Having recently bought a fantastic STi V in cool grey I've become increasingly paranoid about blowing the engine.
Sorry to say I know a few of you members have suffered this - I don't want it happening to me so reckon I should post the sound advice received from Bob Rawle of BR Developments !

Has any STi owner NOT had an engine explode ??!!

"The STi V5 (or V6 which is virtualy the same car) being designed for the Japanese market can both suffer when used in the UK. The main reason these engines fail are :

1) detonation due to use of incorrect fuel and

2)incorrect or "inferior" oil and poor servicing procedure. Most failures are big end bearing related with some snapping a conrod in the process.

So what precautions to take given the car remains standard ... I assume yours is ie original exhaust and induction set ups ?

1. Always keep the car off boost when cold, the oil temperature must be at least 80 deg C before you boost the car, don't be misled by the coolant temp guage, you need to have driven at least 8 miles before the oil is at 80.

2. Letting it idle for a couple of mins before switch off is ok but only really necessary if, for example, you have been driving on the motorway at highish speeds and oil temp is higher than usual, you shouldn't then exit motorway, stop and switch straight off. If your journey involves normal roads with some traffic before and after motorway then all would be ok in any case.

3. Fuel ... sorry to say but 97 ron is not good enough, you need to at 100 ron (Japan is 102). The way to do this is to add Octane booster to your fuel. Suggest you star using 2mls per litre of 97 ron of NF booster, this will take it up to around that level. Be aware also that fuel quality varies greatly, I would stick to Esso, BP or Shell (Optimax) but defo avoid Texaco and never use Supermarket fuel even if it is 97 ron.

4. I would strongly recommend using Motul M300V Competition 15w-50, when I changed over I gained a bar of oil pressure at idle straight off, viscocity index is much much better. This can be bought from Demon Tweeks or ScoobyMania.

5. Oil Filter ... insist on the genuine Subaru part being used, some dealers use alternatives, so ask them to stick to the OEM
part. Its very high quality.

6. Oil change procedure ... basically problems can arise when the filter is not pre-filled with oil before fitting to the engine, be aware that if you fill a filter, let it stand for 10mins you will be able to put in the same amount again, it needs topping up until it stops absorbing oil which can take 20mins or so. I always remove the connector from the crank position sensor and then crank the engine a few times, this starts the pump moving the oil around, then I refit connector to start engine. This is not essential but the filter filling is.

7. Never hold the car at high revs and high load for any length of time, in Japan the car is speed limited and so this would never happen in 4th and 5th, in the UK we do it and the extra heat can cause a hot spot or pick up in the bearing, later on, say as you slow down on a motorway slip road, the bearing loading changes and the bearing picks up and thats that. The red line and rev limiter are to be avoided.

8. Never carry out any mods to the car without getting it checked for correct fueling and det, its easy to fit an induction kit but that can cause lean running and det plus increased oil temps.

Having said all that there is still no absolute guarentee but if you pay attantion to the above you will be in best shape possible. The cars are great, the real problem is that they are in UK not Japan, so sort out fuel and oil quality, some TLC re revs etc and you ought to be ok. I've remapped loads and loads and I love them, they tune really well but just need the TLC to go with it."

He sure know his stuff !!