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Discussion Starter #1
It is tradition in our family that your first car comes with parts in the back seat and being towed home.

My son (14yo) has selected a 2013 STi for his project. I have done the same with my older kids (Mustang GT/SC and Jeep Wrangler). It's fantastic quality time with my kids and teaches them the value of sweat equity. I grew up with a mechanic as a father and I am a mechanical engineer and still love working with my hands.

The STi we purchased has spun bearing and many performance upgrades. Being this is his first car.. we don't need 400hp or even anything over the stock 300hp. But while I have this block split, I want to put quality parts back in it that will stand up to future tunes as he gets more mature. We have about one hour more work and the block will be on the engine stand.

I'm looking for some advise on how you would build this bottom end and the suggested pistons and rods. Also, how you would configure this engine for a new driver.

Car currently has the following

Aem Intake
Perrin inlet tube
Agency Power unequal length headers
Invidia catless down pipe
Nameless catless back exhaust
Grimmspeed external waste gate up pipe
Tial Q 50mm BOV
Grimmspeed boost solenoid
Process West TMIC
Deatschwerks 1,000cc injectors
Deatschwerks 65C fuel pump
Tomei fuel pressure regulator
Grimmspeed Air/Oil Separator
Koyorad aluminum radiator

AP3 Sub 003 Cobb acc port

Tuned by Mike Adkins at M-Tuned

Eibach front/rear sway bars
Perrin front/rear end links
Fortune auto 500 series coiloverswith swift spring upgrade
Front Cusco strut bar
GT Spec full trunk cage
Enkei rims
Hankook Ventura Evo 2's

Defi Boost gage
Defi Oil Pressure gage


2006 STi
1 Posts
Not sure if you two were able to pick any parts out yet. I think going within OEM specs (bore and compression ratio), but using forged parts, should treat you pretty well. If you want the block to be able to be reliable for higher horsepower numbers in the future then you would probably want to look into getting the block close decked.

With Subarus, you can basically control how aggressive the car is by the tune. If you think that the factory specs is a bit too aggressive, then you could have a tuner get you a map that has less boost.

If you live in a state with emissions testing, then it is likely that catless downpipe might have to come off every time you get tested. Could be a decent idea to throw on a catted downpipe (Invidia makes catted downpipes and it should mate up with the existing exhaust the same that the current downpipe does).

Is it the stock turbo? All of those modifications seem to be supporting mods for an upgraded turbo. Its possible that the person that sold it to you swapped the turbo back to stock though, or just always had a stock turbo. If its not the stock turbo, and you want a conservative tune, it might be a good idea to revert it back to stock. Depending on what turbo it is, it might just make the car a bit more sluggish for daily driving.

A great place to look for parts that will be compatible with the car would be rallysportdirect.com or iagperformance.com. You can select your vehicle and both have sections for rods, pistons, etc. IAG would be a great place to give a call since they actually are a very well respected builder, whereas rallysport is just a retailer.

Premium Member
5,647 Posts
Stock pistons or 4032 for stock to moderate power. Many great built blocks are Manley 2618 but 2618 will be short lived.
Stock crank "always"> IAG will tell you to use a new one regardless.
Stock rods are good, but there are better IE stronger and lighter.
You can buy a new SB with improved pistons for $2K?
New head studs - preferably ARP

It spun a bearing!

Needs AVCS gears (can can try cleaning them) and oil cooler and perhaps a turbo. Replace all screens. Need to check cam bearings heads could be trashed too . . .

Replace the oil pickup with KB or IAG.
If the header will be replaced use an ELH. Not saying it is highly necessary,.but they are better.

From your families cars, I suspect your son isn't going to baby it. Consider a good AOS.

So much . . .

presstab made good points though I avoid RSD. I used to be what I would have considered a a good customer.They would not return something that was admittedly past their allowed time. I just feel that could have been far more supportive of someone who spent thousands of dollars with them. I promised them they were going to make me anti RSD "forever"'. I'm fulfilling that promise.
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