1998 sc400 to 350hp/400 tq
12-07-15, 10:53 AM
#1
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1998 sc400 to 350hp/400 tq
Hey whats up everyone, I am reaching out to get some assistance. This is what I am looking to try and do.
Goals: 350HP, 400 Tq.
I have a 1998 sc400, with the vvt-t 1uz motor. I would like to reach the hp and torque I stated above without changing the motor or turbo/supercharging. Is this possible and if so how can i achieve this?
Mods I currently have are BFI intake, supra auto tt lsd trd, process of getting bc coilovers, exhaust work done. Eliminated resenators, two high flow cats. I thinking about going true dual with straight pipe to 3" tip. Or should I go x pipe and get some mufflers?
Your kind words and knowledge are appreciated.
Goals: 350HP, 400 Tq.
I have a 1998 sc400, with the vvt-t 1uz motor. I would like to reach the hp and torque I stated above without changing the motor or turbo/supercharging. Is this possible and if so how can i achieve this?
Mods I currently have are BFI intake, supra auto tt lsd trd, process of getting bc coilovers, exhaust work done. Eliminated resenators, two high flow cats. I thinking about going true dual with straight pipe to 3" tip. Or should I go x pipe and get some mufflers?
Your kind words and knowledge are appreciated.
Last edited by jroy3221; 12-07-15 at 11:17 AM.
12-07-15, 02:22 PM
#2
Aside from nitrous, I think "no" is the answer to that. Without increasing displacement, compression, or incoming air pressure there's just not enough to be had by improving air flows, which is about all you've got if you're not doing any of the above.
You can spray as much fuel as you'd like and play with spark, but it'll only burn as much as it's got air to allow it to burn and it'll only suck in as much as it's got displacement to pull from. Once you've made the intake pretty non-restrictive there's not a whole lot more you can get out of efficiency. The bigger gains with intake and exhaust efficiency are seen when you start introducing forced air or higher displacements.
You might get more HP from working on increasing upper RPM breathing to increase the redline, but likely not what you're aiming for and certainly not torque.
Supercharging seems to be one of the easier ways to get extra HP out of these, though most of the kits seem to be for the pre vvt-i 1uz's. Shouldn't be that hard to convert the intake piping to the front mounted throttle body of the vvt-i engines. Though, I'm not sure how the vvt-i computers deal with forced air.
Be aware, though, at 400Lb/Ft you're getting in to the range that'll start putting a lot of strain on your transmission. I was looking for a thread I was reading about NOS in 1uz a while back (here or somewhere else), but couldn't find it just now: There was a guy putting 100-shots of nitrous in to (I think) a stock engine and trans and killed the transmission in something like 6 months, though I think that was pre-98 (which means pre vvt-i, so a lower base HP, and the 4 speed transmission, not sure if the 5 speed auto is stonger.) And he started killing the rings. Can't remember which went first, but I think it was the transmissions (yes, plural.)
What I'm getting at is, if you want to build that much higher power than stock you'll likely have to also replace quite a few parts in the drivetrain, either before or after.
You can spray as much fuel as you'd like and play with spark, but it'll only burn as much as it's got air to allow it to burn and it'll only suck in as much as it's got displacement to pull from. Once you've made the intake pretty non-restrictive there's not a whole lot more you can get out of efficiency. The bigger gains with intake and exhaust efficiency are seen when you start introducing forced air or higher displacements.
You might get more HP from working on increasing upper RPM breathing to increase the redline, but likely not what you're aiming for and certainly not torque.
Supercharging seems to be one of the easier ways to get extra HP out of these, though most of the kits seem to be for the pre vvt-i 1uz's. Shouldn't be that hard to convert the intake piping to the front mounted throttle body of the vvt-i engines. Though, I'm not sure how the vvt-i computers deal with forced air.
Be aware, though, at 400Lb/Ft you're getting in to the range that'll start putting a lot of strain on your transmission. I was looking for a thread I was reading about NOS in 1uz a while back (here or somewhere else), but couldn't find it just now: There was a guy putting 100-shots of nitrous in to (I think) a stock engine and trans and killed the transmission in something like 6 months, though I think that was pre-98 (which means pre vvt-i, so a lower base HP, and the 4 speed transmission, not sure if the 5 speed auto is stonger.) And he started killing the rings. Can't remember which went first, but I think it was the transmissions (yes, plural.)
