Hi all,

I dont want to be alarmist, but I just have herd that the MY06 STi and WRX has the same engine.

Also that the pistons are weak, that the Euro STi engine and the USDM engine arent the same, that the USDM and the Euro turbos arent the same (vf-39 vs vf-43), that there is people that are breaking their engines with only an full exhaust and that the limit for the euro engine stands in 350 hp.

For the peace of mind of the rest of the MY06 STi owners, I must say that by the moment I have no clues of this to be true. So what I only want is to find clues to deny this.

Please note that I also own a MY06 Euro (Spanish) STi.

Thanks in advice and hope not to bother no one.

 

Well Graham Goode a respected tuner of Subarus is upgrading these cars to 370BHp and 370lbft.:-)
I think there is a limitation with head gasket sealing around the 400bhp mark. But after all this engine has been sold in the states for many years, i dont think Subaru would still be in business if this was a weak unit.

 

I dont think you will find anyone admitting to that here but it is a popular
belief or rumour never the less.... Very early days with the 2.5 and tuning here although there are some big power engines in the states on stock internals... Cosworth do some nice bits too if you are going for it!

 

Didnt this engine just win an award for engine of the year in the 2.0 to 2.5 category?

Sure I read this on here.

 

Weak Engine .... fron Subaru ........ only on SN!!

Pete

 

they recently won "diesel" engine of the year, or so one of the weekend papers stated

 

Right or wrong, these fears were exactly why I bought an Evo. 400 BHP on stock turbo 2.0 engine with just as wide a power band and no more lag than 400 BHP on a Subaru 2.5 and no reliability worries.

 

you really need to compare Torque fiqures on not BHP IMHO. eg 2.0ltr 400Bhp +400Lbs and a 2.5ltr 350bhp + 400lbs. WRC Scoob 300bhp and 550+ lbs IIRC

The Std MY06JDM 2.0ltr engine internals (simular pistons bar size as the 2.5Ltr) are capable of up to 400bhp & 400lbs and relatively speaking, using a calculator not real life , BHP to CC the 2.5Ltr should see about 500hp & 600lbs.

Lithco/Powerstaion developed the T25 with their own designed Pistons, later used Cosworth Pistons. IIRC they only use Cosworth Built engines now.

So are they weaker!!! time will tell. All the tuning pagages suggest they are being cautious to maintain durability, reliabilty and Warranty.

You could get a 2.0ltr on Std internals fit bigger this and bigger that & nitrous 600bhp but probably for only last 20 seconds. "The brighter the Candle burns.........."

IIRC AFAICR IMHO

Tony

 

Looked after subaru engines will last forever

"This is the initial press release when the Legacy was first introduced in 1990. It talks about all its features, specs, and not to forget how three production level Legacy RS's broke the World Speed Endurance record with an average of 138.78 mph for more then 18 days and 62,000 miles!"

they still hold the world record as far as i know

Evo's need service at 4500 miles

 

I am sure I read it was the engine fitted in the WRX and Sti.

Oh well, covered by warranty anyway!

 

Oil is cheaper than an engine rebuild ReggieMY99, running up to 173 BHP per litre on the stock internals (or 203 BHP/litre on the 400) with a warranty, it doesn't seem unreasonable to me to change the oil fairly frequently.

Tony I think your calculator is faulty re 600 lbft. And I don't agree on comparing torque, I compare power and use the gearbox, otherwise an M3 and S2000 wouldn't compete with a half decent diesel.

 

Wouldn't there be less stress though due to a greater surface area??

I thought the greater the surface area that is available the better as the stress can be distributed more and not be so concentrated.

 

If you run the same cylinder pressure (or boost) to get your increase in torque though...

Also a large bore piston can result in a more detonation prone engine because the combustion is slower.

The EJ257 drives well when it holds together, but there is no free lunch with it. It has very thin liners and floppy bores that can oval.

 

Yep and so is a knocklink


i know there has been problems with the 2.5, but i think they solved those issues, i cant believe subaru would release a 2.5 ltr that would be prone to fail on reliability

cheers

 

I had three Subaru 2.5 litre engine failures whilst using a knocklink, wideband AFR, boost gauge, oil temp/pres, fuel pressure, and with regular oil changes.

One cracked ring land and three head gasket failures. It is truly an engine that a single flick of the red light on the knocklink at high boost and it could all be over... it avalanches into sudden detonation for fun. The EJ20 and the 4G63 aren't like that.

 

I'm sure they've solved it on the STANDARD car, but if the limit is 350 BHP this must score as the least tunable turbo engine about. I took my MY00 UK engine to 406 BHP at 1.8 bar boost and it didn't suffer at all that I could tell. It sat in a sandwich of an R1 and GSXR-1000 and stayed there for a mile and didn't blow up. Similar escapades with the EJ257 usually resulted in tears, Porsches were responsible on two occasions, whilst I could outdrag them they took theirs home with working engines. Mine was gurgling and spewing coolant...

