WTB: 2.0L wrx heads

[sedonabugeye]

I am looking for a set of 2.0L wrx heads. Mine slightly cracked, so I am looking for a set of stock heads so I can get my car back together. Let me know if anyone has a set that they are selling and how much. Thanks!

[cody]

Wow! Did you overheat or something? Just curious.

[sperry]

Originally Posted by cody

Wow! Did you overheat or something? Just curious.

It's pretty common for the WRX heads to get a crack between one of the valve holes and spark plug hole. Mine had them, and I bet if you pull your heads off, they've got one too. From what I've heard, it's still driveable. I just wouldn't go looking for an ass-ton of boost. But then again, who runs a bunch of boost on a stock 2.0L motor/heads anyway?

[cody]

Andy.

[sperry]

Originally Posted by cody

Andy.

I'm pretty sure Andy wasn't running 30psi on a stock 2.0L motor. My point is that you'll run into other failures before those cracks allow stuff like a leaky valve or shoot the spark plug out of the motor.

[A1337STI]

Do any of the 2.0L WRX heads have AVC ?
or that just on the 2.5L WRX heads?

[cody]

No USDM 2L heads do. Not sure if there are JDM ones.

[sperry]

Originally Posted by cody

No USDM 2L heads do. Not sure if there are JDM ones.

The JDM 2.0L heads from the EJ207 have AVCS, and whatever the latest STi motor is has dual-AVCS on a 2.0L block. I believe there are even better Spec-C heads as well... though IIRC the USDM STi heads up until '06 or so are the equivalent to the Spec-C heads.

Maybe Aaron can chime in w/ the specifics.

[sybir]

No, you got it - only the EJ207's had AVCS in the EJ20 family. The US STi heads aren't worked quite as heavily as the JDM heads from what I remember, but they're not *really* a restriction until you've got way too much money in the car. AVCS helps fatten the torque curve, but not nearly as much as the displacement does - a lot of the higher-end cars actually ditch AVCS for simplicity's sake.

I'm really not sold on big head upgrades for most street cars. Sure, within reason, there's limits, but if you have a turbo that can make enough boost at any reasonable RPM to require a wastegate to limit boost (in other words, it's not running out of oomph within its efficiency range), you're pushing a lot of air through whatever orifices are available, and smoothing, opening, enlarging, and streamlining is a final step on a fully prepped car to get the last 2-3% - at least on most parts ahead of the wastegate/exhaust outlet (non-pressurized components are a completely different world and are why a good NA build takes so much comprehensive work to so many systems. Flow characteristics, turbulence, etc - they all matter and can be improved, but you're chasing diminishing returns, especially on a street car. Most headwork, and upstream exhaust work, by association, helps spool, and therefore area under the curve, more than it affects ultimate power. Now, AUTC is what most of us care about, especially on street cars, but a lot of time it's going to come down to "feel" mods and perceived changes rather than calculable numbers.

I mean, I used to do the shop thing, I'm not saying there aren't a lot of bits that will get you another 2-3% (and on a 200-300hp car, you're talking 5-10hp with some of the more problematic points addressed, but it's diminishing returns on a stock-type turbo that's flowing reasonable amounts of air and pressure. Picture a garden hose. Put your thumb over the end and fill it with water slowly; you can hold it until it fills up. Turn off the water, and you can really control the flow rate out of the hose. Now, try jamming your thumb over the end with the water on - that's a simplistic way of looking at intake (primarily) and exhaust port flow on the turbo car that's making non-trivial boost. The air is going to get shoved where it needs to be because physics dictate it has to go somewhere. Once the system is pressurized, flow characteristics become moot under most normal conditions.

If you're reading that I'd rather build a stouter bottom end and a little more boost than try to finesse every .25 hp out of a motor, you get the picture. Within reason, a few pounds of boost will make up for sub-optimal flow.

[sedonabugeye]

i wasnt running 30psi, but 20 all day long. i made some decent power on a bone stock 2.0L. But i dont want any cracks at all. mine cracked in the spark plug hole. just tiny cracks, but cracks nonetheless, and i dont want a single one.

so back to my main topic.. does anyone have any heads for sale at all??

and a seperate topic.. what is the difference between wrx 2.0dohc heads and say dohc heads out of an outback or legacy??

[sperry]

I wasn't suggesting you should accept the cracks, just that they're not all that unusual, and they're probably fine for a stock motor.

If that's all that's wrong with the heads you might want to just look at getting them repaired and ported/polished while they're getting worked on. It might be cheaper than buying new 2.0 heads and result in better heads as well. Especially if you were to put some cams in them too.

[sedonabugeye]

ive thought about getting them repaired, but i would just rather not have anything wrong with them when i put them back in. and im just doing a stock rebuild, but i want to be assured that nothing will go wrong with anything that im putting back together.