Houghton

iTrader: (1)

I think you'll find that most people have them adjusted for maximum sensitivity and play safe The only real way to tell is to use det cans.

pslewis

As far as I remember (and I haven't used it much, it's simply TOO expensive) it was about 30mpg.

Sainsburys is, by far, the best mix for me - powerful and excellent mpg ..... I was really SHOCKED bt the Tesco stuff!

Pete

pslewis

Hmmmmmm, then they pick up everything going on in the engine bay!!

All they serve to do is to scare the crap out of the owner with it set high .... and to be totaly useless for the owner who has it set to green!!


I just cannot get my mind around people spending really good money on rubbish ............... CockLinks, Re-Maps, Radar Detectors .....

Pete

Gary C

I suppose, when it comes down to it,

higher RON gives a higher resistance to knock which allows us to advance ingnition and burn the fuel more efficiently,

However, the calorific value of a fuel is a measurment of how much heat energy it contains. If a fuel has a higher RON but is more than offset by a significantly lower calorific value, then more fuel will be needed to produce the same power.

Did find mention in an article that higher RON fuels tend to have lower cal as the lighter more volatile elements are reduced, maybe thats the reason.

Also, just read another article that states that Tesco 99 is boosted by the addition of bio-ethenol which 'increases RON but decreases calorific value'

Depends upon how much they add but petrol is quoted as haveing 1.4 times the CV of ethanol.

ricardo

The bio-ethanol is up to 10% of the Tesco 99.

If it was ALL bio-ethanol then you'd get 71% of the calorific value compared to petrol, in other words losing 29% of the total calorific value.
Since only 10% is ethanol then you are losing a tenth of that, so 2.9% less overall, assuming that everything else is the same.

In mine I still get better mileage on the 99, every time, so it isn't just the calorific value.

matchmaker

How is a remap rubbish? Discuss

Gary C

Please, not in this thread

Gary C

So the change in CV can only account for a drop of about 1 MPG. So Mr Lewis's engine must be burning it inefficiently. The only reason I can think the engine would burn a fuel less efficiently would be if the ignition was significantly retarded.

So maybe Pete, you should get one of those thingymabobs that tells you how much advance you are running, and maybe you are getting knock, maybe you should get a kno£"£ a Knoc^%^& a, no I cant say it

Cant think its anything else

pslewis

I can hear knock!! Thanks all the same, I don't need no CockLink to tell me what I can hear!

Remember one VERY important point ........... I was driving 1960s cars, I was driving before electronic help, I was driving before the Playstation Games ....

Hence, I can 'understand' my car, my engine, my mechanical friend ... I can tell whether something is wrong in a fraction of a second - I can also see the mpg figure being halved

And as for £750 for a Re-Map ....................... what a waste of decent cash that could really help someone, somewhere in the world, save a child from dying even!

Pete

Gary C

I would be very suprised if you can hear high speed knock

I too drove before ECU's, fuel injection, even electronic ignition.

Low speed knock/pinking you can hear easily, remember the mid 80's when they changed the grade and most cars had to be retarded ?, but I can't believe you can hear knock at high engine speed when the ECU advances timing (unless its exceptionaly bad)

So, it comes back to the question, if the CV of the fuel can account for about 1-2 MPG then as far as I can see, the engine is burning it less efficiently. So how is this ? Maybe the fuel is heavily contaminated with water at that station ? maybe your timing is retarded ?

Come on Pete, I am trying to take this seriously (with the occasional light hearted leg pull )

pslewis

Thats EXACTLY what ScoobyNet should be like!!

I am at a loss as to why the mpg figure dropped so rapidly with Tesco 99RON - I am not alone in my experience.

A lot may lie with the fact that it is colder, much colder, than it has been for a long time.

As far as I can see, the ECU meters the same amount of fuel for the same conditions ............. the only long term variables, I reckon, are the throttle position and ambient temperature (of, course, loads vary but, over a tankful, it should be equal between one tank and another)

The reason for more throttle could be that the fuel used is not delivering the same energy per drop of your 'normal' fuel ... so the throttle needs a wider opening to get the same speed - hence using more fuel and a lower mpg.

Clearly, ambient temperature has a marked effect, as the injectors are open for longer - injecting more fuel.

And as 85% of my journeys are under 5miles .... I guess I am skewed on the colder weather (my injectors being open longer, for a greater part of each total journey) ......... those doing greater mileages I would guess that the cold weather would skew their mpg figures much less wildly.

So, I guess it is a factor of the very cold weather and the distance a car normally travels on one journey. this gives the difference between those registering a big difference in mpg ...... and those for whom the weather plays a much lesser part.

Well, thats my conclusion anyway ...................... of course, I changed my oil without carrying out the ***** instructions, 5 months ago - maybe that is the reason?? Maybe its my cheap low grade Comma Oil??

