The Honda S2000 was viewed as an iconic masterpiece within the Honda community as its early debut took to the showrooms in April of 1999. The AP1 (chassis code) matched with a F20C powerplant could do no wrong within the eyes of performance fanatics as owners cherished the 9,000rpm revability of the 2-liter mill and the factory-equipped six-speed transmission that rocketed the S2K to the tune of 240 hp and 153 lb-ft of torque. Owning an S2000 also meant bragging rights of owning the highest specific power-per-unit volume of any mass-produced naturally aspirated piston motor producing 123.5 hp per liter-an amazing feat by any means within the automotive industry. While the AP1 quickly grew in popularity since its debut, it was only a matter of time before power hungry owners of the S2K became complacent of its factory horsepower.
TODA Spec A2 intake and exhuast camshafts paired with TODA F20C valvesprings
Turbocharging and supercharging the F20C became a common mod to boost up the ponies as manufacturers such as Comptech engineered a supercharger kit that added on an extra 50 hp per liter from the S2000's 2.0L engine, bringing power levels to the 300whp marker. Using a Paxton Novi 1000 centrifugal supercharger, the bolt-on S2K kit quickly turns this mild-mannered machine into a fire-breathing beast. The added horsepower was icing on the cake but with any small displacement engine comes a series of drawbacks, which are associated with force inducing the F20C powerplant known to the Honda camp as boost lag.
XS Engineering begins with the removal of the factory cam guide assembly
While many might argue the fact that the F20C cylinder head and factory camshafts were engineered to deliver optimal performance straight from the factory, XS Engineering located in Garden Grove, Calif., was approached by one S2K enthusiast looking to improve on his Comptech supercharged machine. Prior to bringing the vehicle to XS, the S2K was already equipped with a HKS F-CON V Pro engine management to address the fuel and timing on the high-compression 11.5:1 ratio engine. The boosted S2K delivered 303.8 hp and 192.7 lb-ft of torque-power figures that would be more than enough for the average owner but not for this customer. Looking to improve boost response and driveability on the street, the owner enlisted the aid of XS Engineering to install and tune his S2Kwith a set of TODA Racing Spec A2 intake and exhaust camshafts along with TODA valvesprings. The TODA cams are comprised of an intake cam with 295mm degree lift and exhaust camshaft designed with a 290mm degree lift. TODA designed these cams to offer improved midrange and top end improvements over the factory camshafts.
A close-up of the factory rocker assembly before it goes under the grinding tool for modif
With XS Engineering at the helms, the S2K's factory bumpsticks and valvesprings were replaced with the new TODA hardware. Minor modifications were performed on the factory rocker assembly. Koji Arai of XS Engineering took control of his laptop and fine-tuned the supercharged machine. The results were promising at the end as peak power improved to 343.84 hp and 216.44 lb-ft of torque-a gain of 40.04 hp and 24.27 lb ft of torque. Dyno graphs reveal significant gains from 5,000 rpm to redline with an increase of 23 hp and 38 lb-ft of torque at 5,500 rpm over our baseline numbers-a consistent pickup of 20 hp and 37 lb-ft of torque from 6,500 rpm to redline. We noticed an improvement in horsepower from 4,500 to 5,000 rpm due to V-Pro tuning combined with lowering of the VTEC crossover point, which comes in at a factory 6,000 rpm on the F20C. The earlier VTEC activation enabled the 2.0-liter mill to improve on midrange power using the new TODA Spec A2 camshafts.
Using a carbide bit, the XS Engineering team carefully performs the necessary modification
Here's a close-up shot of the modified assembly next to the factory unit.
With modifications complete the new TODA camshafts were dropped in place.
Buttoning up the cam guides and torque down the bolts to specified tolerances per factory
The last step in the process was to check the valve lash clearances before assembling the