Tesco Super Unleaded

[stuthemong]

Well given that Thorney ran 10's of fuel tanks in his own car, throughout a year (to ensure temp/humidty was averaged out) and has his own dyno..... I'd take a lot more salt with hearsay from people on a forum claiming that Thorney's results are rubbish.

All IMHO.

[kds keltec]

stuthemong said:

Well given that Thorney ran 10's of fuel tanks in his own car, throughout a year (to ensure temp/humidty was averaged out) and has his own dyno..... I'd take a lot more salt with hearsay from people on a forum claiming that Thorney's results are rubbish.

All IMHO.

Thank you ! This is why i post the link its the most comprehesive indepentant fuel test that i have seen.....

Many years ago i used to work for a very large world wide company developing building and testing different vehicles and engines on rolling road, climatic rolling road which went down to -40 celcius and 12 seperate dyno rooms !! All the work was for major manufactures and the results are what you see in the press etc (Bhp, corrected Bhp, mpg,and many more)
You would be amazed at some of the results around fuels !!!

This is why i posted the link

[Thorney]

Excuse my short reply but I'm typing this on a phone (and I'm crap at that). As regards the testing we did and are still doing I can confirm the results with complete veracity but yes we were also surprised on the difference on the cal as the common view was that even modern ecus can't advance by more than a few degrees. We spent 8 months on that initial test and are still testing (on turbo engines primarily) we should be releasing that update next month.

[Howitzer]

CarbonM5 said:

M5 Russ said:

My e39 M5 prefers Tesco 99 to Shell Vpower but never used any other super type fuel.

+1

I also tried Texaco super which seemed better than Vpower.Vpower is too expensive and makes for a rough overrun.

Tesco 99 is the cheapest and best ihave tried-their 95 is awful though-the bottom end is so rough,throttle response is numbed and the engine sounds less crisp.

I doubt using 99 would be a 40bhp gain though,probably 20 at most.Its a driveability gain more than anything.

Edited by CarbonM5 on Thursday 14th August 20:36

My friends M5 gets the same issue as my car with Tesco 99, a noticeable drop in economy. Whether on a cruise or fast driving.

Dave!

[RatBoy M3CS]

Well tests and results are what its all about here, which makes for progress for us all to enjoy.. and if these are your findings John, then accepted..

I'm staggered that fuels alone can vary to the tune of 40bhp.. 11%

I do run Tesco's 99 and i do rate it.. and will continue to use it..

Out of interest are the manufacturers claimed results all on regular pump 95, 97 or 99 ..?

Still enjoying the car on the track, and managing to hang onto some of the Porsches..!

Thanks..

Edited by RatBoy M3CS on Saturday 16th August 08:27

[carl_w]

Certainly the claimed power figure for my Z4MC is on 98 RON -- the manual says to only use 95 if you can't find the good stuff.

[Thorney]

if you read you manual you will notice that all manufacturers recommend a min 98. We are still testing now and the main reason for these gains is the development of cars ecu's they really can advance ignition far enough to make use of the better fuel.

[RatBoy M3CS]

Sure, this makes sense now.. i must have misread the earlier post.. and thought the difference on fuels alone was between 95-99 and 40bhp.. apologies..

Does the stock ECU run a static ignition map..?
Or does the S54 engine run independant knock sensors..? and a floating advance map, so this automatically stands the advance off, it it gets really hot and starts to detonate..?

Edited by RatBoy M3CS on Monday 18th August 11:36

[Vixpy1]

RatBoy M3CS said:

Or does the S54 engine run independant knock sensors..? and a floating advance map, so this automatically stands the advance off, it it gets really hot and starts to detonate..?

That and an IAT sensor

[RatBoy M3CS]

I see... so does the CSL ECU automatically advance to get the most out of a 99RON slower burn fuel..?

If the map 'floats' to automatically achieve max advance and results from the fuel, and stand the curve off if it gets too close to det... how can a custom map improve on this..?

I dont know how 'smart' the ecu's are.. i have heard of people ugrading ecu's too..

Does the CSL ECU differ from the stock M3 ECU in this respect..?

Edited by RatBoy M3CS on Monday 18th August 17:34

[matth76]

MrBet said:

I've always filled my E92 M3 up with Tesco super unleaded that says it has an octane rating of 99. In the manual it says use unleaded between octane ratings of 95-98. Am i doing anything detremental?

