02 2.1 Stroker Build

[tonyp1974]

Hello everyone. I recently spun a bearing in my 02 WRX and have weighed all the options and decided to go with a 2.1 stroker motor rebuild. I wanted to go this route because the logic makes sense to me, I have modest HP goals - 300 to 320hp and I figure if I over build the internals and go with a modest tune it will help the longevity of the motor. Here are all the upgrades that are going to be done:

BEFORE REBUILD:
Invidia catted downpipe
Invidia N1 catback
Grimspeed boost control solenoid
AEM cold air intake

REBUILD:
Manley Forged Pistons 2.1 stroker
Manley Rods
ACL Race bearings
New crank
STI 11mm oil pump
2.5L Oil cooler
Killer Bee Oil pickup
Timing belt and 90k maintenance parts
Minor head clean up - replace guides- resurface valves
TGV delete
Blouch TD05 16GXT with 8cm inlet
Agency Power 3" Cast Inlet
Fast Motorsports TMIC
Injector Dynamics 1000cc Injectors
Aeromotive Fuel Pump
Aeromotive Fuel Rails
Agency Power Equal Length Headers with Uppipe
STI oil pan and dipstick

The shop thats doing the work has been great. The fact that they ONLY work on Subarus was very comforting. Does anyone see anything on the list that I might have missed or I should be doing with the build?

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[dnorton]

I'd like to know how this turns out for you since I have a friend who I'm thinking of building a 2.1 myself. If there's anyway you could shoot me a PM when you get her running and tuned just to let me know how you like it would be awesome. There's a few difference's between the two builds but still very close. I'm doing some head work to help the flow and running a 20g XT-R.
Good luck and keep me posted if you have the time,

[tonyp1974]

Will do. It might take a while, should be done in a couple weeks then theres the dreaded "break in". I dont want to drive it too much in the winter so I will just put miles on it when i can.

[cueballsi]

I have some custom JE- MPS spec 2.1L pistons and new Manley rods if anyone is interested :-)

[tonyp1974]

Haha, the shop is taking care of that for me, but thanks! However upon further review, Im switching the headers from AP. Apparently Agency Power is also Vivid Racing which has a 60 page thread on them and most reviews are horrendous. I dont want anything associated with them on my car.

[loofer]

How did the build turn out!? I spun a bearing in my EJ20 and am leaning strongly toward a 2.1L Stroker! Woot! haha!

Would love to hear how the break in period went! As I will be approaching that. Any advice there?

Also, what was the goal of increasing the CCs on your fuel injectors? I am going to stick to the stock injectors and am curious if you upgraded for any specific reason?

Thanks!

[Philydrake]

Loofer- I just burned a hole in cylinder 2s piston head by using stock injectors.. I suggest upgrading a few CCs. Also I never got it tuned :x. Big mistake.

But I'm interested in how much this stroker build cost? I like the idea of keeping my block instead of buying a short block 2.5l

[tonyp1974]

Funny that, I just posted on your thread before reading this. Anywho, after the shop persuaded me a little bit, I stuck with the AP stuff. As of right now I have 500 miles on the car and am still on break in (which totally sucks, zero boost, 4000 rpm limit...grrrrr). Just did the first oil change after 500 miles and the oil looks fine. The motor runs absolutely perfect so far.

Here are a couple things to consider before you build:

I live in a cold weather climate and Im assuming you do. I normally wouldnt drive the car much in the winter but Im trying to get miles on the car for the break in so I let my car warm up longer than most. A block heater might be a good investment.

Most forged internal builds are noisy. Mine turned out very quiet and even the shop mentioned that it is typically loud.

Most built motors you will get an initial puff of white smoke just at start up. This doesnt happen for me all the time but it is normal.

Ill post more updates and pics as soon as I can. Its so cold in Chicago now, ZERO DEGREES.

[Crazykev]

You wanna throw some boost at your motor to break it in correctly.

[KpT KiM]

I'm impressed you could fit the FMS TMIC in there with the air conditioning line. Had to switch to a GR STI TMIC for that reason

[.Boston.]

Originally Posted by Philydrake

Loofer- I just burned a hole in cylinder 2s piston head by using stock injectors.. I suggest upgrading a few CCs. Also I never got it tuned :x. Big mistake.

