Vvti And Premium Fuel

[david_hornet27]

This has been discussed briefly on the forums previously without conclusion, and I have googled without finding a satisfactory answer. Does using premium grade or high octane fuel give any immediate advantages in the VVTi engine? Or does the engine have to 'learn' it is consuming a different fuel over a period of time before it makes any difference. Infact does it make any difference at all ever? Has anybody used premium fuel long term and if so what is your opinion? I can't find anything that seems to give a conclusive answer anywhere and don't want to shell out another 10pence per litre without evidence it is worth it.

Have been meaning to ask the question for some time but thought it might be too boring. However it seems nobody has anything to talk about on here this week so thought I'd make the effort...

[lexynik]

i thought about this for a while too when i got my 200 - the consensus of opinion seems to be it wont make any appreciable difference so i use 95ron asda fuel as its the cheapest - there was one interesting post that said to stick half a tank of the shell v power on top of half a tank of normal fuel every few months or so which apparently has lots of additives in it and thoroughly cleans your fuel system through and helps achieve optimum mpg - this is only what i have read not personal experience

[Nitmoi]

I always use TESCO 95 previous owner also, seems there is no problem.

[LexusForever]

i only run mine on the premium, usually tesco 99 or v power, but the other day i was only able to find asda 95 where i was and had no choice, and there is a noticable difference in power and performance, and the mpg is a good 3 or 4 lower so for me i notice a big difference and can't wait to empty this tank and get back to my usual premium stuff.

[Redsteve]

i only run mine on the premium, usually tesco 99 or v power, but the other day i was only able to find asda 95 where i was and had no choice, and there is a noticable difference in power and performance, and the mpg is a good 3 or 4 lower so for me i notice a big difference and can't wait to empty this tank and get back to my usual premium stuff.

I agree with LF.

When I started using V-Power I didn't notice any difference but I stuck with it (you get double points on your Shell card with V-Power). After a few weeks I thought that it was a waste of money for no increase in performance so I put a tank of regular unleaded in.

Within a couple of miles I thought something was wrong with the car, it seemed very lacklustre in it's performance. It was like this until I put some more V-Power in about a week later.

I think it is a case of you don't notice the difference when you put it in but you sure as hell notice the difference when you stop using it.

Just try putting your gearbox into Sport mode for a week, you don't notice much difference at first but when you switch it back to normal you will think the gearbox has broken, it takes so long to kick down.

Just my experience, I know a lot of people on here don't rate premium fuel.

Redsteve.

[david_hornet27]

Thanks guys. It's interesting from the few posts so far that those that have used premium fuel long term would not go back to 'standard'. Would be interesting to hear if anyone who has used it long term has dumped it and gone back because the price out weighs the advantages.

I think I will start using premium next time I fill up and then try a tank of standard after a couple of months to see if I can notice a difference. Will update when I have more info...

[LexusForever]

the difference in price is currently around £3.20 a tank in my area, but i get around 70 miles more out of the tank, give or take (around £10's worth of cheaper fuel, give or take, so still saving just under £7 a tank effectively), and the difference in power and performance is well worth it even if i don't save anything lol :)

of course that is all based on conservative driving, if i give it some the smile takes over and all the science goes out the window as fast as the fuel goes out the exhaust LOL

[John G]

Any is200 users using v-power? i tend to fil the tank to the brim and every sat fill it back up to the brim whether it be £20 or £50, if its worth me using v-power to gain double points from shell and get better Mpg and peformance i will

[Manc]

i saw top gear do a test on this once and i think they found (an independant tester bloke did the tests!) that the higher octane fuel burnt better and a slight increase in h/p was shown.

They used 3 old cars for the test, but dont get exited cos its not like you're increasing the horsepower with mods like turbos or whatever and you can suddenly keep up with the Subaru's and the like cos you spend another £5 on a tank of fuel.

Seriously tho', I believe it gives you better mpg, just something i noticed, so the cuople of quid you lose on price you prob gain half back thro efficiency.

I think that for the age of the car its worth putting a tank full of high octane in every other week if its got the cleaning additives they claim then it can only be good for older engines? it is only 5p a ltr more so the max 75ltr tank is only 6 or 7 quid more.... what the hell if it costs the earth anyway nowadays, so averaging 3 or 4 quid per week is nowt is it.... but im just the same as you lot, im a tight fisted so & so and i dont use the good gear every time either.

