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Impreza GX 04 EZ30 Turbo GT3076


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Hi all, I bought this little 04 GX around a year ago and thought I'd post up some info and pictures of it's progress so far.




It was originally bought as a 2.0 SOHC with a knocking bottom end, but otherwise fairly straight body, interior and good running gear. After a loud and 'knocky' 1.5hr drive the car was back and ready for it's new heart. An EZ30 3.0 from an 05 Legacy SpecB.




With a fair bit of struggling, swearing and moving things around in the engine bay, the engine was in and ready to start having the ancillaries connected back up. The factory H6 radiator slipped in with a little trimming to the fan housing.


A quick exhaust was whipped up using the original manifolds and a modified classic impreza cat-back




The engine loom from the donor car was stripped of all un-necessary wires, wrapped and pulled through the fire wall and routed to the ecu compartment. The E-Pedal from the donor car, and clutch pedal (Not totally necessary but i wanted to utilize the clutch switch from the legacy) were swapped over with a bit of modification. Despite my best efforts it was simply to much a pain to get the engine to run on the factory H6 ECU, to many of the security features were preventing it from running, so I opted to install a Haltech Elite 2500 ECU with WB2 and plug and play adapter, after a fair bit of head scratching  the engine was purring away nicely, a few of the IO from the original ECU were repurposed to operate the clocks and power up the Haltech to retain the standard immobilisation.


I ran the car around for a couple of days to confirm everything was operating correctly and driving nicely which it was. But now it was turbo time. Which is were the real fun begins!

turbo position was verified roughly, and from there a set of log style manifolds and uppipe fabricated, as well as a downpipe. The rest of the exhaust is simply a cheap Toyo Sports 3inch system, which fits so terribly it was only and good to be cut in pieces, and re-welded to fit better. 440cc Impreza WRX injectors were also installed as they fit the same as the original 270cc units.






A basic eBay 2.5 intercooler and pipe kit was cut to fit and installed



An oil supply tee'd off the oil pressure switch, and the oil drain drilled and tapped into the sump (many people run into the valve cover, but as I can't ac tig weld at present, the sump seemed a better option. 


Once that was done, and catch can and adjustable boost ref FPR was fitted up and the car started and run. 


And that's it so far really, today I've installed a Walbro 255 in the tank and taken the car for a couple of short drives and can confirm it drives nicely and everythings workig as it should. Being only on a base map I barely tipped over 1/3 throttle and only made 3.6psi of boost. But still felt and sounded fantastic! I'll be fitting a Stage 2 Competition Clutch rated to 500hp over the christmas break, so that'll be the next update. 



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  • 2 weeks later...

@Jay762 Cheers, and no I went straight for the Haltech, the relative ease of use and the fact they have a 'plug and play' loom seemed like a no-brainer. Although I'm sure other ECU's are capable of running this engine just fine.


Iv'e since fitted the Competition Stage 2 Clutch, which with bit of swearing getting the box back in went fairly well. And having to replace the driveshaft seals after one decided to start leaking and flick oil all over my wastegate.


After that I messed about getting the factory H6 cover to fit with a bit of hacking (the wingnuts are a bit fugly, until i get some plastic ones)



Iv'e continued to drive the car around on the basemap, approx 100 miles so far to bed in the clutch. The next update (unless something goes massively wrong) will be post dyno. Which is booked in for the 7th Feb.

Cheers, Tom


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1 hour ago, EZTom said:

@Jay762 Cheers, and no I went straight for the Haltech, the relative ease of use and the fact they have a 'plug and play' loom seemed like a no-brainer. Although I'm sure other ECU's are capable of running this engine just fine.

Ahhh right - yes a PnP loom is a big plus 👍

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  • 1 month later...

Following a very successful day at Lloyd Specialist Performance, the results are in!


311hp ATW (around 360-370 at the crank) and 294ft lbs of torque ATW @ 7PSI

very happy with the results considering the unopened engine and stock drive train (excluding the clutch) survived the day!

The eBay GT30 spools up well and carries on through the revs nicely, we capped the rev limit to 6k as the torque was starting to roll over.

The weather has been crap lately so i'll update again once ive had a proper drive on the road 👍



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