1UZ VVT-I Swap- Pics included
cars pictured below
I bought a 99 SC400 with 80K with some minor damage
for a complete drive train swap to put into my 92 and just wanted before I delve into this - Anyone have any tips for pulling out the motor and transmission, personally I'd like to pull the engine and transmission out without separating them
- Anyone know of anything I wouldn't have to swap? Because As of now I planned on pulling everysingle harness from one car into the other....
- Any opinion on which rear end I should stick with or if can even retain the 3.92? or do I have no choice but to go with the 99 3.26 because of fitment and ECU troubles?
- Any tips in general for this swap? Main reason I'm doing this is because of the amount of good things I've heard about VVT-I 1UZ, everyone I hear who has them loves them, and I just can't help feeling that the early 1UZ's lack a little more push...but that thing is eventually going back in when I make the mistake of going turbo manual 1UZ and not JZ

Also anyone know if this diagram of the ECU's is accurate for the 92's and the 99's?
cars pictured below
I bought a 99 SC400 with 80K with some minor damage
for a complete drive train swap to put into my 92 and just wanted before I delve into this- Anyone have any tips for pulling out the motor and transmission, personally I'd like to pull the engine and transmission out without separating them
- Anyone know of anything I wouldn't have to swap? Because As of now I planned on pulling everysingle harness from one car into the other....
- Any opinion on which rear end I should stick with or if can even retain the 3.92? or do I have no choice but to go with the 99 3.26 because of fitment and ECU troubles?
- Any tips in general for this swap? Main reason I'm doing this is because of the amount of good things I've heard about VVT-I 1UZ, everyone I hear who has them loves them, and I just can't help feeling that the early 1UZ's lack a little more push...but that thing is eventually going back in when I make the mistake of going turbo manual 1UZ and not JZ

The wiring harnesses will swap over but your body plug pinouts will be ever so slightly different between an early OBD1 non-VVT and the OBD2 VVT cars.
Also, unless the 1999 SC400 truly has non-reversable body/frame damage it is actually rarer than all SC300 5-speeds except the 1997 SC300 5-speeds.
However, parts for parts the 1UZ-FE VVT-i is a great engine and the A650E 5-speed automatic is pretty good compared to the old 4-speed automatic. The only the a stock 1UZ VVT engine isn't good for is forced induction since it has significantly thinner rods and slightly weaker ring lands than the earlier non-vvt 1UZ's. But it's hard to find fault with a reliable V8 that puts out 290hp and 300 ft-lbs of torque from the factory. From experience I'll say that the same engine and transmission with a very similar final drive ratio will scoot a much heavier LS400 with ease.
I am not experienced or studied in swapping over a 1UZ so I'll have to step back from your main questions and let someone with more knowledge help there.
However regarding your final drive ratio the diff pumpkin (carrier) is exactly the same mounting for all 92-00 SC's, all 91-00 Soarers, the entire GS (and Aristo) series until the 2JZ-GE was discontinued and all MKIV Supras except the 6-speed M/T models. Same diff pumpkins, just some used a slightly larger or slightly smaller companion flange.
The 98-00 SC400 with the 3.26 rear preserves the best fuel economy at cruising speed but if you wanted to you could use a 3.76 (Supra TT Auto) or a 3.92 for shorter gearing and faster acceleration at the expense of some top speed and fuel economy. Your speedometer would be thrown off using the VVT-i instrument cluster. I'm not sure if the ECU will care or not. If it does... I would guess it might affect the transmission shift points. With manual swaps we use either a Yellr Yellowbox speedo corrector or a Dakota Digital for the same purpose. I am not sure where the SC400 VVT-i gets its speed signal from. (Also, with manual swaps into VVT-i SC's there is some more electrical work needed to make the ECU happy and turn off the CEL for transmission shift solenoids.... but you don't sound like you want a manual swap).
I do not recommend you go to all of the trouble necessary to swap an SC400 VVT-i's drivetrain and electronics into a 1992 SC400 shell if you are going to take it all out later on to go with a turbo manual setup. I also don't recommend a 1UZ turbo setup unless you have a lot of fabrication skills, hookups and a deep wallet. It's still better, less expensive and more supported to go with any JZ engine for turbocharging.
However the early non-VVT 1UZ's can accept Eaton M-112 roots superchargers with some Australian conversion parts, an upgraded fuel system and an aftermarket programmable ECU.
I would restore the 1999 SC400 if you like it. Unless there is truly severe body damage that cannot be overcome it will be easier to do that than swap everything into the 1992 SC400. It's also easier to go with a W58 manual transmission swap on the 1992 SC400 than it is to do the same on the 1999 SC400. Also with the '99 model's bigger power numbers it would make more sense to swap a stronger CD009, R154, AR5 or even a Tremec T56 with Grannas Racing conversion bits into that thing.
Now my being not as versed on swapping 1UZ's I maybe proven wrong on some of my points but I don't think I'm too far off.
