djoye

STI BUILD THREAD

8 posts in this topic

I hate when someone creates a build thread that is rarely updated, so I'm making my own! Also, someone needs to fill the void in this sub-forum.

I'm currently on track to install mundane mods on my STi so I feel more confident when passing left-lane lollygaggers (does that phrase mean something else?) on my daily work commute while maintaining speeds in which THP doesn't ticket (70-85 MPH).

MODS PURCHASED:

  • Blouch Dominator 1.5 XT-R turbo
  • ETS top-mount intercooler

To Be PURCHASED:

  • Supporting mods (injectors, boost control, intake and exhaust stuff, etc.)
  • Ringland failure prevention

The plan is to buy all remaining parts this summer, install them, then have it tuned in middle-TN. I'll be happy if I can make 330 WHP on a Dyno Dynamics and we can laugh and joke about its imminent ringland failure.

In an attempt to avoid ringland failure, I'm going by what I've found so far:

  • Good-quality fuel--I typically stick to Shell or the top-tier brands (not ready to go E85 only)
  • Install a catch can (air-oil separator) to prevent oil blow-by from recirculating and diluting the fuel mixture
  • After-market exhaust manifolds apparently lower temps because they increase flow
  • Proper tune (uhhh, duh?)
  • Regular oil changes (check oil level every other week, don't let a modified Subaru go past 5k miles on oil)

This is a picture of the car on the lift I'll be using:

sti_lift.jpg

 

Insert this into your bay (it's not much, but it's all I've got):

15xtr.jpg

The site I've scoped to buy everything else from seems to have good holiday sales that result in significant savings for large orders; July 4th is probably the next major sale so I hope to be sweating my ass off in the garage some time between July and September 2019.

Tino, 66sprint6, mstrpth and 3 others like this

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Sounds like a good plan to start!

Always liked the scooby's!

I didn't know they were prone to ringland failure, though.

Care to share why that seems to be an issue on these cars?

 

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^ I'm also curious as to ringland failure.   If blowby oil gets into the mixture it can cause detonation which is a piston/rod bearing killer. 

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16 hours ago, JohnC said:

Sounds like a good plan to start!

Always liked the scooby's!

I didn't know they were prone to ringland failure, though.

Care to share why that seems to be an issue on these cars?

 

 

6 hours ago, Ashley P said:

^ I'm also curious as to ringland failure.   If blowby oil gets into the mixture it can cause detonation which is a piston/rod bearing killer. 

I want to believe the ringland failure is more of a user error type issue, but pretty much what Ashley P said.

A catch can or air-oil separator is recommended to prevent blow-by oil from recirculating back into the intake and reducing the fuel octane, a custom tune is recommended and an equal-length exhaust manifold is suggested to keep all cylinder temps consistent since one side typically runs hotter on the unequal-length manifolds.

I know very little about tuning, but I get the impression that if ringland failure occurs because of detonation or high temps, how 'bout not tuning it too aggressively for what it is? User error? Anyway, if mine goes, I'll just buy a basic short block with upgraded pistons and rings and then have it tuned more aggressively.

It might've been dumb luck that my last WRX is still running, but I think if I heed the warnings, follow the advice, and keep my oil topped off, I'll be fine.

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I have firsthand experience with destructive detonation.  I put heads on my 455 Pontiac that resulted in about 11:1 compression.  We worked until late, and I gave my helper a celebratory 2 mile open header flogging on the 93 octane remaining in the tank. The next day there was coolant seeping into the cylinders.  Weeks later, the #5 piston ring land broke, and that was a TRW forged piston.  Upon removal, I noticed the rod bearing had lost it's "tension" (a bearing half wouldn't "snap" into a rod cap or rod.)   SO....2 miles of driving cost me two sets of headgaskets, a piston, a set of rod bearings, and an engine R&R.

So, I caution others to beware detonation, and to understand it's different than preignition.  See info at  http://www.turbofast.com.au/racefuel10.html

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I've heard of a LOT of the STi with ringland failure. I think it's tune related, parts related, and system related. I'm sure upgrading the hot side parts would help lower backpressure in the turbine side and would help tremendously. I'd think a really big DP and exhaust would help as well. 

 

As for E85, you don't have to switch to it full time. ON my Q50 I put about 5-6 gallons of E85 in then fill up on 93. Keeps me out of the pinggy zone.

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19 minutes ago, Disney said:

I've heard of a LOT of the STi with ringland failure. I think it's tune related, parts related, and system related. I'm sure upgrading the hot side parts would help lower backpressure in the turbine side and would help tremendously. I'd think a really big DP and exhaust would help as well. 

 

As for E85, you don't have to switch to it full time. ON my Q50 I put about 5-6 gallons of E85 in then fill up on 93. Keeps me out of the pinggy zone.

I reckon after I hook up the Bully Dog I'm gonna go with a 6" exhaust piping to a 12" tip. We'll sell watermelons out of it in the summer.

Also, I never considered E85 as an additive, guess I'd have to log after tuning to determine if it would be effective, but I'm hoping that the tuner knows what is safe for 93. If lowering exhaust temps helps, I'm wondering if I should go with an external wastegate since that would likely flow more than the internal gate. I'm going with an Invidia catted DP, but the cat sits close up enough to the turbo that an EWG could probably be routed back into the piping after the cat to spare me the noise but retain most of the benefit.

JohnC and Disney like this

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