Can I run with ECT Power mode continuosly?
08-22-12, 04:28 PM
#302
Again, ETC and the nannies aren't the same thing... VSC/TC on/of is an independent setting from SNOW/PWR/NORMAL. You could leave them off and be in normal if you wished. (and I'd expect them to be off in any mode for any sort of performance related testing or driving, unless VSC/TC is specifically what you are testing)
ETC is put into snow mode for a dyno- specifically because it allows you to go WOT at a lower rpm in 4th without a downshift. This isn't especially useful or instructive for much relating to street use though.
ETC is put into snow mode for a dyno- specifically because it allows you to go WOT at a lower rpm in 4th without a downshift. This isn't especially useful or instructive for much relating to street use though.
>So,... if the nannies were left on, as you are well aware, the effect on the three modes is dare I say dramatic, or in more subdued tones,....noticeable, since launching a car for 0 to 60 or 1/4 times is key to low times. As for higher gears, you cannot totally remove the transmission mode or ETC from the equation or for that matter TRAC because they all interact!
>
That is why I asked if the data you referred to was with it engaged or disengaged. Problem is most folks would not be able to control wheel spin with VSC/TC off in PWR or normal modes in a 0-60 or 1/4 mile run!
VSC/TC behaves differently in each ETC mode,...the way it intercedes and the level of what is allowed and not allowed!
Do you get snow in NC?
08-22-12, 05:18 PM
#304
2) It was nothing to do with the topic... which if you check the thread title, is transmission modes.
The Topic is about ECT and PWR mode.
You are stuck with Throttle opening being the only thing that controls how the car shifts and You think it is the only aspect the ETC/ECT mode button controls, in the face of documentation that states other variables are involved. But since we do not know which other variables, you contend we should just ignore them.
Last edited by chikoo; 08-22-12 at 05:33 PM.
08-22-12, 05:48 PM
#305
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The only issue with your theory is that it is backwards. The "normal" operation of the car should generally be safer than the PWR operation, so, if it was about shift points and not hitting the rev limiter, the better common sense would reason that normal would generally be easier on the car than power... because it is not and higher RPM is seen in normal mode, it beckons that there is probably something else going on...
08-22-12, 06:07 PM
#306
The same could be said about your theory of it shifting faster, though. If the computer "knew" that in PWR mode the shift was only 50ms as opposed to 100ms (for example, not factual), it should also understand that it can wait to shift at a higher RPM. Why wouldn't the shift speed be programmed into the CPU? If in NORMAL mode, it takes 100ms to shift and initiates the shift at 6400 RPMs but completes the shift at 6600 RPMs (200 RPMs in 100ms), the computer should take this into account in PWR mode and not initiate the shift until 6500 RPMs resulting in an actual shift at 6600 RPMs (100 RPMs in 50ms) and increased performance. Why would they program it any other way if shift speed is controlled by the PWR button? I can't imagine the engineers wouldn't take this into consideration if they wanted maximum performance out of PWR mode and assuming it actually controlled shift speed. Or the more likely scenario is it has no effect on shift speed.
just an FYI, no need for the s when you say RPMs... RPM is already plural...
08-22-12, 06:11 PM
#307
No comment about how the data was recorded. 
I so don't want to spoil this discussion but,...don't forget our trans has a lockup clutch/converter controlled by normal and pwr programs in the ecu
All this talk about mashing the throttle further,...we may as well drive in snow mode,...then we could really mash the throttle further LOL. Totally misses the exercise.
I so don't want to spoil this discussion but,...don't forget our trans has a lockup clutch/converter controlled by normal and pwr programs in the ecu
All this talk about mashing the throttle further,...we may as well drive in snow mode,...then we could really mash the throttle further LOL. Totally misses the exercise.
08-22-12, 06:48 PM
#308
Ok guys I think I've got it! According to the Toyota technical training manual attached, the ECT PWR/Normal switch changes two things:
1. Shift points
2. TORQUE CONVERTER LOCK-UP
So I assume the PWR mode has a sooner lock-up, resulting in a quicker shift.
Note that torque converter lock-up does not necessarily mean more torque or better acceleration. In fact, you are losing the torque multiplying effect of the torque converter. Have you ever noticed when driving with the cruise control on, when you go up a hill, the rpm increases, but it is not downshifting (watch the gear display). Actually the first thing it does is unlock the torque converter.
1. Shift points
2. TORQUE CONVERTER LOCK-UP
So I assume the PWR mode has a sooner lock-up, resulting in a quicker shift.
Note that torque converter lock-up does not necessarily mean more torque or better acceleration. In fact, you are losing the torque multiplying effect of the torque converter. Have you ever noticed when driving with the cruise control on, when you go up a hill, the rpm increases, but it is not downshifting (watch the gear display). Actually the first thing it does is unlock the torque converter.
