Sti Engine burning oil. (Shock horror I know)

I've got a gc8 version 6 sti impreza with a 2.5 block.
It burns oil better than most household boilers.
It's mapped on a power fc. And still has bags of power.
Could anyone shed some light on it?
My own thinking suggests either valve stem seals or turbo seals.
Compression is good across all cylinders
It's not mega smokey but I do get some oil deposits on the rear bumper after a long drive
It burns a litre for about 2/3 tanks of fuel (<2000km) ish.
Anyone had a similar situation?

what grade oil are you using ????

All 2.5s use oil ,
Block the unbaffled Central crankcase breather (large one).
Because you're running v6 heads you cannot pipe the breathers correctly so this could be the issue.
The late Simon Roe (jolly green monster) advised me to do this with mine.

If that does not fix the issue you have a broken ring lands on the Pistons and she will need a set of Pistons .

My 2.5 doesn't use oil... about a pint and a bit on 8,000 miles and is mapped @1.35bar (326bhp/538Nm).
I'm using 5W40 fully synthetic ester based oil btw - so not even a really think oil either.

If you're using a litre every 1800 miles or so that's a lot, unless you are running a thin oil and doing a lot of extended high rev stuff.

Drop my oil every 5000k or 6mts whichever comes first, never burns a drop.

Well documented lads

Mine hasn't since I owned it

same as that mine never used any either.. It'll use none where its at the minute anway

Mine is the same, doesn't burn oil.

But I do have to say they do if driven hard, mine used some at the track day, but never really on daily use

Original 2.5s with original factory piped breather won't consume as much but a hybrid with 2 litre heads will

Baz would you still get good compression if a ring land was damaged

I'm not to sure Keith but I'd im it would be down slightly depending on how bad they are . The standard Pistons are muck on them although a lot is in the mapping.

Here is a picture of one of my old Pistons, the only thing holding the Pistons together was because they were in the bores. As soon as I removed them all the bits fell into my hand




Chances are the boost control on this v6 is not being controlled properly, every single turbo I've had spiked , creeped up the higher you reved it . Like my car when my brother first got it was mapped for 1bar boost but was creeping to 1.5-1.6 bar at 6000rpm so this caused the failure for sure . Also if you planted it say in 2nd gear at 2500-3000rpm it would spike to 2bar and then drop back to 1 bar and then build up to 1.5-1.6 as the revs rose.

It the 2.5 engine causing this.

Every turbo I've had the vf24, vf35(worst) the vf48 and even the new Scooby clinic sc46 had boost control issues .

The solution was to port the wastegate.

Jgm gave the thumbs up when mapping the ported vf48

And Aonghus mapped with the sc46 when it first went on the car un ported and boost creep to 2bar , car was undriveable.

Ported it and a remap and holds 1bar on low boost map all the way to redline and holds 1.3 on high boost map all the way to redline no creeping no spiking.

I guarantee boost control is the route of the problem on op engine . Doesn't matter who mapped it, won't make a difference, you can't map around a mechanical issue like that . 2.5 flow so much that most internally gated turbos cannot slow the turbine down when the wastegate is fully open

Also 1litre per 1000miles I think was acceptable consumption by Subaru on a 2.5 when new

Thanks lads
All helpful info.
It's got a blitz boost controller and dosnt get boost creep.
It's holds wherever it's set. (Around 1.2bar max) practically no lag

using 5w30 fully synthetic valvoline

Il have a look at the breathers and do another compression test as it's a while since it was done.

Pray it's not Pistons please.

Wouldn't matter what boost controller is on it

Think your right baz . Read that about a litre a 1000 km ... sounds excessive but came from Im group iirc .

Mine doesn't use anything like that since Ali had her but before that it used a sup on the track days

Its an engine out in inspect by sounds

[quote author=Tommy 555 link=topic=43917.msg506772#msg506772 date=1423593341]
Think your right baz . Read that about a litre a 1000 km ... sounds excessive but came from Im group iirc .

Mine doesn't use anything like that since Ali had her but before that it used a sup on the track days
[/quote]

Will definitely use a bit if going hard on track oil comes up into the heads through the breathers , turbo fires it into the intercooler and then get burnt by the engine.
That's why I've a rcm track Attack return to sump catch can .

Is that something worth fitting to my own yoke . Wouldn't do many track days like yourself but I'm not afraid to drive it on either

[quote author=Tommy 555 link=topic=43917.msg506779#msg506779 date=1423594921]
Is that something worth fitting to my own yoke . Wouldn't do many track days like yourself but I'm not afraid to drive it on either
[/quote]

You could alright but they are expensive Tommy but everything else I tryed didn't work this does