I have read on some other sites that the ej257 has issues with strength vs the reliable ej207. Most of these are on US sites. Is this true for Australian delievered EJ257s?

Was originally going to go 2L for my 400whp build but doing it with a 2.5L may make it more streetable. Only concern is strength

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STi Ver 6 | 2.1L Stroker | 418whp | 11.5 @ 199kph |

Not fast enough dammit!

207 is the way to go as far as a factor block is concerned. Sean (ASG) had a stock block 207 in a GC8 running 10.2 @ 137MPH at the drags, which was making 440hp on pump and close to 500hp on race fuel. Although it is arguable how long that motor had left after it was sold 10,000km later.

Even if you needed to build the motor from scratch a 207 would be preferable in my opinion. That is not to say that a 257 can't make that power, it is just their fatality rate is higher when it comes to built motors.

If you did a 257 with a set of rods and pistons it be a killer motor still, and it could get you close to your planned goals. There have been few 257 motors with just pistons making easy 340 - 350HP (pretty sure one of Justin's Libertys had this for over 30,000km).

But to see a streetable motor that will handle 400hp look at Daz's build (or Tinos for balla $pec build). To be honest Daz, Justin or Troy need to chime in and write an essay and school us all.

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MY01 JDM EVO VII - 230KW / 430NM @ 1.6BAR

There's quite a few variables involved to come to the best decision but here's my take on it having built a good many of each.

For a crate motor the 207 is hard to beat for moderate power and with the right heads could be made very streetable and yet still have good power levels.

As for the 2.5 using untouched case halves I just wouldn't bother. If the cylinder walls don't crack they'll go oval and have high oil usage in no time.

I've built a good many of these so feel in a fairly good position to answer.

Had mine not had sleeves when i bought it I'd have built either a 2.1 stroker using a 2.0L block or a 2.3 stroker using an EJ22T block sourced from the UK.

If you're dead set on using a 257 then you'll need to strengthen the block somehow. I've used pins around the bores to good effect 500+at the wheels

Here's a couple of pics of my pinned block




If you're going to sleeve it then be prepared for another build maybe a couple as sleeves tend to settle and require another reface. That's not always the case but it happens enough for you to be mindful of that happening.

Another good option is having a CDB Insert done which has a similar effect to the pins i.e. it offers strength where it's needed most.

Either way the 2.5 must have good head studs they are prone to doing head gaskets if you dont.

Also bear in mind for big power the EJ257 factory sleeves are the thinnest of the lot so even if you have it pinned or closed decked you may still crack a sleeve. That's only usually applicable to big power builds though.

The 2.5 is a good option but only if its done right and doing so gets expensive. if you cut corners on a 257 build I guarantee it will come back and bite you.

I think the best bang for buck option is a 2.1 stroker. Best option would be to use a CDB but I understand getting the rear thrust conversion is an issue here.

Personally I'd have no problem with running a forged 2.1 stroker using 207 case halves and having it sit around 500hp. It will have plenty of torque and rev like a dremel. The sleeves on a 207 are the thickest of the lot too.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

I would not pin the bores... they will still warp..

if you are going to go to the trouble of making power with a 257 which can be done. you need to strengthen the block..

1. Close decking is a must.
2. Flange top sleeves.
3. Torque plated
4. Big head studs (14mm i think i used).

the ej22t worked so well as it was a solid block (although they had water jacket galleries)..

I havent had any heating issues with my 257 that i can recall.

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I'm a jockey kunts...

Mine didn't. 30,000 miles on it. 600hp, plenty of track days, Countless quarter miles on it a few of which were in the 10's.

I refreshed it with new rings and bearings before I sold it measured it all with a bore dial gauge and the bores needed nothing more than a slight deglazing hone.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

You were lucky.. i knew of a heaps of cars in Aus and US that had cracked bores from pining them.

If youre going to build a high hp engine its better to be cautious then skimp on a couple of k to get it close decked.

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I'm a jockey kunts...

I've built a few. None of had issues that I know of.
The one quoted was my own engine.

I guess it's down to how the pins are done. You'll see in the pics that my block was slightly recessed for them. The cylinders were also honed after the pins were fitted.

It's all a bit of a lottery as far as the 257 is concerned. That is why I'd advocate building a 2.1 stroker instead. Cheaper, more reliable and far less in the equation to go wrong.
That's coming from someone with a built and sleeved 257 too.

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605whp
Quarter Mile in 10.9 seconds @ 135mph /217kph
0-100 kph 3.2 seconds

Thanks guys. Fantastic replys and definitly given me something to think about. I may have to rethink my plans of a daily driven 400whp sti. I might aim for 350. I also might stick to the proven 207.
Im wanting my cake and eat it too.

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STi Ver 6 | 2.1L Stroker | 418whp | 11.5 @ 199kph |

Not fast enough dammit!

The problem is the differential heating of the bores especially the areas where the pins are.

CD and sleeving the block and torque hone plating has been shown to be the best way to may a 257 reliable.

I did a huge amount of research into this when i did my build speaking with world renown tuners etc and that was the reason i did what i did to my engine.

Also power comes with the heads so you need to get the heads matched to the outlets.

I was looking at EG33 build back in the day but it was too expensive to do but now guys are turning to H6 or even better EG33 motors to pump out decent power without stressing the engine. Thats what id be doing if i was looking at building up a subaru..

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I'm a jockey kunts...

Interesting to see how the USA guys rate the 257
IAG Stage 2 Tuff 2.5L Subaru Short Block for 2002-14 WRX, 2004-16 STI, 2005-12 Legacy GT and 2004-13 Forester XT. Built power output rating: 675BHP.

You can get CNC closed decking done in Perth now and the option of fitting sleeves if one requires.

Photos to follow