Hi all,

I have just bought a 1995 Subaru Impreza WRX-RA. I collected the car from Mid Wales on sunday and drove it back to Maidstone in kent. For most of the journey the car was fine. The engine sounded good with out any unexpected noises. had to stop for petrol on the motorway and could only get unleaded (95 ron) I then drove the car the rest of the way home at 70MPH for 150 miles on this petrol.

About 10 miles from home the car started to make a noise like a loose tapped or something. One of my friends thought it could be a big end. I thought that it went a bit quick to be a big end as I thought you could hear them get louder for ages.

I was wondering if the petrol could be the problem? Should I Just put in some optimax and octain booster and drive the car to see if the noise goes? Could I have done some engine damage?

The oil pressure and water temp etc were all fine.

I did not realise how perticular these cars were about the petrol they run on.

Thanks for your help

Mark

 

Im pretty new to this myself, but is it an Import ? as they should only run on 100 Octane ? but as far as im aware, running a lower octane will cause Pinking ( or det ) which will sound like a tapping .. especially under load, run it on Optimax and some octane booster and see ? but also running a low octane, for prolonged periods will kill the 3rd piston !... anyone correct me if im wrong as im only going by what ive heard,

You can have your ECU mapped though to run on 97 RON as octane additives can get exepnsive.

Matt

 

The car will be an import (nice choice by the way)

You should be running Optimax (minimum) with Octane Boost, unless the cars been mapped to run SUL.

What mileage has the car done, and lets have some pics.

 

thanks for the replies so far.

The car is an import and the ECU has not been remaped.. Unfortunatly I do not have any photo's at work with me.

The car has done 60K miles.

Do you think putting in Optimax and octain booster will stop the noise?

Mark

 

I dont really know, as im not too expierienced in this !! although there are certain products ( such as NOS octane booster ) that will eliminate the pinking noise or dramatically reduce it, you could try adding one of those and see what difference it makes ?

 

Hi Mark,
You really want to get that 95 ron out of the tank or add some octane booster (as you suggested) to boost the octane to around 100. If you do a quick search on here, you'll see the problems associated with running low octane fuel and it can be damn expensive.
You're best bet would be to fill the tank up with Optimax or 99ron and stick some octane booster in there aswell to bring it up to 100-101. Then do an ECU reset (here: http://www.scoobypedia.co.uk/index.p...ledge/ECUReset) and hopefully you'll be back to normal.
95 tends to be ok in emergencies, but I wouldn't trust it at sustained high rpm or under heavy boost.

 

Hi

what ron95 for a standard uk 1999 classic. Its been run on that for a while. Now its my car im going to use super.

cheers
Dave

 

you cant get a 95 mapped without a piggyback chip or an aftermarket ecu fitted. The 95 shouldnt have damaged it if driven steadily, the engine monitors det (knock) and has a knock sensor. If this sensors detects knock, then it will retard the timing until it no longer occurs, so basically you will be down on power (whether you notice that though is a different matter). Also when you filled it with the 95 I imagine you still had some super in the tank so this will have mixed with the normal unleaded.

The cars will run fine on optimax, no need for additives unless you are looking for ultimate power. I quite often used supermarket 95 ron in my 92 import, I had a knocklink installed and there was barely any change in activity (knocklink worked perfectly) I still use 95 now occasionally, even though I now have an aftermarket ecu which has been mapped for 97ron.

The piston issue is more down to a particular cylinder running lean as it is at the end of the fuel rail, and it is also closest to the turbo so extra heat.

Personally I would just give the car a thorough visual inspection, it could just be something loose or it could be somethingin the undertray (if it has one fitted). Start the engine have the bonnet open and gently open the throttle by hand to see if you can locate the source of the noise.

 

firstly when does the noise occur?

if you drive the car gently without using much boost the 95ron should do no damage, if however you were giving it beans on 95ron then you may have done some damage.

changing the fuel now will not stop the noise unless it is det you can hear (ie. you are on full load at the time).

I am just outside Maidstone and here until about 5:30 if you wanted me to listen to it, but obviously you have to drive it.. if you have done a big end you will throw debri through the rest of the engine the more you drive it and damage other bits of the engine.
I hope it is just a tappet and the 95ron is just a coincidence.

I also have some booster.

Water temp gauge is unfortunatly rubbish and will show okay until around 100+ degrees and assuming you are looking at the oil light it is so low a pressure to switch it on it is not much use either.

Simon

 

Hi Simon,

The noise seems to be pretty constant, it happens when the car is idling.

I will not be able to get to Maidstone today, are you there on Saturday?

Regards

Mark

 

sounds more like tappets.. not sure of my where abouts tomorrow I am afraid.

does it increase in sound level with rpm or just tap more frequently?

 

uk turbo's run fine on 95ron but u wont get full power from it.( according to prodrive/subaru)

 

sorted it?

Simon