Z Cars Classics Re-Imagined
In common with the Hayabusa kit the K20 is also an updated version of one of the founding kits for Z Cars. The K20s are found in the Honda Civic Type R in EP3 (2001 – 2005) and FN2 (2007 – 2011) guises.
Performance On Tap
The K20 kit is also a popular conversion, as its higher revving capability is seen as having some of the aura of the bike engine variants, without some of the compromises. Whilst the power peaks @ circa 7400 revs for the standard EP3, they redline nearer to 8k, although the BHP and torque on the standard map tails over 7400. However with a rolling road session, the engine can be mapped to deliver the peak power over 8k with some Civic Type R owners having the limiter set at 8750. You can appreciate why some owners are drawn to this engine.
With engines now 9 – near 20 years old, finding a low mileage engine is now more difficult than it used to be, when Z Cars first starting using the K20. That being said donor cars are quite cheap and still plentiful so given the legendary reliability of these engines, a good service history and regular maintenance could yield a strong engine with most of its original horses intact.
There are a variety of aftermarket forced induction kits available for the K20, where the engine and gearbox are capable of handling circa 400 BHP before forging is required.
Whilst the EP3 has a top speed of 146 mph, the drop to 13” wheels has the effect of shortening the gearing giving the Mini at top speed of circa 120 mph at 7400 revs. However shortening the gearing improves acceleration still further not that it needs it with an 100 BHP per ton over the EP3 variant of the Civic Type R.
Fun with VBOX
At around 740 kilos the Mini will have over 260 BHP per ton. This is comfortably more than any of the super hatches on the market. This gives you some insight into the performance on tap. For those of you wanting still more performance, a supercharger kit with say 320 BHP would equate to a power to weight ratio of around 430 BHP per ton. This is 100 BHP per ton more than a Nissan GTR and within touching distance of many of the current supercars. If you add an aftermarket ECU and wheel sensors, you can utilise launch control and have some fun with VBOX or Dragy.
We have moved away from the HSS or ERW seamed tube where we now manufacture our frames from the stronger seamless CDS tubular steel, ROPT510. The rollcage kit has a universal section namely; the roll hoop and mounting loop for cradle, the rollcage and door bars. Furthermore there is an option to have tie-in bars joining the side hoops to the top of our optional front subframe. This element is common to all our Mini kits. The rear section is now modular in the form of a self-contained engine-specific cradle for each kit which allows the all the critical elements in the rear of the car to be removed in one-go, such as; the engine, gearbox, rear; suspension and brakes.
There are a number of distinct advantages of having a removable cradle, which are covered under the ‘modular engine cradle’ overview.
The cradle for the K20 comes with engine mounts and a sway bar as additional brackets for mounting the ECU, and room for expansion if you were considering future upgrades such as forced induction, enabling hardware such as; a heat exchanger for a charge-cooling system, a rear mounted intercooler as mounting possibilities for a dry sump or an oil cooler. The cradle can also have provision for the engine loom within the cradle so the engine loom can be disconnected easily and remain attached to the cradle as it is removed or fitted. The rear section of the roll hoop and frame can also have bracketry for a bulkhead to be fitted and to run a wiring loom.
Technical DataSheetK20 Kit
- Seamless tubular steel construction using ROPT (Rollover Protection Tube).
- Kit weight. Circa 100 kilos
- Donor engine figures:
- BHP 197 BHP
- Torque 196 Nm, 145 ft-lb
- Mini Kerb weight (basic specification). Circa 740 - 780 kilos.
- Power to weight: 260 – 450 per ton.
Complementing the kit are as follows
The Honda K series engine is a four-cylinder four-stroke engine introduced in 2001. The K series engines are equipped with DOHC valve-trains and use roller rockers to reduce friction. The engines use a coil-on-plug, distributor-less ignition system with a coil for each spark plug.
This system forgoes the use of a conventional distributor-based ignition timing system in favour of a computer-controlled system that allows the ECU to control ignition timings based on various sensor inputs. The cylinders have cast iron sleeves similar to the B-series & F-series engines, as opposed to the FRM cylinders found in the H-series and newer F series engines found only in the Honda S2000.Similar to B series, K-Series has two short blocks with the same design; the only difference between them being the deck height. K20 uses the short block with a deck height of 212mm where K23 and K24 block has a deck height of 231.5mm.
Two versions of the Honda i-VTEC system can be found on a K series engine, and both versions can come with variable timing control (VTC) on the intake cam. The VTEC system on engines like the K20A3 only operate on the intake cam; at low rpm only one intake valve is fully opened, the other opening just slightly to create a swirl effect in the combustion chamber for improved fuel atomization.
At high rpm, both intake valves open fully to improve engine breathing. In engines such as the K20A2 found in the Acura RSX Type-S, the VTEC system operates on both the intake and exhaust valves, allowing both to benefit from multiple cam profiles.