Pete

pmarch

All I know is that on my latest fill of Tesco 99RON, I'm still getting an average 29MPG in my bugeye WRX - not bad for the colder winter weather and the extra warm up time etc.

I tend to coast down to roundabouts, keep a big gap ahead in traffic etc. so I don't brake more than necessary - but I assure you that this is compensated by 'more ample' use of revs and pace on quiet fast open roads where it's worth doing.

scooby-tc

iTrader: (2)

I still get around 280 miles to a tank of tescos 99 on my Type R which is better than shell 'optimism'

WRXewl

iTrader: (1)

Sorry but there is no chance at all you were getting 35mpg unless the car was on the back of an AA truck half the time

E

pnbond007

iTrader: (1)

I have to say, though only in my everyday workhorse Focus 1.8 Zetec, I have started to use Tesco 99-Ron, in place of the usual 95-Ron un-leaded.

I travel 150 miles per day 146 of which is motorway, I have noticed that from brim to brim my mileage is increasing by at least 30 miles extra per tank full, giving me at least 37mpg per tank.

Changing back to unleaded gives me only 35mpg, and the car feels very different. I'm sure the 1.8 should thrive on 95-Ron, but not mine.

Bit off the Scooby topic, but thought id'e give my experience a mention

I would be more than happy to use the Tesco 99-Ron if it was available in a garage close to me in Coventry/Nuneaton, but then I haven't really investigated where it is available.

PNB

Smatt

I have been a great believer in Tesco 99. But just recently I have noticed that my sti has not gone so well on it. I am not a petrochemical buff, but am led to believe that fuel loses its strength or ron if it is in the tank to long.
So this in mind!!
I always got it from Winchester as they were the only tesco to sell 99. Then it was availiable in Newbury & now in Basingstoke. It is sold at every pump in all three stores. That is about 40 pumps. You have different tanks for each bank of pumps. So I imagine that the fuel is probably in the tanks longer.
Simple maths example:
5000 users divided by 10 pumps = 500 users per pump @ 1 store.
Now 10000 users divided by 40 pumps = 250 users per pump @ 3 stores.
These are not hard facts but just an example.
At Sainsburys they only have a few pumps with SUL. Normally a bigger queue for these.
More users = fresher fuel.

I do not go by mpg as it is b*##*cks. I drive to the road.
Open road = Size 9 on the loud button
Too much traffic = get the elderly & infirm in bed earlier

My observations are purely on how well it goes. Having had a couple of Scooby's over the last 4 years, I have learnt to tell how good it feels.

pslewis

Smatt ..... you must visit Chineham Tescos then??

Pete

Smatt

I assume that you live in Basingstoke. Yes I have used Chineham & it is fuel from here that I feel is not as good. Sainsbury's at Hatch Warren is always good I have found.

pslewis

Its the TESCO at Chineham that gave me a crappy 15mpg!!!

Sainsburys at Hatch Warren is my station of choice, 35mpg!!

Pete

Gary C

Well then, bad petrol me thinks (probably dumped some diesel in their by mistake )

pslewis

1 Litre of Diesel in a FULL Tank of Petrol is recomended for Upper Cylinder Lubrication.

Pete

ru'

pslewis

You 'Kiddies' know absolutely NOTHING!

pete

L66bad

I certainly don't want diesel running through my injectors

ru'

Yeah, but pslewis has swopped his injectors for a nice carb setup. None of this new fangled technology for him!

pslewis

Indeed .... the old carbs were good

Exactly why would injectors NOT benefit from a weak mixture of diesel??

You lot pour gallons of crap into your tanks in the vain belief it does something .......

Pete

AlanS

[QUOTE=Smatt]I have been a great believer in Tesco 99. But just recently I have noticed that my sti has not gone so well on it. I am not a petrochemical buff, but am led to believe that fuel loses its strength or ron if it is in the tank to long.
QUOTE]

How and why is this so. Does petrol degrade over such a short period of time. Most station tanks must be filled at least once a week and certainly every fortnight.

If petrol degrades as you say, it must breakdown into other less effective substances. Please explain.

pslewis

Its one of those ScoobyNet myths that petrol loses RON Value ....... now, maybe it does in the long term?

But certainly nothing for us all to worry about with a weekly/fortightly change.

Pete

Gary C

!!!!!

Sorry but, this is just stupid to recomend.

Maybe this was done in the 50's in A35's but I dread to think what it would do now. I'd be worried about the Cat and deposits in the cylinders, its effect on RON...........

Or are you pulling our legs ?

pslewis

Could you give some evidence that it would actually do any harm whatsoever??

I am talking very diluted amounts, remember.

Pete