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Discussion Starter #1
Hi,

Would just first like to say a big hello to the GTA forum (Intro Hello => http://www.alfaowner.com/Forum/introduce-yourself/178979-my-first-alfa-156-gta.html). I just bought a 156 GTA and would like to know if anyone regularly uses Tesco's super unleaded / Tesco 99 Octane.

I think it's been said on this forum that there might be a slight improvement in mpg but that was a few years ago, so was hoping to see if any regular GTA user has seen other benefits over the longer term. How does it compare with Shell V-Power and BP's Ultimate?

Cheers
Bobby
 

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I aint in a GTA but I can speak for most when I say, choose the Vpower or Ultimate option.
I was sceptical at first as I have never really noticed any marked difference in noise/performance/economy.

I'm also Scottish and violently allergic to spending money, but after 3 weeks on Shell V-Power I seem to get similar fuel economy, but more importantly the car is much quieter and more responsive.

Others noted poor performance with supermaket fuels.
 

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Not a GTA, but I used Tesco 99RON until having to cut back financially and went back to normal Tesco 95RON.
 

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you wont get any difference in performance as your car is mapped optimally for 95 ron unleaded.
you may notice an improvement in mpg, which IMO is a result of the fact youve spent more on the tankfull, and therefore want to beleive that you are somehow saving (when in fact you arent) ;)
 

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you wont get any difference in performance as your car is mapped optimally for 95 ron unleaded.
you may notice an improvement in mpg, which IMO is a result of the fact youve spent more on the tankfull, and therefore want to beleive that you are somehow saving (when in fact you arent) ;)
It has adaptive motormanagement, so should take advantage of the higher RON performance wise....
 

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really? if its adaptive - why do people remap?
from elearn:
-self-learning;
-system self-adaptation;
-autodiagnosis;
-control of knock;
...
Stored in the control unit, there is a map containing the entire set of optimum ignition advance values (for the cylinder at the power stroke) that the engine can adopt in relation to the rpm and required engine load.
The control unit corrects the advance values mainly in accordance with:
-engine coolant temperature;
-intake air temperature;
-detonation.
The information the control unit processes in order to drive the single coils is received in the form of electrical signals emitted by:
...
-detonation sensors (on the upper part of the cylinder block/crankcase between the two heads) to recognize the cylinder where detonation is occurring and correct the ignition advance;

System self-adaptation
The control unit has a self-adaption function which recognizes changes in the engine which occur as a result of bedding-in and ageing processes of both components and the engine itself.
There are two adaptation functions according to two intervention plans: minimum and usage

Check on knocking
The control unit can delay the ignition selectively at the cylinder required, according to the combination of figures received from the detonation and timing sensors and:
-reduces the ignition advance in steps of 3° up to a maximum of 9°;
-updates the level to take into account background noise and ageing of the engine

During acceleration, the control unit uses a higher threshold for the increased engine noise.
When the detonation disappears, the control unit increases the ignition advance in steps of 0.75°

With the auto-adjustment function, the control unit:
-memorizes the various advance reductions, continuously repeated;
-adapts the map to the different engine conditions.
etc.etc.

In short, it detects knock and adjusts timing accordingly, i.e. it compensates for RON


It mainly adjusts timing within certain parameters of course, with chiptuning you can also look at other parameters and/or adjust the maps
However, in standard form, it does compensate for the quality of the petrol....
 

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Thats right. Infact most modern cars have the ability to "learn" new fuels. I tried Tesco 99 for a few tanks and did notice better mpg, but all too often my local one had no 99 in stock, and if you alternate every tank then benefits are negligable, it takes a few tankfuls to adapt.

BTW I predominantly have used Tesco 95 (probably 90% of the time) and 81k miles later no problems whatsoever
 

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I tried V power in my chipped Fiat Coupe and it made quite a big difference.

However I haven't noticed any difference on any of the other cars I have used it on, all of the Alfa's included.
 

