Fubaru Kit



The EJ253 Subaru unit is our preferred engine for the Fiat 500 being a compact unit and facilitates keeping the standard look and retaining the practicality of the original car including the bulkhead and rear seats. Rated at 165 - 173 BHP, this would give the 500 a power to weight ratio of circa 300 BHP per tonne. Put into context this is on par with countless Ferraris, Lamborghinis, Astons and 911s. In short, one might say this is sufficient?

As opposed to other Boxer units such as the EA81, the EJ253 is more freely available and powers the following models:

  • Impreza 04-07
  • Legacy, Outback (North America) 05-11
  • Legacy [BL/BP] 03-09 (Europe)
  • Legacy [BM/BR] 09-12 (Europe, with 123 kW/167 hp)
  • Outback 03-09 (Europe)
  • Forester 99 (SF), 05-10 (SG, SH)
  • Baja 05+
  • Saab 9-2x Linear 05, 06

The approach will be to source a donor car with the gearbox and ECU and to be able to drive the car and test the power is delivered smoothly and look for symptoms which might suggest we need to rebuild the engine. If the engine is fit for purpose, we can place the engine through a TerraClean process which is a unique decarbonisation technology which makes a significant improvement to the Emissions, MPG and Driveability/Performance of an engine. One of our associated companies, is an agent for TerraClean. Should there be any concerns, we would rebuild the engine ourselves.

With the engine rotated 180°, the standard gearbox needs to be rebuilt utilising the revised gear ratio set included in the kit.

This is required to address the engine now driving in the wrong direction as a result of the rotation to fit the engine into the back of the 500. This transforms the effective 5 reverse gear and 1 forward gear back into a conventional setup with 5 forward gears and 1 reverse gear. This is a well-established conversion kit provided by Australia-based SubaruGears.

Main Kit Parts

  • Fully welded ROPT510 tubular engine cradle with engine mounting brackets.
  • Trailing arms and fully adjustable suspension.
  • Driveshafts, CV joints and rear brakes.
  • Z Cars front subframe with fully adjustable suspension.
  • Front hubs, uprated brakes and calipers.
  • Mini steering rack and custom steering column
  • Gear ratio kit.
  • Gear lever, linkage and cables
  • Bodywork wide arch kit, seat tunnel
  • Cooling and Fuel kits (using standard tank)

Supplementary Kits

  • New 30 Litre fuel tank kit
  • Uprated fuel pump, fuel lines & fuel return pipe kit
  • Performance exhaust kit
  • Wiring loom, fuse-board kit

Available Upgrades

  • Seats
  • Dashboard
  • Security Pack (Alarm, remote c/locking, immobiliser)
  • Wheels/Tyres
  • Infotainment System (double-din unit, choice of speakers, Sub, Amp)
  • Badges & Stickers
  • Steering Wheel (suggest removable for security)
  • Seat belts, carpets, door trim, parcel shelf, door furniture
  • Glass
  • Sunroof vinyl
  • Electric Heater kit

Sublime Handling

"There’s nothing quite as enjoyable as truly ragging a car and when it talks back to you, and when you can do that within the realms of safety. For me that's when cars are at their best. These cars are amongst the best exponents of that art form"

- A Z Car Owner -

The Conversion

The conversion exemplifies the concept of incorporating innovations or advancements in automobile technology since the inception of the Fiat 500 to enhance the performance, comfort and safety of the classic car.

The kit centres round an engine cradle which the Subaru EJ253 engine is mounted to. We are now moving the engine further back by 50mm towards the rear of the car (unlike the Blue car development car) so the driveshafts meet the CV joints at a less acute angle which would reduce wear. The cradle has pick points for the suspension and trailing arms which essentially means the kit (with the engine mounted) can be easily assembled or disassembled (e.g. for engine maintenance).

With the engine rotated 180° this means the engine fits snuggly into the engine bay with minimal alterations to the bodywork, so much so the rear seat can be retained. The images below show the raised box section required under the base of the back seat.

The dramatic increase in performance necessitates an uprating of the front suspension, with cross drilled solid disks. Having tested the more powerful Hayabusa which has the brakes with this configuration, we feel this would be up to the task. If we wanted to upgrade, we would change the pads for a harder material and add a servo.

There are uprated front suspension conversions but these tend to be single-sheer joints and whilst these are probably sufficient for the Abarth models, the performance of the Fubaru suggests owners would be more reassured with double-sheer mounting when braking heavily, particularly with the top speed being > 120 mph.

The steering box is replaced with a Mini quick rack and gives better feel and gives the driver more confidence that the quicker steering would facilitate more control given the performance capabilities of the conversion.

There has been a major redevelopment of the subframe to the one used in the blue Fiat 500 with the EA81 engine. Essentially this is to facilitate a wholly self-contained unit and replicate the setup with the Fiabusa and the Mini kit by not having the top suspension mount connected directly to the bodyshell. The routing of the tubes has been simplified and we will move to a box section trailing arm.

The frame is mounted picking up on the standard rear subframe mountings for the Fiat 500

The switch to a water-cooled engine means a front mounted radiator would be required. We have chosen to not be too aggressive on the cooling risking overcompensating for air flow through the radiator with a more pronounced aperture or front grill, which can detract from the look of the 500 in our view. For the initial testing, we have a subtle opening near the bottom of the front panel disguised with the front bumper mounted in front. The testing we have carried out to date has admittedly been conducted in 10-15° temperatures, nevertheless the gauge has read normal, so this would suggest the bumper is not acting totally as a barrier. Should the temperatures rise with warmer weather, we will introduce a body colour air dam/scoop to direct air from under the bumper through the opening. There is also the option to add a second fan ensuring a greater surface area of the radiator would have fan-assisted air passing through it in traffic and warmer conditions.

Should these measures ultimately prove ineffective for the height of summer, we can revisit more extreme cooling solutions, including:

  • A removable element of the front panel, for Summer, and quickly replaced for Winter or if the car was as a show, and the looks of the car were required to be preserved.

An opening also behind the chrome centre-mounted Abarth badge/strip. The badge would in-effect be ‘floating’ and act in a similar way to lower opening/bumper, where the badge would distract on-lookers from the aperture behind, whilst allowing more air to pass through the radiator.

The radiator shroud ensures all the air that passes through the aperture is not wasted and cools the radiator before being diverted away from the fuel tank and out underneath the car reducing heat soak. The filler cap is attached to the radiator as being a boxer engine conversion, the cap will be the highest point and will avoid air locks in the cooling system.

Although the radiator is excluded from the kit, this is to ensure we have the correct cooling solution for every customer, so we would expect the customer to specify their requirements and offer a bundle price for the full kit and the cooling kit. The vents already in place for the air cooled 500 setup allows for the natural venting of the warmer air out of the engine compartment which is an advantage over the Mini conversion. This nullifies to a greater extent the spiralling effect of non-recirculating air stuck in the engine bay steadily increasing in temperature, making the radiator having to work that much harder.

We have considered carefully what is included in the kit and the parts or components that we have appeared to regard as discretionary. In the main, the supplementary kits or a variation of them are required to complete the installation. With international interest exceeding that of our home market, each region represents different climatic conditions and vehicle licencing regulations such as the dBA levels on an exhaust. We can provide the kits and bundle them in with the main kits, and can produce a bespoke kit, such as a larger radiator for a warmer climate or increase the tank size for a longer range between fuel stops. Personally I don’t mind stopping for fuel as it is a great opportunity to show off my car! In respect to the exhaust, if we are given a particular target dBA, we can manufacture one and fit it on one of our engines to test it to ensure we are at the correct level.

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