Your explaination may be correct that we can only limit the highest gear ratio.

Ask you. I am currently running at 60 mph in 6th Gear. Blip the left "paddle" twice and the gear position is changed down to 4th gear. Isn't that I "command" the tranny to downshift? I think yes, I have a control over AUTO TRANS to DownShift.

Example No.2. By limiting the top gear to be Third. So, I am running 60mph in Third Gear. I decide to pull the right paddle once, my car will change to fourth instantly. . Isn't that I "command" the tranny to upshift? I think yes, I have a control over AUTO TRANS to UpShift.

Top Gear Limiter it is, I agree. But we still have some control of changing up and down somehow, somewhat.



Even with manual transmission, you will never have full control of changing gear anyway.

For example, you will never be able to change down to first gear when you are driving at 80 mph nor you can running at sixth gear when crawling at 10 mph.

 

Not really... you commanded the aiuto transmission to no longer use 5th and 6th gear. It's only because it happened to be IN one of those that a downshift happened.

That's why it can trick you into thinking you have any "direct' control, but you don't.

If you were in 4th gear at 60, which is certainly possible, and you did the exact same actions, you wouldn't be causing the transmission to do ANYTHING other than not shift into higher gears later on.

Hence you can't directly control the transmission shifts, you can only lock out higher gears.... SOME of the time that will result in the transmission automatically downshifting because it can't use a gear it was just in, but that's really, really, different from you ever commanding a speciifc shift.

Go test drive an IS-F in manual mode and you should realize the difference.




Maybe.

Maybe not.

If the gas is floored, and the rpms aren't pegged, it'll remain in 3rd and continue accelerating until it reachs the correct AUTOMATIC shift point for 4th at wide-open throttle.

That's the entire crux of the issue.

The car is always, always, always, a fully automatic transmission shifting entirely based on a few factors, many of which you have no control over, such as:


Allowed gear range
ECT-Mode
Throttle input/speed/rpms- the shift tables in the ECU basically.
Slope of the rode
Transmission temp
and more


again, no... you have control over what the max allowed gear is. That's the ONLY thing you have control over in the situation. If the other factors don't require a shift, even if you now are "allowing" a previously locked out gear to be used, it won't shift.

Unless it shifts 100% of the time to a speciifc gear you command (which is what M mode on an IS-F does- or the shifter on a manual transmission car does), you aren't commanding a shift. You're simply changing one of the several parameters that lets the automatic transmission determine when and how to shift.


SOME control? Sure... in the same way your control of the gas pedal has SOME control over shifts... floor it and, in most circumstances, the car downshifts... that doesn't mean your gas pedal is a real shifter though... neither are the paddles.


On an older car you certainly CAN do the first example, you'll just damage the car... newer cars lock this out to protect the vehicle from bad drivers... and you probably COULD do your second example but you'd likely stall the vehicle




really, I understand where you're coming from, the paddles can fool you into thinking you are "shifting" the car, but you aren't.

With a real shifter you can shift to "X' and the car goes into, and stays in, X. You can't do that with the paddles. The only thin you can ever do is set the max gear... and some of the time, in some circumstances, that can cause the automatic transmission to command up or down shifts- but it remains an AUTOMATIC transmission that will continue to freely, automatically, shift between all available gears you still allow it to use.... and that really is a difference.

 

how good is the transmission at holding gears? Say I come to a 90 degree bend and I want to lock out upper gears so that I'm within a good power band to pull through the corner, will it start doing stuff I'm not aware of?

 

It will remain a fully automatic transmission within whatever range of gears you allow it... behavior beyond that will depend on the ECT mode and the various inputs the ECU looks at to determine what gear to be in (shift maps, throttle and brake input, vehicle angle and speed, etc)

 

oh ok, so it is pretty similar to a MB auto then?

 

What a helpful thread. Always wanted to know what the paddle shifters really did since it felt like you couldn't control what gear it would be in since it just goes back up after a certain point.

 

Good for twisty and winding roads. Also racing on a roll situation