How do they increase the octane rating? Is it just an additive they put in the fuel.

Short answer (as most have said) is no. Your engine will actually be running safer the higher the octane rating. Less pinking and potential detonation. It's only detrimental if you run a lower rated ron fuel such as 95 ron - same goes for all sports cars - never use 95 ron fuel due to the pinking risk.

[Mroad]

RatBoy M3CS said:

I see... so does the CSL ECU automatically advance to get the most out of a 99RON slower burn fuel..?

If the map 'floats' to automatically achieve max advance and results from the fuel, and stand the curve off if it gets too close to det... how can a custom map improve on this..?

I dont know how 'smart' the ecu's are.. i have heard of people ugrading ecu's too..

Does the CSL ECU differ from the stock M3 ECU in this respect..?

Edited by RatBoy M3CS on Monday 18th August 17:34

I'm no expert but from my understanding the map doesn't float. A standard ECU will have a standard static ignition map and then add to that a correction factor. If "knock" is detected at a specific point it will retard the ignition at that point until knock is not heard. The amount it is retarded from the standard map at that point is the correction factor and that value is stored in the ECU for future use.
This is all well and good if you are say constantly running 99RON fuel (although obviously other factors effect knock such as temperature) but as soon as you stick in a lower RON rated fuel you will get knock "sooner" and the ECU will retard the ignition even more.
Now go and stick 99RON fuel back in again and the old lower RON fuels correction factors will still be used, it will never get to a point where it actually hears knock as it still using the lower RON correction factors. In other words you will be gaining no benefit from say 99RON fuel after you have been using 95RON fuel for a while. To get around this, and from my understanding, the ECU does actually gradually advance the ignition effectively learning new correction factors but this can be a slow process especially to cover all rpm/load etc. points.
This is why reseting ECU's can be a good thing if you are switching fuels, it effectively wipes all the learnt correction factors out and you start with a clean slate.

Perhaps someone with more knowledge than me can confirm, I believe what I have described is the basic way it works, different manufacturers go about it in slightly different ways and I am not sure how more modern ECU's go about this, it may be more elaborate.

Edited by Mroad on Monday 18th August 22:57

[M5Pilot]

MRoad,

That was a good theory and it makes alot of sense. It's probably not far from what's actually going on but until someone comes along with a complete understanding of the ECU and comments we shall never truly know.

[M15ley]

Mroad said:

RatBoy M3CS said:

Edited by RatBoy M3CS on Monday 18th August 17:34

I'm no expert but from my understanding the map doesn't float. A standard ECU will have a standard static ignition map and then add to that a correction factor. If "knock" is detected at a specific point it will retard the ignition at that point until knock is not heard. The amount it is retarded from the standard map at that point is the correction factor and that value is stored in the ECU for future use.
This is all well and good if you are say constantly running 99RON fuel (although obviously other factors effect knock such as temperature) but as soon as you stick in a lower RON rated fuel you will get knock "sooner" and the ECU will retard the ignition even more.
Now go and stick 99RON fuel back in again and the old lower RON fuels correction factors will still be used, it will never get to a point where it actually hears knock as it still using the lower RON correction factors. In other words you will be gaining no benefit from say 99RON fuel after you have been using 95RON fuel for a while. To get around this, and from my understanding, the ECU does actually gradually advance the ignition effectively learning new correction factors but this can be a slow process especially to cover all rpm/load etc. points.
This is why reseting ECU's can be a good thing if you are switching fuels, it effectively wipes all the learnt correction factors out and you start with a clean slate.

Perhaps someone with more knowledge than me can confirm, I believe what I have described is the basic way it works, different manufacturers go about it in slightly different ways and I am not sure how more modern ECU's go about this, it may be more elaborate.

Edited by Mroad on Monday 18th August 22:57

I'm certainly no expert either but this makes sense to me (not saying much really ) I guess the question is how do you reset the ECU so you can take advantage straight away?

[RatBoy M3CS]

The reason i'm exploring this is.. for road use i mostly use 95.. commuting fuel.. when i go to the track, i put 99 in it.. hoping to get some more beans out of it..! which it does seem to do, but if the ECU takes many moons to learn the new det correction factors.. i wont actually be getting the most out of the fuel.. by a long shot.. as the ECU corrections will have been weened on 95 settings.. so how long do you need to run it on 99 to raise the advance curve and get value from 99RON..?

