Circuit Corolla

 

The Toyota Corolla is one of the world’s most popular cars – but it’s not exactly a popular platform for building a race machine! Nevertheless, Brett X saw the go-fast potential in the early KE15 Corolla and continues to drop jaws whenever he fires it into anger on the circuit. This is a genuinely innovative and capable racer.

So what on earth possessed someone to do this to an old Corolla, you ask? Brett explains that the ‘rolla is lighter than the popular Datsun 1600, its flowing rear panels have an aero advantage and, well, it’s unique. No argument there.

Brett picked up his ’69 KE15 Corolla Sprinter after a high-performance build-up was aborted by the previous owner. The rear-wheel-drive Toyota already had a Nissan CA18DET 1.8-litre DOHC turbo engine sitting under the lid (though far from running) and relatively straight, rust-free panels. Brett considered switching to Toyota four-cylinder power but recognized the potential in the combination of CA twin-cam turbo power. Meh, what’s in a badge?

The Nissan engine was installed using Hilux-based mounts, a relocated cross-member and a 25mm recess in the firewall. The fuel system was built from scratch, beginning with a 40 litre fuel cell in the boot, Bosch lift pump and Bosch Motorsport pump. High-flow injectors have also been added following our photo shoot. Controlling the fuel and ignition systems is an Autronic SM4 programmable ECU fitted and tuned by C-N-J Motorsport.

The CA18DET was treated to a Garrett GT28R turbocharger (the biggest that could fit!) along with a custom tubular exhaust manifold and 3 inch mandrel bent system. Scott’s Rods can be thanked for that. A K&N pod filter protects the turbo and engine from foreign debris and the nose has been chopped to accommodate a PWR bar-and-plate intercooler. An aftermarket blow-off valve, PWR aluminium radiator and oil catch can complete the under-bonnet snapshot.

With boost pressure recently bumped up to 18 psi, Brett’s Corolla generates something like ten times its factory output. On the rollers of C-N-J Motorsport’s Dyno Dynamics chassis dyno, the car has belted out 200kW at the wheels. Previously, the standard injectors limited output to 160kW at the wheels – still enough to achieve a mid 13 second ET with abysmal traction from first to third gear...

Drive is channeled into a W58 Toyota Supra close-ratio five-speed which required a remanufactured trans tunnel and a conversion to a hydraulic clutch system. The clutch is a button job teamed with a billet flywheel. A custom tailshaft connects a Nissan R31 Skyline rear-end which currently spins a Toyota Lite-Ace 4.5:1 centre which is welded for maximum traction. Axles are modified Skyline items. Brett is considering a few different LSDs to alter the handling characteristics of the car.

On the subject of handling, you’ll be interested to learn Brett has installed an entirely different type of front-end in the car. While the standard KE15 runs a transverse leaf spring front suspension, this example boasts Corolla XT130 front struts which are modified into coil-overs. Custom top mounts provide adjustable front camber and Brett normally runs around 2.5 – 3 degrees of neg. The rear suspension retains the longitudinal leaf springs although they’re upgraded and combined with Koni adjustable dampers. Interestingly, there are no swaybars on the car at present but a custom front ‘bar is presently being made.

In a world of mega-buck Brembo brake upgrades it’s noticeable that, given a low kerb weight, you can ’get away’ with a much more affordable system. The Mazda Series 4 RX-7 four-pot front calipers with Peugeot discs and R31 Skyline rear discs mightn’t sound exotic but braking performance is exceptional, given the car tips the scales at just 910kg (with half a tank of fuel). A Holden Commodore dual-circuit master cylinder, adjustable bias valve and hydraulic handbrake are also fitted. There’s no need for brake vacuum assistance – don’t be a whimp!

While much of the suspension, brakes and engine were being sorted, Brett had the elegant Corolla body revived and prepared for motorsport. The universal wheel arch flares provide the necessary coverage for 15 x 7 inch Performance Challenger rims, the grille has departed to make space for the intercooler, and acrylic rear quarter windows and bonnet pins have been installed. Oh, and it’s all draped in high impact orange paint and an assortment of stickers.

It’s unlikely the KE15 was ever regarded a lavishly appointed vehicle – and it’s even less so now! In the interest of reducing weight, the cabin has been entirely stripped and refurnished with a single Daytona race seat and Monza harness combined with an aftermarket steering wheel. The dashboard carries two carbon-look pods – one containing the tacho, oil temperature and pressure, water temperature and boost pressure gauges and another containing an A’PEXi Rev/Speed Meter, fuel level gauge and all necessary switchgear. A six-point roll cage and dual 1kg fire extinguishers help meet Sports Sedan racing regulations.

Although only recently screwed together, Brett says his monster Corolla is great fun and quite well composed on the racetrack. The 195/55 15 Falken RSV04 tyres (which were the control tyre in the Mirage Cup) give excellent grip and wear characteristics and you can squeeze the accelerator fairly early through a corner. Turn-in is sharp and braking performance is immense. Brett also points out that the car is very drivable – an important trait given this is his first race machine and he’s recently stepped out of an AWD Impreza WRX.

The car has been thrown into a few sprint and hill climb events and already, Brett has snatched some podium positions. A recent outing at Queensland Raceway also yielded a 57.9 second lap time which is pretty tough to beat without spending a bundle. And there’s a lot of extra performance waiting to be unlocked. Brett is keenly awaiting delivery of the custom front swaybar, investigating some LSD options and will continue fine tuning. A digital dash display is also on the agenda.

When these changes have been made, Brett will take the car to a few motorkhana events to extract even more driving enjoyment. By this time, it’s also expected that the car will have roadworthy approval - which means there’s absolutely nothing that this little Toyota can’t do.

So forget the notion that Corollas are only good for picking up the groceries – there’s no reason they can’t pick up a trophy. Or two.

Contact/Thanks:

C-N-J Motorsport: +617 3290 3966 www.cnjmotorsport.com.au

Brett would like to thank the guys at C-N-J Motorsport, Christian Melian Enterprises, Able Body Repairs and his wife.