95 or 98 petrol - what do you use?

[sunilr1]

So the majority of people here think that filling with "top of the range 98"
' is the way to go, why? cos its 9 is a higher number than 95 I fill my mk6 gti with 95 wollies caltex and comparing it with 98? couldn't detect it apart from m wallet being lighter, lol! This 2L TSI engine in the Tig is not smart enough to detect 98 over 95 anybody who thinks it can, u luv paying tax's.What differentiates petrol these days is the additives not the octane number. What is RON, the resistance to knocking, that's all. If a 98 has more "benefical" additives and you are getting better performance than a 95 all well and good. Our Tig 962 Rline is fed with 95 from woolies. All u 98's gonna beat me off the line I don't think so unless u r a better driver than me in a straight LOL!All u boys filling 98 dream on IMO!!!

[tigger73]

OK here's what happens in your car computer/engine when you feed in fuel that has lower RON than your ECU is set up to run on:



You'll find that the ECU has to pull timing to stop detonation/pinging. If you don't see the value of running on higher RON fuel then stick some 91 RON in your car and you'll understand why you have to run your car on a higher RON fuel.

Check your fuel filler flap and run your car on what the manufacturer recommends. Otherwise you risk doing damage to your engine. If your car is under warranty then you need to use the manufacturer recommended lubricants and fuel to maintain that warranty.

If you're not concerned about warranty then put whatever fuel you like in.

[spacemannz]

My 162 TSI says MIN 95 on the fuel flap. I figure that there is always some variation in octane across the fuel distribution networks.
Reading Tigger73’s synopsis it makes me happy to spend an extra couple of bucks at the pump for 98 in a $50k+ car that I might want to keep beyond the warranty period.
Err on the side of caution in case some dipstick put 91 in the 95 tank and dropped the octane rating down.
Again, not very scientific.
If there is no 98 when I fill up, I won’t lose any sleep putting in a tank of 95.

I guess the only real test is to run the car on a dyno. Perhaps one of the tuners in this forum will think to do a ‘before’ run 95 and 98 before they remap the ecu

[sunilr1]

Same here, our Tig engine is designed to run on 95. No expert here but I guess any engine designed to run on 98 and can run on 95 temporarily has knock sensors that can advance the ignition but this runs the risk of running the engine rich so possibly sending unburn't fuel to the catalyst which will poison it?

[Redfernpoint]

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