What I'm getting at is, if you want to build that much higher power than stock you'll likely have to also replace quite a few parts in the drivetrain, either before or after.
12-07-15, 05:00 PM
#3
^^ The A650E would need to be built at a place like Level Ten to handle more power. They are rated for about 325hp from Toyota from the factory. Not sure what the torque rating is but the point being it's well within the original duty range for a 1UZ-FE VVT-i 290hp/300tq stock engine but probably not too far beyond that.
Matguy is right about how you'd have to get to those power figures, however. Also the rods are far less beefy on VVT-i 1UZ's than on the earlier 1UZ's. Good for the factory power output but not for forced induction.
Engine control I assume would need to be custom.
Lextreme used to cater to forced induction 1UZ builds but they don't appear to any longer. Though the parts themselves such as rods, pistons, bearings, etc. from various vendors are still made.
Australian tuning outfits have gone to the power levels you're wanting with early 1UZ Soarers using Eaton M-90 or M-112 blowers. Some people have done fully custom twin turbo builds. But 1UZ power a far less taken route so the expertise is not as widespread as with 1JZ's and 2JZ's.
Some folks who have hands on knowledge doing forced induction 1UZ's are on this forum, however. There are some build threads you can look up to get an idea of what you'd be getting into. Again, I think all of them involve the earlier non-VVT-i 1UZ's.
Matguy is right about how you'd have to get to those power figures, however. Also the rods are far less beefy on VVT-i 1UZ's than on the earlier 1UZ's. Good for the factory power output but not for forced induction.
Engine control I assume would need to be custom.
Lextreme used to cater to forced induction 1UZ builds but they don't appear to any longer. Though the parts themselves such as rods, pistons, bearings, etc. from various vendors are still made.
Australian tuning outfits have gone to the power levels you're wanting with early 1UZ Soarers using Eaton M-90 or M-112 blowers. Some people have done fully custom twin turbo builds. But 1UZ power a far less taken route so the expertise is not as widespread as with 1JZ's and 2JZ's.
Some folks who have hands on knowledge doing forced induction 1UZ's are on this forum, however. There are some build threads you can look up to get an idea of what you'd be getting into. Again, I think all of them involve the earlier non-VVT-i 1UZ's.
12-08-15, 07:28 PM
#4
Both the above 2 posters are correct. Before I sold my '99 I had basically the same mods as you (BFI, LSD, headers and full custom exhaust) and I only got 270hp to the wheels when it was dyno'd (stock 98+ SC's dyno only about 220-230hp to the wheels). That was a lot higher than any other 98+ SC I've seen on here, but still no where near the numbers you're talking about.
The ONLY suggestions I have that may increase available hp are;
1) Swapping in a manual transmission. This wont add horsepower, but it will decrease drivetrain power loss from around 15% through an auto transmission, to about 7-8% in a manual transmission. I was seriously looking in swapping in an R154, but that would have required a lot of custom fabrication and harness work.
2) A standalone engine management system. From my research I was told I could POSSIBLY expect another 20hp from this, and potentially better fuel economy. However this is big bucks ($1000 for the system itself, $1000 for installation, ~$2000 to have a pro tune it for you).
..in the end, as much as I loved the car, I decided it simply wasn't worth throwing the amount of money into it that would easily build a 500-600hp GTE. And now that its been gone for a little while, I am looking at newer cars altogether to satisfy my need for speed (ie an IS-F).
The ONLY suggestions I have that may increase available hp are;
1) Swapping in a manual transmission. This wont add horsepower, but it will decrease drivetrain power loss from around 15% through an auto transmission, to about 7-8% in a manual transmission. I was seriously looking in swapping in an R154, but that would have required a lot of custom fabrication and harness work.
2) A standalone engine management system. From my research I was told I could POSSIBLY expect another 20hp from this, and potentially better fuel economy. However this is big bucks ($1000 for the system itself, $1000 for installation, ~$2000 to have a pro tune it for you).
..in the end, as much as I loved the car, I decided it simply wasn't worth throwing the amount of money into it that would easily build a 500-600hp GTE. And now that its been gone for a little while, I am looking at newer cars altogether to satisfy my need for speed (ie an IS-F).
