I think we're both agreeing that a 257 can be made reliable but its expensive to do so.

As I've said many times had my current engine not had the sleeves already done I wouldn't use the EJ257 as a platform again. It would always be a stroked closed deck whether that be a 2.1 or a 2.35 would depend on block availability.

In theory the 257 is great but the reality is some what different.

Sleeves are more likely to drop than they are staying put so you need to budget for several possible rebuilds and block refacing until they settle.

14mm headstuds are an absolute must on a big power 257.

Even if you close deck a stock 257 the cylinder walls are thinner than you'd think.

Here is a dissected ODB 2.0L


Here is a 257 see how thin the factory walls are? They still split even with pins an CDB inserts when you start to use them for big power.


The EJ257 can be made into a good platform but its gets very expensive we've both got the reciepts to show that

I just wouldn't use one as a basis for a big power build again.

With regard to torque plate honing that has nothing to do with strength of the block and has no influence on it whatsoever. It's just a process that simulates the heads being torqued down when cylinder honing so it's more accurate. Although it is something I have done on every build I do whether they be 2.0L, 2.2L or 2.5L blocks.

I also have all my engines centreline honed for the crank too. This latest one was quite a way out according to the machine shop i used.

Heads, obviously polished flowed and ported makes a difference but its not as essential on an FI engine as it is an an NA one.

A good example was my GC8 that was running untouched 2.5 heads castings. They weren't ported or polished I literally just changed the valves, springs and retainers. The cams were OEM 06 WRX AVCS cams.

That car made 600hp and ran 10's. No doubt it would have gone on to make 60-70HP more had it had head work and big cams but that work and expense just isn't necessary until you get to that point. I can't believe people think they need cams before this point. 400whp will be more than enough for most.

Stock STI5 heads will do 400whp easy without being touched. Although I'd always recommend swapping out valves and springs if you wanted to do that.

Bottom line is a modified 257 is good for a mid power build say 400 whp. They can be used beyond that but to make it reliable beyond that gets expensive.

The flat six is an awesome platform as Andy Forrest has proven but lets be realistic here. The cost and work involved to build one is way beyond what's being discussed here.

The OP has asked for opinions on the 207 versus the 257, and despite loving how my own built 257 drives I just cannot agree that its the better option for the OP.

In this case I honestly think the 207 is a better platform.

It's only my humble opinion but that's based on building, using, racing almost every combination of EJ engine there is over the 15 years since i bought my first one. The only ones i've not tried is a destroked 2.5 or a stroked 2.5 and to be fair i've no desire to.

Hopefully Tino you'll see this as a good discussion rather than me trying to be a smart ass which I'm not

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

207 scd crate motor , late wrx big port heads , upgraded valve springs , Late AVCS STI oil pump , Killerb pickup and windage tray , arp head studs , STI oem MLS head gaskets . port match heads to manifolds . gtx 500 hp rated turbo , 1200 cc injectors , E85 , good quality ecu and fuel system . 400 hp ATW all day long . Thanks for coming tell your friends :P

Nailed it!! Although I'd forge it and stroke it

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

No offence taken at all.. Youre posting your experience as I am I.

Ive had a 207 stock running a FPgreen.. Yes they are good motors can handle boost but when looking at making big power they are laggy hence why i went with a 257 platform..

Ive had 3 257s. One i bought second hand (mistake just pistons rods, was fked from the beg lesson learnt) Second one used that block but just flange top sleeves but still small head studs (which i thought were bigger) blew head gasket.. Third motor is what i have now has held together really well so far..

As for sleeves dropping not if you use flange top sleeves they shouldnt as there pressed into the block..

I still believe reliable but importantly usable power works with a built 257. And who ever wants to stop at 400whp.. it always begins with a target in mind and once that target is reached u want more. So just save some more extra pennies and over engineer what you want to build.

Something in btw would be finding an EJ22T block which closed decked from factory would be the best compromise and having a bit more displacement to work with. Rev out to 9k. But finding those blocks are very hard if not impossible.

Just my 2cents..

__________________
I'm a jockey kunts...

What about for someone with a WRX that has the EJ25 from factory, and they want to build a motor. Is the advice that they grab an EJ20 block and go from there?

That's an open question with so many variables and not what the OP asked but I'll humor you.

What is the car going to be used for? What are the power goals etc?

Obviously the easiest way would be to build a 257. Again how far you go with that build depends on the answers to the above questions.

Mild to Moderate power a well built 2.5 is hard to beat for an all round / fast road / occasional trackday car. However if you want big power it's not the platform to start with.

Lets look at mine for instance. I've done everything I can to mitigate potential failures. But the truth is I'm expecting issues when I start to push it properly . I wouldn't mind betting that I get a dropped sleeve at some point. Even though they are Darton top hat flanged sleeves I still know of several engines that have had these and have still dropped. So it does happen. The BC Racing UK Time Attack Car I was pit crew on was one of them. The EJ257 got binned in favour of a stroked EJ22T. It made a massive difference to the car more power and revved like a bastard.

For a big power build the EJ257 is not the platform I'd use if I had the choice of them all.

Take a look at Roger Clark Motorsport's Gobstopper 2 for example. That's an MY08 that came with a 2.5 out of the factory but what do they use? A closed deck 2.0L and there's good reason for that.

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

Hi daz , Im new to the subi scene ive got a ej25 in my gc8 its got a closed deck & the liners and studs have been done to. Also has Forged pistons and Cunningham rods, its at 323hp now but thinking about going e85 and the car it being used as a all rounder. The build should be fine with amount of power hey ?.

Thanks in advance for any info , trav



using the Perth-WRX mobile app

Should be good for alot more than 325 hp. Ive got more power than that on mine and I dont have CDB or sleeves.

__________________
Doing it for all the wagons out there

Thanks its good to know these things, how power do you think its good for ?

using the Perth-WRX mobile app

Darren's GC8 is 400 hp at the hubs
EJ 257 std block, Tony knight reoil phased crank, 272 cams,2ltr ported heads, forged JE custom pistons, 1mm larger valves, ported heads,1000cc injectors, TD06SL260-1 turbo
19 psi with 98 fuel