Just tried a few tankfuls of 99 RON Shell. Prevously I’d tried it in 97 RON form, and Momentum 99 RON, and never bettered 38mpg.
With 99 Shell I got a record 41.5mpg, motorway driving at a constant (GPS) 70-75 mph.
Momentum gave 38.5 mpg. Switched back to Shell and up to 41mpg again.
This was on a 1000 mile run to Scotland and back.
2008 Mk3 NC1 Sport
I might make a habit of Shell 99 if it pays for itself.
Never use anything other than V-Power. Their diesel is also the best.
I use it in my 121,000 mile 1998 NB and seem to be getting 39 mpg. Living in a rural area helps and I don’t like using my brakes unless necessary.
Our 1.6 Diesel Focus Estate gives about 56 - 57 mpg on Shell V Power.
In both cases I hope the extra cleaning agents are helping the injectors. The Shell Drivers app gives one discounts occasionally.
I use it in Swmbo’s 104k mile 2002 Sport.
It just seems to run sweeter, and I think the MPG has improved but then it is only used as a “retiral decent run” car now rather than a short commuter.
Additional cost is of zero consequence now as it only gets a tank a month as a rule.
Conversely, I’d not bother with my Auto Mk1. Makes no difference. It would likely be as happy on chip oil!
Never use anything else in my BBR Super 200 NC, loves it. Even better in Germany; 100 octane…
That’s probably not a bad thing as I do believe that “recovered” cooking oil is a major ingredient in bio-fuels.
Always use Shell V-Power
I got just short of 39mpg, fully loaded car on a tour of Scotland around 1800 miles 2ltr NC sport on 72k miles on standard Asda/Tesco petrol. If I tried hard enough I could have got over 40mpg. For what it’s worth my engine runs sweet.
If a petrol engine with an ECU and a “knock” sensor needs a high octane fuel, BUT is run on a lower grade, resulting in knock (detonation), the ECU will retard the ignition until the knock stops. This reduces the efficiency of the engine and so the mpg goes down.
My commuter car is a little “modern” Fiat which is supposed to run on “standard” unleaded, but as I found out recently, is transformed by higher octane fuel.
Having said that, also my Honda 750 is fitted with carburettors and doesn’t have a knock sensor but it also goes better on V-Power or other higher octane fuel than on the minimum grade specified by the manufacturer.
BBR use Tesco 99 in their cars, but that’s probably because the petrol station is just across the road from them. I realise this topic is more about mpg than bhp, but in terms of performance I think the two fuels are equal.
We’ve just come back from West Wales in the Mazda3, five up with a solid-full boot, so at least 400kg of load. Going with a full tank of V-power it was great, flexible and willing, a pleasure to drive in town or fast motorway traffic or on the twiddly hills, especially considering its only a nominal 120ps in a 1200kg car.
However, my usual Shell garage (Westbound A40 near St Clears) was closed on the way home, awaiting fresh delivery, so I filled up with Texaco regular at the next stop. The difference in performance was very noticeable, and I was needing to drop a gear or two on the 70mph hills where usually it’s happy to hold sixth gear without even thinking about flooring it. The Texaco regular is utter pants compared with the V-power. I never thought a modern car like this would show such a difference.
I always used VPower in my Spitfire. Nothing else worked as well.
I sold it in May when got my Mazda. I assumed that the Mazda was made for 95 octane. I have put a tank of V power in while I have had it and it may have been better but nothing conclusive.
At the end of October we are going from Bedfordshire to Bamburgh Castle are for a few days and will use it exclusively for that trip and see how it goes…
For the tankful, I went to Belgium for a few days and got 40.6 mpg. I topped up with Esso Momentum at Dover on return and drove home. When I next filled the average was still 40.6.
Its a 2007 1.8 Icon BTW.
Well since the custom remap I’m getting high 30s day to day, low 40s on a long run and low 30s driving like I stole it. Before this I was getting low 30s, high 30’s and high 20s respectively.
I’ve always used 99ron (either momentum or vpower) but now I’m mapped to 99ron the engine is definitely taking advantage of this.
Fuelling has also been fine tuned to use less at idle and fuelling dips have been ironed out.
As far as I’m aware the mx5 is designed to run on 90 ron.
I’m sure that’s a typo. as I don’t think there is a 90 ron, but I know that the ND requires 95 ron minimum.
PS: I am referring to the UK of course!
If the Wikipedia page is to be believed, you’ll find just about any RON if you travel widely enough. As far as I can see the lowest is Bangladesh at 80 and highest United Kingdom, funnily enough, on a very limited trial basis a few years ago at 102. For 2.5x the standard price!
I’d consider shifting to a higher octane fuel, but anecdotal evidence is what it is.
BBR will obviously want their demo cars to always be performing at their very best. If Tesco 99 is good enough for them that’s the sort of recommendation that will do for me.
I usually use Tesco and found that the 99 made my 2.0 NC feel much more flexible than the 95. Not so convinced on my ND but I’m using the 99 anyway.
Going back to first principles, I would expect the very high compression-ratio Skyactive engine will be best on the 99octane.
This certainly proved to be the case for my Mazda3 Skyactive with a mere 120ps, so I expect the higher state of tune in the 184ps ND will also be happier.
To get the best out of high octane fuel you need the advanced ignition mod, then more power AND more economy.
Paul G
I run my ND on standard fuel, mainly supermarket but about 1 in four or five at BP
I run my NA on “99” from either Shell or Tesco as the engine definitely prefers it
My NA is “probably” driven more enthusiastically.
The mileage for the ND is over 7 months (owned for 10, stored for 3) and the milage for the NA is over nearly three years.