To rebuild or.....

[wirenut]

I know this has been discussed many times before but, I'd like to bring it up one more time. I have a EJ25 from an '06 wrx with 100,000 miles. Checked compression and it's 150-152-151-150.

Looking for 300-325whp. Upgrading fuel pump, injectors, rails, turbo, uppipe, tgv delete, air/oil separator, 3 port boost control, air/water intercooler, considering either meth injection or just running e85.

So the way I see it I have 3 options:

1. Just throw the engine in with the upgrades and see how it does

2. Full rebuild with forged pistons, ect..

3. Head refresh and buy a new oem sti block for around $1800

So what do you guys think? What is the best way to go?

[Sgt.Gator]

That partly depends on how you are using the car. Is this an S and mostly street duty? Or is it an R and mostly Race duty?

If street is the answer and you have the ability to use another DD when this one needs the serious rebuild, you might as well use the current shortblock till it can't anymore. Be aware you are on the absolute edge of what an oem shortblock can reliably handle at that power level. In a street application it's usually ok because you aren't running at WOT for 30 minutes. But don't be surprised if it fails in a few months. It might last a few years though.

If its a race application you better go with the full rebuild.

In either case you definitely want to add: New Timing Belt / New OEM water pump (not the Gates pump that comes in some Gates kits) / New OEM thermostat. The Gates timing belt kits have been questionable the last couple of years, lots of builders are going back to all OEM or the AISIN kits. The problem being Gates is using parts made in China, AISIN and Subaru are still made in Japan.

[wirenut]

It's an S. Not a race car. Was planning on trying the occasional autocross, but mostly just catting around town.

I doubt the car will get more than a couple of thousand miles a year. I did buy the Gates kit about a year ago before I learned about the problems with them. Have to decide weather to use it or try to sale. I might use the gates kit if I go with the old engine and go oem if I rebuild.

[SixStar]

If the engine is already out of the vehicle I would absolutely suggest going through it.

It doesn't take much to increase the reliability of these engines, and it also doesn't take much for them to fail in spectacular fashion. Also consider that once a 255/257 spins a bearing the cost to rebuild goes up a couple thousand dollars easy.

[q4stix]

While I agree that once the engine goes, it's more costly to repair, my personal 07 WRX is a daily driver and has 325whp / 350wtq for the past 30k miles and is now at 90k miles and I'm not afraid to get on it.

I have basically everything changed other than the longblock: key points are VF48, Process West intercooler, Tomei unequal length headers, Cobb downpipe, etc. The stock injectors are fully maxed out in the cool months. 11.6 target AFRs, all tuning done myself.

While I have another shortblock ready to build up, that's only because I have a Dom 1.5 XT-R and ID1000s going in when I do the 100k service for the timing belt. Other than that, I've never had a concern. On the other hand, I just met a guy that's had his fairly stock car tuned to the max by two well know tuners and has already been through 3 shortblocks and is on his 4th. Essentially, the tune and abuse has a lot to do with the reliability.

I'd personally say that if you keep it at 300 or 325 but don't max out the boost or the turbo CFMs, you'll be ok. Knock at peak torque will kill the pistons as well as going lean due to high RPMs and lack of injectors. E85 would be fun, but I'd worry about the shortblock with 20psi on E.

[wirenut]

Hey guys thanks for the info! It was a lot of help.

I've decided to do a full rebuild w/ forged pistons, sti rods (I think), ARP studs, head rebuild, etc...

At the end of the day I won't be happy unless I build the best car that I can build.