Ej257 with ej207 heads

Drexer13 · 10-20-2009, 02:04 AM

I have a friend that is selling the motor out of his sti, it has a spun bearing so it’s pretty cheap. It’s coming as a complete long block so I would have the turbo, injectors and sti tmic. I also just found some ej207 heads for a pretty good deal I was wondering if they would mate and if that might be a good combo. I was just thinking that if I’m going to be building the 2.5 anyway I might as well build it to spin up to 8k. Some advice would be great.
Thanks

basco · 10-20-2009, 07:46 AM

they would mate but why would you want to use them there essentially the same heads with a slightly different cam profile that is more favorable to a two litre.

c2bcoolwrx · 10-20-2009, 01:51 PM

EJ207 heads are better than EJ205 heads. But, if your going to get the EJ257 heads I would go with those b/c of the AVCS. Also, I believe (someone correct me if I am wrong) there are some wiring issues to figure out w/EJ207 heads on an EJ257. Also, I would not go the hybrid route if you already have a STI/EJ257 longblock.

So, I agree w/Basco put the longblock in. I would also throw some forged pistons in there and even consider a mild cam upgrade (i.e. Kelford 264s or Tomei 252s) to help improve the top end, depending on what turbo you choose to run (smaller the turbo = smaller grind cam; larger the turbo = larger grind cam).

basco · 10-20-2009, 10:47 PM

the 207 heads do have AVCS...and the wiring problem is the same if you have just a WRX and want either 207 or 257 swap

Drexer13 · 10-30-2009, 05:43 PM

what's the fix for the avcs? Is it rpm induced?

basco · 10-30-2009, 06:35 PM

to wire it in and use an ECU or tuning system that supports it...but if you don't hook it up it will always be in high lift mode so your not sacrificing high end power...but my only question to you is why are you so dead set on using a different set of heads...your stock wrx ones will be fine...just research the "Hybrid" Build

Kjott21 · 10-31-2009, 03:20 AM

What version are the EJ207 heads? There were a couple of JDM STI heads that came with nice big port heads.

If you don't want to run the AVCS you can always plug the camshafts and run them. One of the local guys did that.

If you want to run the AVCS you would need to run an EJ207 ECU or get a standalone and wire them up. Neither is really easy.

VD5505 · 11-02-2009, 07:08 PM

I would fix whats wrong with the EJ25 and go with some EJ205 head and have then sent out and get P&P really nice and get some valve springs and a nice set of Cams for them, go with the thicker Cometic head Gaskets to lower the compression back down to around 8:5.1 or so, and if you have some money put some nice forged pistons in there like CP or something. I wouldnt hassle with AVCS. The Hybrid setup is a really nice set up i like it alot and you can make alot of power with it. but you will need something bigger than STI injectors.