Those are two nice looking cars though. *IF* that '99 SC400 can in fact be repaired I think that is the best route to go with its drivetrain.
Kahn has great points and info!!!
The wiring harnesses will swap over but your body plug pinouts will be ever so slightly different between an early OBD1 non-VVT and the OBD2 VVT cars.
Also, unless the 1999 SC400 truly has non-reversable body/frame damage it is actually rarer than all SC300 5-speeds except the 1997 SC300 5-speeds.
However, parts for parts the 1UZ-FE VVT-i is a great engine and the A650E 5-speed automatic is pretty good compared to the old 4-speed automatic. The only the a stock 1UZ VVT engine isn't good for is forced induction since it has significantly thinner rods and slightly weaker ring lands than the earlier non-vvt 1UZ's. But it's hard to find fault with a reliable V8 that puts out 290hp and 300 ft-lbs of torque from the factory. From experience I'll say that the same engine and transmission with a very similar final drive ratio will scoot a much heavier LS400 with ease.
I am not experienced or studied in swapping over a 1UZ so I'll have to step back from your main questions and let someone with more knowledge help there.
However regarding your final drive ratio the diff pumpkin (carrier) is exactly the same mounting for all 92-00 SC's, all 91-00 Soarers, the entire GS (and Aristo) series until the 2JZ-GE was discontinued and all MKIV Supras except the 6-speed M/T models. Same diff pumpkins, just some used a slightly larger or slightly smaller companion flange.
The 98-00 SC400 with the 3.26 rear preserves the best fuel economy at cruising speed but if you wanted to you could use a 3.76 (Supra TT Auto) or a 3.92 for shorter gearing and faster acceleration at the expense of some top speed and fuel economy. Your speedometer would be thrown off using the VVT-i instrument cluster. I'm not sure if the ECU will care or not. If it does... I would guess it might affect the transmission shift points. With manual swaps we use either a Yellr Yellowbox speedo corrector or a Dakota Digital for the same purpose. I am not sure where the SC400 VVT-i gets its speed signal from. (Also, with manual swaps into VVT-i SC's there is some more electrical work needed to make the ECU happy and turn off the CEL for transmission shift solenoids.... but you don't sound like you want a manual swap).
I do not recommend you go to all of the trouble necessary to swap an SC400 VVT-i's drivetrain and electronics into a 1992 SC400 shell if you are going to take it all out later on to go with a turbo manual setup. I also don't recommend a 1UZ turbo setup unless you have a lot of fabrication skills, hookups and a deep wallet. It's still better, less expensive and more supported to go with any JZ engine for turbocharging.
However the early non-VVT 1UZ's can accept Eaton M-112 roots superchargers with some Australian conversion parts, an upgraded fuel system and an aftermarket programmable ECU.
I would restore the 1999 SC400 if you like it. Unless there is truly severe body damage that cannot be overcome it will be easier to do that than swap everything into the 1992 SC400. It's also easier to go with a W58 manual transmission swap on the 1992 SC400 than it is to do the same on the 1999 SC400. Also with the '99 model's bigger power numbers it would make more sense to swap a stronger CD009, R154, AR5 or even a Tremec T56 with Grannas Racing conversion bits into that thing.
Now my being not as versed on swapping 1UZ's I maybe proven wrong on some of my points but I don't think I'm too far off.
Those are two nice looking cars though. *IF* that '99 SC400 can in fact be repaired I think that is the best route to go with its drivetrain.
Kahn has great points and info!!!
And interms the more or less far future plas for my black SC, I'd like to hopefully one when I've got the time and resources, go turbo 92 1UZ with a CD009 trans on a EMU masters standalone ECU, but that's really not happening anytime, but that's why I'm keeping my 92 1UZ with 99k on it
Sorry for only posting that photo, I only one of that angle yesterday on my laptop, but here's the reason I"m using the 99 as a parts car....
Last edited by BlueJ; Aug 12, 2017 at 12:00 PM.
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I'd get wiring diagrams and component locations for both cars and compare paying special attention to the sections under the dash. when you have the 99 harness out you can also compare wires at connectors. I suspect wiring at the fuse panel in the drivers kick panel will be a challenge.
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I'd get wiring diagrams and component locations for both cars and compare paying special attention to the sections under the dash. when you have the 99 harness out you can also compare wires at connectors. I suspect wiring at the fuse panel in the drivers kick panel will be a challenge.
Hey Blue J yes i have an older set of gold badges if you want to trade for those
I bought a 99 SC400 with 80K with some minor damage
for a complete drive train swap to put into my 92 and just wanted before I delve into this .Based my response off your comments about minor damage, lol.
The swap can be done just take you time since you will have both cars side by side.
Good luck with the project.
And I almsot forgot the HVAC system, that thing is ridicoulous... threw out my 92 HVAC system out of frustration from that thing, despite it working perfectly...kind of regret it now...
I'll post some photos tomorrow when I can






