Lexus SC300 Twin Turbo

In the Beginning there was Lexus

These pages chronicle my feeble quest for the ultimate Lexus. I am the proud owner of a 1992 Lexus SC300. It started out life as an black automatic with the standard US spec 2jz-ge naturally aspirated inline-6 putting out 225hp. It came loaded with all the goodies except a decent amount of performance.

Singing Lessons

The first items that had to go were the stock speakers. It place of the front and rear speakers went in some Polk Co-axials to improve the mids and highs. The factory 10" free air sub was also removed in favor of two 12" JL Audio 12w0's mounted facing each other in an isobaric setup. At first I had these in a custom box I formed in the corner of the trunk with fiberglass. Later on, I rebuilt the box using MDF and more angles than I can count. Pushing the subs is an MTX Thunderpro 280. Now the sound has a lot more depth and pretty good imaging for the limited amount of work done.

Daddy Needs a New Pair of Shoes

Next up on the chopping block were the pathetic, little 205/60/15's and 15x7 stock wheels. I proceeded to install a set of 18" OZ Racing Saturns (also known as MSW 55C). 18X8.5's on the front and 18X10's on the rear. Pirelli Supersport 7000's were mounted in 255/35/18 and 275/35/18 sizes. The car was also immediately lowered with a set of Eibach Springs and Tokico Shocks. The difference in handling was phenomenal to say the least. The ride became a little stiffer but definitely worth the trade-off. The looks also improved dramatically as the car took on a much more aggressive stance and the wheel wells were filled to the limit.

Chin Music

Next up came some more cosmetic changes. A Kaminari front lip spoiler was attached to the stock bumper and all rear emblems were removed, remaining holes filled and painted. The Kaminari spoiler was a fairly well made and sturdy fiberglass unit and added a more aggresive look while still blending well with the factory lines.

Breath in,  Breath out

Well, now my car had some mean looks but needed the HP to back it up. I proceeded to remove the stock exhaust and intake for better air flow. In their place went a Top Speed cone filter intake and two Thermal 2-3/8" stainless steel canister mufflers with Thermal 5" slash tips. I'm guessing this added around 15hp, not bad, but still no where close to what I wanted.

Laughing Gas

About a week later, a 80 hp dry shot of NOS was installed. A remote bottle opener and bottle heater were also installed for optimum results. The difference taking off from a stand still was night and day. Those big 275's on the rear would hook up and I was gone. It also obviously helped on the top end but it wasn't as dramatic as the new and improved low end. The sound of the exhaust while spraying was throaty and powerful, no weed-wacker engine here.

Time for a Mild Facelift

The Kaminari had survived many low dips and steep parking lot entrances but a huge rock in my path eventually destroyed it. I had considered getting another one, but a week or so later a 3/4 Ford truck I was following passed a parking space that he then decided he liked, and on came the reverse lights. Before I could honk or get it in reverse, his massive aftermarket bumper was crushing my bumper and hood. Faced with having to replace my bumper, I decided to get one from overseas. I settled on a Do-Luck front bumper cover which is an all fiberglass unit. After a long, long wait (long long story), it finally arrived and didn't fit over the US spec bumper reinforcement. After some meticulous trimming with a dremel, it was attached and sprayed. The bumper gave the car an even meaner look, similar to a Supra bumper. It is a 2 piece unit and I chose to leave off the lower portion as it made the car look too low and unbalanced. It also would have lasted about  five blocks on Austin streets.

Whoa Mule

After a couple of high speed stops, I realized my stock brakes worked about as well as sticking my feet out the doors. Since I didn't want to scuff up my wingtips, I decided I needed some race inspired brakes. This was especially important now that I was running NOS and in the process of major engine upgrades. The choice was obvious for me, since the 12.6" 4-piston brakes from  the MKIV Supra Twin Turbo would bolt right on. These brakes are MASSIVE for a production car and have been called "...best production car brakes we've ever tested..." by a leading car magazine. I also went with stainless steel brake lines for better response. Installation was simple and after a short break-in period it was time to see what they could do. WOW is all I can say. Now during a high speed stop, the ABS will begin to pulse immediately as the front tires grab furiously at the asphalt. The front end dives as your seatbelt fights to keep you attached to your seat. Even after multiple high speed stops, I found no evidence of the brakes starting to fade. I should have done this upgrade a long time ago and these brakes should have came on the car originally.

