GX470GT

im used to having all my torque at lower rpms. The gs400/430 have max torque at 3400rpm, how can i obtain that in the ls400.

low stall torque converter?

selkirk

GS400 and LS400 have the same drivetrain, don't they?

Your cams will affect where the engine makes torque, but a low-end torque monster will "run out of breath" at high RPM.

3UZFTE

You probably are achieving max torque around than, but your in a heavier car so you might not feel like it. Forced induction or a rear end change are usually the cheapest solutions. What year is your LS4, it'll make a big difference if you have VVT-i, it'll help achieve that, which is what the GS4's have. Which actively changes your cam profile and compression ratio.

If were talking about the same years, than yes, they have the same drivetrain. Cams effect it, but aren't solely the issue. The biggest problem is displacement. No 4.0L will ever be a torque monster when it's hauling a 2-ton weight around. Like wise, you have to spin the 4.0L past 6,000rpm to make some mean horsepower just to move that amount of air.

RA40

iTrader: (6)

The Toyota cars pretty much have a similar power band some more obvious than others. The LS is like that, you don't feel it as much but you are moving.
I don't recall what year yours is, anyway, you are on the rise from 2,500 to drop off at ~5,000. At 3,500 it is in that mid-range of the power band. If you get the engine to breathe a bit better, you may nudge it simply there, anything else is going to be more $$.

PureDrifter

iTrader: (10)

the only significant difference between =year GS/LS is the intake, exhaust, and a little tiny bit on the ecu programming.

GX470GT

what i wanted to really say was that looking at the engine specs on both the gs400 and ls400 for the same year of 1999, the gs400 shows max torque at 3400rpm vs 4250 on the ls. same goes for HP the GS400 says max hp at 5600 vs 6100rpm on the ls.

So what im trying to say is that you will get pushed in your seat in the gs400 more than in the ls400 despite the 200lb weight difference. And yes the ls400 is fast when looking at the speed needle but its very smooth due to all the power in the top range of the rpms.

So what im trying to figure out is what would i need to change to mimic the GS400 Torque curve, is it cams, or ecu or torque converter, exhaust???

PureDrifter

iTrader: (10)

your information is incorrect.

http://www.lexus.com/contact/pdf/2000/2000GSspecs.pdf
http://www.lexus.com/contact/pdf/2000/2000LSspecs.pdf

both have HP/TQ peaks at 6000 and 4000 respectively.

rear end gearing, trans gear (iirc), and ECU settings are the same.

RA40

iTrader: (6)

That's pretty minimal real world.

Dropping down slightly on tire size will allow the engine to spin up. The usual exhaust stuffs...

GX470GT

thanks for correcting me puredrifter.

i was mislead by MSN Autos. Thats where i got my numbers from.

SRV1

iTrader: (2)

A 2UZ engine swap will give you a nice lower torque curve

James