2.5 lite engine owners - what fuel do you use?

[v8250]

Dear All, I'm interested in knowing what fuel you use in your 2.5 litre engines. Your engine, like mine, should be of standard tune. The reason? I'm trying to get to the bottom of all the naysayers/hearsay re' standard 95RON petrol. There's much duff info' on the net/within the forums. If you use 97-99RON please state specifically why. If you've used 95RON petrol and experienced problems, please indicate. This should make for an informative listing...

Note: please do not reply with forum type hearsay comments, only hard facts, thank you

v8250 - 2006 Forester XT - Sainsbury's UL 95 RON [No problem experienced]
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[paulmoonraker]

2007 STi, Shell Vpower or Tesco 99. Because it's mapped for that, and if I use a lesser fuel the engine will explode into a million tiny pieces.

[miket74]

I would never run anything apart from momentum or shell 98. I've just departed from my relationship with Subaru and a 2008 STI due to looming ringland failure. The car was run on these fuels while I had it and I can't vouch for the previous owner but the engine in these 2.5L motors is so fragile I would never consider running it on 95. Once Subaru replace the chocolate EJ25 I'll be a returning customer. I also reckon it's down to luck with these engines so put cash aside for a possible engine failure.

[RB5Bird]

RB5Bird, MY2015 WRX STI, only use VPower (or tesco momentum once a month to use up my money off bits). It says to only use Super on the inside of the fuel cap, what does it say on other models?

[GibsonSG]

I've had two 2.5 WRX's, one hawkeye, one hatch, and between the two done approx. 100k miles. Both totally standard tuning and both ran on 95 RON with no issues (keeping fingers crossed now!)

[cailean]

Is this issue also in Legacy 2.5's (NA) or only the turbo'ed ones?

[bonesX]

Shell is 99 RON BTW

My Subaru's are mapped for 99, so that's what I use

If I am caught short and need to use 95, I'll drive more like a grandad till I can fill up on 99 again

The mapper's I've spoken to (3) all say it shouldn't make any difference

[BenWRXSEi]

2006 hawk WRX wagon. The owners manual says 95 RON is fine, but mine has been PPP'd which specifies 97+ RON. I run it on any super I can find.

[pikeyboy]

I ran 95 Ron in my 2004 outback no problems at all.

[PomBstard]

The three N/A 2.5s I've had (still got one) all took 91RON fine. In fact, the 91 stuff we get here is now E10 which means up to 10% of it could be plant-based ethanol. The 2.0T has a big sticker on the inside of the filler flap saying 98RON only, so that's what it gets. No probs from any of them.

I think the recommended fuel for the 2.5T (from 2004'ish onwards) over here is 95RON, though I've spoken with a few others that have always used 98 for their own belief that its better.

[Contaminated]

2010 WRX hatch. PPP certificate says it will run fine on 95 but 97 is recommended. Only ever put 97 in it.

[bonesX]

Have you tried 99?

[adingley84]

• v8250 - 2006 Forester XT - Sainsbury's UL 95 RON [No problem experienced]
• Adingley84 - 2005 Forester 2.5XT - Tesco Momentum 99 RON. 100k miles and runs like a dream
• Adingley84's Mum - 2006 Forester 2.0 N/A - Tesco 95 RON. 70k miles and air punp/valves just went at cost of 2.5k.

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[Konan]

Please forgive me if this is too far away from the data you requested, but it might have some relevance for testing.

Having run standard 2.0 WRX on 95 vs 97 and looked at the knock correction tables, I saw no correction when on 97 but timing pulled in some cells on 95. The standard WRX is supposed to run on 95, but I ended up running 97.

If you're interested in some cold hard data from your own car, some of the sub £10 VAG-COM cables + free software will enable you to read the fine/rough learning tables.

[lemmingjames]

just stick whatever in mine (Forester XT PPP). What i have noticed recently (though the tyres are nearing the legal limit) is that im getting more mpg using 95 than i am using 99.