[Custer175]

I want to start out by saying Ive had a wrx for 2 months, it is my first subie, and my first turbocharged car. I am a noob so please take it easy lol. However I do have a decent amount of mechanical experience, and understanding.My 04 ej205 wrx got a serious case of rod knock last weekend. It blew all the oil out of the exhaust, and some also came from under the engine (not sure what from haven't pulled the engine yet). the engine had 90k miles on it. I know I will be replacing the crank bearings for sure, and possibly pistons (thinking one broke a ring, hence the oil in exhaust). I want to mildly build the engine. More for durability than performance, as it will be my daily driver, but I do tend to have a heavy foot, and autocross the car on occasion. The car will be running COBB ap stage 2, and possibly a future pro tune. I want to keep the stock turbo, possibly rebuild mine. I will also be replacing the clutch, most likely with a stage 2 clutch. So i guess what i wanna know is what parts should i buy to make this engine as bulletproof as possible? Is boring the cylinders, and adding forged pistons worth it? and what about headers? Is a lightweight flywheel recommended? And what about lightweight crank pulleys? everyone seems to have a different opinion on them. Will porting and polishing the intake manifold and heads offer good gains? As of now I know that I will be buying an aftermarket turbo inlet, and a catless up pipe, as I have heard good things about both, and they both seem to offer good bang for the buck. But most importantly, I want to get my engine as close to a new engine as possible. Im sure I have more questions, but this is a start lol. Thanks in advance guys!

 

[SD_GR]

Look into a stock clutch, a new 2,5L block with your existing heads, and a new map for that block, all provided your existing motor is actually blown. Porting won't hurt but it's not fun either. If you want to donut or farm it out, sure.

 

[Custer175]

Doesn't a 2.5l hybrid require larger injectors as well? and i would have a shop port the manifold

 

[Donkey]

But most importantly, I want to get my engine as close to a new engine as possible. Im sure I have more questions, but this is a start lol. Thanks in advance guys!

This will answer most of your questions: Unabomber's Manifesto - NASIOC For autocross a lightweight flywheel is a nice addition,especially if the motor is coming out anyways. Alot of this is going to come down to how much $$$ you want/can to spend. I don't know off any engine that doesn't respond to porting/polishing. I myself kinda fancy the 2.1L stroker kits over doing the 2.5L short block. TGV deletes are recommended along with a good catch can/oil-air seperator.

 

[Custer175]

My budget is around 2 grand so a stroker kit is out of the question. Forgive my ignorance but what is a tgv delete?

 

[DiRty Impreza]

tumbler generator valve i believe, recurculates air to the intake??

 

[Custer175]

what is the advantage of deleting it?

 

[xxxxxxxAnub1s]

Tumble generator valves do not recirculate air into the intake, they're there to create a swirl effect in the incoming air (or tumble it) creating a cleaner burn with fewer emissions. They also aid in low speed (RPM) engine operation and cold start conditions.

Removing them means removing a certain restriction in the air flow creating a condition where you could make more power, but sacrificing that cold start and low RPM operation advantage, also increasing emissions output.

Edit: to clarify, the advantages that the TGV's create are at or near idle speed, really if you're building an engine you don't intend to be environmentally friendly, might as well remove them.

 

[Custer175]

is it a removal kit or do i simply get rid of it?

 

[xxxxxxxAnub1s]

is it a removal kit or do i simply get rid of it?

Um, both? There is a way to DIY, but the easiest solution is to buy pre-deleted TGV housings, or have the service performed for you by a reputable Subaru parts manufacturer/modifier like Grimmspeed. Doing it yourself isn't exactly the easiest solution.

 

[Custer175]

Cool Ill have to look into that

 

[xxxxxxxAnub1s]

Cool Ill have to look into that

GrimmSpeed

There's the link to the Grimmspeed service.

 

[Donkey]

My budget is around 2 grand so a stroker kit is out of the question.

If your budget is 2 grand then alot of the stuff you mentioned is probably out of the question.

 

[Custer175]

Yeah, I'm starting to learn that as I'm researching parts

 

[MainFrame]

With a $2000 budget you'll be lucky to get it fixed and returned to stock. I don't know if you're planning on doing all the work yourself, but it usually costs around $1,000 just to have someone R&R the engine. You throw in a replacement shortblock, gasket kit, oil pump, water pump, tensoner, etc, and you're easily ariving at $3,000.

 

[Mikie13]

some further info...if you're planning on building the block for longevity, then a stock rebuild is fine if money is a concern. If you wanted to do stronger internals, then no point in staying stock with the power. A turbo upgrade would be a much wiser investment if you are actually going to be building stronger anyway...especially if you thought about rebuilding a TD04. That's virtually pointless for how cheap you can just get a used one second hand. Look into VF39/43 or 16G options.

Also, regardless if you do stay stock turbo'd though...you'll probably be better off with a protune, especially if you are doing TGV deletes and an inlet. An OTS Cobb map will be rather tame and doesn't take into account usually anything but a downpipe.

 

[zax]

I myself kinda fancy the 2.1L stroker kits over doing the 2.5L short block. TGV deletes are recommended along with a good catch can/oil-air seperator.

This. This. This. The 2.1L is a much better suited build for the 2L heads.

 

[MainFrame]

This. This. This. The 2.1L is a much better suited build for the 2L heads.

Unless you have the heads worked over.

 

[zax]

Unless you have the heads worked over.

Which you should have done anyway while they're off

 

[MainFrame]

Not really needed if you're sticking with a 2L block..