Tescos New 99ron Fuel

[Leeky]

yep thats right :) Tesco have started selling 99ron super unleaded and eventually its going to be available from most of the stations.

Apologies if this is old news, only just heard about it.

apparently it is actually a little stronger than 99 (in the region on 100/101) but unlike Shell optimax it should still be at least 99ron for a good while after it goes into your tank - optimax quickly becomes 97ron or less as it sits in your car.

Havent seen it myself yet but its over the net and in this months j-tuner

[JustJJ]

Yeah Tesco have been selling this for a little while in certain parts of UK... mainly south (east?) I think not sure tho.... I think its been a couple of months... glad to hear they are rolling it out all over tho... could do with some of that here... especially seeing as I dont think its that expensive either is it?

[Flamby]

this sounds good, I think they have been doing it at the tesco's in town for a while leeky haven't they? good to hear though as I might switch to that or try it atleast, and I don't mind on the cost as its part and parcel of having the car really.

[nrgizerbunny]

Leeky where do you get your info from?

[mikeb]

Tesco's have been trialling it in the SE for months now. I would choose it over Optimax anyday.

Why don't we get Shell's V-Power in the UK?

Lifted from mkivsupra.net:

Tesco petrol - reply from Tecso

--------------------------------------------------------------------------------

I emailed Tesco to ask if they would be extending the trial of their 99RON petrol outside of the South any time soon, here is their response....

---

Thank you for your email.

I would like to confirm that we are currently trialing two new grades of Petrol.

1. 99 Octane Super unleaded petrol

Unique to Tesco this grade is now available in 12 stores around the South East.

It has a very high octane content and will benefit high performance vehicles.

2. 97 Octane Super unleaded

This is a standard super unleaded grade with an octane level of 97 RON compared

to normal unleaded at 95 RON. Again this will benefit high performance vehicles,

but not quite as high a quality as the 99 octane product.

The store below are currently included in the trial however roll out of both of

these grades to further stores will be dependent on how well they sell.

Bedford 1

Cheshunt Extra

Crawley Hazelwick

Gallions Reach Extra

Gillingham

Lakeside

Ramsgate Manston

Salisbury 2

Sandhurst

Sevenoaks Riverhead

Stevenage

Winchester

We have no further information at the moment with regards to further store as

this will depend on the sales. However, please do not hesitate to contact us

with any further queries regarding the sale of these grades in the near future.

Thank you for your time.

If you have any further queries please do not hesitate to contact us at

customer.service@tesco.co.uk

[jerry phipps]

Cool look forward to when it arrives near me

jerry!!

[Guest]

yeah they sell it in rainham, well gillingham, bout 7mins from my house, so yeah southeast i guess. lol

ive been using it all the time, its very gd fuel. recomended. feels smooth

[Leeky]

Leeky where do you get your info from?

←

Check out this months J-Tuner magazine ;)

[SMW]

Cheshunt extra Tesco have been selling it for about 3 months now - about 2 mins from my house so I use it a lot.

Got some about a week ago and it was £1.009 p/l.

[Guest]

mine in gillingham was wither 98 or 99 p a litre.

[sotal]

I was reading about this stuff on a motorbike site and they were saying how you should stick well clear of it.

Not sure how true it all is but they were saying (this is for uk vehicles not jap imports) that your vehicle is setup for whatever RON fuel (as we all know) so on my motorbike it says to use 95RON. Basically the higher the RON number, the harder the stuff is to ignite so it makes sure you don't get any pre-ignition knocking etc. In a Jap Import that is perfect because they are setup for 100RON fuel and the fuel does ignite too early if you use 95 RON. For a UK car it's not good at all because the fuel ignites too late. They were testing the 99RON Fuel in UK bikes and got an average of a 10% drop in bhp when using it.

Don't know if it's the same for cars but it's worth bearing in mind rather than just going with the sales pitch from Tescos!!

[Blue84]

Lakeside is the local one to me where I fill up, did get it for a lil while but now it's over 90p a litre...last time it was 92.9p I don't get it, go for the 95.

When I did use it it seems to be decent, had no problems at all

[knowlson]

Hope my local garage gets it

[Karma Supra]

I rememebr an "optimax only" Leeky... "nothing else will do" he mindlessly bleated... :D

Milly has this stuff at work, she said it makes a huge difference!!!

[mikeb]

I was reading about this stuff on a motorbike site and they were saying how you should stick well clear of it.

Not sure how true it all is but they were saying (this is for uk vehicles not jap imports) that your vehicle is setup for whatever RON fuel (as we all know) so on my motorbike it says to use 95RON. Basically the higher the RON number, the harder the stuff is to ignite so it makes sure you don't get any pre-ignition knocking etc. In a Jap Import that is perfect because they are setup for 100RON fuel and the fuel does ignite too early if you use 95 RON. For a UK car it's not good at all because the fuel ignites too late. They were testing the 99RON Fuel in UK bikes and got an average of a 10% drop in bhp when using it.

Don't know if it's the same for cars but it's worth bearing in mind rather than just going with the sales pitch from Tescos!!

