Turbocharged Lexus IS300 - Altezza Fever

All car lovers have that magic car, the model they have to own in spite of any financial or other logical reasons to the contrary. We're talking about a car that's as important as oxygen itself.

For Mark Yuen of Cinnaminson, N.J., it's all about the Toyota Altezza. Not only does the Altezza have high style, but Japanese tuners have turbocharged the beegeezus out of the 3S-GE four bangers since the Altezza came out in 1998.

This only increased the intensity of Yuen's Altezza Fever. The moment the windows opened for deposits on America's Altezza, the Lexus IS300, Yuen dropped a deposit on the car and the color, spectra blue mica, he had been dreaming of.

In the interim, his fever mutated as his J-spec aspirations took on a life of their own. He became enamored with Japan's VIP look or big-sedan style, a look defined by lowered vehicles, augmented with wide body kits and fitted with gargantuan wheels and tires. This vein of customization can be seen in Japanese tuner magazines like Big Sedan, CARisma and Auto Moda along with more than one offering from the Option magazine lineup.

Yuen got the keys to his dream machine in July 2000 and was quick to tickle the IS300. The car was dropped via coils and the rolling stock was upgraded with 18-inch Volks and 225 tires. The big question was, would Yuen's VIP concept take flight? He approached J&I Autobody of Delran, N.J. with his twisted ideas and was met with enthusiasm, not sarcasm.

Yuen and the J&I staff came up with some drawings and then tackled the tedious task of taking the two-dimensional drawing into a three-dimensional world. The VIP style dictates the body pieces be molded into the OE sheetmetal. Why not graft on a Japan-spec kit? The U.S. bumpers and other irregularities actually made the custom approach better.

The result is an eight-piece extravaganza consisting of a front bumper spoiler, side skirts, rear valance and door panels. When it came to widening the wheelwells, Wald USA had a fender flair kit that fit the bill. The Wald kit provided the VIP punch and tied the custom body tuning parts together. The final additions were front air splitters, a Hippo Sleek rear spoiler and a Pittura Sport roof wing. The muscle-bound sedan was delivered to Nixon Autobody for final paint. The stock-to-shock transformation took seven months and the results speak for themselves.

With its enhanced bodylines, the Lexus now rolls on J-spec Yokohama AVS Model 5 aluminum and Toyo Proxes T1-S rubber. The 19-inch combination consists of 8-inch rims and 235/35ZR-19 tires in front and 9-inch rims and 265/30ZR-19 tires out back. That's big on an IS.

Yuen wanted an advanced level of performance and after considering supercharging he elected to go with a turbo set-up. His search for boost led to TBKO (Taabo Kyoso), a tuning shop in Mount Airy, Md. Owner, Jeff Stevens, a turbo specialist, fabricated a turbo kit for Yuen's IS300.

"The project first required building a manifold," says Stevens. "Once we positioned the turbo in a good location, clear of the motor mount and low, to reduce under hood temps, we could then fabricate the downpipe and position the wastegate."

Stevens fabricated aluminum intercooler piping and experimented with several different sized intercoolers until he was able to position a very large front-mount intercooler without cutting the front bumper support or interfering with other systems.

Says Stevens, "We then experimented with several locations for the mass air meter, settling on blow-through design for improved drivability and consistent transmission shifting."

The hard parts of the turbo system consist of TBKO 321 stainless-steel tubular manifold, 3-inch TBKO stainless-steel downpipe, a TBKO-spec T04E turbocharger, Turbonetics Racegate, Spearco front-mount intercooler, mandrel-bent piping and a TurboXS blow-off valve.

Generating turbo power is about more than hard parts. "The fuel system had to be reengineered, making it a return system," adds Stevens. "To make things worse, the lay out of the fuel tank is like a saddle tank, so fuel had to be transferred from the passenger side to the driver side via a jet valve." Stevens says this jet valve works with the regulated pressure passing through an orifice to create a vacuum. "The vacuum side is connected to the passenger side of the fuel tank and sucks fuel over to the driver's side where the fuel pump is located."

"There is a problem associated with this decision," says Stevens. The jet valve is too restrictive. "We had to make calculations to modify the jet valve based on the amount of fuel we were returning at idle, part, and full throttle. We were able to get it just right, and attain a balance between both sides, which eliminated any chance of long-term fuel level problems."

"We were also able to increase the return flow, so we could maintain precise fuel rail pressure, which was crucial with the IS300," adds Stevens. "The injector duty cycle cannot be altered directly because doing so makes the ECU's logic think the engine is misfiring. Therefore a consistent pressure is critical. A lack of consistency results in a surge at idle and hiccups during initial throttle."

To increase flow volume, a Walbro high-flow, high-pressure pump, Aeromotive regulator and a Cartech billet FMU were installed. The car was ready for test runs and Stevens experimented with different line pressures in the transmission until he attained good response and proper shifting.

Engine tuning is executed with a TBKO piggyback ECU computer while a TBKO shift computer keeps the gears changing. With a few road trips under its belt, the IS300 was scheduled for a dyno tuning session. After only a few fine tuning runs, the 2JZ-GE pumped out 321 whp and 300 lb-ft of torque at 7 psi. Our own long-term IS300 laid 174.6 whp in stock trim, so Stevens is up 147 hp at the wheels. It should be noted that the engine runs a factory bottom-end and the stock 10.5:1 compression.

At this point in the car's evolution, the suspension had some catching-up to do. Yuen wanted to maximize the sporty suspension Lexus delivered from the factory so he elected to go with coil-overs. The weapon of choice was Tein's CS system.

The CS or Comfort Spec system featured ride adjustable coil-overs with 448 lb-in. springs in front and 336 lb-in. springs in the rear. The system uses rubber upper mounts but pillow ball mounts are available as an option.

Bracing can give a vehicle extra stability that makes all the difference on the road. In the realm of VIP-style sedans, bracing is more critical because the cars are usually bigger, heavier and much more commuting oriented than traditional sports cars. Yuen fortified the chassis of his IS300 with a Do Luck rear cross member bar, Cusco triangle brace and Cusco front and rear strut tower bars. Yuen has taken his lust for J-spec gear and opened SKR Performance, a comapny that imports exotic JDM stuff to the U.S.

There's no doubt Yuen is living large in his VIP-inspired IS300. However, large does not always mean satisfied. Yuen has some more tricks up his sleeve including a move from the current TBKO Stage I kit to Stage II status. That's the thing about fevers: Just when you think it's all under control, there's a flare up.

the SOURCE
HKS USA, Inc.
(310) 763-9600

J&I Autobody
(856) 764-0092

Meguiars
(800) 347-5700

Nixon's Auto Body
(609) 871-7600

Rotora
(888) 990-0899

SKR Performance
(856) 461-2229

Spearco Intercoolers
(805) 581-0333

TBKO
(301) 829-4902

Tein, USA
(562) 633-7387

Toyo Tires
(800) 678-3250