Torque/Power
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Driver School Candidate
Joined: Jun 2019
Posts: 13
Likes: 1
From: Kansas
Torque/Power
Howdy everyone, I just recently acquired a 1994 SC400 and I’m looking for ways to improve low end torque and power. I don’t have piles of money that I can throw into the car right now so if you can give me some reasonably cheap options it would be much appreciated!
Welcome UZ1!
Honestly? There isn't much power adding on the cheap for a 1UZ-FE.
A cat back exhaust and/or resonator delete can improve sound. There is the "BFI" OEM intake air box mod that gives a very moderate increase in power (5hp or less than 10hp at most). There is also changing your A340E automatic transmission's stock torque convertor a more performance oriented one.
For more money definitely not on the cheap you can do:
--swapping the rear differential from the stock 3.92:1 diff you have to a 4.272:1 diff from an SC300 Automatic or 4.083 from an SC300 5-speed (some GS300's came with 4.08 as well and so did 97-98 Supra Non-Turbos). You can add a Yellr Yellowbox speedo corrector to make up for the gearing changes to your speedometer.
--An Eaton M-90 or M-112 supercharger install (see the Lextreme site for writeups on that)
--If keeping the V8 engine stock (ie: no supercharger or custom turbo setup) you can also convert to an SC300 or Supra MKIV Non-Turbo W58 5-speed manual transmission. That really livens up the driveline and makes it a much more engaging car.
--Then there is one more thing that can be done and that is to remove the 1UZ-FE and swap in a GM LS1 V8 with a custom wiring harness and aftermarket SC-to-LSx engine mounts or custom engine mounts.
Good luck!
Honestly? There isn't much power adding on the cheap for a 1UZ-FE.
A cat back exhaust and/or resonator delete can improve sound. There is the "BFI" OEM intake air box mod that gives a very moderate increase in power (5hp or less than 10hp at most). There is also changing your A340E automatic transmission's stock torque convertor a more performance oriented one.
For more money definitely not on the cheap you can do:
--swapping the rear differential from the stock 3.92:1 diff you have to a 4.272:1 diff from an SC300 Automatic or 4.083 from an SC300 5-speed (some GS300's came with 4.08 as well and so did 97-98 Supra Non-Turbos). You can add a Yellr Yellowbox speedo corrector to make up for the gearing changes to your speedometer.
--An Eaton M-90 or M-112 supercharger install (see the Lextreme site for writeups on that)
--If keeping the V8 engine stock (ie: no supercharger or custom turbo setup) you can also convert to an SC300 or Supra MKIV Non-Turbo W58 5-speed manual transmission. That really livens up the driveline and makes it a much more engaging car.
--Then there is one more thing that can be done and that is to remove the 1UZ-FE and swap in a GM LS1 V8 with a custom wiring harness and aftermarket SC-to-LSx engine mounts or custom engine mounts.
Good luck!
Thread Starter
Driver School Candidate
Joined: Jun 2019
Posts: 13
Likes: 1
From: Kansas
Differentials
Welcome UZ1!
Honestly? There isn't much power adding on the cheap for a 1UZ-FE.
A cat back exhaust and/or resonator delete can improve sound. There is the "BFI" OEM intake air box mod that gives a very moderate increase in power (5hp or less than 10hp at most). There is also changing your A340E automatic transmission's stock torque convertor a more performance oriented one.
For more money definitely not on the cheap you can do:
--swapping the rear differential from the stock 3.92:1 diff you have to a 4.272:1 diff from an SC300 Automatic or 4.083 from an SC300 5-speed (some GS300's came with 4.08 as well and so did 97-98 Supra Non-Turbos). You can add a Yellr Yellowbox speedo corrector to make up for the gearing changes to your speedometer.
--An Eaton M-90 or M-112 supercharger install (see the Lextreme site for writeups on that)
--If keeping the V8 engine stock (ie: no supercharger or custom turbo setup) you can also convert to an SC300 or Supra MKIV Non-Turbo W58 5-speed manual transmission. That really livens up the driveline and makes it a much more engaging car.
--Then there is one more thing that can be done and that is to remove the 1UZ-FE and swap in a GM LS1 V8 with a custom wiring harness and aftermarket SC-to-LSx engine mounts or custom engine mounts.
Good luck!
Honestly? There isn't much power adding on the cheap for a 1UZ-FE.
A cat back exhaust and/or resonator delete can improve sound. There is the "BFI" OEM intake air box mod that gives a very moderate increase in power (5hp or less than 10hp at most). There is also changing your A340E automatic transmission's stock torque convertor a more performance oriented one.
