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arthur t

Original Poster:

61 posts

85 months

[news] 
Monday 1st October 2012 quote quote all
I have just come back from a driving holiday around Europe, (Amazing)

it was great fun, but at one stage i bought 95 Ron fuel and while on the Autobahns prob cursing around 120mph my engine light came on and i did not know if it was linked to the low Ron fuel. has anyone had the same problem?

the light turned off once i let the car rest.

I have a 2005 Waggon - seems they are the Subaru of Piston Heads!

ScoobieWRX

4,863 posts

106 months

[news] 
Tuesday 2nd October 2012 quote quote all
Do not run your wagon on anything else other than the very best fuel you can get wherever you are. In the UK it's 99RON from either Tesco (Momentum) or Shell (V-Power).

In Germany Shell V-Power equivalent is rated at 100RON. That is the stuff you want the next time you go.

Never ever use 95RON unless you are using some kind of Octane Booster like Millers CVL Turbo or Silkolene Octane Booster with it, or 97/98RON if you can't find anything else, and drive sensibly, but just not 95RON on it's own.

Having bombed along at 120 for a good while on 95RON you're lucky your motor didn't suffer any lasting damage!!

If you must you do those speeds you should slow down gradually to allow the engine to cool down in a reasonable longish time. Come to a halt or drive very slowly soon after those speeds and you may suffer some overheating issues which in turn will lead to serious detonation/knock and engine damage under load thereafter.

Subaru are tough but they have their limits smile

zombies

139 posts

35 months

[news] 
Tuesday 2nd October 2012 quote quote all
Im on my 3rd scoob and for the previous 2 on 90% of fill ups I used 95

if 95 was no good you would know about it
im not saying 98 or 99 is not the best but 95 should be good for a UK spec motor

ScoobieWRX

4,863 posts

106 months

[news] 
Tuesday 2nd October 2012 quote quote all
At the time my bugeye was manufactured/registered (2002) 98RON was the best fuel at the time. There was a sticker in my filler cap that specified use 98RON only.

Do you not think the manufacturer puts that in there for a reason?

It's no different for current UK Subaru either although these days it's 99RON.

Running on 95RON also means your car is down on power. I guarantee it will have been detting like a goodun on 95RON and the ECU will have pulled a good deal of timing to try and stop the detting/knock like it's suppose to, but it's still no guarantee the engine isn't still detting now, and you won't know anything about the consequences of knock until something happens.

Always use the highest grade fuel you can in your scoob.

arthur t

Original Poster:

61 posts

85 months

[news] 
Tuesday 2nd October 2012 quote quote all
I think you are all right and I will have to stop being a cheap arse.. lol

I asume when I get it mapped it will have to run on 98Ron as standard or big bad things will happen.
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arthur t

Original Poster:

61 posts

85 months

[news] 
Tuesday 2nd October 2012 quote quote all
I think you are all right and I will have to stop being a cheap arse.. lol

I asume when I get it mapped it will have to run on 98Ron as standard or big bad things will happen.

paulmoonraker

2,516 posts

43 months

[news] 
Tuesday 2nd October 2012 quote quote all
I ran my WRX PPP on 95 all the time. No issues (40K miles)... My STi only had 99 however...

VictoriaYorks

528 posts

22 months

[news] 
Tuesday 2nd October 2012 quote quote all
What number is BP Ultimate? I'm worrying now that it's not as high as 98

cheesesliceking

942 posts

120 months

[news] 
Tuesday 2nd October 2012 quote quote all
its 97 Vic smile

VictoriaYorks

528 posts

22 months

[news] 
Tuesday 2nd October 2012 quote quote all
Is it? The website says 95 I think confused
I only filled up this morning as well, will be another couple of weeks before I need to go again.

paulmoonraker

2,516 posts

43 months

[news] 
Tuesday 2nd October 2012 quote quote all
Hang about everyone! I don't think 95ron fuel is gong to cause a UK spec WRX to explode into a ball of flames. Sure, if it's been mapped then you may have a problem, but the knock sensor shoud be able to retard timing enough so that there is not a problem on a standard car...

paulmoonraker

2,516 posts

43 months

[news] 
Tuesday 2nd October 2012 quote quote all
BP is 97 by the way, and it's not very good acording to most mappers. My STi was 20bhp down when running on that (after mapping)...

arfur

2,853 posts

94 months

[news] 
Tuesday 2nd October 2012 quote quote all
My Forester runs on 99 vpower or tesco 99. In Germany I use 102 smile

I find if I run on 95 (in emergency) it definately moans like hell and I have to reset the ecu to force it to be happyish ... The difference is very noticable and when the emergency ends and 99 is in again I have to reset the ecu again

150k miles with only 5-10 95ron fillups ...

still only does 23 to the gallon though frown

WeirdNeville

5,772 posts

95 months

[news] 
Tuesday 2nd October 2012 quote quote all
They have knock sensors and intelligent ECU's.
A standard scooby is NOT going to grenade itself just because it's on 95 Ron fuel. It won't quite make the power as it will have to retard the ignition, but it won't kill the engine. If you've mapped it to high octane fuel then obviously YMMV.

These are world market cars and they're designed to run on everything from the top notch fuel in Germany or Japan down to watered down crap sold out of bottles at the road side in Mali.

