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Old 04-13-2009, 08:27 AM   #1
Scooby Newbie
Member#: 208438
Join Date: Apr 2009
Default EJ16 to EJ25 MY07 USDM 2.5 STI conversion done

Dear all,

I would like some advice on some issues I'm facing with my car now.

My car was actually a Subaru TS 1.6 Impreza. I down EJ25 engine STI with 5 speed gearbox using 6 speed flywheel.
Initial problems face:
1)Clutch slipping,
2)boost only up to 1.3 bar,
3)when I floor, that is, partial throttle to full throttle, I heard had some screeching noise similar to the noise of a metal sheet suck to a vacuum cleaner but more sharper.

When I brought back to my mechanic to diagnose the issue, he found a hairline crack in pistons. What could have caused the hairline crack? According to my mechanic, he overhauled the entire engine before installation and told me that the engine internal were in good shape.

After which, I changed to forged pistons and noise still persist. I was unable to check at that point as I was running in.

Since clutch was slipping, I changed to Ogura twinplate few days ago.

Current problems faced now
1) Ever since I changed my clutch, car keeps stalling because rpm too low and I really got to rev very high to keep the engine alive. Each time I depress the clutch, the rpm is below 1000 but not stable going up and down intermittently. While car running, there is no problem.

2) Screeching noise still persist.

3) Car is currently boosted to 1.5bar using manual boost controller. While driving at 100km/hr, when I full-throttle or half-throttle, the car runs smoothly till 120kmhr and then gives a sudden jerk, something like misfire or power cut. Once I release the accelerator, and accelerate again hard, it runs without jerk. It only happens if I want to speed up.

4) Other than that, alot of rattling noise from gearbox and engine.

Please advise on the above issues.

Mods done to car:
Wiseco forged pistons
Unichip Q
Walbro fuel pump
Tomei replica equal length extractor
Modified STI downpipe & muffler
Manual boost controller
Ogura twinplate clutch
Cylinderhead mildly ported but not polished
Stock VF 43 turbo
Stock 5 speed WRX gearbox with 6 speed flywheel
The rest are stock STI.

Would appreciate your kind advice on the above issues.
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Old 04-13-2009, 08:53 AM   #2
Scooby Guru
Member#: 88618
Join Date: Jun 2005
Chapter/Region: SCIC
Location: New Zealand
1994 Legacy
"The Silver Slug"


Just a guess, but are you in the UAE? Not that it matters or helps, but I'm just curious since you had an EJ16.
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Old 04-13-2009, 10:26 AM   #3
Scooby Newbie
Member#: 208438
Join Date: Apr 2009

No, in Singapore.
boyster_no1 is offline   Reply With Quote

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