Running an RCTS Supercharged Elise against a stock Lotus Exige S in a dyno shoot-out (on a 248C Dynojet), it's possible to see that the Exige S tops the RCTS Elise by a couple of wheel-horsepower at the top end (dyno plot in Figure 1). Actual power at the RCTS car's flywheel is estimated to be about 216 hp, putting it into the same league as its stronger factory sibling at 220 hp.
However, the RCTS Elise has much more torque than the Exige S from 1800 to 5500 rpm and horsepower is also significantly stronger in this range as well. Note the strong torque plateau from 3400 to 5000 rpm, 3500 rpm sooner than the normal Elise shown in Figure 2 (6000 to 8000 rpm) and about 2000 rpm sooner than the Exige S (5000 and 6900 rpm) shown in Figure 1.
This changes the demeanor of the peaky stock engine (190 hp at 7800 rpm and 138 lb-ft at 6800 rpm). One additional feature is the magnetically actuated supercharger pulley that can be pre-programmed to engage automatically at throttle loads above a driver-specified value and disengage at 1000 rpm for a nice, quiet idle. Also, the pulley is programmed to remain inactive unless engine coolant temperatures exceed 158 degrees F.
On the road, the RCTS Elise is dynamite. Taking the already trick and ultra-pure chassis from Lotus and adding the extra supercharged punch from RCTS produces a true racecar for the street. The combination of instantaneous throttle response, incredible sounds and heroic torque is absolutely intoxicating. Driveability is excellent, while power comes fast and smooth as the first three gear shifts are snapped off like a sport bike on steroids. The exhaust note is delightfully racy under load (with the optional OEM Lotus performance exhaust) while the TTE supercharger screams as the car blasts toward redline. No engine codes blemish the dashboard, temperatures stay perfectly in check and the engine never misses a beat.
Power falls off at speed in fifth and sixth gears, but this is a torque/mass issue at high revs that's also evident with the Exige S. However, an even more powerful solution is on the way. RCTS has plans for the next phase of its Elise development program: a twin-charged motor.
The new system will use the TTE supercharger for low-end power and a ball-bearing turbocharger for the top. Engine internals will also be worked over and beefed up to deal with the extra loads. Click onto the RCTS website for updates. For now, this sensational modification is good enough.
The cost of the RCTS supercharger kit, fuel system and HKS electronics at press time is CDN$9,995 and will depend on world currency rates. The full kit can be installed in about 30 hours by a qualified technician or at the RCTS workshop in Calgary.