fuel

[joey]

should i use unleaded or super unleaded on a 150bhp engine...any ideas or advice would be helpful. thanks.

[The_Doc]

It’ll tell you what octane to use inside the filler flap, use whatever it says to use there.

[clarky92]

should i use unleaded or super unleaded on a 150bhp engine...any ideas or advice would be helpful. thanks.

I used 95 on the 110etsi and also the 150tsi I used to have. Great fuel economy on those and no issues on 95. But there is definitely a difference between 95 and 99 now in my Clubsport. It feels sluggish on 95

But you can put in whatever the sticker on the fuel filler cap says and the car will run

[The_Doc]

should i use unleaded or super unleaded on a 150bhp engine...any ideas or advice would be helpful. thanks.

I used 95 on the 110etsi and also the 150tsi I used to have. Great fuel economy on those and no issues on 95. But there is definitely a difference between 95 and 99 now in my Clubsport. It feels sluggish on 95

But you can put in whatever the sticker on the fuel filler cap says and the car will run

Yeah, the clubby specifies 98 octane, the 95 is an alternate fuel for when you can’t get 98, but should only be used to get you to some 98 asap. It shouldn’t hurt the car, but you’ll notice the loss of power.

[valentino]

I always try to use the higher octane premium fuel in my GTI
Wether  its a waste or not who knows

[BillSan]

On the other hand I've now done 30k miles in my CS and only put super unleaded in about 5-10 times.

It hasn't caused any problems at all and I can't say I've ever noticed a lack of performance.  Admittedly my car spends most of it's time on urban roads and usually in traffic where performance isn't an option.

I've got a few longer and more spirited drives planned though and I plan to try 98 fuel now that you've reminded us.  I'll see if I notice any difference but I'm not expecting too.

[jh_97]

Ran 95 in my 7.5 for the first few tanks, then trialed V-Power 99 for three tanks. At first, I thought the engine felt a tad smoother with the 99 but no difference with performance or MPG. Going back to 95, I couldn't tell a difference, so perhaps it was all placebo... That said, I still run the odd tank of V-Power hoping the additional detergents etc help to keep everything clean, although I do have a Shell station a mile up the road that's pretty cheap. Granted I'm not in a TCR or Clubsport, but the manual says not to expect any additional benefits when running higher octanes, despite the VW website saying they do recommend it for performance Golfs 
https://www.volkswagen.co.uk/en/need-help/need-help-faqs/fuel.html

I'd say trial a few tanks of both and see if you think the extra cost is worth it.

[monkeyhanger]

It's as simple as checking the fuel cap - if the cap recommends RON95, use RON95, if it says RON98, use 97/98/99.

Some people think higher RON fuel is more calorific, its not. The more powerful cars need more fuel per combustion cycle to derive that power. You cannot get enough RON95 in per combustion cycle to generate 300+ hp without it pinking when compressed.

Higher RON fuels are less volatile, so you can inject more without fear of pinking. The likes of my S3, the Golf R and very high outputs of GTI editions are recommended RON98 because otherwise they would be limited on output. When these cars know they're running on RON95, the engine management limits output to about 280ps, because that's as high as you can reliably get with RON95 fuel and no pinking. If you have a 245ps GTI, there's no need to feed it 97/98/99, apart from the possibility of having more detergent additives in it.

I usually use RON97 from Costco for my S3, but I have been away with work, drove Newcastle to Heathrow for my flight. By the time I got my car back from Heathrow external parking, it was 10pm,Watford Costco petrol station would be closed, so went with Tesco extra 3 miles from Heathrow to fill up for the journey home. It's Momentum 99, made absolutely no difference to the car's output or mpg having RON99 vs the usual RON97, the car can compress and combust both without pinking.

[Adam T7]

My annual mileage is small so running higher cost RON 99 Shell V Power doesn’t really hit the wallet but hopefully the added detergents help. I ran with half a tank of E10 once as that’s all I could get to get me home, couldn’t tell any difference in performance TBH.

[monkeyhanger]

My annual mileage is small so running higher cost RON 99 Shell V Power doesn’t really hit the wallet but hopefully the added detergents help. I ran with half a tank of E10 once as that’s all I could get to get me home, couldn’t tell any difference in performance TBH.

If yours puts out less than 280ps, or if it puts out more but you weren't wringing it's neck then you wouldn't see any difference. All things being equal, you'd see a marginal improvement in fuel economy using an E5 higher RON fuel than E10 RON95, because of half the alcohol content. Ethanol only outputs around 70% of the energy pure petrol does, so with 10% ethanol, you've only got 97% of the energy vs pue petrol, with E5 fuels, its 98.5% - marginal difference,maybe 0.5mpg if you are very careful.