Engine change....2.0l turbo 2.5l turo

[Docmartin4x4]

Have purchased a 03 wagon WRX PPP with big ends rattling !! So though about fitting a short engine but 2.5l as opposed to the standard 2.0l. Will all parts just bolt on on will there be other changes required. I take it a remap will e required after as well.

 

Mart

[martyc]

I'd be inclined to stick with the 2.0 unless there's a good reason to go to the 2.5 (professionally built lump) as the Pistons have been known to fail and it's not as reliable as the 2.0

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[kershaw-330s]

But as an answer to your question it could be a bigger job than you think it depends which 2.5 block you get but the case ings are the same it's the heads and the avcs systems that could be a pain . But a well sorted built ej257 is a peach it's just a shame about their standard form

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[quit]

Why ? The 2.5 is garbage

[savage bulldogs]

You can fit 2ltr heads to a 2.5ltr bottom end as there's quite a few 2.5 classics running 2ltr heads to retain their original inlets/loom . I think the 2ltr heads would probably need a bit of machine work due to the 2.5 ltr having bigger dia pistons (but I'm not 100% sure)

You'd also need someone who knows the piston bowl and head chamber sizes to calculate the correct head gasket thickness needed to achieve the 8.5.1 ideal compression ratio .

As said above in standard guise the 2.5 is the weaker engine but when "pinned" and forged they do make nice figures [emoji6]

[Docmartin4x4]

Well thanks for the replies, the consensus is obviously to stay with 2.0l, so that is what i will do gentlemen.

Rebuild or get a 2nd hand unit that is the next question?

 

Mart 

[kershaw-330s]

That now all depends on budget and how much power etc your after

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[Docmartin4x4]

Good point! Budget is not excessive unfortunately and I would like 340-350 hp at the end of the day, if possible.

At the moment she is running 265ps as it has PPP, prodrive quote a figure of 4.8 0-60, so I would to get back to that as a starter and then have the ability to build on it if I wanted to.

 

Mart

[Scoobyghost]

Always a risk going for a second hand lump. If it's been sat in a yard for some time it would need belts/servicing.

[Tidgy]

Time to dispell some myths ;)

 

First off the standard 2.5 is pretty poor, ringlands and headgaskets are known to fail. However built right, there fine to 450bhp and keep the right side of reliability.

 

For road use a built right a 2.5 is about as good as it gets in scoob, the low down grunt they produce makes them spool allot better than 2.0's.

 

Anything above 450 then block needs work, pinning is an option but personally i'd go for close deck converting given its only about £500 give or take. In fact i just have. Just finished running in my closed deck 2.5 converted Type R.

 

I had a forged 2.5 in my old hawk and yet to see anyone get near this on a 2.0.

 

 

 

 

I've had 2.0's and i've had 2.5's and i'd go 2.5 all day long

[quit]

389 on a 2.0 ? Seen plenty pushing that, tho most start going 2.1 stroker route

My mates Sti was about 370 on standard engine !!!

[Tidgy]

thats a 2.5 mate, no chance of getting a torque figure or spool like that on a 2.0 ;)

 

Was limited by the top mount, had an sti one on it and was getting temp issues.

[quit]

Seen some good figures with the standard Sti top mount tho !

[Tidgy]

like all tuning varies from car to car, was pushed to just over 400 and then backed off due to temps. i wouldn;t wanna run more than that on a top mount thats for sure

[quit]

Yeah ! I keep thinking about going for a front mount but I don't see any point st the moment

[Tidgy]

Yeah ! I keep thinking about going for a front mount but I don't see any point st the moment

 

what power you running?

 

Anything bigger than a TD04 will see an improvement when a front mount is fitted and mapped.

 

thing is people get hung up on claims it causes lag. unless you get one with a stupidly large core then they don't. once you swap out the standard turbo you see improvements in power from a front mount, cooler temps allow more aggressive timing with the map, issue is always heat so improving the air cooling leaves more wiggle room for the mapper.