timing according to type of fuel used (octane number)."

[biggriffin]

Forget all the waffle.
Go to garage fill up with your fuel of choice drive car report back,Then refill car with super duper 97/99 from your retailer, drive car report back.
Easier than page after page of waffle.

We all know car runs better on super fuels, also helps clean cats on 2.6/3.2 and according to tests done by all fuel companies' there are gains. 
.   thankyou and goodnight.

[Diamond Black Geezer]

Mr BG. Um....that's great, but that doesn't take into account the 'placebo' effect, or the human factor, that "We all know car runs better on super fuels" which does make the driver somewhat preconditioned to an opinion, and hardly impartial.

I do, however, thank you for your kind and constructive words.



PS Thanks Migmog, (I don't have a manual, by the way, so that's appreciated  )

[Mr Gav]

Don`t forget that the knock control only retards the ignition not advances it, and at the end of the day if you want proof of what is going on put it on a dyno 

For what it`s worth my MV6 gave no better or worse MPG regardless what fuel I used.

[Diamond Black Geezer]

Many thanks Mr Gav.. only retards it, then. And it's Dyno-only  Fair enough.

I was hoping that a Tech 2 would be able to give date, as it can with the trims (which I've now learned it totally unconnected!  )

[Mr Gav]

Many thanks Mr Gav.. only retards it, then. And it's Dyno-only  Fair enough.

I was hoping that a Tech 2 would be able to give date, as it can with the trims (which I've now learned it totally unconnected!  )

If you want concrete evidence of what is happening with each fuel then you would need to dyno it, that's the only scientific way you`re going to get results.

As you say there`s the placebo effect to consider when doing your own test so they`re not really worth while.

A remap would probably make a worth while difference (and it already sounds like you`ve made your mind up  ) so get it done and enjoy it and forget about a couple of mpg difference, after all you don`t get a large saloon with a big V6 engine and worry about fuel consumption 

If you`re wanting a bit more go then the best single mod you can do is get a 3.7 ex plod diff, better acceleration through all the gears and not too much of a hit on mpg