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Frankenstein Impreza - AKA "The Souparu"


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Hi everyone,


Just starting this thread to document the build/rebuild of a GC8 Impreza I'll be picking up in a week or so.

To cover off the history of this - a good friend of mine bought this car about 4 years ago. The car had been built up at that point (may even have been a thread on here) with an STI Shell, Spec-C hawkeye engine (or just heads), rebuilt bottom end, front-mount IC, some rollerbearing turbo (not sure what), various bits.

Went really well, then the turbo died. TD05-20G went in. The car was running some small diameter mag wheels and semi slicks, but friend wanted some 4-pots on it, so swapped out the wheels for some Imolas to clear the new brakes. Blitz Nur Spec came off as it was too loud, custom system went on.

For a while it wore some flouro-green wheels before the Team Dynamics were bought; this is the only picture I currently have:-



After a while, the engine developed a slight knock (we think), and the car was taken off the road. Here it's languished for the last 3 years, until being bought by me (it's actually got mould growing on it right now)...


Soooo the plan is to strip it down, do the jobs, check out the knock and go from there. Hoses will need replacing, brakes will need refurbing etc. Depending on the condition of the bottom-end, it may just be bearings, it may be more serious rebuild, it may end up being a new short-block.

Any advice on where to go with it gratefully accepted!


Will get some pics up as soon as possible. Oh, and the Nur Spec comes with the car, and will be for sale shortly on here should anyone want it ;-)





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What year / model is it ?, as only certain heads will fit the pre v4 scoobs (without loom mods and adapters)

Oe gaskets , acl shells ,timing belt kit and machining costs will cost the best part of £1k .

find a good local engineer to check the block and head faces for trueness .also get him to check the crank over and I'd advise not to get it reground if it's over oe tolerances.

Best of luck and don't forget those pics n updates [emoji6]

If it's not broke .....upgrade it 😊

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It's a 1995, need to check the specific base model when I can check the VIN. 

I don't believe that any part of the bottom end of heads came from the base car, so a lot of this project will be discovering what's actually on it!

There was a full set of build documents with the car, but these have been lost by the previous owner (I did see them so I know they existed!). 


Need to track down a good machine shop in Oxfordshire, any recommendations anyone?




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  • 2 weeks later...

Update folks! 


Finally got back over to look over the car again today. Few more pics lower down. Dirty and needs going over as I thought, but straight and with plenty of potential :-)

Spare Blitz Nur Spec was picked up, and is now for sale in the classifieds:- 



Other things I noted:-

Blitz dump valve,

HKS turbo Timer

Project Mu front discs


VIN shows model number:- GC8C48D

Which means its an Import WRX 4-Door. as far as I know from Impreza codes.

So, some pics:-


Front end, needs tidying and re-aligning:-




Wheels are in perfect condition!



Dirty dirty engine:-





Much more to come :-)



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Finally got the full spec of the car, even happier now!

Resprayed from the original silver to the Rb5 metallic grey
New (at the time) radiator
Front mount intercooler
Alloy sti/spec c lower arms
STI v6 6 bolt gearbox and bell housing - the stronger one.
STI v6 full red suspension and running gear
STI v6 prop and rear diff etc
Full STI v6 interior including all dash and wiring
Alarm and immobiliser for insurance and theft purposes
Fully forged rebuilt sti spec c engine
Powerflow 2.5” single exit cat back exhaust
HKS Type 2 turbo timer
Upgraded front callipers to later model STI  - fully reconditioned and powder coated black

Engine spec list

STI v9 steel con rods
Billet steel nitrided and treated crank
ACL race main bearings
ACL race big end bearings
All valves were checked, de-coked and re- lapped in to head
Valve seats re ground - as Subaru's are prone to exhaust valve seat pitting
Forged ally pistons at subaru standard 92mm bore size
Commetic steel head gaskets
New valve stem oil seals
New cam shaft seals
New crank case bolts and all dowety seals replaced.
Exedy clutch kit
Closed deck block
Lightened and dynamically balanced complete bottom end inc. fully lightened and balanced steel fly wheel with dyno balancing print out from machinist.
New oil pump with steel gears
New water pump
New radiator hoses
All new exhaust and inlet gaskets
New mass air pressure sensor
New mass air flow sensor
New spark plugs
New coil packs
New STI red ht leads
All idler rollers replaced
Cam-belt and auxiliary belts


Car is with me Monday, expect more pictures then.



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The v5/v6 inlet manifold won't fit any other version of classic heads .Also the wiring for the v5/ v6 engine sensors/dash and ecu plugs are different .

So it's probably got a v5/v6 ecu and if you need to buy any sensors ,fuel system components and engine bay pipework you'll probably need to make sure they're compatible with a v5/v6 phase 2 engine .

Rather than the v2 phase 1 95/96 Shell that the reg and vin plate model code will say

If it's not broke .....upgrade it 😊

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Finally have her!

She took her first trip in 3 years today:-


Got her back and gave her a wash down:-









She's definitely poorly though, dropped all her coolant in the sump by the looks of things. Will drain the oil out when it stop lashing down!



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45 minutes ago, Sandals said:

Looks stunning!

Thanks! Once the mould was cleaned off, most of the paint is half-decent. Needs a load of shallow dents taking out but that's easy enough.

Even the exhaust polished up with minimal effort!

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2 minutes ago, ScramCannon said:

Thanks! Once the mould was cleaned off, most of the paint is half-decent. Needs a load of shallow dents taking out but that's easy enough.

Even the exhaust polished up with minimal effort!

It's amazing what some metal polish and some elbow grease can do!!

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Good hey! Current theory is that it's blown a head gasket and dumped all the coolant in the sump, where it's sat for three years.

This is supported by the fact that it's been empty of coolant. Filling it up - the level keeps dropping, so I'm pretty sure it's going that way. Will get the engine out for a rebuild soon as possible.

In the meantime, small job today, new Battery tie down:-



Assisted by my small helper!






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  • 5 months later...

Finally back to this - house move completed, and new workshop getting there:-


Car has a new home:-



So - started some break down:-




And we discover something the previous owner('s garage) mentioned, The "burnt out sensor", which looks to be the remains of the intake air temp sensor. Can anyone confirm? It's on the same piece of loom as the MAF plug:-




Also - the rubber bung on the end of the air hardline near the turbo intake has seen better days. Pretty sure this was letting in significant air post-MAF.


Combined, I think these two things certainly contribute; if are not the cause of the hot-idle issues I've been seeing.


Question I have for anyone - where should the intake air temp sensor fit? The MAF housing and intake piping I have appears to have no location for it.




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That could be the oe air density sensor plug but I'd have to check mine when I get chance .

Afaik They don't have a air intake sensor as standard , I fitted a aftermarket one from jt inovations on mine in the fmic core to throttle body pipework when I had a mafless map done .


As this will give the correct reading for the temps entering the inlet .

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