But I'm interested in how much this stroker build cost? I like the idea of keeping my block instead of buying a short block 2.5l

ej20 is still an open deck block
if you go the route of an ej257, you will have a stronger semi closed deck block and would help give you a piece of mind for future power goals.
Personally I would much rather stroke the 2.5 over the 2.0 if your just caring about power
ps sorry to hear about your misfortune, the stock wrx injectors are pretty much worthless when it comes to making power.

[mod maniac]

I built a 2.1 stroker and love it. The off boost power is nice. Mine makes 325 whp and turns 7500 rpm's.

[tonyp1974]

Nice, Im not too concerned about going over 320 HP at the moment. I just wanted to overbuild the motor with modest HP goals so it has a better shot of lasting a while. I dont beat on it but I want it to have a little "gitty up" when needed. I have crazy dreams of this build lasting 75,000 - 100,000 miles.

[tonyp1974]

Originally Posted by KpT KiM

I'm impressed you could fit the FMS TMIC in there with the air conditioning line. Had to switch to a GR STI TMIC for that reason

Ill post some pics once it gets above 20 degrees out here. I dont want to be outside at all!!

[tonyp1974]

Originally Posted by Crazykev

You wanna throw some boost at your motor to break it in correctly.

If I said zero boost in an earlier post I was mistaken. However, it is very minimal (maybe 1-2psi). Not sure why so low but the guys at 6 Star have yet to steer me wrong. I have read a few break in threads and it seems opinions vary and are all over the place on this subject.

[GBC]

I recently (<1000 miles) rebuilt my ej20 - got an sti 79mm crank, forged rods, Mahle forged pistons (very slight overbore to accommodate them). Also went up to an 18g, bigger injectors/fuel pump/oil pump to keep up. The exhaust is 3" catless.

The power is great - but the car only dynoed at 275 whp with a protune by Yimi. Seems the tuner thought the car had a 16g (in fact has an 18g) and so was too conservative once he got the whp numbers he was expecting. (The mechanic is Renner - they sent an incorrect email to the tuner.)

Thats the story - here are 2 concerns:

1. i was told to NOT be gentle during break-in (prior to tuning) - that rods stretch slightly under stress, and its important that they stretch a bit during break in to prevent indentations forming on the cylinder walls (which happen when stress is too uniform).

2. i expected to get about 300 whp from this set-up on a dynojet - which i think is a bit low bc a plain 2.0 shd make that - stroked i'd expect 325-350 assuming boost of about 20psi on Ca. 91 octane swill.

Thoughts? What boost shd i tune if i want to get 50k more out of this engine? what whp shd i expect? isnt 275 a tad weenie?

thanks fellas -

[kakarot09]

well the overall horsepower is going to be limited by fuel and turbo selection not displacement in this case. So yes the 2.0 would make about the same power but not likely to make the same torque. As far as tuning it the numbers do seem a bit low. 275 is possible on the stock sti turbo and generally an 18g will make a bit more. You didn't mention any other supporting mods, are there any? What 18g turbo is this?

[GBC]

supporting mods:

- sti 79mm crank, forged rods & pistons (slight overbore)
- upgraded fuel pump and injectors (dont know the precise size - but my mechanic chose them to match the 18g and he builds and races subies as a side gig)
- 18g turbo - (dont know which)
- upgraded oil pump
- 3" catless DP and 3" catback - catless up pipe
- sti intercooler

protuned at Yimi - was there when it was on the dyno - took him 3 hrs or so, many pulls (as i cringed) - when the tuner was done, he handed me the dyno sheet and i questioned why he maxed at 275 whp - he said "thats all you get on a 16g" - when i informed him it was an 18, he said it spooled like a 16 - but the reason for that is the increased displacement will spool the 18 faster

...so bottom line - i spent a lot of $$ on this rebuild, and i expected 300+ whp - my guess is the tuner held back bc he was expecting 275 on a 16g setup - and so he held back on psi.

i'm trying to get my facts straight before confronting my mechanic and tuner both later this week - THANKS MUCH FOR YR INPUT !

[FuJi K]

Find out what you got. 18G? What pump and injector size? What fuel?

[kakarot09]

If he spent the time tuning it and said that's what you get it may just be the way it is. Maybe you actually have a 16g.

[GBC]

assuming a 300whp goal, what psi should the tuner be shooting for?