martwrxsl

I been reading lots of forum posts on people saying never put certain octane ratings of fuel in the wrx. The problem is sometimes when you need fuel and shell and tesco aren't there you don't always have a choice. Does it really do that much harm putting 95ron into a my03 wrx on rare occasions, when needed in emergency? I'm considering getting my car mapped soon for just 99ron fuel. Would the performance difference really show that much? Would putting lesser octane fuel into my car after the remap cause problems?

53

iTrader: (41)

Not ideal if mapped to 99ron to go lower IMHO. I carry a bottle of NF octane booster if I get caught out between shell V-power visits. 97ron is ok as your car is now.

martwrxsl

thanks for the reply wrx53. same year as mine. i got a wrx53 sl with 34,000 on the clock before christmas. just got the centre decat and back box by h&s. im really confused about the fuel things though. i have been putting the tesco 99ron in since i bought the car, on recommendation from a mate. does it totally ruin the engine if you stick 95 ron in or is it just purely a performance thing?

back to the remap for 99ron only. will my car stall and misfire if an emergency I have to top up with 97ron. just curious because there not always shells and tesco when you drive to different places.

octane booster? how much do you put in? sorry to seem stupid but i'm new to this.

z4mr

ron:
YouTube - Fifth Gear Tests Octane Octanes Fuel


additives:
YouTube - Myth about fuel additives, 5th Gear

Bez300

iTrader: (2)

Mine has been mapped for 99ron. If I can't get that I run Shell V, dont notice any differance.

Have it mapped on what you you most of.

you could always just put a fivers worth in till you get some 99

Flaps

iTrader: (1)

In my 04 i've occasionally had to use *cough* 95 ron *cough*. To be honest I noticed no difference between this and BP Ultimate, it wasn't as good as the Tesco stuff though that I use 99% of the time.

53

iTrader: (41)

I think one bottle of NF does 5-6 full tanks.

It's not about gaining power, anything above what your mapped to is wasted IMHO. Its about stable combustion and giving your engine what its expecting. UK cars are labelled to run on 97 IIRC, will you kill if by running 95? probably not but why take a risk and reduce performance. By adding the NF in an emergency as a precaution you suppress chance of detonation.

martwrxsl

Thanks for the responses everybody. i would never put 95 ron in my car by choice. maybe in some little hilllbilly garage when your running on fumes in the middle of nowhere, the last thing on your mind is putting 97 ron plus into your car. i just always feel that everywhere i go i'm limited to the 99ron petrol stations within distance. i.e. doing a search of tesco garages before i make a journey.

i do use 97ron when i'm short. would it be a safer option to get my car mapped to 97ron just in case? performance gains for 97ron vs 99ron couple of bhp?

What octane booster do you recomend? I will buy a bottle and keep it in the car.

53

iTrader: (41)

Nitrous Formula NF Race octane booster, if you are at all worried get it mapped for whatever you put in the most.

wolfie28

I used 95 ron in my old Bugeye WRX all the time and had no problems at all in 60,000 miles (the car was standard). People get too hung up on petrol grades in my opinion, how do you know your actually getting the grade you pay for just because it says it on the pump .

If its modded or personal choice fair enough but if 95ron is good enough for all Ferrari's then I'm sure its OK for a standard WRX.

jasonius

iTrader: (1)

My 05 WRX has a sticker on the inside of the filler cap stating: 98 RON FUEL ONLY..!

You can argue with Subaru..!

fivetide

iTrader: (1)

My 03 WRX has the same sticker.

TBH 95 RON is unlikely to damage the car at all. What will happen is the ECU will retard the timing to protect the motor from the lower quality fuel. It does this very quickly so you will lose some power. It also takes it a long time to learn to trust the fuel again.

Upshot of this is that on a standard car you'll not notice much but if you've had the car mapped then it will mess up the map and you'll probably notice a big difference.

Still subaru say super unleaded so that's what it is getting. Mine is mapped for 99 and if i'm going somewhere new i have a look for Shell stations on route via their website.

5t.

ps. martwrxsl you'd be advised to look at a remap in the near future if you have decatted the car.

wolfie28

As mine did. I was just saying that a standard WRX can run on 95 ron unleaded and it won't blow up.

Subaru also state only Subaru official parts only, however most of us choose to uprate/mod our Scoobs with better quality parts.

I also don't put the Subaru stated tyre pressures in maybe it will blow up . I'm such a rebel .

satancom

Good videos

jasonius

iTrader: (1)

Obviously, exactly as fivetide says. I know the one time I had to run my WRX (standard) on 95 (fuel shortage) it was like it was running on 3 cylinders..!

jasonius

iTrader: (1)

There's something strange about the consistency of their findings regarding the OB's IMHO..

Did I hear correctly in that they ran the engine for an hour for each test..?

Having said that, they picked the cr@pest ones on the market..! Would have been interesting to have tired NF or Millers and also on a more performance orientated engine. Also, would have been a good benchmark to have compared plain SUL on the same setup.

johnnyroper

mine was mapped on tesco99,while mapping jgm aka simon said fine using vpower no difference in performance.
he also said it would be ok on 95 if i could not get 99 but just to keep off boost until back on to the 99.