will a wrx/sti run ok on 95 ron?
16 August 2012, 07:54 AM
#91
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Some people are just dumb, its a known fact that the engine will knock on low octane fuel under high boost, ive run 95ron one time in my Legacy Turbo and my Knocklink went crazy the only one time i tried to use the accelerator pedal, the reason i even filled it with 95ron was becouse the tank station didnt have 98ron and i was on my way home after i bought the car. Since then ive only used 98ron and the engine never knocks with that. But i guess if you never exceed 3000rpm and go under boost you can run 95ron with no problems, but i think the most owners want to use the car and then you need 98ron or higher to be safe. Doesnt matter what is says in the book....
16 August 2012, 08:01 AM
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Tony
16 August 2012, 09:28 PM
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i have been running an 03 stock WRX on 95 ron for the last couple of miles (just to get home) and never heard anything at all, i assumed the ecu would automatically retard the timing, starting the think i was wrong now! 
16 August 2012, 09:37 PM
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On a standard car it's fine. I've just bought a 2001 WRX, the previous owner used 95 RON, learned knock was minimal. It'll certainly run/feel better on 99RON but your engine will be fine. This is the learned knock from the car on the day I got it -
17 August 2012, 02:24 AM
#97
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Truth is, the wrx ppp develops more power than a standard sti. Sure, slightly different exhaust etc, but I'd be interested to see if an sti *could* run on 95. Not just rhetoric, name calling, and "my mate down the pub heard from his mates sisters brothers 2nd cousin twice removed that it makes your engine go bang" type statements. Has anyone ACTUALLY had an engine let go specifically because of 95 RON?? I've not seen any concrete evidence anywhere on any forum, talking to other owners, nor talking to Subaru mechanics. Cars sold in the UK have to be able to run 95 RON without problems, so where's the evidence? Surely Subaru would then be liable if an engine did let go...
Last edited by chickentikka25; 17 August 2012 at 02:26 AM.
17 August 2012, 10:50 AM
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Come to think of it, my bugeye wrx is almost 10 years old and has done almost 65k now, due to the fact its completely standard I doubt the previous owner was much of an enthusiast so ill make a guess its been run on 95 Ron, but the engine is entirely healthy.
17 August 2012, 10:56 AM
#100
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Well thats not true to start with 
for example, all 2ltr UK STI's ran 265ps, the wrx ppp on the MY01/02 cars was 245ps, this increased for the 03-05 cars to 265ps (on super unleaded fuel), if ran on 95 ron the figure is about 20ps lower.
Yes there have been plenty of cases of engines letting go because of running 95 ron (or even a bad batch of fuel) in UK/EU spec STI's, originally back in 2002 when the STI was introduced to the UK, about 5 reported cases (on here) of melted pistons due to the incorrect type of fuel used, it was even reported by one of our more senior members that the car he test drove was detting due to incorrect fuel (and its bad when you can hear it det), so its pretty much proven its a 
to run 95 ron fuel in a car that clearly states on the fuel cap that 98ron fuel must be used (though the handbook does state that in cases of emergency 95 ron can be used, but I wouldnt exceed 2.5-3k rpm on that, much cheaper to buy a bottle or 2 of octane booster for those situations).
Plenty of evidence, this includes speaking with knowledgable Subaru Mechanics or speciallists who will advise against running 95 ron on an STI.
Total myth about having to be able to run 95 ron, as its been pointed out many a time, around 90% of garages provide a minimum super unleaded fuel of 97 ron, you would have to be out on the scottish isles not to get 97+, and cars like the Honda S2000 have a minimum fuel requirement of 97 ron.
Also if the engine let go due to running the fuel that Subaru didnt recommend, its the owners fault unless the tank at the petrol station had been filled incorrectly, and Subaru will not cover damage done in this way.
Tony
for example, all 2ltr UK STI's ran 265ps, the wrx ppp on the MY01/02 cars was 245ps, this increased for the 03-05 cars to 265ps (on super unleaded fuel), if ran on 95 ron the figure is about 20ps lower.
Sure, slightly different exhaust etc, but I'd be interested to see if an sti *could* run on 95. Not just rhetoric, name calling, and "my mate down the pub heard from his mates sisters brothers 2nd cousin twice removed that it makes your engine go bang" type statements. Has anyone ACTUALLY had an engine let go specifically because of 95 RON??
to run 95 ron fuel in a car that clearly states on the fuel cap that 98ron fuel must be used (though the handbook does state that in cases of emergency 95 ron can be used, but I wouldnt exceed 2.5-3k rpm on that, much cheaper to buy a bottle or 2 of octane booster for those situations).
I've not seen any concrete evidence anywhere on any forum, talking to other owners, nor talking to Subaru mechanics.
Cars sold in the UK have to be able to run 95 RON without problems, so where's the evidence? Surely Subaru would then be liable if an engine did let go...
Also if the engine let go due to running the fuel that Subaru didnt recommend, its the owners fault unless the tank at the petrol station had been filled incorrectly, and Subaru will not cover damage done in this way.
Tony
17 August 2012, 10:58 AM
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17 August 2012, 02:41 PM
#104
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I bought my 03 WRX with PPP and on the certificate from Prodrive says that the car is mapped to run safely on 95 however it is preferential to run at 98+.
I always use V-power or Tesco momentum though. More power, cleaner engine and less prone to knocking for 5p a litre more? Bargain!!!