08-22-12, 07:00 PM
#309
Oh and the document also says this about retarding the ignition timing during shifts:
Engine Torque Control To prevent shifting shock on some models, the ignition timing is retarded temporarily during gear shifting in order to reduce the engine’s torque. The TCCS and ECT ECU monitors engine speed signals (Ne) and transmission output shaft speed (No. 2 speed sensor) then determines how much to retard the ignition timing based on shift pattern selection and throttle opening angle.
08-22-12, 07:23 PM
#310
You kinda did though....when you wrote-
Are most folks on totally crap tires or something? Because I've not had any problem with wheel spin with VSC/TC off and good summer performance tires...
All my throttle controller testing was done with VSC/TC off for example, in normal mode, with 0 tire spin... (On Hankook Ventus V12 tires)
At a track (1/4 mile) it'd be even easier since you've got VHT on the track helping out.... heck, at the track folks are usually figuring out how high they can brake torque their launch without spin, so launching from idle is easy with good traction and the nannies off.
Normally? A few days a year worth. Nobody drives in it though.
I've lived plenty of other places with lots of snow, but not with this car.
Not sure the relevance on that question.
Ok guys I think I've got it! According to the Toyota technical training manual attached, the ECT PWR/Normal switch changes two things:
1. Shift points
2. TORQUE CONVERTER LOCK-UP
So I assume the PWR mode has a sooner lock-up, resulting in a quicker shift.
Note that torque converter lock-up does not necessarily mean more torque or better acceleration. In fact, you are losing the torque multiplying effect of the torque converter. Have you ever noticed when driving with the cruise control on, when you go up a hill, the rpm increases, but it is not downshifting (watch the gear display). Actually the first thing it does is unlock the torque converter.
1. Shift points
2. TORQUE CONVERTER LOCK-UP
So I assume the PWR mode has a sooner lock-up, resulting in a quicker shift.
Note that torque converter lock-up does not necessarily mean more torque or better acceleration. In fact, you are losing the torque multiplying effect of the torque converter. Have you ever noticed when driving with the cruise control on, when you go up a hill, the rpm increases, but it is not downshifting (watch the gear display). Actually the first thing it does is unlock the torque converter.
While I appreciate the Toyota-sourced info... that document is pretty clearly written for a much older, less advanced, 4 speed automatic... not what comes in the 2IS.
We already know several features ETC-PWR has (the chart I've posted) that aren't mentioned at all there... so I don't think we can conclude that document is accurate or complete for the transmissions in the 2IS (as one example your document explicitly states it shifts significantly higher in PWR mode (10 mph higher in one example listed), when we have definite proof it doesn't do that in the 2IS.
It is not. Which is why I want you to see more than just that.
The Topic is about ECT and PWR mode.
You are stuck with Throttle opening being the only thing that controls how the car shifts
and You think it is the only aspect the ETC/ECT mode button controls, in the face of documentation that states other variables are involved.
The Topic is about ECT and PWR mode.
You are stuck with Throttle opening being the only thing that controls how the car shifts
and You think it is the only aspect the ETC/ECT mode button controls, in the face of documentation that states other variables are involved.
Well now you're just lying.
I've said exactly the opposite half a dozen times in the thread.
Hell, I was the first person in the thread to link to a chart from Lexus listing all the other things the ECT button controls apart from throttle.
From
Likewise I've said repeatedly in the last several days throttle opening is not the only thing controlling line pressure, but that it's the only one we are sure of does so and the driver can control
if you're going to ignore half of what I say, and blatantly make up the rest of what you claim I'm saying but didn't, I'm not sure much more productive can come of a discussion between us.
Last edited by Kurtz; 08-22-12 at 07:29 PM.
08-22-12, 08:00 PM
#312
It is generally accepted that one thing the button does is to firm up shifts. Because of this, the shifts happen faster. Back to normal mode, the shift takes longer.... What if the commanded shift point is the same no matter which mode you are in, but, the softer shift takes longer, which allows engine RPM to climb higher than it does in PWR mode...
I'm talking about a 0-60mph or 1/4 mile run, pedal to the floor, 100% WOT.
I think WOT shifts in both normal and PWR modes are set at the same point, a few hundred rpm below redline, say 6200.
However, in normal mode, the torque converter lock-up after the shift is not as soon. This allows the rpm to keep going a little higher. It also allows a tiny bit more torque multiplying effect while the torque converter is unlocked. Overall this results in better acceleration and better 0-60mph or 1/4 mile times.