These petrol stations have become pirates... :arrrggg-matey: ...i paid £1.50 for a bloody tin of beans&sausages i needed for work whats going on? Think its time we sent in the boys :shruriken:

[John Lawley]

I think the main reason you don't notice the increase in performance staright away is beacue you still have the lower octance stuff in injectors and pump and it takes a while to clear but you notice when you swap the other way as the engien has set itself up for 99 RON and is then getting knock because of comtamination with the lower octance stuff straight away for a few miles, i fill up once every month to 2 months so always use V power or tesco 99 RON, the LPG easily makes up for any extra cost, currently done 1500miles on the last tank of petrol and still haven't got to half empty...

[david_hornet27]

Since I started this topic around 3 months ago I have been using the 'super' fuel and have been converted. As others have mentioned there is no obvious difference when you start using it, but after religiously putting only V Power or 'super' fuels I recently put a tenners worth of regular fuel in when the tank was empty and was horrified by how rough my engine sounded and the obvious drop in smoothness and performance. I must admit I have not noticed any improvement in MPG whilst using the 'super' but will now continue to use it going forward just for the improved engine performance and refinment.

My brother is still convinced it is just a 'placebo' effect though and I guess this subject will always divide opinion!!

[AndyCheltenham1]

I used VPower for over 12 months and then got fed up with the higher costs so changed back to normal shell petrol over 6 months ago and personally cannot see any difference-the car still runs exactly the same,no loss of power,runs just as smooth and the fuel consumption is no better/worse.Maybe the cheaper fuel doesnt clean my engine as good but for me it still runs perfect so I'll keep using the cheaper shell fuel.I still wont use supermarket petrol as I think that is poor quality..

[BHT]

I used VPower for over 12 months and then got fed up with the higher costs so changed back to normal shell petrol over 6 months ago and personally cannot see any difference-the car still runs exactly the same,no loss of power,runs just as smooth and the fuel consumption is no better/worse.Maybe the cheaper fuel doesnt clean my engine as good but for me it still runs perfect so I'll keep using the cheaper shell fuel.I still wont use supermarket petrol as I think that is poor quality..

You're definitely right in saying the supermarket fuel is poor quality. They buy the cheapest fuel to sell it at a cheaper price, but it is at the same time the worst fuel. I always use shell fuel as I personally believe it's the best. It must be good if Ferrari use it

[John Lawley]

That tank of fuel lasted up till 2 weeks ago and covered 4000miles, i still only use V-power or other hgih octane stuff it's just better :)

[Malc]

That tank of fuel lasted up till 2 weeks ago and covered 4000miles, i still only use V-power or other hgih octane stuff it's just better :)

Wow, 4,000 miles eh !

Let me have some of that. I'm lucky if I get @400 / 420 on a tankfull unless it's always on a good long steady run when the petrol consumption is rather kinder.

Malc

[John N]

This has been discussed briefly on the forums previously without conclusion, and I have googled without finding a satisfactory answer. Does using premium grade or high octane fuel give any immediate advantages in the VVTi engine? Or does the engine have to 'learn' it is consuming a different fuel over a period of time before it makes any difference. Infact does it make any difference at all ever? Has anybody used premium fuel long term and if so what is your opinion? I can't find anything that seems to give a conclusive answer anywhere and don't want to shell out another 10pence per litre without evidence it is worth it.

Have been meaning to ask the question for some time but thought it might be too boring. However it seems nobody has anything to talk about on here this week so thought I'd make the effort...

The improved performance from 'high' octane fuels comes from the fact that you can advance the engine ignition timing further without causing pre-ignition (pinking). The engine ECU is constantly trying to advance the timing as far as it can until the 'Knock Sensors' tell it the engine has started to pink, it then backs off the ignition timing.

When you put 'high' octane fuel in for the first time it takes the ECU a short time to realise it can advance the ignition further, so you don't get an instant change. On the other hand when you change back to 95 octane an engine that has been running on 99 octane will immediately start to 'pink' and the knock sensor will tell the ECU to retard the ignition to avoid damaging the engine.

So the change from high to low octane fuel is more noticeable than the change from low to high!

