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

It was only Kia that he mentioned. Others seem to have no problem. Don't know why.

I usually use normal BP or similar fuel - rarely supermarket stuff. Occasionally if going for long journeys or on holiday I will use super unleaded in my 4/4 with normal Sigma engine. A friend who is a retired motor engineer told me that after a couple of weeks in the tank the extra ethanol in super just evaporates so left with normal + extra additives. So I use super for the odd clean out or if heavy usage over a week or so.

I ran my Duratec +4 for 2 years on BP or Shell Premium it made absolutely no difference to the MPG or the power. With the Wolf Performance ECU map it's almost impossible to use all the power anyway. I now use Premium every 3rd or 4th tank to clean the engine

You are piddling against the wind with that message. Almost by definition posters on here regard their Morgan as "special" and wish to treat it as such despite its mundane mechanicals. And why not? After all, wasting money on fuel is small beer compared to wasting money on a toy car in the first place, whether a Morgan or some other brand. And part of being old and in most cases retired is the fun of wasting both time and a bit of money. God only knows I waste enough.

I wonder if any TM ers are using avgas? Isnt that something like 103 octane?

Pick your spec - upto 116 Ron

Prices make your eyes water:
https://www.sunocoracefuels.com/fuels

Home deliver by the can.

Probably no need to use super in the n/a gdi Plus 4 but we will be recommending it for the Ecoboost conversions since the (two) knock (pre-ignition)sensors allow more ignition advance and boost with a higher octane. The detergents are probably going to keep the (expensive) ultra high pressure injectors cleaner too. The motor will run perfectly well on low octane supermarket fuel or even French high ethanol fuel if that's all that's available but I wouldn't go for it by choice. By the way, mention of AVGAS puts me in mind of using it in the 1987 Safari Rally in our Escort RS2000. We were sponsored by Shell and got drums of it from Nairobi's Wilson Airport.

I had not really thought about the knock sensor issue but when fitting the throttle bodies and the ECU the knock sensor is no longer utilised so it makes sense to use the higher octane fuel which is less prone to pre-ignition.

The ECU is actually capable of handling knock detection etc but it is very complicated and probably not worth the effort.

/drift mode on

When I had my GTR33v many moons ago there was a chap that ran a very tweaked one. It had a dashboard mounted computer for almost real time map adjustments. It could be adjusted around the knock point using the additional (many) things bolted to the engine. He used 98/99 all the time and when doing anything silly used some US octane booster imported.

His idea of mixing was a bit like Olivier Reeds idea of "roughly a double".

95 regular as he used to call it was about 750hp
98/99 super was in the region of 800hp
98+booster was depending on the mix he made, 900+

Then one day on 99 momentum (+ a lot of octane booster) at a track day he blew the brains out of it, £20k for the rebuild. It was about the only RB26 engine I ever saw detonate. The more you go hunting the edge of the envelope the sharper the cuts are.

I use 99/98 whenever I can. Mostly because I do little milage in the Aeros and want as little BioEthanol as possible. But if 95 goes in I don't panic.

As mentioned earlier I prefer higher octane in the Plus8 as it seems to keep the MIL fault away. The extra detergents and less ethanol are secondary but nice to have.
The Gems system is reputedly slightly adaptive to driving conditions but not hugely so.
My preference is due to having tried higher octane and liking the cure it gave and the potential for cleaning the fuel system. I didn’t expect better performance as the ecu /map are standard.
The Millers experience with the Focus and my mate’s non improvement in his golf shows how fickle things are. So...you pays your money and makes your chouce.
I don’t worry about putting 95 octane in the Plus8 if it is the only available. Perhaps changing to 99 octane on alternate tankfulls might be a compromise. It is not abig deal.

Please see https://www.consumerreports.org/car-maintenance/study-shows-top-tier-gasoline-worth-extra-price/

Not exactly answering the question, but thought it's of interest.