I agree in principle, run any turbo car on the best fuel you can, but to sugges running a car on 95 Ron will kill it is just scaremongoring.

paulmoonraker

2,516 posts

43 months

[news] 
Tuesday 2nd October 2012 quote quote all
WeirdNeville said:
They have knock sensors and intelligent ECU's.
A standard scooby is NOT going to grenade itself just because it's on 95 Ron fuel. It won't quite make the power as it will have to retard the ignition, but it won't kill the engine. If you've mapped it to high octane fuel then obviously YMMV.

These are world market cars and they're designed to run on everything from the top notch fuel in Germany or Japan down to watered down crap sold out of bottles at the road side in Mali.

I agree in principle, run any turbo car on the best fuel you can, but to sugges running a car on 95 Ron will kill it is just scaremongoring.
yes

Is fuel not 92ron in most of the US states?

VictoriaYorks

528 posts

22 months

[news] 
Tuesday 2nd October 2012 quote quote all
I will use Shell from now on then. Can't use Tesco because of who they choose to sponsor smile

paulmoonraker

2,516 posts

43 months

[news] 
Tuesday 2nd October 2012 quote quote all
Go and look in your manual. It should say 95 is fine except for the STi model.

ScoobieWRX

4,863 posts

106 months

[news] 
Tuesday 2nd October 2012 quote quote all
There's no scaremongerng about it. Subaru want you to run your cars on the best fuel available. Fact!!

In 2002 it was 98RON and Subaru puts a sticker on the inside of the fuel filler cap stating 98RON specifically. If you want to run your WRX or STi on 95RON great, that's up to you, you must know better than the manufacturer and come to that tuners too. scratchchin

The basic boxer engine and turbos haven't changed much at all although the factory mapping has in order to get these cars through Euro emissions legislation. The factory maps them leaner and leaner as the generations go on. 95RON is fine for normal everyday family cars N/A or small engined small turbo cars designed specifically to be economical, but not a fire breathing Subaru.

The ECU will only retard so much timing until it starts taking big chunks of timing out and adding fuel. If you get to that point, and you won't know much about it, the car starts to feel really off, and properly down on power however, the damage to your pistons and further on down the line is done and continues to be done if you keep using 95RON and drive it hard. Thereafter it's just a case of running borrowed time.

Your Subaru is a high performance machine, whether it's a WRX or STi, and mechanically there is not much difference with either. Treat them with respect by putting the right fuel in and they will perform the way they're meant to without risk of internal damage. If you run your car on 95RON and the engine develops internal issues due to poor fuel you can't blame the car.

I wouldn't be asking anything more of my Subaru other than gentle drives and normal legal limit motorway trips if i were running it on 95RON. I certainly wouldn't be driving my car hard on boost or at speeds of 120mph.

If you think you're saving money on fuel it's a false economy in the long run. If your car is down on power you have to press the pedal further to get the same/similar performance that you would on 99RON. That just uses more fuel than if you ran it on 99RON in the first place.

You don't have to believe a single word i've written, because it's just an opinion however....

JollyGrnMonster

828 posts

77 months

[news] 
Tuesday 2nd October 2012 quote quote all
Detonation or pinking in old money puts holes in pistons on turbos cars.

The lower the ron the quicker the fuel ignites so it explodes and the piston has to travel to the top of the bore with the explosion trying to push it down.
The only way to stop that is to spark it later in the cycle (retard the timing).
If a car designed as subaru's are to run the best available (agreeing with you again fransis - scarey) the ecu will detect the detonation and retard the time but it has to det first.
Then it will advance the timing again as it is always trying to run full power and detonate and retard it again. So yes the ecu will slow the engine damage rather than continual det and the det it sees will be smaller than otherwise.
But that assumes it hears it. The number of cars I get in, add detcans and listen and it is detting, and the ecu is doing nothing to stop it or is retarding the timing slightly but novwhere near enough. Sometimes its also the opposite the ecu has pulled loads of timing for no reason.

Simon

Edited by JollyGrnMonster on Tuesday 2nd October 19:12

ScoobieWRX

4,863 posts

106 months

[news] 
Tuesday 2nd October 2012 quote quote all
Subaru ECU's run a retard strategy that not only pulls timing at the point of issue but further up the line too, often for no reason. I've seen it do this on so many different scoobs, modified and standard when logging. It's like a form of predictive retardation and i'm pretty sure it means to do it.

That's all well and good but, when it doesn't pull enough as simon says which is very common, is when you get serious problems. Get/make up some det cans and see for yourself, or buy a Knock Alarm off eBay. You can log your own car parameters using a free download called FreeSSM, and a VagCom cable off eBay for a few quid. Then you can see everything a main dealer can see.

The ECU is only reactive so until it knocks it won't pull timing, and ultimately it only needs just one or two almighty knock instances to kiss goodbye to your pistons and anything else that gets damaged in the process, and then it won't matter how far the ECU retards timing. hehe

e.g. A chap who is a member on PH came to me early this summer with a normally aspirated Legacy, not turbo version. It was knocking a fair bit. I asked him, what fuel do you use? He answered...95RON. I suggested he use 99RON rather than remap his car just to get it running better on 95RON so i went to see him and reset his ECU. A few days later i asked how the car was doing and he said he rarely hears a single bout of knock!! It hasn't gone completely because on a very hot day he gets a brief touch of it and then it's gone (ECU adjusting/learning).

I don't expect to hear from him again now that he runs 99RON and the weather is much cooler.

Just put decent fuel in your scoob that's all i'm saying. smile
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