[JohnSub2013sti]

I joined this forum to learn and read. I recently bought a 2013 Subaru WRX STI Sedan USDM. All of the work / tunning will be done by myself not a shop

Previous Vehicles

• 2000 Oldsmobile intrigue
• 1996 Yamaha FZR 600cc
• 2000 Mustang coupe
• 2006 VW Jetta TDI
• 2016 Ford F150
• 2006 VW Jetta TDI
• 2010 Subaru Legacy
• 2015 Ducati Monster Stripe 821cc

The Purchase
I live in Ontario but purchased the new car in Quebec and trailered it back

Initial Maintenance (Completed)
It took a lot of work to get it to the point where it could become my daily (wasn't very well maintained), but I'm finally there.
When fixing it up I upgraded a few components (It came with an aftermarket exhausts and cold air intake). Aftermarket upgrades of note listed below

• Forged Internals Rebuild Kit (Manley H-Beam Rod's, Manley Pistons, King Racing Bearings)
• GATES TCKWP328CRB High Performance Timing belt & Water pump Kit
• ITM Engine Components High performance 12mm Oil Pump
• Secondary Air Pump Delete Kit
• M-PACT 15025ST1X Performance Clutch Kit with Hi-Torque Steelback Disc
• AEM Air Intake
• Invidia Cat back Q-300
• RALLY Skid Plate for 2011-2014 Subaru WRX & STI RED
• Aem wideband 30-0334 wired into the rear o2 sensor
• Aem digital boost gauge 30-0306
• SMY Dual 52mm gauge cluster
• GDT Cylinder 4 Chamber Cooling System

Next Steps
The next things I would consider doing would be
Low priority

• Killer B pickup/baffle/oil pan
• E85 flex fuel kit

High priority

• Cylinder 4 cooling mod
  • GDT Cylinder 4 Chamber Cooling System - GetaDomTune
• AOS
  • Taking a look at the Subaru EJ25 Turbo PCV System (flatironstuning.com)
  • 2018-2021 STI Air/Oil Separator (AOS) Install Instructions | IAG Performance - YouTube
• EWG (so I can install the Invidia 3" cat less downpipe I have)

Tunning Solution

• I have both a COBB and Tactrix cable
• Subaru Monitor List - Customer Support Center - Confluence (atlassian.net)
• RomRaider • View topic - Latest RomRaider LOGGER Definitions
• How To Use · vimsh/mafscaling Wiki · GitHub

Goals

• Improve system reliability
• 350 whp
• Fix some cosmetics (rust / cracked bumper)

 

[Karlot]

welcome!

few things i want to point out, the aos, good call, get that, also make sure you have a killer b pickup/baffle combo as well as the cylinder 4 cooling mod.

flex fuel really isnt available anymore with cobb's greenspeed update. you'll have to either have multiple tunes and an ethanol sensor, or run e85 full time.

you do not need an ewg to install the downpipe.

you have not mentioned tuning, keep in mind, for everything, including that built block, you will need to have a tune done/adjusted for the new parts or you will risk hurting that new motor. so do you have tuning squared away? if so, if you are using catless, dont buy an accessport, you'll want to go opensource (also, you'll have to find a tuner willing to tune catless, that'll be hard itself).

are you planning on going with a large turbo? i ask because the block you put in is extreme overkill for a stock turbo lol. so i'm curious as to your goals/what you will use the car for.

post up here with questions and feel free to start a journal to show us all the build process. most of all, enjoy it, these cars are so dang fun

 

[JohnSub2013sti]

killer b pickup/baffle combo: Ya I considered this when doing the rebuild, I wouldn't mind doing this probably with an oil pan too for that extra Oil capacity / surface area. Stock baffle and pickup was in good condition thou (I know they sometimes crack)

Cylinder 4 cooling mod: I'd be down to do this to

What's the car for: I'm going to daily it and the theme for now will mostly being parts to improve reliability and make a more stable system. However, I would like to turn the power up a little eventually. I like overkill lol, overkill is good

Tunning: I added a section for tunning in the main post, I have a COBB & Tactrix Cable. The plan is to do the tunning myself. I concede that because of my intake and exhaust I should not be running a stock tune.

However, in the case of the short block Its stock cylinder size / compression ratio. A custom tune is ideal yes, but I don't understand why the stock tune would be hurting it. Do you have any resources on this as to why it would hurt it?