John N

[GEN]

This has been discussed briefly on the forums previously without conclusion, and I have googled without finding a satisfactory answer. Does using premium grade or high octane fuel give any immediate advantages in the VVTi engine? Or does the engine have to 'learn' it is consuming a different fuel over a period of time before it makes any difference. Infact does it make any difference at all ever? Has anybody used premium fuel long term and if so what is your opinion? I can't find anything that seems to give a conclusive answer anywhere and don't want to shell out another 10pence per litre without evidence it is worth it.

Have been meaning to ask the question for some time but thought it might be too boring. However it seems nobody has anything to talk about on here this week so thought I'd make the effort...

I claim no technical expertise but here is my experience over a number of years:

used to use VPower Shell fuel for my Porsche until I discovered that Tesco has a higher octane (99) fuel and have been using that since. The only visible difference was the lower price at Tesco.

have used Tesco 95 octane for the LS400 - as far as I am able to tell it runs just fine.

have experimented with a variety of fuels on cars (other than those above) but have yet to see a difference. Was I lucky? Maybe.

as for the suggestion that Ferrari use Shell I assume reference is made to the Ferrari racing team. Does anyone actually think that the fuel used by Ferrari for racing is the same as what we can buy at the local station?

I am grateful for the technical explanation of why higher octane works the way it works but it does seem inconclusive - based on that explanation alone it would seem that all cars would benefit from a higher octane. Is that the conclusion? Or are there other parameters to consider for each model?

All the best

[andynorman]

The manual for my old Mk 1 said to use premium fuel but specified the octane as minimum 95 (or maybe even 93, I can't remember). Made me think that in other markets a lower octane basic petrol is available and that all that we get here is "premium" in those terms.

[John Lawley]

That tank of fuel lasted up till 2 weeks ago and covered 4000miles, i still only use V-power or other hgih octane stuff it's just better :)

Wow, 4,000 miles eh !

Let me have some of that. I'm lucky if I get @400 / 420 on a tankfull unless it's always on a good long steady run when the petrol consumption is rather kinder.

Malc

lol, yes my car has an LPG conversion so as soon as the engine has warmed up it stops using petrol, the mileage would of been further if i kept topping up the lpg instead of waiting till it ran out before re-filliung.

the ferrari F1 teams fuel is very simular to the v-power on the pumps, it was brought in in '94 to reduce the power along with a cut from 3.5 litres to 3 litres and they still hit 1,000bhp in 05.

[John N]

This has been discussed briefly on the forums previously without conclusion, and I have googled without finding a satisfactory answer. Does using premium grade or high octane fuel give any immediate advantages in the VVTi engine? Or does the engine have to 'learn' it is consuming a different fuel over a period of time before it makes any difference. Infact does it make any difference at all ever? Has anybody used premium fuel long term and if so what is your opinion? I can't find anything that seems to give a conclusive answer anywhere and don't want to shell out another 10pence per litre without evidence it is worth it.

Have been meaning to ask the question for some time but thought it might be too boring. However it seems nobody has anything to talk about on here this week so thought I'd make the effort...

I claim no technical expertise but here is my experience over a number of years:

used to use VPower Shell fuel for my Porsche until I discovered that Tesco has a higher octane (99) fuel and have been using that since. The only visible difference was the lower price at Tesco.

have used Tesco 95 octane for the LS400 - as far as I am able to tell it runs just fine.

have experimented with a variety of fuels on cars (other than those above) but have yet to see a difference. Was I lucky? Maybe.

as for the suggestion that Ferrari use Shell I assume reference is made to the Ferrari racing team. Does anyone actually think that the fuel used by Ferrari for racing is the same as what we can buy at the local station?

I am grateful for the technical explanation of why higher octane works the way it works but it does seem inconclusive - based on that explanation alone it would seem that all cars would benefit from a higher octane. Is that the conclusion? Or are there other parameters to consider for each model?

All the best

All car engines benefit from the cleaning additives in the premium fuel, but you won't see any quick difference in performance, and the difference is very small. Cars with electronic engine management systems that adjust the ignition timing to match the fuel octane, are the ones that benefit from the higher octane fuel. (All Lexus)

But the difference in performance is small and is hard to notice as you only have to push the accelerator down another millimetre to get the same performance on 95 octane as 99. This is why people don't notice a improvement, to prove the performance had improved you would have to put the engine on a test bed.

The difference in quality between brands of fuel can make a bigger difference.

Personally I stick to Shell V-power or Tesco Premium when I'm desperate.

John N