What petrol should I use?

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Fri 25 Jul 2003 23:40
What petrol should I use? - Halmer
In our

2002 2.0 Passat
1987 1.3 Golf

We use normal unleaded. I've never put Super unleaded in either of them. Should I?
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Sat 26 Jul 2003 01:54
What petrol should I use? - Dynamic Dave
If the car currently runs ok on what you're putting in the tank, why go to the expense of running it on dearer petrol?
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Sat 26 Jul 2003 08:29
What petrol should I use? - Halmer
So which cars actually need Superunleaded and why?
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Sat 26 Jul 2003 10:34
What petrol should I use? - Roger Jones
Some cars have a preference for super unleaded expressed in the form of a higher RON (research octane number) on their filler caps and in their handbooks. This is the case with my Golf VR6, in which 98 RON is preferred, although it will run happily on regular unleaded (95 RON); it is not the case with my MB E320 Coupé. I believe higher RON is associated with higher compression ratios, which tend to be a feature of high-performance engines. Pinking (a hollow knocking noise) is one sign that you may need to fill up with higher-RON fuel. But there's no point in paying the extra for super unleaded if the fuel specified for the car is not 98 RON or thereabouts.
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Sat 26 Jul 2003 10:50
What petrol should I use? - madman
The higher the RON the slower the burn (I think), therefore putting higher RON fuel in an engine that doesn't need it is false economy, you will probably end up using more fuel anyway.

In my microlight days people used to put leaded into their 2 strokes, the lead was there to raise the RON for high compression engines (not in a 2 stroke) and to lubricate the valves (none in a 2 stroke).

Just because it is called SUPER unleaded it is no better for the engine unless (as in the cases above) the engine was designed for it.

madman
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Sat 26 Jul 2003 11:13
What petrol should I use? - Big John
The later Passat should run better on super unleaded (especially Shell Optimax) as it uses antiknock sensors etc... On the old Golf 1.3 carb it will probably not make any difference to performance.
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Sat 26 Jul 2003 22:40
What petrol should I use? - NitroBurner
No!
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