Attached in the main post is what I'm monitoring

&&

Thank for the reply I know you post a lot here; Glad to have joined the community

 

[JohnSub2013sti]

@Karlot I really am just looking for information on comment you made about the tune. It doesn't make sense to me

 

[Karlot]

what part doesnt make sense? i'll try to clarify

 

[JohnSub2013sti]

Needing a tune in the case of a new shortblock with aftermarket components

• Built short block (Manley H-Beam Rod's, Manley Pistons, King Racing Bearings)

A tune in this case would only account for tolerancing as far as I know (essentially fine tuning it to the specific components).
I don't understand what is so far off that a stock tune isn't good. I have a stock compression ratio, stock cylinder volume, and OEM crank.

My specific question would be why am I hurting the engine without a tune?

 

[Karlot]

ahh ok, a tuner will be able to explain this better than i can. in theory, so long as afr is not changing, you might be ok with the existing tune, assuming the tune was done with the motor in good health. that said, with a new motor, you have a few things that might change, clearances for one, and the fact that every motor runs different. the cost of a new shortblock will be 8k or more, vs the cost of a tune at 500ish, why risk it? plus if a valve job was done, that could ahve a small effect.

i also notice the kit you posted, doesnt have oem case halves? are you reusing case halves? if so, would that not bore to a 99.75 to ensure proper ring seal?

 

[Karlot]

also, that kit you posted states 8.5/1 or 9.8/1 for compression ratio.......i'm about 99% sure the oem sti is 8.2/1 for compression ratio........

 

[JohnSub2013sti]

-The short block cost me 3,000ishCAD bc I just built and installed it myself. I was actually originally going to order the parts from IAG but they essentially told me not to build and engine and instead buy a short block from them (said it wouldn't work). So, I hung up and order the parts from Celtic Motorsport. That being said I'm not in the mood to build another right now lol. I understand your points and rational about a tune. I thought you were saying there was a glaring issue
-The sti cylinder heads where in decent condition so I just reused them. I figured I could upgrade them down the road if I really wanted. But from my understanding there not often a failure point on the block
-The cylinder walls were in good condition on the case halves so all I did was add a cross hatch as recommended by Manley. Trust its sealed, piston rings were gapped and installed correctly
-You're right about the compression ratio (my mistake thanks for the catch)

 

[Karlot]

-The short block cost me 3,000ishCAD bc I just built and installed it myself. I was actually originally going to order the parts from IAG but they essentially told me not to build and engine and instead buy a short block from them (said it wouldn't work). So, I hung up and order the parts from Celtic Motorsport. That being said I'm not in the mood to build another right now lol. I understand your points and rational about a tune. I thought you were saying there was a glaring issue
-The sti cylinder heads where in decent condition so I just reused them. I figured I could upgrade them down the road if I really wanted. But from my understanding there not often a failure point on the block
-The cylinder walls were in good condition on the case halves so all I did was add a cross hatch as recommended by Manley. Trust its sealed, piston rings were gapped and installed correctly
-You're right about the compression ratio (my mistake thanks for the catch)

i do understand why iag says to buy their shortblock, it's because they offer a warranty, which is cool, so i get why they wanted to push you that route. although i'm surprised they said ti wouldnt work.
and was the motor blown? if so it's a good idea to go through the heads just to ensure they werent contaminated with metal in the oil, if it wasnt blown then no worries, the weak point in them is the valve springs....but those dont really give an issue unless you are running crazy amounts of boost.
and no worries, i know buying a motor is expensive af, hence being on the safe side.

 

[JohnSub2013sti]

My rational for that one is their warranty is only 12k miles too if you install it. Like tbh that's not a lot. I'd rather just build a spare engine down the road if I was really worried mine was going to blow. Eg if the power was really turned up. My plan from day 1 was to build my own engine. Idk it just wasn't a great experience talking with them

I had a spun rob bearing on the motor. Was immediately shut off after the rod bearing spun. && I literally went through over a case of break clean (12 cans a case) when I was building it lol. The heads where thoroughly cleaned, and all mating surfaces where lightly cleaned up

Thanks again for your feedback

 

[Karlot]

My rational for that one is their warranty is only 12k miles too if you install it. Like tbh that's not a lot. I'd rather just build a spare engine down the road if I was really worried mine was going to blow. Eg if the power was really turned up. My plan from day 1 was to build my own engine. Idk it just wasn't a great experience talking with them

I had a spun rob bearing on the motor. Was immediately shut off after the rod bearing spun. && I literally went through over a case of break clean (12 cans a case) when I was building it lol. The heads where thoroughly cleaned, and all mating surfaces where lightly cleaned up

Thanks again for your feedback

nice, sounds like you did your homework lol. you should post up a journal detailing the build/plans/progression etc of your car.