12-09-15, 01:26 PM
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KahnBB6, SCENFORCER Thanks also, good to hear it from more then one person. Keeping it clean looking and manual swap will have to do. I think I will be happy with the manual swap and if I can find some good mufflers. If not straight pipe with 3" tips will have to do.
12-10-15, 12:48 AM
#7
Sure, jroy. We don't want to deter you if you really want to do serious work to your 1UZ but it is a lot of investment to reach your goals with one. Huge contrast to what people are used to being able to do with GM LS engines. However the huge longevity of the 1UZ more than makes up for that I think.
For a manual swap you may want to look into an R154... but I'm inclined to defer you to the more common W58 (in good/rebuilt condition) if 230whp is all the 98-00 SC400 puts down stock.
scEnforcer, what do you think? If it's above 270whp with a manual swap then I'd think the R154 or an AR-5 or CD009 would be a better choice since they're all stronger and getting near 300whp on a regular basis is beginning to push the duty range of a W58, right? I'm not sure if 1UZ swap kits exist yet for the other two but I know the R154 has 1UZ support now just like the W58.
Also jroy, look up the 98 SC300 VVT-i threads written by Cartmill that detail how to remove and keep the shift solenoids inside your A650E Auto and keep them hooked up inside the car somewhere so that you can eliminate the CEL with your manual swap. (That is, unless you ever get into an aftermarket ECU)
For a manual swap you may want to look into an R154... but I'm inclined to defer you to the more common W58 (in good/rebuilt condition) if 230whp is all the 98-00 SC400 puts down stock.
scEnforcer, what do you think? If it's above 270whp with a manual swap then I'd think the R154 or an AR-5 or CD009 would be a better choice since they're all stronger and getting near 300whp on a regular basis is beginning to push the duty range of a W58, right? I'm not sure if 1UZ swap kits exist yet for the other two but I know the R154 has 1UZ support now just like the W58.
Also jroy, look up the 98 SC300 VVT-i threads written by Cartmill that detail how to remove and keep the shift solenoids inside your A650E Auto and keep them hooked up inside the car somewhere so that you can eliminate the CEL with your manual swap. (That is, unless you ever get into an aftermarket ECU)
Last edited by KahnBB6; 12-10-15 at 12:55 AM.
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12-10-15, 11:29 PM
#8
^ Yes, I would definitely stay away from the W58 as you approach the 300 wheel hp mark. These cars are pretty torquey with the V8 and that'll stress the W58 more than the horsepower itself.
But you're right, if you're willing to do the work to install an R154 then you should definitely consider one of the 6speed alternatives that you mentioned (especially the G35/350Z manual tranny). From what I've read they'll hold the horsepower and are great sporty transmissions
..I completely forgot about these options when I wrote my original reply!
But you're right, if you're willing to do the work to install an R154 then you should definitely consider one of the 6speed alternatives that you mentioned (especially the G35/350Z manual tranny). From what I've read they'll hold the horsepower and are great sporty transmissions
..I completely forgot about these options when I wrote my original reply!
12-12-15, 08:24 AM
#9
Pretty much $4-5k of head work, cams and ITB's and you'd get there. OR, $600 Nitrous kit.. Its a really small 4.0 V8, you don't have a lot of options. Even then, when the motor is maxed out and ready to explode, any BPU 1J/2J would still pass by you no problem.
There's a guy on Lextreme who is at 365hp on his 1UZ with a ton of custom internals. Here's his list of parts..
http://www.lextreme.com/forums/showp...84&postcount=7
There's a guy on Lextreme who is at 365hp on his 1UZ with a ton of custom internals. Here's his list of parts..
http://www.lextreme.com/forums/showp...84&postcount=7
12-14-15, 11:59 AM
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I most likely going to keep doing research on it as you guys suggested, and for now just keep it clean and get it running good. I been talking with my friend who said the KA24 trans is another option and is way cheaper so I am going to look into that to. I believe that is the s14 trans Thanks guys so much.
12-16-15, 01:50 PM
#11
I most likely going to keep doing research on it as you guys suggested, and for now just keep it clean and get it running good. I been talking with my friend who said the KA24 trans is another option and is way cheaper so I am going to look into that to. I believe that is the s14 trans Thanks guys so much.
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