2.5 blocks

[sultan]

As I've posted before, I'm looking at doing a 2.5 motor. New EJ257 and drop in forged pistons is one option i'm looking at for my power target.

But there are other 2.5 blocks - are they all pretty similar? I.e BH legacy. Are there ones that would be appropriate to build a 250kw motor out of and ones that wouldn't (assuming the n/a block was built with forged turbo pistons and rods)? Is the crankshaft a problem? Will it still bolt up to my 2.0 heads? I've attempted to research this but haven't found useful information about the different block types.

[nt_a_foz]

Heads will bolt on.

Thats about as far as i can help but i suspect the new ej257 MAY be semi closed where the olders would be most likely open deck.

I would be replacing rods at that power level either way also....

[Tony]

If you find a later model (8 bolt) n/a 2.5 block then it should be semi-closed the same as the STI one (my mechanic has one which he got from a wrecker, we pulled the heads off and it was anyway).

The crankshaft from one of these engines will also be fine to use for a turbo application - well it was what I was going to use when I considered building a 2.5 anyway...

[DAKRNK]

If your aiming for 250kw, you could just use a 2lt block IMO, Im currently doing a 2.5lt set up and its working out well so far.

[sultan]

i already have 240kw 2.0, it doesn't interest me. i want 2.5 for torque and turbo response

8 bolt n/a block is the way to go then, thanks tony

another thought - will my existing tune be OK for run-in period given that all i'm changing is the shortblock?

[gotasuby]

is it maf or map based?

[funkytown]

i surely would do a run in on a motor with a tune from a different capacity engine.

doesnt seem logical at all.

[pl0x]

 funkytown said:

i surely would do a run in on a motor with a tune from a different capacity engine.

doesnt seem logical at all.

When Nt_a_foz was looking at 2.5 the tune from the 2.0l was going to be good enough for run in.

but id check with your tuner not some people over the internet

[sultan]

 gotasuby said:

is it maf or map based?

map

[99GTB]

I know mine was sweet with a 2L factory ecu as it was maf based, but if map based the tune should be checked at a minimum and possibly adjusted slightly especially for run in.

[Guest]

 Tony said:

If you find a later model (8 bolt) n/a 2.5 block then it should be semi-closed the same as the STI one (my mechanic has one which he got from a wrecker, we pulled the heads off and it was anyway).

The crankshaft from one of these engines will also be fine to use for a turbo application - well it was what I was going to use when I considered building a 2.5 anyway...

Iv only seen open deck late model 2.5 N/A engines?

[Tony]

 caged']

[quote name='Tony said:

If you find a later model (8 bolt) n/a 2.5 block then it should be semi-closed the same as the STI one (my mechanic has one which he got from a wrecker, we pulled the heads off and it was anyway).

The crankshaft from one of these engines will also be fine to use for a turbo application - well it was what I was going to use when I considered building a 2.5 anyway...

/quote]

Iv only seen open deck late model 2.5 N/A engines?

I thought they were all open deck as well (hence why I said "should be" rather than "will be"), but the one my mech has is definately semi closed.... Will try and find out if he had any info about which vehicle it came from (engine was purchased from a wrecker).

[Guest boostin]

Optical grabbed a couple of EJ25 blocks off me last year. One was a dirty old EJ25D from a BG Grandwagon, the other was a EJ25..? from a BP Outback. The old 25D had thicker cylinder supports than the newer block.