CARB-Legal 2JZ-Swapping a Lexus SC300!!!
Built by Club Lexus mod KahnBB6 over six years, 1993 SC300 2JZ-swap proves meeting CARB regs can be done with time, patience.
One of the most classic engine swaps available to a Lexus is the famed Toyota 2JZ-GTE. Found in the U.S. under the hood of the Supra Turbo, the 3.0-liter turbo-six proved easy to build. It can handle more power than you can imagine and not buckle under pressure, too. No wonder it’s such a popular choice for pumping up a classic Lexus.
Now, building one to meet California’s CARB regulations is a journey unto itself. And we are all in for such a journey today. Back in 2015, current ClubLexus forum moderator KahnBB6 began his journey building a 2JZ-GTE for his ’93 SC300. The catch? It had to be CARB-legal.
CARB-Legal 2JZ Swap Means Playing on Hard Mode
“A big question might be ‘Why the heck would you go to this much trouble just to get a stock-ish 320hp engine at easily 4x the cost of going NA-T or swapping in an Aristo GTE engine?'” said Kahn. “The short version is: I really like this engine and I’ve wanted it in my car since day one. Well before that time, actually. Also, the fact that I’m not going to make 600whp out of the gate with restrictive cats doesn’t bother me. Lacking turbo(s) does. Since my car has to abide by Cali smog laws and I don’t have the patience to ‘find a way to get it to pass’ which is not a set in stone thing… I decided I wanted the most ridiculous swap I could attempt.”
A Journey of a Thousand Miles Begins with a Single Step
“The primary reason for this thread is to document what it takes to recreate a smog legal swap. Or at the very least, one that uses fully a reconditioned USDM twin-turbo system,” Kahn said. “Several folks have done it in the past, but there isn’t a single repository for all the tiny little things needed to do this– especially if passing smog is your goal.”
Kahn added this would be a long and complex journey, linked to his time, finances and floor space. Thus, the journey continues today. However, he also did something few threads attempt: an absurd amount of thoroughness for every aspect of the 2JZ swap. The thread itself is 73 pages long as of this post. On every page, you’ll find tons of info on how he made his 2JZ swap CARB-compliant. Not to mention giving his SC300 the turbo power it deserved.
Keeping CARB Legal Nearly Kills Build
One of the biggest hurdles in the 2JZ-GTE CARB build happened early on, involving the SC300’s stock 2JZ-GE, and — surprise — getting it to pass smog.
In a separate thread from November 2015, Kahn noticed his Lexus started rough (“as if timing is off or a spark plug has gone bad or coolant has gotten into the spark plug galley”). The ECU was suspected to be the main culprit, though it wasn’t the only part at play. Spark plugs, ECU coolant temp sensor, EGR Y manifold replacement, all addressed to finally pass the STAR Test Only smog test.
Unfortunately, this put the entire 2JZ-GTE CARB build in jeopardy. The SC300 at the time was Kahn’s only ride. He could either tap out and make the needed remaining repairs on the 2JZ-GE (involving a coolant leak into his oil), or park it and be without his Lexus for a long time. The latter, of course, would not have worked at all with his life in Los Angeles.
After taking a few days to calm down, Kahn was ready to do a more radical rebuild of his stock engine. Which, of course, meant using the CARB build parts on the rebuild. However, his fellow Club Lexus members convinced him not to sacrifice the build by just having him change his oil every 1,500 miles or so. As long as no overheating issues occurred, all would be well. Super Moderator gerrb put it best when he told Kahn (and everyone else) to “not spend money uselessly, rebuilding items that do not need to be rebuilt. Save that money for something else you need on your build.”
It appears he and his SC300 are finally closing in on the finish line as of mid-July 2021. If you’ve got a few hours, why not see how six years of work is paying off. It might help you in building a CARB-legal 2JZ-GTE swap of your own.
Photos: Club Lexus Forums/KahnBB6
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