In PWR mode, the torque converter lock-up is sooner. You will feel a firmer shift. The rpm will drop sooner because of this, and you will have less torque multiplying effect. But the side effect is 0-60mph or 1/4 mile times are a tiny bit slower.
My theory here is that the Lexus engineers did not focus in tuning the shift points that precisely to get the last tenths or hundredths in acceleration. They just arbitrarily put it at a few hundred rpm below redline at 6200, to allow a safety margin and for variance in the time taken to complete the shift, as we see here between normal and PWR modes.
08-22-12, 08:13 PM
#313
Ok this is my theory building on mitsuguy's.
I'm talking about a 0-60mph or 1/4 mile run, pedal to the floor, 100% WOT.
I think WOT shifts in both normal and PWR modes are set at the same point, a few hundred rpm below redline, say 6200.
However, in normal mode, the torque converter lock-up after the shift is not as soon. This allows the rpm to keep going a little higher. It also allows a tiny bit more torque multiplying effect while the torque converter is unlocked. Overall this results in better acceleration and better 0-60mph or 1/4 mile times.
In PWR mode, the torque converter lock-up is sooner. You will feel a firmer shift. The rpm will drop sooner because of this, and you will have less torque multiplying effect. But the side effect is 0-60mph or 1/4 mile times are a tiny bit slower.
My theory here is that the Lexus engineers did not focus in tuning the shift points that precisely to get the last tenths or hundredths in acceleration. They just arbitrarily put it at a few hundred rpm below redline at 6200, to allow a safety margin and for variance in the time taken to complete the shift, as we see here between normal and PWR modes.
I'm talking about a 0-60mph or 1/4 mile run, pedal to the floor, 100% WOT.
I think WOT shifts in both normal and PWR modes are set at the same point, a few hundred rpm below redline, say 6200.
However, in normal mode, the torque converter lock-up after the shift is not as soon. This allows the rpm to keep going a little higher. It also allows a tiny bit more torque multiplying effect while the torque converter is unlocked. Overall this results in better acceleration and better 0-60mph or 1/4 mile times.
In PWR mode, the torque converter lock-up is sooner. You will feel a firmer shift. The rpm will drop sooner because of this, and you will have less torque multiplying effect. But the side effect is 0-60mph or 1/4 mile times are a tiny bit slower.
My theory here is that the Lexus engineers did not focus in tuning the shift points that precisely to get the last tenths or hundredths in acceleration. They just arbitrarily put it at a few hundred rpm below redline at 6200, to allow a safety margin and for variance in the time taken to complete the shift, as we see here between normal and PWR modes.
Change the shift pattern.... which is generally assumed to be both how and when it shifts.
Because in your above example both modes are programmed with the same shifts, they just end up feeling/reacting differently due to the converter lockup difference.
I suppose it could only be changing the pattern for part-throttle driving though... and it gets us there without requiring any bump in transmission line pressure based on which ECT mode the car is in.
08-22-12, 08:35 PM
#314
While this sounds plausible it kind of directly contradicts one of the stated things ECT-PWR does.
Change the shift pattern.... which is generally assumed to be both how and when it shifts.
Because in your above example both modes are programmed with the same shifts, they just end up feeling/reacting differently due to the converter lockup difference.
I suppose it could only be changing the pattern for part-throttle driving though... and it gets us there without requiring any bump in transmission line pressure based on which ECT mode the car is in.
Change the shift pattern.... which is generally assumed to be both how and when it shifts.
Because in your above example both modes are programmed with the same shifts, they just end up feeling/reacting differently due to the converter lockup difference.
I suppose it could only be changing the pattern for part-throttle driving though... and it gets us there without requiring any bump in transmission line pressure based on which ECT mode the car is in.
Of course, at part throttle the shift points are totally different between normal and PWR modes. PWR holds gears much later, but not necessarily to redline. And normal mode can shift at redline when you floor it. So the full rpm range is available in both modes. Just the shift points change mostly depending on pedal position but also all those other factors.
08-22-12, 08:44 PM
#315
We already know several features ETC-PWR has (the chart I've posted) that aren't mentioned at all there... so I don't think we can conclude that document is accurate or complete for the transmissions in the 2IS (as one example your document explicitly states it shifts significantly higher in PWR mode (10 mph higher in one example listed), when we have definite proof it doesn't do that in the 2IS.
Driving Pattern Select Switch The pattern select switch is controlled by the driver to select the desired driving mode, either "Normal" or "Power." Based on the position of the switch, the ECT ECU selects the shift pattern and lock−up accordingly. The upshift in the power mode will occur later, at a higher speed depending on the throttle opening. For example, an upshift to third gear at 50% throttle will occur at about 37 mph in normal mode and about 47 mph in power mode.