For more money definitely not on the cheap you can do:
--swapping the rear differential from the stock 3.92:1 diff you have to a 4.272:1 diff from an SC300 Automatic or 4.083 from an SC300 5-speed (some GS300's came with 4.08 as well and so did 97-98 Supra Non-Turbos). You can add a Yellr Yellowbox speedo corrector to make up for the gearing changes to your speedometer.
--An Eaton M-90 or M-112 supercharger install (see the Lextreme site for writeups on that)
--If keeping the V8 engine stock (ie: no supercharger or custom turbo setup) you can also convert to an SC300 or Supra MKIV Non-Turbo W58 5-speed manual transmission. That really livens up the driveline and makes it a much more engaging car.
--Then there is one more thing that can be done and that is to remove the 1UZ-FE and swap in a GM LS1 V8 with a custom wiring harness and aftermarket SC-to-LSx engine mounts or custom engine mounts.
Good luck!
Lexus Champion
Joined: Jan 2014
Posts: 2,089
Likes: 52
From: illinois
you can throw in a higher gear diff from an SC300, that will make it a lot quicker from a dig but your highway mileage will suffer. that's probably the absolute cheapest thing to do for a really noticeable effect.
^^ Exactly. Unlike with a Ford 302/5.0 or 351W or a GM LT1 or LS1/2/3 there really isn't a lot you can do out of the box for very little money to make the 250-260hp 1UZ-FE V8 power powerful or torquier. That's why even turbo and supercharger builds on the 1UZ V8's are somewhat involved and pricey right from the start and those are really the best options for adding more power to the 1UZ.... if someone is willing to spend the money and put in the time.
To be fair, all 2JZ engines don't really respond much to non-forced-induction power adding attempts either. But from the factory they are designed for boost even as non-turbo engines.
OldManTan is correct. You can find a full open diff from an SC300 Automatic (4.272:1) and swap that right in for an immediate bump from your 3.916:1 SC400 diff. But that will indeed make your highway fuel economy suffer a bit. Though it is a fun final drive ratio undoubtedly.
As I mentioned in my previous post you can correct the speedometer inaccuracy that will result by purchasing and installing a Yellr YellowBox V5 speedo corrector. They even make a plug and play harness for the SC/MKIV if you request it at the time of your order.
If you'll swap in a higher ratio diff it would also be a good time to install a 2-way clutch style LSD if you want to take the car drifting. Alternatively it is super rare to find one but there were 93-96 Supra Non-Turbo 4.27 Torsen LSD diffs and 97-98 Supra Non-Turbo 4.08 Torsen LSD diffs. Torsens, at least the very common T-1's, don't like shock loading but other than being rare they're a good LSD option for mild setups. And a stock 250hp 1UZ-FE SC400 would be right in that category.
The only other non engine modification that will make a big difference for an SC400 (other than the LS400 front brakes that all the SC's can benefit from) is a manual transmission conversion. That would totally change the car's character.
An SC300 W58, MKIV W58 or even an R154, AR-5 or what other common manual transmissions have aftermarket support in the form of already thought out and engineered swap kits, bellhousing adapters and clutch kits that fit the 1UZ engine.
To be fair, all 2JZ engines don't really respond much to non-forced-induction power adding attempts either. But from the factory they are designed for boost even as non-turbo engines.
OldManTan is correct. You can find a full open diff from an SC300 Automatic (4.272:1) and swap that right in for an immediate bump from your 3.916:1 SC400 diff. But that will indeed make your highway fuel economy suffer a bit. Though it is a fun final drive ratio undoubtedly.
As I mentioned in my previous post you can correct the speedometer inaccuracy that will result by purchasing and installing a Yellr YellowBox V5 speedo corrector. They even make a plug and play harness for the SC/MKIV if you request it at the time of your order.
If you'll swap in a higher ratio diff it would also be a good time to install a 2-way clutch style LSD if you want to take the car drifting. Alternatively it is super rare to find one but there were 93-96 Supra Non-Turbo 4.27 Torsen LSD diffs and 97-98 Supra Non-Turbo 4.08 Torsen LSD diffs. Torsens, at least the very common T-1's, don't like shock loading but other than being rare they're a good LSD option for mild setups. And a stock 250hp 1UZ-FE SC400 would be right in that category.
The only other non engine modification that will make a big difference for an SC400 (other than the LS400 front brakes that all the SC's can benefit from) is a manual transmission conversion. That would totally change the car's character.
An SC300 W58, MKIV W58 or even an R154, AR-5 or what other common manual transmissions have aftermarket support in the form of already thought out and engineered swap kits, bellhousing adapters and clutch kits that fit the 1UZ engine.
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