 

[JohnSub2013sti]

I have a lot of experience with fixing cars, and work as a mechanical engineer in automotive. My uncle is also a certified mechanic which also helps (would do engine rebuilds at dealerships all the time, just not for Subaru). So, I have a good knowledge base of cars, just new to this platform. Tunning is also still magic to me (something I need to better understand)

Moving forward ill post stuff about when I install new stuff. Unfortunately, I didn't really take any pictures for the initial stuff the car needed. I'm going to fix some rust on it this weekend I'll take pictures of that

 

[Karlot]

I have a lot of experience with fixing cars, and work as a mechanical engineer in automotive. My uncle is also a certified mechanic which also helps (would do engine rebuilds at dealerships all the time, just not for Subaru). So, I have a good knowledge base of cars, just new to this platform. Tunning is also still magic to me (something I need to better understand)

Moving forward ill post stuff about when I install new stuff. Unfortunately, I didn't really take any pictures for the initial stuff the car needed. I'm going to fix some rust on it this weekend I'll take pictures of that

i mean, you can start the journal whenever in the process lol. take pics moving forward haha. my journal has pic 1 from when i got it, and then jumps forward like 4ish years to the next photos lol

 

[JohnSub2013sti]

Today will be my first oil change after 100km.



I did have something interesting happen with it, too. I put in some fuel (91 octane) and it didn't want to start. I think it might be bc of how cold the new gas was but idrk. I did an ecu reset to get it to start.

I'll post pictures of rust today, too, and little imperfections. It will help me keep track of em if anything

Sent from my SM-S901W using Tapatalk

 

[JohnSub2013sti]

Hey Karlot, why don't you think a catless downpipe would require a ewg with a stock turbo setup?

My assumption was that this creates more spool due to a greater pressure differential.

Possibly so much that the stock wastegate couldn't handle... eg boost creep

Or have people done this before without issue ?

My thought on a ewg is its a good mechanical safety

Sent from my SM-S901W using Tapatalk

 

[Karlot]

Hey Karlot, why don't you think a catless downpipe would require a ewg with a stock turbo setup?

My assumption was that this creates more spool due to a greater pressure differential.

Possibly so much that the stock wastegate couldn't handle... eg boost creep

Or have people done this before without issue ?

My thought on a ewg is its a good mechanical safety

Sent from my SM-S901W using Tapatalk

an ewg is a good thing to have. why i know it's not needed? because i did it. for approx 10k miles i ran a catless downpipe, stock turbo, stock internal wastegate, and a quality tune. i had zero boost creep (which lets be real, isnt much of a worry on a stock turbo to begin with). i did eventually get an ewg, but i got it mainly because i know i'd need it for a bigger turbo, or rather would want it. i was running 21psi peak at the time, it tapered to like 15ish...idk whatever it could make at redline, so not alot. but it never creeped, never caused an issue. is a quality ewg better, yes. is it necessary on a stock turbo setup? not at all.

i'd have to look for my dyno, idk if i could even find it. but on that setup with catless dp/stock turbo/iwg, i think i made in the 300-305whp/320wtq range. could have been 330wtq, but it's been like 8 years since that took place lol

 

[JohnSub2013sti]

I've got a wideband installed now & catless down pipe with AOS / cylinder 4 cooling mod ordered. I'll post about these on a later date

 

[Jay11STI]

Just to add to the conversation, I have a different experience. Many years ago when I first started modding my 2011 sti, I went with the good ole catless downpipe, AEM intake, and OTS tune + AEM. Yes it was way back when Cobb supported AEM CAI and DP. I ran that tune for a month or so and saw lots of boost spike and creep. I tried high and low versions and it was just uncontrollable in the winter. It was so unpredictable and unsettling to be on that tune. The only time the car threw a check engine light was due to boost creep that caused an overboost situation. I remember being on the highway cruising at like 60mph seeing the boost gauge being pinned for no reason lol. Seems like protuning with EWG and ECBS solved it.

I know not everyone had the same experience as I did, however it seemed like EWG was best solution at the time for me.

 

[JohnSub2013sti]

Boost is one of the things I'm focused on rn. As in with this setup I have a lot of it

I'm not currently getting boost spikes but the values I'm seeing are quite high 16.5 psi @ 5000rpm 100% throttle in a 3rd gear pull...... With the wgdc completely 0'rd out (disabled)

I want to see what the maximum is so I'm slowly working my way up. I guess it's not too crazy since stage 1 maps can hit this boost level.... but still. I don't have a EWG or ECBS. A EWG would be nice for peace of mind imo

I can post one of my tables later on today that shows how the car is boosting.