Lexus SC400 Build Aims for 500 WHP, 200 MPH
Nothing is going to stop this Lexus SC400 owner from achieving his lofty goals. No matter how many engines it takes!
We all have our own unique dreams and aspirations. Some of us want to be teachers, others astronauts. But Club Lexus member Kyleg250z has something entirely different in mind. You see, he wants to build up his Lexus SC400, and not in the way you might think. No, this particular Lexus isn’t going to be some kind of show car or weekend cruiser. It’s going to be a downright monster, by the sounds of things.
“I’m working towards 500+ whp with a goal of hitting 200 mph in the standing mile. This is my second serious car build. My first was a 280Z modified with a turbo. The Datsun is scary fast due to its light weight, but it’s unstable at high speeds.”
Step one of this high powered Lexus SC400 build begins with the OP learning how to weld on the fly. And, of course, ordering up a large turbo and all the associated goodies. It’s rather refreshing to see the OP taking on a project like this himself, even if it does take a long time to figure out.
“Next up, making the manifolds. This took roughly 100-150 hours, partially because I was new to TIG and fabricating on this level. Partially because I checked fitment with every cut/tack. The system was very complicated. The two manifolds each have a wastegate in front of the crank pulley and merge into one turbo. The turbo dump goes under the passenger side manifold in a very tight space.”
The way things are turning out so far, it’s hard to tell he’s a rookie, however. And the fabrication just keeps going. The OP discovers the motor mounts are broken, so he fabs up a new set of those, too. Then he positions the intercooler using custom mounts. In the meantime, the turbo tubing is coming together nicely as well.
With everything buttoned together, it was time to test out this Lexus SC400 turbo setup on the dyno. But a slipping transmission doomed things from the start, resulting in a disappointing 266 hp outing. Thus, the OP found a replacement in a junkyard and proceeded to completely rebuild it. Months later, he was back on the rollers.
“Dyno round two, three months later. The torque converter was slipping on the dyno. Worried this might happen. I brought the wires for the lock up into the car and also made a switch that would lock the transmission in 3rd gear for the pull. We made pulls in 3rd with the locked converter to tune the car. In the end, I got 374 whp @12 psi which is ~470 crank if you’re generous. There is no room left for more. Adding boost or timing makes no extra power over this number. The small cams and poor factory head porting are the limiting factors now.”
At this point, many would just give up and live with that impressive result. But not the OP. Instead, he goes out and buys a new engine. In this case, a 1993 model with beefier internals. Unfortunately, a rusty crank and some other issues rendered it useless. But he soon found yet another engine, and this one turned out to be a gem.
A full rebuild on the third engine is currently underway, and we’re excited to see the results of all this hard work. Be sure and bookmark this incredible Lexus SC400 project by heading over here, and stay tuned as the OP works to achieve his lofty goals!
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