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....., it takes a few tankfuls to adapt.
...
You can sometimes speed the process up a bit by disconnecting the battery for 10 minutes or so... resets the parameters to factory default as the starting point from which to subsequently adjust...
 

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Discussion Starter #12
I'd be interested to know if there has been any longer term study on it's claims for being cleaner. VPower has cleaning 'additives' but Tesco 99 claims its cleaner from the start by producing lesser engine deposits - my main concerns are on the longer term effect of using Tesco's. Sadly, the memories of contaminated supermarket fuel from 2 years past are still fresh... I have always wondered why they did not rebrand the 99 and made it distinct from their standard unleaded - something like Tesco's Finest :)
 

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All modern fuels have cleaning additives anyway. I remember back in the early-mid 1990's shell introduced their advance range of fuels with detergent additives to keep engines clean.

People avoided supermarket fuel for a while as they did not contain the additives. Although the supermarkets added them as well after a while.

Maybe the V power type fuels have a better detergent package, but if you believed the hype from way back then the ordinary fuel won't be all that bad anyway.. :)
 

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from elearn:
In short, it detects knock and adjusts timing accordingly, i.e. it compensates for RON


It mainly adjusts timing within certain parameters of course, with chiptuning you can also look at other parameters and/or adjust the maps
However, in standard form, it does compensate for the quality of the petrol....
are you saying that it will make more power if you use 99 ron as opposed to 95 ron?
Do you have any proof? Im pretty sure weve discussed this before?
Id be interesed to see the graphs on a dyno back to back between a gta run on 95 ron and then on 99 to see the increase.......
 

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are you saying that it will make more power if you use 99 ron as opposed to 95 ron?
Do you have any proof? Im pretty sure weve discussed this before?
Id be interesed to see the graphs on a dyno back to back between a gta run on 95 ron and then on 99 to see the increase.......
I'm just telling you what the workshop manual tells you, and what i've noticed :)
Don't expect major differences, but yes, it does have an effect (after a while)... Don't expect a difference just filling up with 99 after using 95, it takes a while to adjust...
P.S. there have actually been tests on a rolling road, done by car magazines, showing a difference on modern motor mgt systems.... I'll see if I can find one...
 

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See here f.i.
http://www.caranddriving.com/features2/BP%20ultimate.pdf

However, ultimately ;), you're obviously free to use what you want.... I notice a difference using 98 instead of 95.....
Obviously, don't expect a major power increase.... it just adjusts the timing somewhat to take advantage of the later onset of knocking...

edit: one more:
Tested: the best performance fuels - Car and Car-Buying News - What Car?
hmm.... the first one appears to be an informercial for BP ultimate using a Lotus Elise as a test mule, the second seems more unbiased, but uses a BMW M3 as its test donkey - a car which is mapped to run on super unleaded from the factory...

shame there are no actual test results printed
 

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for what its worth i used to have a CRX del sol, an import SiR model which is mapped in Japan to run on their higher octane fuels. I thought it seemed a lot more agressive and more powerful on the 95 fuel than V power and there was no noticable difference in economy when i was doing motorway trips upto leeds and back and if anything this is when the better fuel should have made the biggest difference.

It did make the engine slightly quieter i would say or smoother, but as far as anything else .. no difference and as a result couldnt justify the price difference and have used 95 since
 
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are you saying that it will make more power if you use 99 ron as opposed to 95 ron?
Do you have any proof? Im pretty sure weve discussed this before?
Id be interesed to see the graphs on a dyno back to back between a gta run on 95 ron and then on 99 to see the increase.......
I think what would happen is potentially the power could increase to a certain extent when using high ron fuel.
I read earlier that the ECM will adjust the ignition with 0.75deg increments when it doesnt detect knock but at the end of the day it depends to what the upper limits are for ignition timing.
To your point if the upper limits are not very far off the baseline 95 octane optimised maps then there won't be much to gain. But if lets say there is an extra 4 degrees of margin then there would be some positive effects.

I have always used v-power but i can say that i haven't really noticed and difference, on the contrast my old Vauxhall V6's would fly with high octane fuel.
 
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