I have an 07 WRX which was mapped originally by Duncan and was perfect, i fitted a new 3" exhaust system including equal length headers and had the map tweaked by AD Edmundson when they visited the IOM so i could use the car between me visiting the UK for Duncan to do a RR session.

Now i serviced the car prior to the map and did a trackday 1 week later, the car used 2ltrs of oil on the track day (but hasnt used any since) i noticed that the car was quick upto 100 but wasnt as rapid as before above 100.

then last week it started to develop an engine rock, and i thought engine mount might be goosed, but it has got worse and the check light came on this morning. So i pluged in the reader and it gave me the code of P0304 cylinder 4 misfire detected.

could this just be a plug or coilpack or am i looking at a worse situation??

 

text duncan mate he will know!!!!

 

yeah just spoke to him, told me to try chaning coil packs over and see if fault moves if not change the plugs and see how we go

 

Check the injector too as they can stick !

 

While you have plugs out, put a compression test on,
using oil, if your running 350bhp on std internals, sorry to say, could be rings,

I had that "T" shirt too, now got a forged "T" shirt

Bez

 

yeah its std internals but only running about 300, i want a forged engine but not got the cash to do it, so if thats whats needed i will cut my losses.

i have tried injector cleaner as i thought it might have been a sticking injector but thats not resolved it

 

Mine was only running 300 when I blew it, but I do drive my car hard,
5th gearbox 2nd engine. but now got the 6 speed box in so that should be ok.

The compression test will give you the info you need.

Bez

 

Sorry but much as post #5 as Bez says. These engines have a history of broken ringlands and I suggest you get a compression check as a starting point.
Anyone with one of these engines should never take it near the red line, there is no need in any case, hitting the rev limiter can easily total the engine and beyond 350-360 bhp, they will break sooner rather than later. Even relatively new standard cars have suffered this issue and Subaru is well aware.
If you go for forged pistons also consider steel rods if you are going much above 400 bhp.

 

cheers guys your help has been valuable as always.

Sad to say that the engine is goosed.. compression in 1,2,3 are 150 and 4 is 50

question is can i afford a new forged build or do a sell as is .....

 

Assuming you have "only" cracked ring lands and its only just happened then you might get away with a set of drop in forged pistons, at the same time fit high strength 11mm head studs, decent head gasket and change mains and big end bearings to ACL/Mahle. then you will have an engine capable of 450 or so bhp solidly.

I expect if you were on track you hit the rev limiter a few times ?

If the failure is det related then the rebuild cost could be much greater.

The std engine is "ok" at 360 bhp or so given its treated with respect, but if you are going to track one of these cars then piston change is a must. Cylinders 2 or 4 are the most common to suffer.

cheers

bob

 

sorry about the bad news bud.
Hope you get it sorted within your budget,

Bez

 

no i didnt hit the limiter, was reving to 5500-6000 in each gear but i thought lack of power on track was clutch related as it was std clutch and done 49K and it slipped twice.

i did 20 laps of jurby autodrome in iom and its 1.03ml track.

the issue started a week - ten days ago and at first thought it was a blockage in the injector as when you powered through it cleared but started to get progressivly worse so stopped driving it until yesterday.

i only drove it yesterday to take it to the guy that mapped it to see if he could work out the issue, and got 3 miles before the CEL came on.

 

If you did not go anywhere near the limiter then the issue is somewhat different. However the solution is still the same, the extent of the problem will not be known until the engine is stripped, worst case you will need a rebore and all that goes with it, best case a set of drop ins, to be honest the cost difference is the machining cost, so probably not a great deal in the scale of things.

It will be important to think through the "why's" though as if you were away from the limiter the 2.5 engines are normally "robust". What was your fuel strategy, did you have an uprated fuel pump, if so what was it and how long had it been installed ?

The WRDX on std turbo will not normally make 300 bhp but thats not to say yours didn't.

best regards

bob

 

im not sure of the exact figures as it hadnt been on an RR i presumed it was more than the GB270 due to the mods and is much quicker than my mates GB.

it was standard when i bought it (12K on the clock) and it was running induction kit, 3" straight through and equal length headers and was running 1.38bar boost. i had a walboro fitted at scoobyworld approx 12mths ago.

Normally i do drive it hard, with living on the IOM its hard not too no speed limits etc and i have had 148 out of it.

i always always use vpower as thats the best available here and its almost £1.50 a ltr - worst thing is ive just filled it up ....

i think if i do it i want to do it properly i.e build something that would take more power and abuse than i would give it, rather than have to do it again.

 

i suppose the issue could have been brewing for a while