brociouz

iTrader: (65)

You know what would suck, if the rev limiter in neutral works only in the '09+ 2IS's, but an '06 IS tries and and his engine blows up. Fail.

chikoo

Yes. You can go through the gears IF you are pushing it. For example:
(edit: I see that you have explained this example in a lot more detail)

I start the car and shift to 'S'. Automatically the limit is '4'.
I use the '-' paddle to bring the upper limit down to '2'.
Now I floor the gas pedal and it will start moving in '1' and shift to '2' automatically at it's optimum point.
The engine is roaring and now getting near to red-line.
At this time I use the '+' paddle to change the upper limit to '3'.
Guess what happens? The transmission will shift to '3'.
Again as you approach the red-line, up the limit to '4' and it will shift to '4'.
So on and so forth for '5' and '6'.

And if for any reason, you had to slow down, the transmission will down shift to the optimum gear for you. So what is wrong with this implementation? Nothing as far as a DD goes that wants to hold gears and experience red-line revving without hurting the power train.

Kurtz

iTrader: (1)

Well, there's the fact that if you just left it in D you'd get much faster shifts, so all you're doing with the paddles is slowing the car down...

Because by the time the human driving the car realizes he's actually near the rev limiter and moves the paddle, he's already bouncing off it.

If you paddle up soon enough that you don't hit the rev limiter then all you've done is duplicated what the car would've done if you'd left it in D, while doing a lot more work to get there.


This is why people who use the paddles at the drag strip get bad results.

If trying to "push" the car then let the computer do the shifting with the full range of gears available to it. It's much faster and more consistent than the human driving it is.

If you really want to be able to shift the car directly with paddles then trade up to an IS-F. You're only fooling yourself thinking you're doing it in a 250/350.

chikoo

LOL...see my response in the other thread Kurtz...

lamar411

really informative post, never really understood it.

EV02is

iTrader: (1)

this and the stupid rattles on my dash are the only things i truly HATE about this car.

chikoo

What? the post or the paddles?

metalgear

Very interesting! Thanks for sharing the info!

syzygy

No, you can't. You've precisely described the circumstances during which you can't control when the car shifts.

I already provided an example (at WOT) in one of my previous posts in this thread, but I'll walk through your example and explain where you're wrong -

Start the car, put it into S mode, the default is S "4". No problem there. Use the - paddle to set the limiting gear to "2". Fine.

Go WOT from a stop, you'll go through 1st gear (through 40 MPH), then (while having the pedal mashed down at WOT) you will go through 2nd gear from 40 MPH to 60 MPH.

Here's where you are wrong. You don't have control over when the car will shift into 3rd gear while at WOT. You don't.

If you were to press the "+" paddle while going WOT at, say, 45 MPH (you are still in 2nd gear @ 45 MPH before you fiddle with the paddles) the car will not shift into 3rd. The car will still shift to 3rd gear at 60 MPH.

If you were to press the "+" paddle at 55 MPH while going WOT, the car won't shift into 3rd.

If you were to press the "+" paddle at 56 MPH while going WOT, the car won't shift into 3rd.

If you were to press the "+" paddle at 57 MPH while going WOT, the car won't shift into 3rd.

Do you see why you have no control over when the car shifts? The car will shift into 3rd (while you are going WOT) at 60 MPH regardless of when you set the limiting gear to 3.

When you pressed the + paddle to set the limiting gear to 3 near redline, you didn't force the car into 3rd gear. You simply set the limiting gear to 3 before the car reached the maximum MPH limit of 2nd gear (60 MPH) and then the automatic transmission, as per its usual shift logic, shifted into 3rd gear. You are simply given the illusion that you had any sort of control.

If you just happened to be too late in setting the limiting gear to "3" (or higher) before the car reached the maximum MPH allowed at 2nd gear (60 MPH), you'd bounce off the rev limiter and would significantly slow yourself down.

That's precisely why there's no point in waiting till your near redline to press the + paddle.


Let's go through another hypothetical example -

Let's say you are cruising along (no acceleration) at 40 MPH with the limiting gear set to "2". You are just cruising, you aren't going WOT. While cruising, what happens when you press the + paddle? You've set the limiting gear to 3.

