Talk Morgan Forums Community The Malvern Arms Is it worth using super unleaded in a Plus 4?

What has not been mentioned is that the premium fuels such as Shell V-Power contain lubricants and detergents that are highly beneficial to engine condition and longevity.

My partner won’t go near Morrisons for fuel after having a couple of engine issues with her diesel Freelander. Her garage told her it was not an isolated incident and not to use their fuel. And I always thought that all supermarket diesel cane from the same refinery 🙄.

I always ran the Roadster on 98 Octane as I was convinced after the remap that it ran better. Ditto my 4/4 when it went onto throttle bodies....it did not like 95!

As far as my new toy....well I guess it ran on 80 octane in its day!

Not worth an answer. Damn! I'm answering.

With a modern +4 the engine is an almost standard Ford Mondeo/focus which is set up to run a best average mpg/to power set up for road use. There for can't see the point of running with high octane fuel, except for the occasional use for clean through.

As far as I’m aware there have been only a few specifically (statically) tuned special editions that take advantage of High Octaine fuel. As has already been called out - with these cars there is no choice as the ECU is statically coded to require it.

All other models certainly in the post carb era are set up (again statically) to run on 95 Oct. higher octaine fuel is a waste of time and tbh the adatives for cleaning benefit most, the engines that have a coaking issue such as the infamous 4.2 Audi V8’s.

Dynamically coded Normally Aspirated ECU’s do exist - the Aston Martin V8 Vantage being a great example. The ECU programming is very sophisticated and can significantly enhance performance based on fuel quality - on the flip side the ECU can literally save the engine when running on poor fuel found in some countries... a kind of one size fits all.

Forced induction cars (mainly turbo) cars also run a more dynamic ignition map to help with the variety of loading and boost conditions.... again a byproduct of this is that they can also adjust themselves for the absence of detonation brought on by higher octaine fuels. Hence the Jap car penchant for Tesco99.

Both the Turbo and AMV8 examples use knock sensors to identify detonation and allow the ECU to retard the ignition. Some of the latest variable compression engines take things further with the ability to reduce compression to help further reduce early detonation due to poor fuel combusting in an uncontrolled way through compression ignition.

That’s why I go for it - it’s a better quality of fuel
Not because of the octane count

Me too, also in my DS3.

Even my modest 16 year old 4/4 is currently valued at £24k; with an average annual mileage of 3,000 miles, I calculate that buying V Power costs me about £50 a year extra.
So, for me, it’s a no brainer.

Thank you to everyone for their insightful answers. Has so far been a very interesting and useful read.
Cheers
HB

First of all, it is clear that only cars with knock sensors can achieve more power through more octane.
But...an expert had told me three years ago that with many very new engines the ECU notices that the fuel has more octane, but nevertheless does not set the ignition to more early because the insurances complained.

This is an indirect proof that more power and smoother running is possible with more octane.

You have to try it out in each individual case.
The Sigma 1.6 definitely converts higher octane into more power. In reach really more top speed at a well known steep hill on the Autobahn.
I can't say it for other Morgan engines except the 3.0 Roadster, it was definitely the case.

It also fits with the insurance statement that Peter's AMG is stated with power at 98 octane and that less octane leads to less power.
The reverse official performance claimed at 95 octane would lead to a different performance at 98 octane, but the car would no longer be insured.

I spend @ £2500 a month on Morrisons diesel mainly in the 2x Crafters, but also in a
Caddy
Doblo
Merc GL
Merc GLE
2X Passats
Mazda 6
BMW 5 series

Never had a problem, they all get their filters changed once a year
And the Crafters do in excess of 30mpg, on a 300ml run per day.