Interior Decorating

After years of Texas heat and one Texas flood, ouch, the original interior was in need of some attention. I completly removed the discolored ivory carpet and recolored it in black which looked great and provided a stunning backdrop against the ivory seats. New two-tone ivory/taupe leather seat covers and armrests were custom made to continue with Lexus's two tone interior theme. The results were well worth the effort as the car now felt showroom fresh. 

The Heart Transplant 

At the end of January 2000, my SC300 was dropped off at Powerhouse Racing to receive the 2jz-gte engine and 6spd from the MKIV SupraTT. A 3.13 limited slip differential, custom driveshaft, modified RMM downpipe, stock intercooler, modified shifter assembly, SupraTT in-tank fuel pump, custom tachometer driver circuit, Supra 6spd ECU, and numerous wire splices were completed for the conversion. After lengthy delays waiting on parts from Japan, I finally received the call I had been waiting for and picked up my car on April 19th. The drive home was an eye-opening experience. Running around 12psi of boost, the car was transformed into a beast. The 6spd felt great and provided wonderful cruising in 6th gear. The car pulled well and an LS1 F-body was summarily dispatched within 5 miles of leaving Powerhouse. No vibrations or any other irregularities that I feared might arise, could be found. The car simply felt like it came from Lexus like this. Actually, if I lived in Japan I could have bought an SC, called the Soarer, with a 1jz-gte which is a 2.5 liter version of the 3.0 liter 2jz-gte. Unfortunately, the US market did not receive this version so I had to have my own made.

More Boost Please

12 psi made the car ridiculously faster than the original NA engine, but I had more in mind. Most BPU Supras run around 18psi or so and I was about to join them. I installed a Greddy Boost Cut Controller from a Toyota MR2 to remove the fuel cut safeguards in the ECU when boost above 14psi or so is measured. Next I proceeded to do a "free" mod to increase the boost known as the VSV bypass. Now my car was able to make around 18 psi which definitely gave the car an additional kick in the pants.

Let's Hookup

Now that my car had a lot more power, the Pirelli P7000 Supersports found themselves out of their league. For track use, I definitely need a better tires with softer compound. I purchased another set of wheels, 17x10 and 17x8.5 OZ Competitions, and a set of Kuhmo V700 Victoracer road racing tires in 275/40/17 and 315/35/17 sizes. Luckily my rear fenders had already been rolled to the max to allow all this meat to work. Under compression of the rear suspension, the 315's slip right inside the fender lip. Looking at it when the car is level, you would think it would hit, but alas, after some hard test driving, the setup passed muster. Next up were a set of 315/35/17 BFG Drag Radials for the 1/4 mile blasts.

No more Asthma

It soon became apparent that from the downpipe back, my exhaust was choking the potential of my turbo setup. From the RMM downpipe to the Thermal cans, the original piping was still in place, which in addition to being crimp bent and severely undersized, still retained the stock resonators and looked more like Lombard St in San Francisco than an exhaust system. I bought some 2.5" mandrel bends and had a new piping in place which took a much more direct route from downpipe to exhaust cans, sans any resonators. The results very impressive above 4000rpm and netted a significant increase in power, going from 370rwhp to 411rwhp. Sound was also much improved, actually being quieter at idle and cruising speeds and louder under WOT.  

Onward with the Quest

Well, that bring's you up to date on the current status of my SC. Certainly the modifications are not over, since this road is one without a final destination. Future plans include an HKS Triple Disk clutch and Greddy 3-core Front Mount Intercooler, which are on the way from Japan, bringing my NOS system back online as a wet system, a new exhaust setup, Tein HA or Ground Control coilovers, Tanabe sway bars, and of course, the big turbo upgrade.