Rock-a-Lex

iTrader: (4)

What are the factors that prevent my car from shifting at or close to redline? I notice that my car consistantly (with power mode on or off - doesn't matter) shifts at around 5600rpm! I want my damn extra 500rpms in each gear dammit! lol What could cause this guys?

...sometimes this happens and only in some gears!

evil00017

I have wondered this to. Im not sure but I have a feeling it has to do with how the ecu learns your driving style. They say if you unhook your battery let the ecu reset and drive the car hard around for awhile it will be more responsive and shift closer to redline and what not. But if you drive the car everyday like I do you only drive like a jack@ss for like 10% of the time maybe less. So wouldnt that make the car learn that you dont drive fast for the majority of the time and switch back over to grandma mode and shift at 5600 rpm the majority of the time? I dunno if this is true but that has been my rationalization. I just hope someone will eventually break the ecu code or toyota releases it and then they can tweak us to be aggressive all the time and much more.. I heard a rumor cobb tuning was talking to toyota about buying the ecu codes for toyota. I assume that means lexus too.

HuyMan751

use e-shift with pwr mode. that'll help you get to redline

Rock-a-Lex

iTrader: (4)

...yeah, I realize this is an option earlier but it is a temporary solution to mask a perhaps underlying problem. Many stock GS4's on youtube are all hitting or coming damn near close to redline and WITHOUT being in "M" mode. I'd like to dig deeper into this.

JiBBeL

iTrader: (2)

Checked my 430 the other day after reading this thread, no problems for me getting over 6000 RPM before shifting.

ChampGS3

iTrader: (6)

Hey Rock, I feel your pain, I flatted the accel in my 98 GS4 the other day on an onramp and mine shifted right at 5600 also, also note the trans switch was in pwr mode.

Needless to say I was dissappointed. Not so much because the last 500 rpms prob only nets 10 more hp, but not having the car shift as often would be a benefit.

Also I believe landing at a higher rpm into 3rd or 4th gear would yield better acceleration. I am not one to switch to manual mode and do the whole eshift thing, seems kinda gimmicky and too much work. It would be nice to have a good 5spd manual from time to time but everyday the auto serves me best.

Anyone know how to get the car to shift at redline in full auto mode? Maybe my normal lazy driving style has truly grandma'd the ecu's maps of my driving profile?

JBrady

My 1999 LS400, same engine/trans as GS400, ranges between 5800 and 6200 on shifts. It is definitely the "adaptive" transmission as agressive driving over time will yeild the higher revs and vice versa.

It IS DEFINITELY an advantage to get the full rev range available. Short shifting is below peak power and reduces the power under the curve. It is also a BIG advantage to remain in the lowest gear for the longest time as the torque multiplication is a big factor in acceleration.

The MAIN reason for the red line of 6250 is the lightweight and weak connecting rods. With better rods a redline of 7000 would be very reasonable.

Here is a STOCK early 250hp 1uzfe from a Tokyo taxi, stock heads, cams, valves, springs... UNOPENED wrecker yard engine with the only mods being a racing intake manifold, racing headers, dry sump oil system and proper tuning.
Engine makes 307hp @ 6500rpm and 271tq @ 5000rpm. Notice the power curve is still respectable even at 7000rpm where it is making 280hp.

Our engines have MUCH better heads/ports with higher compression and more camshaft timing and lift. Address the intake and exhaust restrictions as well as the tuning and redline and our engines should top 350hp and probably get close to 400hp.