Gernby

iTrader: (1)

Lance,

I hope you weren't including me in the "you guys" statement. I'm still hoping you will answer my question about whether you did the pedal dance before the drive. I'm just curious if the pedal dance has any effect on brake assist. My other question / suggestion about using ECT-Snow hasn't been acknowledged either. I've done quite a bit of driving with ECT-Snow, and I know it makes the tranny follow the manual shifts MUCH better. As I'm sure you will remember, I was the one that suggested it be used for dyno testing long before anyone started actually doing it.

RocketGuy3

iTrader: (1)

It might be worth trying what someone suggested earlier, too... using the console shifter in S-mode... although it would probably still be worthless.

But it's still a little harsh to bash the car for being a porker. I mean it could use a little slim fast, but that is something that you absolutely had to know you were getting yourself into before you made the purchase. You can read the curb weight on any spec sheet; plus, Lexus or not, just about any car in this class is somewhere around the 3500-lb range.

lobuxracer

iTrader: (2)

Greg,

No, your comments have been constructive from my perspective. Direct answer: no, I did not do the pedal dance for this drive. I can't say whether braking is or is not affected by empirical observation, however, I can say Toyota's documentation does not support the idea that they will ever give full control over braking unless you do something to disable the skid control computer completely. Documentation also suggests fully disabling the skid control computer will result in a limp mode.

I did think about using the snow mode after I'd tried everything else. I too (on your suggestion) have tried using it and found it to be more controllable in some regards, and in all likelihood it would have been far easier to have the car respond the way I wanted on the drive I completed.

I know it sounds like heresy to those who haven't actually put a car around a track, but there are times when I'd really like to have the engine pull from down low while exiting a turn so I know I won't put more power to the wheels than I want. I've seen some amazingly fast guys use this at the track and I've found it saves me a tremendous amount of attention because I no longer have to focus on throttle position, only on course, heading, and traction.

I can mash the gas to the floor without being concerned about stepping sideways or even upsetting VSC because there just isn't enough torque at the wheel when I'm still in the turn. But just as you said in the other thread, I'm using the engine's torque curve to pull me through the turn and get into the sweet spot just as things straighten out, so I'm not shifting in the turn, I'm not focused on throttle position, and I am pulling away from the guy frantically trying to balance all five things at once because I've eliminated one of them completely. I also find this technique to be infinitely more controllable on a public road where I may need to make a major adjustment in a big hurry.

The IS350 makes this technique extremely difficult to execute, and I end up spending way more attention on controlling the transmission and brakes than I would if these systems were fully manual.

Gernby

iTrader: (1)

I'm glad to hear that the pedal dance wasn't performed before the drive, since that leaves hope for better results. I want to take my Hoosiers to the track as soon as I find new employment. I never considered the problem that brake assist would cause on the track until you mentioned it. That would totally destroy my experience since I'm a very late braker.

I understand the thing about downshifting in a corner very well. My S2000 had a nasty habit of "stepping out" when it hit VTEC in a corner (often), and I'm sure a downshift would be MUCH worse.

Koz

You said, "So here I am, braking to enter the turn - the gearbox is downshifting at the wrong time, the brakes are jamming themselves on harder than I wanted, and I'm trying to focus on line and traction. But I can't. I'm forced to focus on what the electronics are doing to the car because it isn't reasonably predictable. I really hate the nannies, every last one of them!"

If you are open-minded and can set aside that big ego you seem to have, you will see that I was ONLY trying to help with the difficulties you were experiencing. I too have spent many years road/street racing motorcycles and know how important juggling all the aspects of going fast are and enjoying the ride with all the nannies on the IS.

Before anyone can comfortably drive the IS350 in a spirited manner, they must first practice managing the nannies, regardless of how much experience they have. I find that the VSC is best left off, when driving aggressively, do to it being too intrusive when you what the car to change directions abruptly. On spirited back road twisties I've never had the VSC kick in.

As far as unnecessary downshifting from braking, I don't have that problem because when I'm driving in the spirited mode I am already downshifting manually with the floor selector as I am braking. When I enter a turn I have the revs up and I'm in the throttle slightly. The revs are nice and high so if I have to shed a little more speed I simply let off the throttle to let the engine drag me down. This also keeps the trans from downshifting if I have to ease into the brake a little. The brake assist will not trigger if you ease into it. I find that this method works pretty well. It also helps if you know the road well so you do not have to disrupt your line by being in the wrong gear or having to tap the brakes.

