Hi,

All I want to know is: - Would my car be perfectly ok running on standard unleaded fuel? It's currently running on Optimax. But someone has said that it may run smoother on regular UL. So whether it does or not all I want to know is, would it be ok? It's a 1999 Euro Import. (UK Spec). On the inside of the filler flap it says to use only Super UL fuel. But as it's from another country (I think Belgium Originally), I thought maybe there Super UL maybe only as good as our regular UL?? Anyones help much appreciated.

Thanks,

Chad.

 

You can stick whatever grade of petrol you wish in it, it will not explode but it will run better on SUL/Optimax, your choice...

 

Run better? As in more power do you mean? Will it be noticable? As it's only UK spec anyway. Very quick for a UK car mind you.

 

Yep, as I understand it the ignition timing will retard with some loss of power if you have been running on SUL and switch to regular UL, it will run absolutely fine, but you won't be getting the best out of it..

 

mines goes better on optimax, i noticed i was getting some hesitancy with unleaded. Drives ok though, and when it was over £1 a litre its all it got!

 

Switching back and forth between 95RON to 98RON is not a problem on new age cars (such as my bugeye) as ECU apparently self adjusts. Maybe more a problem with classics as you have to reset the ECU - and if I had a classic I would tend to stick to one grade, with 95RON OK for standard UK car but you will not get optimum performance or economy.

 

I thought this was a complete myth and had been running my MY04 on std UL until one day I decided to try some of the real stuff nad have never looked back. I get better responsiveness, the engine runs smoother and I get on average 30-40 miles per tank extra. OK its a little bit more expensive, but why buy a car like ours and run it on performance hampering products ? It doesnt make sense.

 

sorry if this is ressurecting a dead thread here, but im a new owner of an 03 plate wrx with ppp and wondered, im not doing any harm to it running on 95 ron am i?
only put 2 tanks thru it so far, heard no pinking or detonation or anything, so im hoping the octane level is high enough!

im sure i may not be getting the best out of her using this fuel but dont want to damage an expensive engine thru being a tight **** at the pump! lol

cheers

 

Glad you searched!! a lot of people dont!

someone correct me if i'm wrong but the car has been mapped for 95?

For the price difference i would always put optimax or SUL in...

STOP being a tight **** at the pump!!

 

yep i discovered the search button lol!.. and unlike many other sites it actually turned up some information that was of use!

if its mapped for 95 ron thats fine then, doesnt hesitate or do anything i wouldnt expect from a car running a turbo, but i will run a few tanks of 97 or optimax thru it to check, only problem is where im based the nearest optimax filling station is about a 30min drive!.. not really worth the hassle i dont think

 

Just an update to say that with a an unmodified new age with it's adjusting ECU, I don't lose any sleep about always having to fill up with either 99RON Tesco or 98RON Optimax (my first choice of fuels if handy). I'm normally pretty light on the car anyway and arguably, the odd tank of 95RON is OK for a sympathetically driven standard spec. car. There IS however a performance edge when using 98/99RON and economy is also better. I can achieve an average of 32MPG in summer and believe me that does include some spirited driving at times and a proper mix of road and traffic conditions -the secret is in restricting brisk acceleration for a sensible purpose and planning ahead in traffic to cut out unnecessary throttle and braking.