Tesco's 99 Ron Fuel

[spartacus]

Has anyone had any probelms running this? I filled her up today with Tescos 99 Ron and she generaly ran well for the first 20 minutes or so, then in traffic the tickover seemed to be much lower than normal, say < 900 rpm, and she actualy cut out at one point, but restarted ok and continued my journey. My cerb is a 96 4.2, wondering if the fuel map takes a while to adjust to the higher octaine rating?

[Toady1]

I wonder if it actually is a higher octane than the usual 97 super they stock, (i know it says that it is 99ron on the pump) as when i changed from optimax to tesco's 99ron i thought it made my car run slower. Then the other day i put optimax back in my car and it seems to run better again. mmm....

[mad mark]

not noticed anything different myself. (Optimax v Tesco's99)

[dean_ratpac]

i thought mine ran better on the tesco's but hear it doesn't have as many cleaning agents? otherwise it popped and banged louder with Tesco's too.

the only one i know is over windsor slough way, i've not found one near kingston yet.

[spartacus]

dean_ratpac said:

i thought mine ran better on the tesco's but hear it doesn't have as many cleaning agents? otherwise it popped and banged louder with Tesco's too. the only one i know is over windsor slough way, i've not found one near kingston yet.

There's a Tesco in Leatherhead, which is a nice run from Kingston, if you take the Oxshott road there's a turning on the right just before the Leatherhead roundabout which crosses the M25.

[mart 63]

Anybody used sainsburys 97 super,i've always used optimax but the super is only 92p.

[olly]

We've always used Sainsburys in our car.....

Tesco it definatley doesn't like (rougher running & less happy to idle) & optimax makes it pop & bang less, so have stuck with Sainsburys !

[gazzab]

I thought that supermarket petrol was best avoided?
Werent these fuels contributors to all the nicasil (sp?) probs in the late 90s?

[olly]

There are all sorts of stories about Supermarket fuel :
No additives
The sludge left in the bottom of BP's tanks etc etc

At the other end of the scale
The same tanker delivers to Sainsburys & then goes to BP/Esso/etc.....

I never know what to beleive so go with whats easiest & what makes the car sound better !

[easto]

Optimax definately best for me but station is miles away. just been to Tescos but they haven't got the 99R stuff as yet. So put BP ultimate in, certainly not as responsive and backfires are very strange...

Does the car auto-remap to fuelling. Im sure ive read a post about resetting the ECU to gain best results when moving from extensive use of one 'ron' to another

[purpleheadedcerb]

olly said:

There are all sorts of stories about Supermarket fuel : No additives The sludge left in the bottom of BP's tanks etc etc At the other end of the scale The same tanker delivers to Sainsburys & then goes to BP/Esso/etc..... I never know what to beleive so go with whats easiest & what makes the car sound better !

All myths propogated by the big petrol firms trying to edge out the supermarkets who are beating them at their own game. It's all the same stuff except for the 'post mix' additives (so a bloke down the pub said who once saw it on a forum!!Ha.)

[NJW 77]

Ive heard the no additives theory from different sources, as well as the bottom of the tank theory, now Im just confused.

Found my first Super 99 Tescos in Bow, East London yesterday, but was in the Audi so tried it out anyway. Dont think the car was any faster, but it felt like it

At 95.9p/l it is 5p/l cheaper than my local Optimax

[satman]

spartacus said:

wondering if the fuel map takes a while to adjust to the higher octaine rating?

Im sure the map isnt self adjusting as such...the Redrose cars had a button to adjust the ignition advance, which meant that the ECU used in those cars had 2 maps...fairly sure all the others dont.

[Julian64]

True and false. It does have an ability to change while running but only a small amount compared to a giant amount for a remap. On your dealer software or the MBE software I'm thinking of the adaptives.

[spartacus]

Julian64 said:

True and false. It does have an ability to change while running but only a small amount compared to a giant amount for a remap. On your dealer software or the MBE software I'm thinking of the adaptives.

I drove her again since the original problem, sat in a fair bit of traffic, no re-occurance.
Either the problem was totally unrelated to the 99 ron fuel, or possibly the map (adaptive to be precise) have slightly adjusted the timing to compensate, who knows!

[purpleheadedcerb]

I did a 300 mile trip yesterday and used Tesco 99, then Half a tank of Shell optimax and the Sainsburys 97ron and couldn't tell the difference between any of them!