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I have an 03 forester X and when new had trouble with unleaded fuel causing a blockage in some valve. (engine light kept comming on) Subaru dealer recomended premium fuel and the problem went away. I now dont have access to cheap fuel and wonder if anyone else has had this problem and what you run your vehicles on. Any advice appreciated. Cheers
Bill

I cant see the octane rating of fuel making a difference to the function of a valve. Did he describe or name this valve?
What fuel is recommended on the sticker on the inside of your fuel filler door?

Running 91ron Unleaded in a car designed for 95ron Premium will make it ping and possibly make the 'check engine light' come on.

have an 07 myself

Generally I've always believed japanese cars run a lot better on PULP.

However with the forester PULP 98 RON versus 95 RON = no difference. Maybe a slight improvement on lt/100km. In my older carb and turbo L-series was a huge improvement, esp on Adelaide 44C days...Would expect the ECUs have advanced somewhat since the 80's but.

95 RON versus 91 RON - simply woeful.

Sven

Not sure what the valve was, may have been something to do with the emission control from memory. The book recomends unleaded 95ron or over 90ron if it is not available. I dont remember it pinging even when towing a camper trailer and premium fuels were not available

Bill

Minimum fuel requirement is 90 RON However all of Subarus emissions, power figures and economy figures are calculated on 95 RON fuel.

Did the fuel you use that gave you trouble have ethanol in it?

We won't run our cars on any thing that contains ethanol or is not 95RON or higher.

Thanks for all the info. Have never used ethanol blended fuel. Its looking like premium fuel is the go. Will just have to wear the price hit and stop being miserable!!
Cheers, Bill

the previous owner of my outback recomended premium and it seems to run better when on premium

I've been experimenting with fuels in my new 6cyl outback and surprisingly there is no noticable difference between 95ron ethanol and premium. Running Newcastle to Sydney on premium I got 9.2l/100km, ethanol was 9.0. Running Sydney to Newcastle on ethanol I got 8.6.

Since it's only done 3000km I think the engine is still settling in because the fuel consumption seems to keep going down. Around town I get 10.5.

I was up at Stockton beach on the weekend and I had half ethanol half premium. Under full load at over 5000rpm the engine was occasionally pinging, but nothing too major. Just driving around on the flat sand was fine. (Apart from using 36l/100km!)

I use Shell V-Power in my 03 XS Forester and when I use any other fuel I can sense the difference and my wife is even better at sensing the change, even when I fill up with Caltex instead of Shell she will say "what fuel did you put in this time - it's running like pig".

My choices of fuels are:

Shell V-Power
Caltex Vortex
BP Ultimate

followed by the Unleaded from each of them in the same order.

I used Caltex E10 back in January this year between Wallangarra and Tamworth and never again will I use E10, the acceleration was negligible and the pulling power was non-existent.

My Fuel Log

Running Sydney to Newcastle on ethanol I got 8.6.

isnt it up hill to newcastle lol should be worse

i run 95 in the rex

cheapest in the std brumby

the vortex and the ruffy (ea8it) if i dont use 95 they both ping

dibs

There shouldn't be a difference in modern cars between using E10 and Premium Unleaded. Ethanol actually increases the Octane rating and being Alcohol it also should help to stave of detonation. You should also use slightly more E10 than Premium Unleaded because the stoic ratio for Ethanol is incredibly rich compared to Petrol.

Storm wrote:There shouldn't be a difference in modern cars between using E10 and Premium Unleaded. Ethanol actually increases the Octane rating and being Alcohol it also should help to stave of detonation.

Yes! it may increase the Octane Rating but it just doesn't have the "bang" that Premium does.

The Liberty runs great on PULP but slightly hotter, slight improved economy; when run ULP normal but with E10 it runs flat poor acceleration etc not more economical.
It seems ECU are factory set for the recommended fuels with slight variations when different fuels are used.
Yes, there also seems to be difference between fuel makers(refinaries) and probably from region to region.

Suparoo wrote:I cant see the octane rating of fuel making a difference to the function of a valve. .

The difference in the fuels are generally more than just the octane rating, The fuel companies used to add fuel additives into the fuel (I am assuming they still do, I know people that have and still do put in a bottle of carbie/ injector cleaner every second or third tank which is about 12 or so dollars a bottle whereas the premium fuels do the same thing I used to save 200 dollars alone on a poper injector clean just by using it.
Depending on the individual car depends on the difference with the fuels and you normally won't notice the difference in the first two or three tanks unless the tank is almost dry and the fuel system is already in good nick!

Not all E10 is created equally , the good stuff is 95 E10 and the rubbish is poverty grade ULP with 10% ethanol .

I run 95E10 in my RX-T and it drives if anything a tad better than Shell V Power .

A .

Subyroo wrote:Yes! it may increase the Octane Rating but it just doesn't have the "bang" that Premium does.

Higher Octane allows more "bang" assuming the timing is optimised. Other things that allow more "bang" are richer mixtures (Ethanol is naturally richer especially on a modern car) and more efficient cooling (again Ethanol provides a natural cooling compared to Unleaded).

discopotato03 wrote:Not all E10 is created equally , the good stuff is 95 E10 and the rubbish is poverty grade ULP with 10% ethanol .

I run 95E10 in my RX-T and it drives if anything a tad better than Shell V Power .

A .

Lol, that rubbish poverty grade is 95 E10. 10% of the fuel is Ethanol and that alone increases the Octane rating by 5 points from 90 to 95. If they ever release it Australia wide E15 would be the same as the old Leaded Super (about 97-98 Octane) that was available back in the days of the GTR 186 and 202 Toranas, GTS 350 Monaros, GTHO Falcons, and R/T E38 and 49 Chargers. E20 would be 100 E20 the same rating as racing fuel from 10 years ago.