 

hmm yep thats a 2.0 ltr you are talking about on your evo not a 2.5 ?

subarus 2.0 ltr a very relieable and easier to tune

well lets hope they solve those problems because the 2.5 is a good engine with good low down torque

 

It was a Subaru 2.0 UK engine I took to 406 BHP.

I love the drive of the 2.5, but in the UK models it has a few downsides that IMHO only make it the equal of a good 2.0, if that:

Single scroll turbo (which is small, but any bigger and you might blow the engine, same with the injectors)
Low rev limit and early power peak
Loooong exhaust manifold
Low compression and short stroke compared to the 4G63

The 4G63 manages to spool up its TD05 like an EJ20 spools up a TD04 yet can make +100 BHP. The EJ257 has an almost identical power band to the 2.0 Evo from what I can tell living with both.

The torque hit of the EJ257 is nicer though at sensible boost.

I'd add as well that for 200 BHP with a cat that remaps to 250 BHP, the engine in the wife's Golf GTI is amazingly lag free, it hits full boost at 1500 RPM. It is only 2.0, but I don't think a Subaru 2.5 engine would manage any better than that on the same size of turbo. The Subaru engines behave smaller than they are compared to the competition I'm afraid.

 

If you read back to say 1999/2000 then the subaru 2.0 engine was only capable of taking 19psi boost on an STi/16Psi boost on an UK/WRX as the engines were made of 'chocolate' (both on here and 22B). Anything above that and you would be classed as a silly fooooool

IMHO only time will tell what the 2.5 reliability is like. As from the above we can see times have changed.

Tony.

 

The key element to the increases in the boost on the 2.0 was good turbos and engine management, neither of which we lack on the 2.5. My problems were hybrid 2.5s with 2.0 heads which can't be compared to the new models. I was all for trying a 2.5 Scooby with a 20G but I was put off by pat and Mr Litchfield to be honest, both agreeing it was on borrowed time even at 400 BHP which I thought was sensible having taken my previous 2.5s much further, although the headgaskets always went by 15000 miles. Type 25 would of course be nice, but the Evo did what I wanted much more cheaply, loads of people run c.400/400 on variants of the stock turbo on stock internals right back since the Evo 5.

 

Whilst not being very techie on engines, I would guess that there is obviously a limit on the new 2.5 engine.

It may well be an award winning engine, but as standard, not modded!!

Why doesn't the 2.5 performance pack mirror the 2.0 changes. Mike wood says that they have taken it further, but are not planning on releasing a PPP2. Obviously IM are not willing to give a warranty when pushed a bit further.

The American STi is standard with 300bhp, so what is a factory standard engine & map. IM have them made to their spec & price.

Why has the JDM stayed at 2.0?

As for a WRC engine (WRC Scoob 300bhp and 550+ lbs IIRC0)
These engines cost £50,000 at least, I would imagine. Also they only have to do a limited mileage. Two rallies this year & one last. In anger they now only have to do 350Km = 220 miles.

 

Oh well, wrong again for a change LOL

at least my calculators not as bad as my keyboard, now that always spourting out rubbish and spoolink misstacks LOL

Tony

 

How far above the 'standard' 350bhp can you take a Type25, without having to start changing internals that is?

I understand that it has a relatively conservative map

 

600 lbft would be rather nice. I'm sure Alan G had about 530 lbft on his 2.5 which I am told is more animal rather than mineral in behaviour

Type 25 is an uber engineered beast with already uprated internals and incomparable to a stock 2.5 IMHO. I would suggest you discuss with Litchfield and Powerstation - not sure if they would offer a turbo upgrade and big power if you lost your warranty?

 

If the new age engiens have chocolate pistons, then how bad does that make the Classic's pistons??

 

Martin, I have a larger version of the Type-25 turbo here if you really want more power There is nothing internal in the Type-25 engine that will stop you running more power, particularly your generation of engine which has forged rods as well.

Back on topic, I don’t think there is anything particularly weak on the standard engine but sooner or later you reach its limits as with anything.

Powerstation happily tune the UK 2.5 engine to 340bhp/340lbft which is a considerable increase over standard. Some tuners may offer more but I know of at least one other Subaru specialist that has done their own extensive testing and come to the same conclusion on the limits. Neither one would call the engine chocolate but I think it is relatively easy/cheap to exceed the limits and this has created a snowball of internet rumours.

Iain

 

I'll leave mine standard for the time being then!

 

Maybe the key to keeping this engine happy is regular oil changes, an oil catch tank and oil cooler??

Assuming it will be seeing some hard use in modded form

 

Slightly better built than BMW alternators you'll find!

 

Thanks Iain, don't worry I'm not about to start changing turbos, it's fast enough for me (for now anyway)
I was just curious as to the potential of the engine.

I'd be far more likely to go for a more aggressive map, at some point in the future, assuming that this is viable?


Martin