Now, what will the car do almost immediately? The car will shift into 3rd gear as per its usual shift logic. Its shift logic forces the car to go into higher gears as soon as possible during cruising in an effort to save gas.

If you were to do this in real time, you'd see the car go into "3rd gear" almost as soon as you pressed the + paddle, giving the illusion that you had some direct control over putting the car into 3rd gear. You didn't. You never have direct control over what gear the car can be in when wanting to put the car into higher gears. You only sometimes have indirect control (i.e. where you're cruising in S2 at 40 MPH, the transmission's shift logic wants to put the car into the highest gear possible ideally, therefore knowing this you can indirectly coax the transmission into 3rd gear by pressing the + paddle).

When you're going WOT, you never have (even "indirect") control in terms of putting your car into higher gears. Never. The car will shift at optimum shift point X regardless of when you press the + paddle.

chikoo

I see that you did not read my post properly.

You are focused on speed, I on the other hand, rightfully so, am focused on the tach.
Goes to to say that you may not have much experience driving stick shifts if your shifting methods are solely based upon speed.

Kurtz

iTrader: (1)

Which doesn't change a single thing he said... since you are always at the same reading on the tach for a given speed in a given gear at WOT.

Either way you're incapable of directly shifting the car. Ever.



And you must not have much experience driving anything if you don't understand that your speed and rpm are directly related in every gear. At X mph in Y gear you will always be at Z rpm.

Here's a nice calculator where you can do the math yourself.
http://www.csgnetwork.com/rpmcalc.html

(and pretty much the first lesson I learned in how to properly drive a manual in normal driving (the DD you discuss) was to ignore the tach and shift by feel and sound... which, again, is not possible with the paddles because they are not shifters)

syzygy

If it helps, replace the parts where I said "60 MPH at WOT" with "6800 RPM at WOT."

And replace "57 MPH, 56 MPH, 55 MPH, etc." with "6700 RPM, 6600 RPM, 6500 RPM, etc."

I made those numbers up (that is, I don't know if it's actually 6800 RPM) but you only need the relative numbers to understand the point.

It's not necessary to make a distinction between tach reading and MPH reading when you're going WOT. I apologize if I didn't make that clear. I merely assumed that most people here knew enough about cars to know at least that.

If you have limited your car to 2nd gear (S2) and you go WOT starting at 40 MPH, while going WOT if you press the + paddle at 5500 RPM (i.e. well below the optimal shift point for WOT through 2nd) your car will not shift into 3rd gear. That is just a fact.

I can't possibly dumb this down any more than I already have, and I didn't find your response to be useful or clarifying.

chikoo

I definitely agree with you on this....but given the lexus engine bay is so much sound proof and NVH transmissions from engine to cabin nearing zero, the next best thing is the tach.

Again, get an IS250 and try out what I said. I know and understand your point of this not being a true shifter, but fail to understand how you do not understand my viewpoint. To give an example, it is like wisting the powertrain's arm to shift by keeping it in high rpm where it will shift whenever I want to shift because at that time it is in the best power band and doesn't really care.
Now that is not going to give you a better 0-60, and in addition make you look like a reckless driver going on speeds that are unsafe on the streets.

lobuxracer

iTrader: (2)

He doesn't fail to understand your viewpoint. Your description of what is happening is wrong. You can't tell the transmission when to upshift, you can ONLY force it to downshift, and even that you can't directly control.

I played with S mode very briefly on my 350 and figured out I wanted an IS F because I want direct control, not indirect control. Believe it or not, the F also has an S mode available just by pulling on the paddles with the gear lever in D. I've never used it. I only know it is there because I read about it. I ALWAYS pull the gear lever to M if I want to shift myself.

FWIW - to the OP - no, you did not hurt your engine. The rev limiter saved it any damage. Yes, the rev limiter works in neutral and every other gear including Park. Saying the rev limiter is "useless" is foolish at best. Clearly the poster has never over-revved an engine and made a pretty hole in the side of the block. Luckily for the Gran Turismo crowd, this is now impossible in a modern car. It was not always so.

freeflight

Thanks for explaining the gear limiters. Why do you say the car will shift into 3rd gear exactly at 60MPH ?

My impression was the transmission shifts to 4th gear before car reach 60MPH, I will verify this in S mode.