95 vs. 98 RON Unleaded - How much difference does it make?

[DreamInCode]

Today just noticed that owner's manual 'recommends' use of 98 RON fuel. I've been running mine in 95RON from Tescos since I got it couple of months ago.

Has anyone tried running it in both and noticed any significant difference to justify the higher expense? Is there any chance of long term to the engine if it's always run on 95?

 

[Sparks43]

Today just noticed that owner's manual 'recommends' use of 98 RON fuel. I've been running mine in 95RON from Tescos since I got it couple of months ago.

Has anyone tried running it in both and noticed any significant difference to justify the higher expense? Is there any chance of long term to the engine if it's always run on 95?

View attachment 235483

Always run my S3's with High Octane fuel - Shell V power usually - You do get better mpg and better for the engine with the cleaning agents especially over supermarket fuel.

 

[DreamInCode]

Always run my S3's with High Octane fuel - Shell V power usually - You do get better mpg and better for the engine with the cleaning agents especially over supermarket fuel.

Makes perfect sense to use higher octane fuel for a high specific output engine. I'm just not sure about the standard A3 engine. May be I'll bite the bullet and run it on 98 for a few fill ups and see how it goes.

 

[AdamInKent]

Today just noticed that owner's manual 'recommends' use of 98 RON fuel. I've been running mine in 95RON from Tescos since I got it couple of months ago.

Has anyone tried running it in both and noticed any significant difference to justify the higher expense? Is there any chance of long term to the engine if it's always run on 95?

View attachment 235483

It might be worth pointing out that the high octane label only applies to high power cars. Most A3’s will use the preceding label shown in the manual which is for RON 95:

The label for your particular car should be on the inside of the fuel filler flap.

 

[KXL]

Ouch, running a S3 (or 2.0TFSI 190) on supermarket fuel. There's also Momentum 99 petrol on some/most tesco filling stations which would suit the car better. I've only ever used supermarket fuel in emergencies on my 1.0 / 1.5 normal engine let alone a high performance motor. On the S3 I believe you can actually feel the difference between 95 and 98/99 RON fuels. Some tests show even a significant bhp increase with higher RON fuel. My experience on both 1.0TSI and a 1.5T (on a Volvo V40), Esso/Shell/Jet/BP/Texaco 95RON fuel were indistiguishable from each other peformance/economy wise. Esso 97 (at the time) gave me smoothest engine, Vpower 99 gave me more mpg (but not enough to make it cheaper to use it all the time). I didn't really notice any more power, but then again even if I have 5bhp more on either engine and without a specialist timing gear or dyno it would not really be noticeable to me. In an S3 or similar, you may be able to feel the difference.
Actually remember in my Volvo V40 the fuel grade recommended was 95-98RON. 95 was for normal driving, and 98 was for 'hot weather' and 'maximum performance and economy' as stated in the manual.

 

[auzzam_crd]

Can't comment on the s3 particularly but I second a performance engine should be run on higher octane.

That's what I run in the Supra and it does feel noticeably better! Even pops the odd flame lol

 

[HulkRS3]

Tesco Momentum 99ron for me

 

[Damian01]

Tesco Momentum 99ron for me

+1 for Tesco 99 momentum

 

[RS3 S.]

I mostly use Shell V power in mine but the price at my local at the moment is £1.45 a litre!!!!!. Sometimes use the Esso synergy but that's only 97 Ron. Never use standard 95 Ron.

 

[KXL]

Sometimes use the Esso synergy but that's only 97 Ron. Never use standard 95 Ron.

I thought Esso by now would have shelved their 97 RON and now are the 3 supplier for 99 RON alongside Tesco Momentum and Shell VPower?

 

[DE1975]

Just looked up the compression ratios for the various petrol engines. It's 10.5:1 for the 1.0 and 1.5 TFSI and 9.3:1 for the S3.

That surprised me actually as it would suggest the strongest argument for using higher octane fuel is in the 30/35 TFSI engines over the S3!

 

[KXL]

Well back in the day on my weekly (have done this same trip for years) Sunday 830 morning East to West London city run with a short stint at 40mph A40 (so very minimal traffic) on the said 1.0TSI, would give me 48-51mpg everytime on this trip on 95RON/Momentum99/Esso97. The latter 2 would give me always over 50mpg. On the Vpower 99 trips the said trip computer showed 57-59mpg same trip. Perhaps the Vpower 99 is the the true 99 RON king? On a 1.0TSI well can't feel any more oomph though I never put pedal to medal in the city.

 

[DreamInCode]

Just looked up the compression ratios for the various petrol engines. It's 10.5:1 for the 1.0 and 1.5 TFSI and 9.3:1 for the S3.

That surprised me actually as it would suggest the strongest argument for using higher octane fuel is in the 30/35 TFSI engines over the S3!

WOW! Didn't know that. Everyday is a school day!

That and both TFSI engines also produce 100hp/l, so should see some increase in power with higher octane fuel.

 

[Billy Shears]

Well back in the day on my weekly (have done this same trip for years) Sunday 830 morning East to West London city run with a short stint at 40mph A40 (so very minimal traffic) on the said 1.0TSI, would give me 48-51mpg everytime on this trip on 95RON/Momentum99/Esso97. The latter 2 would give me always over 50mpg. On the Vpower 99 trips the said trip computer showed 57-59mpg same trip. Perhaps the Vpower 99 is the the true 99 RON king? On a 1.0TSI well can't feel any more oomph though I never put pedal to medal in the city.

That's really interesting actually. I used to read the Honest John website a few years ago (it's more than dreadful now) and he was always adamant that Premium fuel would me more economical because it helps create more torque in low rev ranges.

 

[dave_beastttt]

Who remembers BP102?

 

[KXL]

That's really interesting actually. I used to read the Honest John website a few years ago (it's more than dreadful now) and he was always adamant that Premium fuel would me more economical because it helps create more torque in low rev ranges.

Even on my 1.5T Volvo V40, the mpg gains were there, but just a lot less. Eg...my place to Stansted (done it many times) usually 48-50mpg doing around 40-70mph depending on the road I'm on. Once I forgot at the time I had a tank of Vpower, and saw 52mpg end of trip, was thinking nice....next day I realised. However as Vpower and Esso 97 were quite a chunk more expensive, the extra mpg gains, did not offset the extra price (on the 1.0TSI it came very close, but still no). So I only fill those occasionally, maybe when Shell app gives some £ off per litre or when I get enough clubcard points for those Esso/Tesco stations.

 

[Jassyo06]

I've ran 2 S3's over the last 6 years and Used unleaded and super unleaded in both cars
My findings between both types of fuel where
Engine was slightly more responsive with super unleaded

MPG not that much difference that's worth mentioning


Sent from my SM-A715F using Tapatalk

 

[Spike107]

Anyone putting Super unleaded in a 1.0 car is literally throwing money down the drain... Your not going to see any performance gains for the extra cost. Your better off with 95 Ron and chucking on a can of Redex in every so often if your worried about the addional addatives imo

 

[Maddave]

Fuel is changing in September, apparently they are ditching E5 and bringing in E10 (vegetable fuel lol). Only likes of Shell Vpower will have proper ingredients for about 5 years, until that is banned.