98 RON on 118TSI

[Jalopy]

2010 118TSI just been for 60k service. The car shudders (mildly) on start-up for about 20 seconds and have been advised by the service guys to run on 98RON. Have always run on 95 and the cap says 91/95. Also have read on various forums that running a car with a 91/95 spec on 98 will give no advantage on consumption or performance. So question is why are the service guys recommending 98? Should ask them should I not but would appreciate your thoughts too.

[brad]

2010 118TSI just been for 60k service. The car shudders (mildly) on start-up for about 20 seconds and have been advised by the service guys to run on 98RON. Have always run on 95 and the cap says 91/95. Also have read on various forums that running a car with a 91/95 spec on 98 will give no advantage on consumption or performance. So question is why are the service guys recommending 98? Should ask them should I not but would appreciate your thoughts too.

I had a 118tsi m6 from new & now have 125,000km on it. It's had a bluefin tune since 50,000km.

I can confirm that running 91ron is for emergencies only & will kill your torque & increase fuel usage by about 15-20%. You might save a few cents at the bowser but your c/km will be about the same or a bit worse.

95ron is the minimum you should use on a long-term basis.

Any fuel with ethanol in it (eg United Plus95 or 100ron or any of the 94ron e10) will send the O2 sensors into a spin & fuel usage will increase thus negating any saving.

100ron e10 or half a tank of e85 mixed with 98ron will make the vehicle very spritely but the fuel usage on diluted e85 will make your eyes water.

It's true that not all cars show any change when using 98ron as their CPU doesn't allow for it but the 118tsi does respond & improve using 98ron.

98ron will definately give better torque & better fuel consumption than 95ron. I doubt it will fix your 20 second vibration on start-up. but the other advantages are worth the extra spend.

Keep in mind that Germany, Czech Republic & Austria (skodas by the thousands in those 3 places) don't even sell 91ron. The minimum available at the pump is 95ron (either straight or e10) or 98-100ron as the PULP. The 91 ron on the Australian fuel cap is to satisfy the needs of tight-arse Aussies.

For the start-up vibes, get them to pull out the sensor at the front of the intake manifold & spray some carbon removal spray onto the valves (both turned off & while running). You might have a bit of carbon build-up in the intakes.

mine gets an initial shudder & then settles into a clockwork smooth idle. Whenever I think it's an issue I have a drive of one of our work corollas & all is forgiven.

[Martin]

Put a tank of 98 through it just to comply with the request - but I agree, it should not need it

A number of things can cause this problem, cracked dual mass flywheel (manual), intermittent cam position sensor, air leak, etc

[Antiplastix]

I m very sceptical about additives but "Nulon total fuel system cleaner" added to a tank of fuel has smoothed out my idle.

[Martin]

That's not a fuel/performance additive - it's a cleaner for the fuel system, injectors and valves
It's the same formula as the Liqui Moly, Repco and other brands
It certainly does work and is very cost effective
I've put it through all three of my cars with noticeable improvement in the idle

[woofy]

I used to put that Nulon cleaner in my first car years ago as the dual carby system on it was very temperamental...sometimes I forget about the bad old days of being a student.