Having had a Lexus IS 300 as a long-term project we can attest to the high-quality and sporty appeal of the sculpted sedan. The car is rock solid and a winner from the inside out. As familiar as we are with the IS we can hardly imagine driving a turbocharged version every day. James Ceron of Cerritos, California doesn't have to use his imagination to conjure up such an experience--it sits in his garage every night. Ceron's 2001 Lexus IS 300 has been fitted with XS Engineering's bolt-on turbo system.
XS Engineering has developed the kit for more than a year ensuring the Lexus retains its luxurious aura while infusing the 3.0-liter in-line six with nearly an atmosphere of boost. The kit on Ceron's car is one of the first near-production prototypes. Ceron had a '98 Eclipse that he had built into a real musclecar with the help of XS Engineering. He happened to mention that he was selling his Diamond Star and was planning to buy an IS 300. The crew at XS told him about the kit and after paying $33,000 for the car and rolling up a mere 900 miles on the engine, the blue Lexus was dropped off at XS Engineering.
The basis of the car's transformation from ballet to bully is a custom-crafted XS Engineering T4 turbocharger that runs confidential wheels and housings. The key to making a turbo system work is the exhaust manifold. Designing a manifold is a balance between positioning the turbo and fabricating runners that provide optimal flow. XS Engineering's tubular manifold uses 1.75-inch primaries to move the spent gases out expeditiously. The manifold is home to a 40mm HKS external wastegate that bleeds off the boost as the T4 reaches its 13-psi ceiling. The system runs a downpipe that starts at 2.5 inches but enlarges to three inches where it meets up with a modified APEXi N1 system. On the cool side, the turbo pressurizes polished piping. The piping leads to a massive 24x11 XS Engineering GTR intercooler that keeps charge air temperatures down, ensuring reliability. Rounding out the system is an APEXi twin chamber blow-off valve that keeps the boost from backtracking into the compressor when the throttle is suddenly closed.
Spark energy is generated by the Lexus' stock crank-triggered, direct-fire ignition system. The plugs, however, have been upgraded to Denso Iridiums. Denso has been in the market for a couple years and has made substantial inroads, appearing on many wild rides in these pages.
On the fuel side a Holley fuel pump pushes fuel through -6 lines to a Vortech FMU and SX regulator. From this point the fuel system retains its original rail and injectors. An APEXi Super AFC piggyback computer that modifies the signal from the mass air meter to the ECU is the main tuning instrument. The Super AFC allows tuning of plus or minus 50 percent of the stock fuel curve at eight separate engine speed settings.
When it came to the tuning phase of the project the XS crew were Maestros and the basic piggyback Super AFC played like a Stradivarius. With a simple pump and regulator tuning strategy, a stock ECU and piggyback fuel computer and race-gas-sweetened fuel XS technicians coaxed and impressive 415.8 hp out of the internally stock 10.5:1 compression IS 300 engine, an amazing feat by any estimation. Peak torque checked in at 419.2 lbs-ft.
Making power is important but using it wisely (read effectively) is key. The Lexus provides a unique hurdle to total power realization--its automatic transmission. In stock format, the slushbox does not take kindly to big power gains. It is programmed for smoothness not brute force and retards engine timing to ensure nearly transparent gear transitions, which also makes it hard to lay down power consistently. Unique problems require unique solutions and Level 10 had the answer. The company took the Lexus gearbox and performed a valve body upgrade along with a few of its other tricks. XS developed a boost sensitive line pressure increase device and the rear was fitted with a TRD limited slip differential. With these mods up and running Ceron was off to the races.
Lexus is known for style and this fact was not lost on Ceron. Along with 415 wheel horsepower he added the proper street stance and body mods. For enhanced underpinnings the IS runs APEXi World Sport coilovers and TRD sway bars. The coilovers allow height adjustability and firmness control. Rolling stock consists of ALT Wheels X-Philes of the 19x8 variety and Toyo Proxes T1-S rubber. The Lexus's silhouette has been enhanced with a hard-hitting C-West body kit. The kit was installed and color matched by Derek Teklak of Body Pros in Garden Grove, Calif.
Inside the IS 300 has, for the most part, retained its stock look with the Super AFC being cleverly mounted in the center console and the AVC-R boost controller positioned just to the left of the driver. Ceron has incorporated Sharp Precision Instruments' Defi Heads Up Display (HUD) monitoring for boost pressure, speed and rpm.
The Defi system comes in handy because you need to be heads up when at the controls of this beast. When the boost hits the Lexus is instantaneously transformed from docile luxury car to a tire granulating speed demon. Drop the hammer and the T4 is quick to spool and deliver the thrust. The IS 300 accelerates with enthusiastic verve while the chassis delivers stability and control without missing a beat. We were impressed with the overall feel of the package despite only running seven psi. Imaginaing the drive with nearly double the boost is a trip; one we would like to take. The only shortcomming of the car is the transmission. While it does handle the power, and that is an acccomplishment in itself, it needs more zip, more line pressure, firmer shifts. Ceron knows this and has a number of possible fixes in the works. Stay tuned as we will follow his progress.
Are you a pressure player? The XS Engineering kit is a reality. The XS braintrust used the early automatic-shifted cars to get the kit up and running but has targeted the five-speeds for full production. The downtime required to fortify the automatic transmission made developing a shippable, bolt-on kit unrealistic. As the five-speed IS 300s hit the street the kit will be much less labor intensive, cheaper and a much more viable proposition (provided the manual gearbox can hold the power). So, if you want to get into a pressure filled situation with your IS XS Engineering can make it happen.