The STi PPP certificate says that it must still be run on 97ron though.
I always use V-power or Tesco momentum though. More power, cleaner engine and less prone to knocking for 5p a litre more? Bargain!!!
The STi PPP certificate says that it must still be run on 97ron though.
17 August 2012, 04:15 PM
#105
no mention of 95 being "emergency use only" or damaging the engine. If i had an STI blow up due to 95 i would be going to Subaru and showing them this page in THEIR drivers manual , and asking why they say it can be run on 95.
Last edited by CharlySkunkWeed; 17 August 2012 at 04:22 PM.
17 August 2012, 04:53 PM
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(also note the wording in the handbook )Its an old argument and subaru will not cover damage done to the engine by misuse of incorrect fuels.
If you look in the back of the handbook it will give you the minimum requirement for fuel etc, even in the brochure it states 98 ron minimum, if you wish to run a UK STI on 95 ron (god knows why if super is available, 5ppl or 3 quid a tank or 3k for an engine... hmmm, hard one
) help yourself but it will det.Tony
Last edited by TonyBurns; 17 August 2012 at 04:55 PM.
17 August 2012, 06:26 PM
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Yeh you're probably right on power front - I had 261 vs 265 but it may well be (mine's MY05). Either way. PPP = fine on 95 RON, so why not the STi? Interested to know! Map? In which case that's changed easily enough....
Interesting point made about Subaru won't cover issues by use of incorrect fuels; they say themselves in my manual that 95's OK
Interesting point made about Subaru won't cover issues by use of incorrect fuels; they say themselves in my manual that 95's OK
17 August 2012, 07:37 PM
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They dont actually say its ok to run 95 in an STI, they still state quite clearly that you need to run the car on 98 octane, what they say in the book is that it "may" be used if 98 is not available, but if you check out the table in the back it will clearly state what fuel is to be used minimum (98 ron).
Yes maps are different, much more agressive as ive stated, hence why 98 ron fuel, and the ppp will only produce its power of 265ps on super, it will be well down on that on 95 (see 20ps less), as that map on the wrx is a custom map from Prodrive.
Tony
Yes maps are different, much more agressive as ive stated, hence why 98 ron fuel, and the ppp will only produce its power of 265ps on super, it will be well down on that on 95 (see 20ps less), as that map on the wrx is a custom map from Prodrive.
Tony
19 August 2012, 06:54 PM
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Ah the non committal 'may' word, always to be treated with caution! Thanks Tony. And Ginger, yep, I get more mpg and loads more performance on a decent fuel - but I have a fuel card which stipulates 95 RON. I have argued the point, but the bean counters just don't get it ....
19 August 2012, 07:29 PM
#111
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A couple of well respected mappers have said before that it is possible to run the STI on 95ron. The ECU is a very intelligent piece of kit and it will pull timing back when it sees knock, so if you run on 95 all the time it should be fine. The problem comes when a car ran on 98 or 99 ron is run on 95ron and immediately driven hard, sometimes the ECU cannot react quick enough to this drastic change.
Im not advising running on 95ron but for a case like the OP I think you could. Personally if your going to mod it a bit anyway then do the mods and take it and get it mapped for 95 and have the second map on 97/99, whatever rating the super is near you, best of both worlds then.
Im not advising running on 95ron but for a case like the OP I think you could. Personally if your going to mod it a bit anyway then do the mods and take it and get it mapped for 95 and have the second map on 97/99, whatever rating the super is near you, best of both worlds then.
19 August 2012, 07:41 PM
#112
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A couple of well respected mappers have said before that it is possible to run the STI on 95ron. The ECU is a very intelligent piece of kit and it will pull timing back when it sees knock, so if you run on 95 all the time it should be fine. The problem comes when a car ran on 98 or 99 ron is run on 95ron and immediately driven hard, sometimes the ECU cannot react quick enough to this drastic change.
Im not advising running on 95ron but for a case like the OP I think you could. Personally if your going to mod it a bit anyway then do the mods and take it and get it mapped for 95 and have the second map on 97/99, whatever rating the super is near you, best of both worlds then.
Im not advising running on 95ron but for a case like the OP I think you could. Personally if your going to mod it a bit anyway then do the mods and take it and get it mapped for 95 and have the second map on 97/99, whatever rating the super is near you, best of both worlds then.
Ps, tony knows more than subaru and most of the mappers you know
19 August 2012, 07:50 PM
#114
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Actually, YES I DO 
Would you like to see my dyno run on 95 ron ? or would you like to speak to gary from G R Performance who gave it a clean bill of health on 95 ron ?
But then again tony you wont listen to any mappers/subaru or me so i feel my work here is done!
Would you like to see my dyno run on 95 ron ? or would you like to speak to gary from G R Performance who gave it a clean bill of health on 95 ron ?
But then again tony you wont listen to any mappers/subaru or me so i feel my work here is done!
19 August 2012, 07:53 PM
#115
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(and pretty much every mapper will tell you not to run the car on 95 ron fuel as it can cause damage to the pistons as it does det )
19 August 2012, 08:00 PM
#116
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Right im bored of you now, i will check in here in another month to see your still harping on about the same old shyte
ps, do you still deny classic scoobs have a nps
The credibility of the man
19 August 2012, 08:22 PM
#119
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No, it will knock on 95, that's for sure. As per my pic above, as a result of that initial knock the ecu will pull the timing back so it won't subsequently knock.