Subaru WRX Rally Car build – Part 2

The completion of the Subaru WRX rally car build

Blog lagging build

It’s been a long while since we updated the blog on the build of this Subaru WRX rally car. It was actually completed in mid 2019 so we’re a bit behind! Righto, let’s continue from where we left off from WRX rally car build part 1.

Fuelling the Subaru WRX rally car

We ran braided -6 fuel lines throughout the car from the fuel tank to the engine bay. There was some fabrication required around the tank. This was due to having to fit adapters to change from 8mm rubber fuel hose to the -6 lines. Braided fuel lines should never be fitted directly to barbed fuel fittings. The lines are different and don’t seal correctly.

The clearance between the floor pan and the fuel tank is tight on WRX’s therefore we had to make up a cover plate where the lines enter the interior. In the engine bay we terminated the lines onto -6 couplings and connected them up. We also used a fuel filter with threaded fittings instead of the standard barbed WRX filter.

Stopping power – Brakes

The next task was to tackle all the brake plumbing. This Subaru WRX rally car uses a hydraulic handbrake rather than the factory cable and drum set up. Because of this, the rear calipers will be used for stopping and parking. Alongside the hydraulic handbrake a new brake bias valve was fitted. The pair work in combination and allow the driver some control over front to rear braking effort.

The master cylinder and new brake lines on the Subaru WRX rally car

Dash 3, stainless brake lines were run and terminated at all the wheels. We bolted a new master cylinder in up front with some neat banjo fittings on the lines. To keep everything in board and out of the way, fuel and brake lines were all run along the left side of the trans tunnel. The whole lot was then neatly secured with P clips.

With fresh fuel in the tank and fluid in the master cylinder, both systems were bled and tested. No leaks found so on with the build. Our next step was to tackle the rest of the interior. A new roof vent was measured and fitted into the roof. This proved trickier than normal because the roll cage regs have changed (Vee bars in the roof) and clearance was tighter than it had been on other Subaru WRX rally cars.

Switching it up

Over a couple of days the rally ancillaries were wired in to a new switch panel. The panel also includes a battery volt meter and USB ports. Both of these are valuable additions that we now incorporate into our Subaru WRX rally car specs. The USB ports will be handy for charging everything from phones to in car cameras. The voltage display also allows us to check the electrical system is functioning correctly with a quick glance.

The interior of the Subaru WRX rally car showing switch panel and lines.

Alongside the electrics other items such as fire extinguishers, driver foot tray and co-driver’s foot rest were fitted. The front door cards also needed some mods to clear the roll cage. One of the last items on the interior list was fitting the seats. As both seats had come out of the same type of Subaru WRX rally car and we’d made the mounts to the same measurements, it should have been a straight forward job. Hmmm. Not exactly!

Downright Dangerous!

Our measurements were correct and both seats fit and would have bolted up fine. The problem was with the co-driver’s seat. When we flipped it upside down to bolt on the rails, we discovered it was cracked. Not just a hairline crack, the whole seat base was a web of cracks! We can only presume that the seats were taken from a crashed car in a previous life and re-used.

Broken and cracked seat

This is one of the risks when buying second hand rally cars. You don’t really know what you are buying unless you completely strip the car and check every part thoroughly. This is the third Subaru WRX rally car that has come through our workshop with dangerous seats and/or mounts.

 It’s hard to say if the previous owners knew about the issues (or created them). Ari Vatenen nearly lost his life due to a broken seat at WRC level in the 80’s. Somehow the issue of seats and seat mounting seems to be overlooked as a critical safety issue. Needless to say we fitted a new co-driver’s seat as there was no way the old one was being re-used.

The quick fit parts

With that astonishing hurdle overcome we fitted; the race harnesses, helmet hammock, first aid kit and spare wheel tie down. Most of these items are “clip or tie on” which makes for a quick job. We did have to drill holes and bolt in the spare wheel tie down. We’re currently in the process of developing our own jack mounting system which will bolt in beside the spare wheel in all Subaru WRX rally cars (and other brands as well)

Under the bonnet

Our attention then turned to the engine bay. A new radiator found its way to the front as the old one had a stick through the core. The dump pipe needed some attention before being fitted too. In the previous car the exhaust had copped a knock at the rear. The force had travelled up the complete length and cracked the dump pipe. Some quick welding and it was bolted into place on the turbo.

Fitting the catch can

We also properly addressed the engine breathing. The previous car had pretty poor engine breathing therefore we suffered with blown oil seals. In the newly built Subaru WRX rally car we fitted a neat polished aluminum catch can. It was bolted to the firewall and plumbed it in to the engine vents allowing much better breathing than the old system.

Springing to life

After a few checks it was time to fire up the engine. First turn of the key and the quad cam boxer sprang to life. After a few minutes warm up we were confident everything was good. We booked the car in for a new exhaust whilst we got on with the last few items on the list.

Protection and handling

Under body protection came in the way of a new sump guard, a set of mud flaps and some HDPE rear deflectors. We have our own design sump guard which is light, strong and quick release. The remote canister gravel suspension from the donor Subaru WRX rally car was also fitted to the new machine.

50mm remote canister suspension in the WRX rally car

Body & paint

All things considered most of the metallic silver paint was pretty good on the body. The roof however was faded and we’d fitted different colour front doors. After the exhaust was fitted, we took a quick trip to our mates at Alcorn Body Repairs to have the paint sorted to match the rest of the car.


With everything done and sorted it was off to our venue for some shake down. During the space of two weekends, we covered more than 400km of testing. The new Subaru WRX rally car never skipped a beat and the owner was very happy with his new machine. The car will be out on the stages during the 2020 Rally WA season.

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