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MonkeyVR6

102 RON petrol!

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Just brimmed my VR6 on Aral 102 Octane petrol. I'm in Germany and normally use Shell V-Power Racing 100...but the 102 octane stuff is slightly cheaper.

 

Do you chaps get this stuff in the UK yet? I remember BP doing 102 petrol near race tracks, but at an utterly obscene price, about £2.50 per litre.

 

Am I going to notice a difference?

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Not seen anything like that here in the UK.. best I think is Tesco's super unleaded which is 99RON!

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Tesco Super (all I ever put in my VR), Shell V-Power, and BP Ultimate are all 99ron, never seen anything higher octane over here.

 

In mine the difference is noticeable between 97 and 99, so I should think you'll feel a difference albeit a small one.

 

If I have to put 97ron in due to a lack of 99, that's when I can feel it most, when stepping down a fuel grade.

 

Then again it could all be psychological! :cuckoo:

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I'm pretty sure tesco is 99 shell is 97 and esso is 96/97. Normal stuff is 95

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The petrol station at Silverstone does 102 RON and im sure they do at other race tracks but it is stupidly expensive!!

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VPower = 99

Tesco = 99

Ultimate = 97

Esso = 98

Morrisons E85 = 105

 

I hear BP are pulling the 102 from silverstone etc. I think people were filling up with Vpower and adding octane boosters, which is cheaper :lol:

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Normal is 95, most supers are 97, V-Power is 99 it was 97 when it was Optimax I believe. They had 100 octane v-power in Germany when I was there 2 years ago yet we still haven't got it over here :(

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Last time I went through the respective websites (how sad?!) Tesco 99 and Shell Vpower were 99 ron with BP Ultimate and Esso Energy whatever trailing behind at 97. BP's Ultimate Ultra (or some similarly irritating oxymoron) comes in at 102 but I've never actually seen it on sale anywhere...

 

For what it's worth my VR is definitely happier on the 99 ron stuff, Esso coming next and a noticeable lethargy with BP's lowly Ultimate 97.

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We had 100 Ron in the early 80s in the UK mate :D

 

I was just a feotus then though! :wave:

 

Yeah I was waiting for that :lol: A bit of history for you then :D -

 

Fuel back then was rated in stars. 5 Star was 100 ron, top of the range uber stuff. 4 star was less ron an not so good quality, then 3 star, and finally 2 star for Schitty Skoda Estelles and the like. It's why in the 80s you used to get low compression normall asp engines to take advantage to of the cheap, low octane fuels. They didn't have knock sensors back then :lol:

 

Trouble was, it was all leaded fuel and was banned as it was proven to be poisonous. The lead made a great upper cylinder lubricant, so when unleaded came along (95 only initially), all the Golf GTis and things that were quick as fook on 5 star, were suddenly sluggish slugs.

 

And the low grade 2 star fuel for cheap skates was so dirty, carbs had to be cleaned out quite regularly :lol:

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My last fill in the G60 was with Tescos normal unleaded as they had run out of super.

 

Filled up yesterday with their new 'Momentum' labelled 99RON, not sure if it is any more use or not but my oil temps are now sitting 6 degrees higher on an identical pre-super run so it burns hotter.

 

The only real advantage of a higher octane fuel is a reduction in the tendancy to knock, unless your ECU can add a shed load of advance you won't see the full benefits of the higher octane stuff.

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I was just a feotus then though! :wave:

 

 

Don't you just hate people born in the '80s...?! :lol:

 

Calvin Harris doesn't "I got love for you if you were born in the 80's" :lol:

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Ive never noticed a real difference running between the normal and higher octance stuff on any of my cars or bikes.

Had this debate with a guy at work was bricking it when the V-power recently ran out as he said his standard S3 would run like crap on 97 :lol:. Surely you only need to use it if you dont have knock sensors and the car is mapped to run with that rating of fuel. Otherwise to me it shouldnt make a markable difference.

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Yep /\

 

There is no performance advantage on a standard car. It always runs the factory preset ignition timing until it detects knock, and then retards it. VW will have set this fairly conservatively to not ping on 95 Unleaded. It won't magically add more advance if you put 99 Ron in.