Koz

Tuxlex

Lance, I know exactly what you mean about the brake assist.
It has bothered me even during normal driving. On occasions
when I had to perform semi panc stops I completely hated it.
The brakes would grab and would not let up even after I tried
to gradualy release the brakes. This behavior would take away
from my driving enjoyment every day. I could never come to a
smooth stop and sometimes feared that I would even get rear
ended.

Then last week I switched to the TSB updated brake pads. These
new pads made a big difference. The brake assist is still evident
but not as severe as with the original pads. The brakes can be
modulated a lot better now.

You might want to give the new pads a try.

The other nannies and the fact that the IS will never feel the same
as a vehicle with a manual transnsmission are just the way it is,
but there are small improvements that can be made.

The voicing of your feelings has confirmed what I too have been
thinking I could get used to with time but have not been able to.
Since the transmission is fully electronicaly controlled, I've been
thinking about trying to separate it from the ECU's control. It
would be quite simple to come up with circuitry to manualy select
any gear at any time or RPM. What I don't know is how the ECU
will react when it notices that feedback sensors are not responding
as expected. I could live with a few codes being thrown but I do
not want to end up in some sort of limp mode. Let me know if you
are interested in working on a project of this sort.

Gernby

iTrader: (1)

How do you think it would be "quite simple" to come up with circuitry to manually select any gear at any time or RPM? Do you have any experience with the MANY ECUs that are in the IS? I wouldn't call myself an expert by any means, but I know for sure that it wouldn't be simple.

Tuxlex

If you take a look at the wiring diagram for the IS you will notice that
there are electric solenoids for every clutch/gear in the transmission.
All that needs to be done is to connect a few logic gates and power drivers
to these solenoids and supply them with 12 vots to select the various gears.
The logic gates would be controlled by both the shifter and the paddles.
The gear display is another story. That is controlled by the system
bus signals. But that is a secondary problem that is not essential to
the operation of the transmission.

Gernby

iTrader: (1)

You are making way too many assumptions about what needs to be done. I would include replaceing the engine's ECU to that list of things, since it would probably go into safe mode. The "system bus" that you refer to is CAN bus, and I have quite a bit of experience with it (see the piggy-back ECU link in my sig).

edwin907

This is a very interesting thread.

But simply put, use the 6 speed to good advantage by keeping the revs up in manual mode and it's not a bad handling car at all at eight tenths.
The brakes do require a delicate touch, and the PS2 tires I mounted really help the handling.

Doubt we'll ever see it but an ECU reflash to cure some of these issues (perhaps in performance mode?) is something I'd pay real money for.
Can't imagine the liability Lexus would have to consider if performance mode disabled the brake assist!

Gernby

iTrader: (1)

I totally understand why Toyota designed all the nannies to improve safety, but I don't understand why they didn't at least sell the rights to disable them to the aftermarket. I don't think they would have any liability in doing so.

edwin907

Excellent point!

In all the surveys I've filled out from Lexus the only point I've consistently commented on is the slow transmission shifting in manual mode. I can live with the rest, even the brake assist.

If I want to take handling to the limit, I just take the Ducati. Unfortunately, I've had 7 broken bones in my shoulder alone over the years to prove it!

Tuxlex

My feeling is that the shift lag is not due to the transmission, but rather
the response time of ECU as it first reduces engine power before a shift.

Gernby

iTrader: (1)

I don't think this thread is about shift lag at all.

IS_Mine

Because car enthusiasts don't buy Lexus cars.. they buy BMWs. :P

Okay I had to throw that in there, but perhaps.. Toyota doesn't think the enthusiast market for these cars is great enough to even consider releasing such things. Did other companies take these steps? I figured people would have to "hack" the ECU for any of those changes to occur. I don't know maybe the JDM market will surprise us and release such toys.

And our cars are still relatively new. I'm sure within a few years more toys will be available, especially with the IS-F release people will want to hype up their 350 as much as possible.