[Mroad]

RatBoy M3CS said:

The reason i'm exploring this is.. for road use i mostly use 95.. commuting fuel.. when i go to the track, i put 99 in it.. hoping to get some more beans out of it..! which it does seem to do, but if the ECU takes many moons to learn the new det correction factors.. i wont actually be getting the most out of the fuel.. by a long shot.. as the ECU corrections will have been weened on 95 settings.. so how long do you need to run it on 99 to raise the advance curve and get value from 99RON..?

I am not sure how long it takes to relearn the correction factor for a particular point, hopefully someone can help here? The problem comes because it has to relearn for ALL the rpm/load etc. points which means it won't relearn until you actually hit all those points while driving and that could take a little while.
If you definitely want maximum power from the engine then run it on a tankful of decent fuel, refill with the same (so now you've made sure it's not diluted down by any previous lower RON fuel in the tank) then reset the ECU (basically disconnect the battery for roughly 15 to 30 minutes). If you do this before a trackday then you will definitely be getting the best you can out of the engine.

Whether you could tell the difference depends on the car/engine used though, obviously turbo engines have the most to gain.

[drivin_me_nuts]

mainly use 99 Tesco in my E39 M5. Use the 95 stuff from time to time and the difference is very noticible. 99 does a good job and the car is smoother and easier to drive.

I've used Vmax on occasion and really can't tell feel any difference between that an the 99. Can anyone else running an E39 M5 tell the difference?

[DjSki]

Website of the people that make the 99 fuel for tesco with spec's if anyone is interested............

http://www.greenergy.com/tesco_99_octane/index.htm...

[mondeoman]

Mine loves texaco premium.

I get about 1.5 gallons extra, no matter what driving style.

With Shell I get about 1 gallon.

Worked out that as long is its no more than 7p/litre more expensive than cooking petrol then I'm quids in (30k mpa)

[Thorney]

Edited by RatBoy M3CS on Monday 18th August 17:34

[/quote]

I'm no expert but from my understanding the map doesn't float. A standard ECU will have a standard static ignition map and then add to that a correction factor. If "knock" is detected at a specific point it will retard the ignition at that point until knock is not heard. The amount it is retarded from the standard map at that point is the correction factor and that value is stored in the ECU for future use.
This is all well and good if you are say constantly running 99RON fuel (although obviously other factors effect knock such as temperature) but as soon as you stick in a lower RON rated fuel you will get knock "sooner" and the ECU will retard the ignition even more.
Now go and stick 99RON fuel back in again and the old lower RON fuels correction factors will still be used, it will never get to a point where it actually hears knock as it still using the lower RON correction factors. In other words you will be gaining no benefit from say 99RON fuel after you have been using 95RON fuel for a while. To get around this, and from my understanding, the ECU does actually gradually advance the ignition effectively learning new correction factors but this can be a slow process especially to cover all rpm/load etc. points.
This is why reseting ECU's can be a good thing if you are switching fuels, it effectively wipes all the learnt correction factors out and you start with a clean slate.

Perhaps someone with more knowledge than me can confirm, I believe what I have described is the basic way it works, different manufacturers go about it in slightly different ways and I am not sure how more modern ECU's go about this, it may be more elaborate.

Edited by Mroad on Monday 18th August 22:57

[/quote]


Thats a pretty good way of explaining it. When we remap a car we change the parameters of fueling and ignition timing (along with non combusting areas such as throttle position maps etc etc) but what we never change is the capacity to retard ignition in regards knock control. Basically this means that remapped cars get even greater performance from higher octane fuel (both in terms of power and better fuel consumption) but they still run the same protection systems if 95 octane is used. What is interesting (and to some extent unexplained) is why some cars are able to adapt to the higher octane fuel quicker than others. In the testing we've been running three full tanks before testing to ensure that the cars ECU adaption is occuring, we can of course clear these (they are are called fuel trim learn values) out by hand on the diagnostic equipment but people tend not to have £25k worth of diagnostic kit when then own a car This means that the cars ECU has plenty of time to adapt. However some cars show an immediate gain straight after re-fueling and some cars need time to adapt. Generally speaking though its less than a tank for the full effect to be felt.

Our current testing is concentrating on VXR Astra's which use a turbo charged engine with close reference to fuel consumption and its effect from octane levels and remapping.