 

But as there is less chance of knock running 98/99 RON, the knock sensors should never engage (especially on a hot summer's day) and therefore peak peformance will be maintained.

 

Where you have the ability to add more advance, such as with standalones, then you really do start to notice the benefits of high octane :D

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surely if it says "use 98(or 99?) RON" in the filler cap then thats what the engine is best tuned for?

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Then it would say "98 RON ONLY" like import Subarus wouldn't it? But it says 95/98. 98 is 'recommended' because there's less chance of knock.

 

As I said, the ignition timing you get is preset. It doesn't add more. How does the car know you've filled it with 95, 99 or even diesel?

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I'm sorry but unless there is something different about the Corrado VR6 ECU that i don't know about then your prettey much all mistaken. Knock sensor's were installed on cars engines to allow ecu's to control the ignition timing. If the ECU isn't advancing/retarding the ignition timing enough you loosen/tighen up the knock sensor. So when you put in a higher octane fuel you should see the difference prettey much straight away. There is however a nominal fuel rating upon which the cars timing is based, so your car will have it's advance/retard limits, but these are usually well within the boundaries of the fuels readily available.

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You could be right Kip, and I could be wrong, so I've run it by Vince for confirmation as I'm sure we've discussed this before. I would say though that the tension of the knock sensors has no bearing on the amount of timing it can advance/retard by because it's fixed to 12 degrees maximum.

 

From the VR6 Bible - http://www.fennelfamily.com/gti-vr6/eng ... anual.html - I found this:-

 

Functions of Ignition System:

 

.Ignition timing correction

.Dwell angle regulation

.Idling speed stabilization

.Selective cylinder knock regulation

 

The control unit uses the engine load and engine speed signals as well

as

the signal from the throttle valve potentiometer to calculate the

ignition

timing.

 

If signals from the knock sensors indicate knocking combustion, the

control

unit retards the ignition timing of the knocking cylinder by 3' to max.

12'

until the knocking tendency of the concerned cylinder is reduced.

 

When the knocking tendency no longer exists, the ignition timing is

returned

to the nominal value in steps of 0.5'.

 

When knocking occurs, the ignition timing can be different for all

cylinders

because of the selective cylinder knock regulation.

 

Fluctuations in the idling speed range are compensated by changing the

ignition timing with the help of idling speed stabilization.

 

The control unit receives the idling speed signal from the throttle

valve

potentiometer.

 

Dwell angle regulation guarantees the necessary charging time of the

ignition coil and, therefore, ignition voltage, regardless of speed and

load conditions.

 

Coolant temperature signals are required to correct the ignition timing

of a cold engine and activate knock regulation.

 

The first paragraph is slightly misleading though because although it does use load, engine speed, throttle position etc to determine timing, it takes those readings and looks up a 16x16 table of fixed timing numbers. It doesn't say the timing is constantly advanced until it hears knock, but as I say, I'll confirm it either way.

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Either way, I regularly get 30 or 40 more miles out of a tank with Super, which negates it's extra expense per litre.

 

I have also just managed a 37.1mpg run on a leisurely commute back to home over 40 odd miles. This is from cold, with a few miles of twisties, some full throttle out of a couple of roundabouts onto dual carriageway, 35 miles on the motorway at 56mph and a mile of traffic round Chiswick.

 

Not bad for 170k mile 2.9 litre!

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Either way, I regularly get 30 or 40 more miles out of a tank with Super, which negates it's extra expense per litre.

 

I have also just managed a 37.1mpg run on a leisurely commute back to home over 40 odd miles. This is from cold, with a few miles of twisties, some full throttle out of a couple of roundabouts onto dual carriageway, 35 miles on the motorway at 56mph and a mile of traffic round Chiswick.

 

Not bad for 170k mile 2.9 litre!

 

That's very good indeed!

 

I wonder what the extra mileage from the Super unleaded can be attributed to? With the same tank volume and driving style, I don't see how it's possible personally, but I'm not disputing your findings, that's very impressive :D

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I was just a feotus then though! :wave:

 

 

Don't you just hate people born in the '80s...?! :lol:

 

I was born in the nineties!

I used to run the polo on standard stuff, i tried 99ron for a while but didnt notice much difference. I only run the c on 99 though.

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