←

Flame speed is a function of fuel chemistry, NOT octane rating. Higher octane fuel can withstand higher cylinder pressures/temps without causing knock, but it will still be ignited perfectly well by an ignition spark. Most modern cars (less than 5 years old) will adjust timing automatically to take advantage of higher octane fuels.

The reason the bike testing gave worse results with higher octane fuel was not inherently down to the octane rating of the fuel, more likely the burn speed (perhaps they used high octane 'racing' fuel, which would normally have a faster burn than pump fuel?). As such the fuel would need a different ignition map, and if modified correctly it is most probable that they would have ended up with an increase in power output.

All 'pump' petrol should have the same (or very similar) flame propogation speed, regardless of octane rating.

[Leeky]

I rememebr an "optimax only" Leeky... "nothing else will do" he mindlessly bleated...  :D

Milly has this stuff at work, she said it makes a  huge difference!!!

←

When was that? :P Im am an Esso Supreme fan you know, i dont like optimax ;)

[nrgizerbunny]

in Japan they use a different scale to measure octane number. IIRC its MON not RON.

the octane number is a measure of the fuel to resist self ignition under pressure. So higher octane means you can run a higher compression ratio before the fuel goes bang.

If you don't give two hoots about the environment then adding benzene to the petrol tank in small quantities will take the research octane number well over 100.

[mikeb]

in Japan they use a different scale to measure octane number. IIRC its MON not RON.

←

They use RON in Japan, same as us. And if they don't, they certainly sell 100 RON petrol badged on another scale.

[sotal]

They just use an Octane Figure in the USA, which is MON+RON/2

(MON=Motor Octane Number and RON=Reseach Octane Number)

As for the bikes further reading after your comments proves a haunch that I had, and that is that bikes don't have knock sensors (or atleast mine and the one in the test don't!) Probably EFI bikes would have knock sensors?? So that could well be why it is worse to put it in?? Just something to bear in mind that more isn't always better!

[mikeb]

As for the bikes further reading after your comments proves a haunch that I had, and that is that bikes don't have knock sensors (or atleast mine and the one in the test don't!) Probably EFI bikes would have knock sensors?? So that could well be why it is worse to put it in?? Just something to bear in mind that more isn't always better!

←

Yeah, that would explain it. Carburated engines are unlikely to have an ECU with much intelligence, as it just needs to handle ignition timing.

You're right on the USA octane numbers, but I'm sure they use RON in Japan. <_<

[sotal]

I thought it was quite interesting how they got the MON and RON numbers:

To get the RON and MON figures they use a standardized Single Cylinder Variable Compression ratio Engine. They run the engine at a constant speed (600rpm to get the RON - 900rpm to get the MON). Then they increase the compression ratio until they get knocking. :bookworm:

I'm guessing that cars won't automatically adjust the knock for better fuel - I would have thought they would have a limit so I would still be weary about putting high RON fuel in a standard UK car that was mapped for 95RON fuel and any Carb engined cars should definatley stay well clear of the stuff

[mikeb]

I thought it was quite interesting how they got the MON and RON numbers:

To get the RON and MON figures they use a standardized Single Cylinder Variable Compression ratio Engine. They run the engine at a constant speed (600rpm to get the RON - 900rpm to get the MON). Then they increase the compression ratio until they get knocking.  :bookworm:

I'm guessing that cars won't automatically adjust the knock for better fuel - I would have thought they would have a limit so I would still be weary about putting high RON fuel in a standard UK car that was mapped for 95RON fuel and any Carb engined cars should definatley stay well clear of the stuff

←

They don't 'adjust the knock'. They control it by adjusting the timing. Most modern cars run high(er) compression as this improves efficiency and performance. But lower octane fuel can't handle the high compression with optimum timing. The knock sensor detects this and *momentarily* retards the ignition timing to get around it. If you then use a higher octane fuel, the ECU doesn't have to pull as much (if at all) timing, and the engine can is able to make more hp.

Some of the more advanced modern engines (I think BMW do this), have multiple knock sensors and can work out exactly which cylinder is knocking and adjust the timing individually on a per cylinder basis (they will all have slightly different knock thresholds, even in the best designed engines). Clever, huh? ;)

You're right about the way they test a fuels octane rating by altering compression ratio, but obviously that's not an option for a 'normal' engine. I guess they keep the timing constant and advanced for optimum power for the tests. <_<

[Bizarra]

Don't think that we can get anything like those over here at all. Local Texaco have one pump marked high octane, but it was permanently empty. When I queried this they said that there was no call for it, but that I could buy a red bottle of good stuff & add it to my fill. When I went in they were out of that too :ffs:

[Jesus]

Anybody on here been using it and confident with it?

I need to fill up, and my local store has it.

[TheNissanMan]

OK now another question as seems to be some good knowledge on here...

I drive an import and have advanced the timing (MX5) which apparently helps with UK fuel and has made the car feel quicker....

If I started to use Tesco's 99RON would I have to put the timing back or would I just get better performance again...

Here's hoping I haven't just shown my true ignorance :D