EddScott

I've noticed a few of the local Impreza owners are happy to fill up using the local supermarket fuel i.e. Safeway and Tesco.

Now, I've always used Optimax and was advised to use nothing but by Power Engineering when I had the TEK3 ECU mapping done.

I'm pretty sure one of the local cars has a PPP ECU which is quite similar to my ECUTEK.

Will using UL fuel eventually damage the engine? The Impreza I suspect is a PPP appears to be itching to give any other Impreza a race but I would guess it won't be too healthy to push the car if its got normal UL in it.

How important is it really? I've got no intention of changing but would like to know how critical it really is.

/edit - think they are all UK cars some ranging between P and X reg.

alistair

UK cars (including PPP) should be set to run on 95 octane.

For the difference in price, I really can't see why you'd risk it though.

greasemonkey

If Power Engineering mapped your car for Optimax, then Optimax you should use, unless PE tell/told you that there's enough knock correction in it to run on 95 safely.

Er, no. The TeK 3 is a custom remap, and by their very nature, custom remaps tend to be more vehicle/fuel specific than the PPP one, which has wider tolerances and safety margins designed into it.

You shouldn't be asking us. You should be asking the people who mapped your car, as only they know how much leeway you've got

See above in the case of your own car. As for the other two, Super Unleaded is strongly recommended for the PPP equipped cars, and while an as-new car should run safely on 95RON, there's always the possibility that on a car with an underlying problem - such as a slight MAF sensor under-read - could be pushed beyond safe limits when run on lower quality fuel.

EddScott

Like I said I've always used Optimax before and after it was mapped and have no intention of changing.

I was really only asking weather it was OK to put unleaded/95 RON fuel into a standard Impreza or one with say a PPP. I never did as I thought it was best for the engine to use Optimax.

greasemonkey

It is best to use a Super Unleaded fuel of some sort, with Optimax being one of the better ones.

I wasn't sure when I read your original post whether you were considering switching yourself (on the basis that you thought the PPP was similar to your TeK 3), or whether you were wondering about the wisdom of the two other owners' choices.

While the retail spec UK cars should be able to cope adequately with Supermarket 95 RON, and thus I suppose you could say it's "okay" to use, it's not something I'd do if I owned a UK car.

Yorkie

I ran my MY99 on it (95RON) for the 3 years that I had it. I swapped it for a MY02 and initially ran that for 12 months on 95 until just before I had the PPP fitted, at which point I switched to SUL. I have to say I noticed a difference in the smoothness of the car after a couple of tankfuls and also its responsiveness seemed to be inproved. Obviously after the PPP was fitted it lived on a diet of SUL. I now have a MY04 STI and I have been using BP Ultimate at every fill up and I intend to continue, purely and simply because I think the Impreza engines run better on it probably no matter what model year.

greasemonkey

You will find some heavily polarised opinions on BP Ultimate round these parts, some of them none too positive. It might be a worthwhile experiment to run half a dozen tanks of Optimax, or even Esso/Total SUL through your current car to see if you notice any differences.

steve_g

Is it really worth the risk?

For the sake of around £4 more for a full tank of petrol you may as well just pay for the SUL or Optimax.

RON

My uk my00 has been run on regular for all of it's 30k with no trouble, the only trouble I did have was when I used optimax for about 4 tanks full, even with a reset the car hated the stuff, so back to regular it was, loves the stuff, can't get enough of it!!

greasemonkey

Lol, another peculiarity of the AE802 ECU!

MR2Mk1

iTrader: (1)

Sorry for thread revival but I wanted to ask the same question so didn’t see the point starting a new thread.

I have a completely standard year 2000 UK Impreza Turbo wagon. So are people say yes I can use normal 95RON on and old UK Turbo and it should be OK or I should always use 98-99RON just in case something happens?

CharlySkunkWeed

iTrader: (7)

if your car is standard , i say you can use 95ron. If you read the owners manual it actually says it wont do any harm , just wont perform as well as if you used High octane. (mines a newage though)