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Old 07-07-2019, 11:35 AM   #10
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Join Date: Oct 2011
Chapter/Region: W. Canada
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When you take the motor out but before you start disassembly, you may consider doing a leak down test to check for any potential issues. This test would be easier to perform on an engine stand.

Originally Posted by UncleFester View Post
So as long as the heads are straight, they dont need to be sent off for any work?
Basically, yes. You may opt to do some port polishing, or refresh seals, or upgrade springs. I don't know enough about the new 2.0L head design to confidently offer any more suggestions beyond that though.

Originally Posted by UncleFester View Post

I'd like to come away with at least 450hp/tq once tuned again. That's why I'm wondering if I may need some performance head work while they're off.

If the stock turbo can give me 450+ and the stock heads can handle it, that's the best case scenario for me.
I'm not familiar enough with the new FA/FB engine platform, but from what I've read and by way of comparison, the stock heads on the old EJ25 started becoming the limiting factor around the 450 hp level. There's plenty of variables that would shift this number up or down. However, I have no personal experience with these power levels in a Subaru so I'm not sure how far you could push the envelope with either EJ25 heads or the newer 2.0L heads. I'm sure someone more experienced than I might come along and correct me. At these levels you might need to start looking at cams, but again, I just don't know. I'm just basing this of what I've read. Any work on the heads can also be done at home, but there's not many guides for the unfamiliar DIY'er so a shop may be in order.

As for the turbo, I imagine you may be out of it's efficiency range with your goals, considering the stock power levels. You'll probably want to consider upgrades in that area too.

All in all, while asking NASIOC may (arguably) be a good start, you'll definitely want to talk to an experienced tuner, preferably the one you'll be taking the car to after all these upgrades are completed. That way they will be mostly familiar with the build when you bring it in and they can help steer you in the right direction.

Also, if I'm not mistaken, I believe the 2015 WRX-only ditched the air pump in favor of the EGR system.
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