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Old 07-13-2004, 12:28 AM   #56
big_adventure
Scooby Specialist
 
Member#: 40501
Join Date: Jul 2003
Location: Paris, FR
Vehicle:
2005 Decathalon 21sp
One WheelSeanPower

Talking Done!!!!!

She is a MONSTER.

I put in the new O2 sensor and everything is perfect. I see -480mmHg of vacuum at idle. The motor is smoother and quieter than my stock motor, despite the more agressive heads and cams. I'm a bit rich right now, around 10.5:1 at WOT, and my timing is still the timing I used on my stock motor, so there's a lot more in her, but I had it out for a while tonight, and hit 22-23psi on 93 octane gas with NO DET AT ALL! This engine is awsome.

About that boost - I have a Garett GT30R-11 turbo, and it's a custom job. The wastegate is only an 8psi gate, so I put a big, fat helper spring on it to build and hold boost better. On my stock motor, with the high-flow cat from TXS in place, that gave me 17.5-18psi as my wastegate pressure. With the new motor, and no cat, it's a massive difference - 22-23psi wastegate (my CLB settings are 1. Everywhere). Getting rid of that backpressure made my turbo even more alive than before!

I'm also breaking in (and getting used to) my new Exedy twin-plate clutch.

The good things:

- It'll hold 600+ lb/ft of torque. My last clutch looked like salt-water taffee.

- The pedal effort is not much harder than stock, very positive.

- The entire clutch, flywheel, mid-plate and pressure plate combination weighs only ~30lbs - can you say "fast revving"?

The bad things:

- Sure, it only has 35 miles on it, but there is definite, pronounced, loud chatter when the clutch is disengaged.

- If you want a smooth, slipping launch, you have to pull into it at over 2K revs and balance the throttle perfectly.

Ah, well, it's a race part, so there are sacrifices. It's totally drivable, it just took me 10 minutes to get used to it. It's kind of like driving a sport-bike for the first time - you don't want to smoke the tires every time out, so you take it easy. Then you stall it at a light. Woops. No stalls so far here, but there have been a couple of stiff launches.

But it'll hold the power. If I never have to change the clutch on the car, it'll be a little too soon for me. I've seen her in pieces too much lately.

Anyway, I'm really looking forward to tuning her and hitting it hard soon, but I need to wait a couple of weeks to break in that clutch. More when it happens!

There is one, expected caveat - I'm using the Rev6 US UTEC with the JDM ECU, so I do get the 4 "harmless" injector OBDII codes, P0261, P0264, P0267 and P0270. These are expected, and cause no issues at all that anyone can see.

There is one, unexpected caveat that I still haven't completely resolved - I get a clunk somewhere from the exhaust hitting the tranny or the frame. It only happens when I do something harsh with the transmission or hit an awkward bump when I'm in gear but off the throttle. The exhaust hangers helped some, but I'm going to need to find a solution. I think it is caused by the transmission's exhaust bracket on the STi 6MT being MUCH longer and thus MUCH more flexible than on the 5MT - where I never got this. I think I'll reinforce that bracket with some metal plate. We'll see.

Current mod list:

2004 WRX wagon
V7 STi RA Spec C engine and ECU
V7 STi 6MT transmission
STi gold Brembos
STi axles
R180 rear diff
STi trailing arms
Tein coilovers
Rota Torque 17x8 wheels, steel grey
UTEC
TXS TBE (non-RFL) with race pipe
Garett GT30R-11 turbo (Ported AVO 320 turbine housing .63 A/R, Turbonetics T04 comp cover)
APS DR500 FMIC
APS BOV
RC Engineering 750cc Injectors
Perrin catch can
Kartboy exhaust hangers
Exedy twin-plate clutch
GReddy electronic boost and EGT gauges
TXS Tuner (Da Tuna!) WbO2

You will see more from this soon!

-Sean
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Last edited by big_adventure; 07-13-2004 at 09:18 AM.
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