Shell Nitro vs Tesco 99 Momentum

[jackcramerr]

Guys

I didn't see any mpg or performance difference between both these super fuels after 4 fills of tank of each of them. 34mpg tops with full daily highway drive. 24-28 mix driving. I know many things can influence the conclusion but thought it won-t hurt to share the experience. But one thing for myself is certain, I cannot cross 34mpg.

[rayaans]

It does appear that modern Lexus vehicles don't benefit from higher RON fuels in terms of performance and MPG. Having said that, the benefits of them may be a long term thing, especially with the extra additives that are supposed to help clean the debris out.

It is worth remembering that the US and UK cars are exactly the same in terms of engine and power produced. Therefore these cars are meant to run on Premium US unleaded which is 91 Octane, the equivalent of 95 octane in the UK.

[Linas.P]

I don't think that in short term there are any difference in MPG regardless what you use. If you use only the cheapest and dirtiest fuel over the time you will get built up, which will eventually impact the MPG. However, premium fuel itself doesn't burn better or result it better MPG, it is more for maintaining engine condition. Though, I personally believe that carbon built-up is inevitable and with premium fuel you just accumulating it slower. I am looking into "hydrogen-cleaning" my engine. There are as well plenty of videos of how to DIY it with simple water (just don't use tap water in UK, it is so hard that you get calcium build-up instead of carbon - use deionised water).

Myself I am doing cycles of filling every 2-3rd tank with Super Unleaded (whichever brand) between cheap supermarket fuel. The only positive thing is that Super Unleaded have additives to clean the engine. Now it is my 3rd tank on Super Unleaded as the MOT is soon and emissions are a bit of worry.

The good news are that Lexus informed me that I have recall for fuel sensor which is not done yet - so if any issues I will blame it on them :D

I actually get better MPG on cheap fuel from Asda. Normally 34-38 on motor way, 24-28 in urban. Long term consumption 28.7 MPG.

[J Henderson]

When you get that recall done Lexus will give you some petrol for free (£25 worth, IIRC) so don't go in with a full tank. 

[Linas.P]

14 hours ago, Kodiak Sky said:

When you get that recall done Lexus will give you some petrol for free (£25 worth, IIRC) so don't go in with a full tank. 

Thanks ... this info will come very handy :)

So basically it is even better, I can blame both sensor and Lexus fuel if anything goes wrong during MOT emissions test :D

[agent_dess]

My votes goes to Sainbury fuel, get better mpg compared to adsa, shell, tesco.

[Linas.P]

40 minutes ago, agent_dess said:

My votes goes to Sainbury fuel, get better mpg compared to adsa, shell, tesco.

Is that on premium or standard? 

Actually just wanted to note as well..it is actually is very hard to compare fuel in Lexus IS250. This is because it has "Smart" ECU which can change ignition timings based on driving style or fuel used. That said it is very unlikely to see any difference in MPG what ever fuel you use. I generally find that I get highest MPG from asda standard fuel (the cheapest), but this after finishing tank of premium. My guess is that when it tastes cheap fuel it temporary retards ignition timing which translates in some fuel saving... We are talking here about 0.1-0.2MPG.

I guess to make any meaningful conclusion somebody needs to do 10k miles on single brand fuel in controlled environment which is obviously impossible. My personal opinion is that it is good idea to use premium fuel periodically to help reduce carbon built-up etc. (or fuel additives from super market whichever work outs cheaper). Neither helps improve MPG in short term, but makes economical sense in long run.

[agent_dess]

Sainbury premium, I normally use asda as it closest to home, shell i really use as it's not nearby, bit I've observed Sainbury fuel many times and it seem better. But each to his own.