When I bought my car the dealer told me to use the cheapest fuel I have been doing that for 18 month, the car is running fine. Last week when I filled up I noticed a small sticker 
close to the fuel bung recommending to use premium fuel. Should I change to premium? What will happen if I keep filling up with non premium?
Does your engine knock when going up hills? If yes, then yes if no, then no.
Also if you have >9:1 compression then yes.
I have a Great Wall 4 wd, 4 cyl 2.4 l engine no not knocking at all! I pull my yacht (1400 kg ) no problem.
its for sale by the way 
I worked on the road as a sales rep for quite a while and ran the test of value on the different fuels and grades.
In short $50 of premium took my commodore further than $50 of standard.
More expensive per Litre, less litres in the car and further distance travelled. Result, always ran that car on premium.
BP Premium was the best by the way, some other premiums were not as good.
My 2L Van doesnt make anywhere near the difference no matter you use. Just run the test, you could save yourself money using more expensive fuel.
. Did that and went looking for a car that could pull 1400 kg in and out the water at boat ramp, checked a few 2nd hand 4wd and drove in front of GW dealership. Went in for a laugh Lada style, took a test drive and just got convinced. 2nd hand 4wd for $24,000.00 are mostly old and bitten up. Could not really trust the dealers..... Some still had red dust in little corners
Sounds like you've got it sorted, I reckon a lot of the negative comments come from in regard to 4wds are die-hard 4wders trying to compare the cheaper 4wds to the hardcore ones. We bought an 'awd' wagon (won't disclose make as it's not relevant) a couple of years ago for the wife to drive around and for us to make those family trips - my dad (semi-retired with a Patrol kitted up for touring) made the comment that it "wouldn't be able to tow a 25ft caravan around Aus"! We don't have even have a caravan, we've got a boat - but only tow it 400m to the local boat ramp. The wagon's been great, no complaints here.
I was happy to use the 4wd for a good use on the weekend - towed a carload of tourists that got stuck in soft sand after driving straight onto a beach.
Well, could not afford a fuel guzzler (Land Cruiser) and my GW will do me as good as a LC. I used in soft sand, deflated the tyres and had no prob. You would say it is only 2.4 liters and you work the gear box a bit more but I would give a 9 of 10 rating and recommend it to anyone!
98ron used to make a bit over 10% difference to economy of my 1990 Rangie. Makes bugger all difference to my current Pajero though.
i duno if us fuels at difrent but the mythbusters done this .. useing 3 difrent quality fuels in the same cars .. the top fuel got the car the furthest .. it worked out it was better to buy the best as it costed the least per km
Not relevant for you WA type folk, but just stay away from the 91 RON with 10% ethanol and you'll be fine.
While ethanol is high octane, it is also low density (less energy per litre) but more importantly it is hydroscopic - meaning it absorbs water which corrodes the crap out of your fuel system.
A final note - while the difference between 91 and 96 ocatne is simply a few octane numbers, the 98 stuff (ultimate, vortex, optimax, whatever) has extra additives which help dissolve gums and stuff like that.
Why to waste money on petrol?
My car runs on salt water.
All I need to do is just fill up once a week
You can actually tow with a GW? I used to work at a dealership that sold GW. Most people complained that they couldn't tow.
def makes a dif .
MY11 forester . Tank of unleaded around town will give me 400-450ish .
Premium will give 500-550ish
and the GW pulls it along ok, have to ride the gear box a bit to get it to 100kmh and it use low range to go out of the ramp! I guess I could have spent $ 60 k and get a LC but why?
Just got my 4wd back from its 150k service & paid the bill... Upside is, not another service for the next 10k (6mths)...and hopefully not as much need doing next time.
I had heard that Shell 98 was "brewed" (or refined) to be 98, but I had heard that Caltex use an additive to get theirs up to 98.... That was via Sydney Petro-Chem / Oil & Gas guys.... That was Clyde v's Kurnell....
But I'm not sure if is urban myth...
I'm doing some work at Shell North Geelong at the moment.... I did some rough calculations, and they spend between $3 and $10 per minute at that joint !! (I said "rough", and I mean rough!).... And possibly $20/minute in peak times.... Imagine that volume of gold coins spewing out of a slot machine !
