SC400 (1uz-fe) stock HP capacity work sheet....

[jibbby]

I have compiled this information from reading up on several forums and here are my findings on the STOCK HP capacity for 1UZ-FE SC400/Soarer cars....

ENGINE (stock 1uz-fe)- Has been reported to hold 420whp on a dyno test, but many think the stock engine can hold as much as 500whp with a proper tune and fuel mix..(pistons and rods are the weakest points)

TRANSMISSION - Reports indicate the 400rwhp can be managed without trouble......A few have pushed over 350whp with no trouble also......One tranny was reported to fail from power at 320whp with (150,000 miles).....(2nd gear seems to be the most common breaking point)

STOCK FUEL INJECTORS - 370whp has been the reported max point before the engine starts running lean....

STOCK FUEL PUMP - 250-275whp is about it...That is my guess from my findings..

STOCK DRIVE SHAFT - Reports of up to 500whp has been managed on the stock driveshaft...Any more power it probably snaps...


If anyone has different info or something to ad please post....

 

[Peewee]

Are those figures with or without NOS?

I find it very hard to believe 370rwhp on stock injectors.

 

[Lextreme II]

TRANSMISSION - Reports of trannies giving out at the 320whp...Although a few have pushed to 350whp without trouble....I would say 320-350whp is pushing it...(2nd gear seems to be the most common breaking point)

I have broken two transmissions. Now I am running little more then 400 rwhp and the third transmission is holding up pretty good. So my assumption would be if you have a good working transmission with oil cooler should able to handle 450 rwhp.

 

[Maingear]

Would the weight of a vehicle have much of a bearing on tranny life? Could a 2200lbs/1000KG car get away with some trannys deemed otherwise unfit for 400HP?

 

[jibbby]

Pewee- No nos on this thread...Just stock...., reports on several posts from RDM and others reported the stock injectors running lean at that 370whp mark...If you know other wise please post away..

Lex - 450whp WOW!!!! RDM20.. Blew out his stock tranny at the 320whp mark with 150,000 miles on it. He said it lasted 3 days when the final tune was set..."In his words second gear gave up the ghost"...Like I said that is one isolated incident on the 1992 SC400....Based on my and your hp power output in our cars I agree with you atleast to the 400whp mark...450WHP may be pushing it, no? ...Not many threads report transimission failure so the facts are limited, and hard to find... Many seem to think the tranny is the weakest link in the 400 Lexus's...I did see a few running at 350whp mark with no troubles...

Thanks fellas this info is helpful..I am trying to find and complete the facts related this thread...

 

[jibbby]

Would the weight of a vehicle have much of a bearing on tranny life? Could a 2200lbs/1000KG car get away with some trannys deemed otherwise unfit for 400HP?

Weight and traction I believe would have a bearing on transmission life...Less weight less work and stain on all moving parts....

 

[Lextreme II]

I think the most important thing is the health of the transmission to start with. I remember my second transmission was crap when installed. So not too long after the installation the tranny gave up. With a good healthy transmission should able to handle 450 rwhp. Currently I am running 18 psi daily now. (addictive to boost) and I am sure i am in the early 400 rwhp easily. Good heathly tranny with oil cooler can handle mid 400 rwhp.

 

[jibbby]

I will edit the first post based on this info...Thanks for the news, and Lex I did not know you were running 400whp on your LS...Awesone!!!!!!...I would have thought 400whp maybe pushing it....

 

[MaxPower]

Unless the stock injectors are like 400cc/min, 370rwhp is impossible with the standard injectors, even at 100% duty cycle it is not gonna happen.

8 251cc/min injectors will support around 330fwhp at 85% duty cycle is possible, 100% DC around 380fwhp.

 

[jibbby]

Peewee and Maxpower - both of you seem to think the stock early model Lexus/Soarer fuel injectors cannot support 370rwhp....What do you think they will support before running lean....(1uz-fe stock fuel injectors)?

Like I said RDM20fan reported on his 1992 Lexus sc400 running lean at exactly the 370rwhp when building and tuning his car.......He had posted that info on a few of his threads...

 

[MaxPower]

with stock fuel pressure, the HP thats in my post. Up the fuel pressure to around 65psi and around 400fwhp at 85% DC. Its really as far as you want to take it with fuel pressure, but there is then a chance of them not closing and going static open which can = a new motor.

New Flow Rate = sqrt(new pressure/old pressure)*original flow rate

 

[jibbby]

I would like to ad to this thread by saying a stock Sc400 tranny running nos cannot handle much more then 300whp for the duration of two years...

I base that statement on my own experience...The 400Ft + pounds of torque created with the nos is what did in my stock Sc400 tranny over time woud be my guess as too why my tranny started failing. My 1992 SC400 tranny had 110,000 miles on it...

 

[mikeedmr]

Sound Performance does upgrades for A340E. They don't make any horsepower claims, which isn't reassuring, but people have successfully run them with 700+hp. Of course that's a turbo 6, not a torque monster v8.
http://www.supraforums.com/forum/showthread.php?t=291468

For those of you who with a lot of power that want to keep OD and avoid a GM 3 speed, this may be your ticket.

 

[jibbby]

I thought I would bring up this thread to update...

92-94 1uz-fe motor 500whp has been reported with stock internals..

95 and newer 1uz-fe motors failure has been reported to be around 320-350whp...(rod failure)...

If anyone cares to add to this go right ahead...

 

[cjsupra90]

Injectors should NEVER be quoted on Drive Wheel HP. They should only be quoted on flywheel HP. You can have two vehicals make the same identical flywheel HP but two totally different Drive Wheel HP numbers. Drive Wheel HP numbers are not an acturate measure of power being produced by the engine and injector sizes are directly related to the power that the motor is producing at a specific BSFC (Brake Specific Fuel Comsumption).

 

[jibbby]

Sup90 - This is an older thread that I created a while back to just get an idea of the power capacities of the early model LS400/SC400/soarer's - 1uz-fe's, transmissions, drive shaft, fuel injectors, etc... Nothing is solid and or carved in stone...

I was and am just trying to make people aware of the stock capabilties of the above mentioned components or atleast get close to those figures...It really helps when you start to plan to modify your car from stock and know exactly what each part is capable of handling..... That is all... I also don't think used transmissions should be rated either entirely by engine horsepower but rather both by whp and torque at the wheels....

Knowing what I know today I would still say all those above figures are close to reality on most of the used mechanical and moving parts as described above...

Again, anyone is free to jump in and say otherwise or add to it... Just back it up with some proof please....

 

[jibbby]

Supra90 your right on your comment - flywheel hp rating for stock injectors should be the call and not at the wheels..... I don't know the answer to that though, the only numbers I got where from sc400's at the wheels with the stock injectors... I know I've pushed my stock injectors into the mid 300whp numbers with nitrous on my SC400 and that is in addition to what reads I found also...

 

[cjsupra90]

Supra90 your right on your comment - flywheel hp rating for stock injectors should be the call and not at the wheels..... I don't know the answer to that though, the only numbers I got where from sc400's at the wheels with the stock injectors... I know I've pushed my stock injectors into the mid 300whp numbers with nitrous on my SC400 and that is in addition to what reads I found also...

Is your NOS a wet or dry system?

 

[jibbby]

Dry system.... You can see where the nitrous feed line is drilled and fitted right into the throttle body itself...

A wet system would have been my preference though but the dry system works just fine for me for what is going on 5 years now.......