2005 Subaru Impreza 3.0 Turbo H6 EZ30

𝗛𝗶𝗴𝗵𝗹𝗶𝗴𝗵𝘁𝘀

● Impreza running a 3.0-litre turbocharged Subaru flat six

● Engine made 375hp on the dyno at 7psi of boost

● Discreet appearance with potential for further tuning

● Thought to be one of a kind in the UK

𝗢𝘃𝗲𝗿𝘃𝗶𝗲𝘄

Are you the sort of person that happens to have a flat six lying around in the garage and, on seeing a car from the same manufacturer, think “I wonder if that will fit?” and then actually go and try it. Well, if you're not, then let's give thanks to the talented people who can and do follow through on the flights of fancy that we're all guilty of entertaining from time to time.

This car is the product of one such pondering, mating the Subaru H6 engine from an Outback 'parts car' with an Impreza 2.0 GX Sport. But the owner of this car didn't stop there. Out of the box, the 3.0 flat six is only a little more powerful than that in the WRX and not very tuneable so, naturally, he decided to turbocharge it too.

In order to make all of this work, he assembled the necessary electronics to make the engine interface smoothly with the car, upgraded the suspension with WRX and STI parts, uprated the brakes and installed a beefier clutch. The result, while still retaining the cosmetics of the slightly used Impreza GX donor car, provides few clues that there is an unusual noise that emanates from the car on start up.

With too many other projects on the go and in need of the space, he's now decided that it's time for this one to go to a new owner which means that this is your chance to put your stamp on the next stage in this car's journey. There are certainly choices that can be made. You could simply continue to drive the car as-is, perfectly usable as it is today having reportedly run reliably for two years. If so, it's possibly worth tidying up the paint and bumpers. Or, if you're so inclined, you could move the performance on a step; the engine has further tuning potential which would probably then necessitate some work on the chassis and brakes.

Whichever way it goes, you're very unlikely to see another one. As far as we know, it's the only such conversion in the UK. That alone makes it worth celebrating and will be reason enough for some to take the plunge but, rarity aside, it's an interesting, quick and usable car.

𝗛𝗶𝘀𝘁𝗼𝗿𝘆 𝗮𝗻𝗱 𝗱𝗼𝗰𝘂𝗺𝗲𝗻𝘁𝗮𝘁𝗶𝗼𝗻

● Registered new 28 January 2005 as a Subaru Impreza GX Sport

● Still showing on the V5 as a 2.0 engine which will need to be addressed with the DVLA

● The engine is from a 120,000 mile Subaru Outback which received a major service with a new water pump, timing chain & tensioners, no more than 10,000 miles ago (around 2 1/2 years)

● The full specification for the conversion can be found in the 'mechanicals' section below

● The MOT is valid until 14 May 2024

● V5 present in the owner's name

● HPI clear

𝗜𝗻𝘁𝗲𝗿𝗶𝗼𝗿

● The cabin gives nothing away about the potency of this car, being cloth black and largely standard

● The front seats look to be WRX items (Impreza anoraks can comment if they were in fact offered in the GX) and, while there is some bolster wear, are in generally good order with a few marks

● In the back, the rear seats also show a few marks, all of which could perhaps be addressed with a deep clean

● The vendor tells us that everything is in full working order, including the Pioneer double-DIN stereo upgrade, though does note some wear to the headlining

● Much like the back seats, the boot has a few marks which may come out with some effort

● In general, it's a no-frills, functional interior that may benefit from a little attention but probably won't bother those who are focused on the driving

𝗘𝘅𝘁𝗲𝗿𝗶𝗼𝗿

● The appearance of the exterior is also stealthy, resembling a WRX with a (now superfluous) bonnet scoop and a small rear spoiler

● An STI front splitter, deeper side skirts and OZ Ultraleggera wheels are a nod to the car's performance credentials

● While fine from a distance, closer inspection reveals scuffs and marks around the car, notably to the bumpers, and a small dent to the roof, which has also received paint at some stage

● The headlights are aftermarket as OEM items could not be sourced when they needed replacement

● The tyres are nearly new Bridgestones all round

● In summary, there are areas for potential improvement but nothing that would stop you driving it in the meantime

𝗠𝗲𝗰𝗵𝗮𝗻𝗶𝗰𝗮𝗹

● EZ30R 3.0-litre H6 Flat 6 from a Subaru Outback fully serviced at the point of installation, around 2.5 years and 10k miles ago

● Upgraded with 440cc WRX injectors, Sytec fuel pressure regulator, Walbro 255 Fuel Pump, GT3076 Turbo, Tial Wastegate and a custom large front mount intercooler set-up

● Haltech Elite 2500 ECU, EZ30 PNP and WB2 Kit which, as well as being tuneable, interfaces with the rest of the car

● The factory ECU is still in place and takes care of controlling the ABS, speedo, immobiliser, alarm, etc. and the Haltech ECU fully controls the engine and feeds into the rev counter so everything works as it should

● The engine was tuned at Lloyd Specialists Developments on a Hub Dyno and made 375hp @ 7PSI of boost

● A custom turbo manifold system leads to a 3" turbo-back custom stainless exhaust with 2 resonators and a Kakimoto silencer

● The clutch has been upgraded with an Organic stage 2 competition item

● Chassis upgrades include WRX shock absorbers and lowering springs, and STI alloy lower control arms

● WRX front brakes have been fitted

● The owner recently replaced the e-throttle pedal as the old one failed and occasionally on a warm start it will rev a little higher for a few seconds before settling - this can be re-calibrated via the Haltech software but as it's such a minor inconvenience, he's not found the need to do it

● That issue aside, everything is reported to be working just as it should and the car goes, stops and steers without issue

𝗦𝘂𝗺𝗺𝗮𝗿𝘆

This is a well-executed engine swap carried out by an electrical engineer and the result is so well integrated that it could almost pass for an OEM configuration. If this car doesn't put a big fat Cheshire Cat grin on your face, we don't know what will.Cosmetically, the limitations of the donor car are still there but it doesn't detract from the driving experience and so the car could be used just as it is. We imagine that the next owner will want to tidy it up a little, however, and suspect that the temptation to further explore the performance potential of this set up. We look forward to seeing where it will go next.

To arrange a viewing, please request this in the Q&A section. You can click through to the seller's profile and use the "Email Me" function to arrange a viewing privately. This seller is located in Eynsham, Oxfordshire.