Deception

iTrader: (1)

i know some people had told me that it is bad to downshift. they say dont neutral drop the trans and stuff. is it bad for the trans?

GSteg

iTrader: (15)

I'm assuming you mean shifting while the car is still in motion? It's not 'bad', but it does put stress on your drivetrain, especially if you're downshifting at a high RPM. Our transmissions are electronically controlled. If you're at a high RPM and decided to just throw the gear down to 1st, your car will probably not shift into that gear.

Deception

iTrader: (1)

well i mean like at a stop and shift it into L which i assume it is first gear. usually my friends tell me its bad for the trans because it will make the trans not shift into gear anymore

GSteg

iTrader: (15)

That's fine. When you're at a stop, putting the lever in L would be equivalent to putting it in Drive. The numbers L, 2, 3, etc just means it's the highest gear the tranny will go into. Put the lever in 3, and the car will still start out in 1st gear, and end in 3rd gear. Throw it in 2 and the car will still start in 1st. Our tranny is electronically controlled and it will operate in whichever gear it's comfortable with.

Solo_D33A

I never really though it matters if I downshift, I mean people downshift in manual cars anyways street or track. Strain isn't that much I think as there's more strain on acceleration and braking...

On acceleration, the engine's putting strain on gears and drivetrain then to the wheels.
On braking, the brakes put strain on the wheels then drivetrain, and some also pulling the engine.
On engine braking, the engine's putting strain on gears and drivetrain then to the wheels, only in reverse order of accel.

Only thing I might be worried is the torque converter because I didn't have much knowledge of it.

That's what I think...

cliffud

iTrader: (3)

hmm. i downshift if i have to slow down quickly for a turn but i only go down to maybe 3, never 2 or L. i hope it's not bad.

what do you guys think about putting the car into neutral when going 90 on the freeway to see how far you'll roll w/o gassing it?

lol

GSteg

iTrader: (15)

Unlike a manual transmission, we can't revmatch while downshifting. Downshifting while you're revving high will send a sudden jolt to the engine, forcing it to rev any higher. Then again, anytime you're doing anything at a higher RPM will wear out your car faster, regardless of it being auto or manual

GSteg

iTrader: (15)

It shouldn't be too bad if you go down to 3rd gear. I tend to downshift into 2nd gear sometimes Putting the lever to N while cruising at 90mph? You can do that. Not sure if it's a good idea to put it back into D while you're still at 90mph though. I wouldn't want to find out

Solo_D33A

Well, we can't revmatch because our tranny's old tranny, new ones like the BMW's does revmtach.

... if I remembers putting to D in high speed just put it back to which ever gear (5th normally when you're at 5th gear speeds) it's supposed to be.

Also, yes I'd revmetch, but to those that doesn't revmatch their manuals (I've known many people that does this because they're not as skilled) it's worse than our auto downshifting.

Another thing, auto trannies (not the DSGs though) some how when they downshift, the rev goes up slowly unlike if you downshift in a manual without revmatch and releasing the clutch quick... So in our case, our tranny doesn't send a "sudden" jolt, but a slow drag to the engine...

sometimes I wish we can get CVT... wonder why CVT never got popular.... (other than it can't stand that much power as I've heard....

swat1727

iTrader: (2)

y not use ur e-shift?

ShaneC

i believe the car downshifts on its own under heavy braking. so i dont think its bad to downshift with the shifter unless your downshifting it too mych to where the rpm is too high. that will just be adding more stress on parts. just my 2 cents

Solo_D33A

but when the ECU thinks it'll be too much rpm after you downshift, it wont let you, I've tried it, on e-shift, it'll just beep like when you use e shift to lower to 2 when the engine's cold. on the snake shift, it just simply doesn't downshift to that gear.

3UZFTE

Solo, i think your just talking. Agreed, the transmissions are electronically controlled, ive agreed with about 75% of the stuff you said, how do the brakes put strain on the engine? How is the drivetrain or gears "strained" by acceleration or deceleration? CVTs suck for performance, because you want gear ratios when you are running hard, you do not want the computer to control the ratio every second, hense the name Continously Variable Transmission. How can we "revmach" with an auto transmission? As soon as the trans is shifted, the lower gear with slow the rpms down. Unlike in a manual, you can press the clutch, to seperate the trans and engine, to increase the rpms enough to stop the trans from bogging down, when the gears are shifted, so that the engine does not have to drop rpms to make the shift or accelerate in the next gear. It is not bad to use the difference positions on the shifter, it is bad however to red line you vehicle, or do go from 5th gear to 3rd, and watch your rpms go from 2,000rpm to 6,500 is a split second, When i'm getting off the free way, i ALWAYS kick it into 4th, then 3rd, but never 2nd or Low, because the gear ratio isn't high enough for me to get the light braking i want, i was don't come flying off the freeway to land in 2nd gear, and be at 6,000rpm. Starting in L is the same as starting in D, you are just simply locking out the next gear or gears.

Solo_D33A

I guess putting stress is more proper, but anyways... as I've said already on the post about how is strain(stress) applied...
"On acceleration, the engine's putting strain on gears and drivetrain then to the wheels.
On braking, the brakes put strain on the wheels then drivetrain, and some also pulling the engine.
On engine braking, the engine's putting strain on gears and drivetrain then to the wheels, only in reverse order of accel."

All in all, they won't usually get "strained/stressed out", you know when it is because you'll most likely be breaking one thing or another...

Here's a more in depth if you don't already know how the stress is applied, I may be wrong (I am not a mechanic nor did I ever studied anything about mechanics, so my knowledge may be limited to what I've read or experienced), but as far as I know, this is how it goes.

On either accel or deccel(engine braking), all the driveshafts, diffs, gears, torque converter have torque being applied by the either the engine trying to spin faster or engine trying to stop the spin. Any form of torque applied is a strain of some sort, why they don't break is due to how hard they are made intended to be used.

Then the brakes put strain in all that including the engine because when you put the brakes on (assuming you are applying more braking power on the brakes than the engine's basic rotating power itself, ie braking that made the engine to drop rpm faster than it would normally), they becomes the same as how you engine brake, trying to stop the rotating force. Which in this case, the engine's also rotating, but it'll take a certain time for it to stop, while braking you may shorten that time, how? by pulling the engine to a stop.

Yes, I know the basics of a cvt, but if computer can optimize the ratio set for the particular speed for maximum power, why not?

And as it seems on wikipedia(not the best way of finding reputable info,I know, but it's fastest and easiest), it's now capable of high torques as well by the use of some advanced lubricants....
http://en.wikipedia.org/wiki/Continu...e_transmission

I guess I left out about the revmatch statement upstairs that I revmatch/heel toe/etc in my old Talon, which is a 5spd.
"Also, yes I'd revmatch, but to those that doesn't revmatch their manuals (I've known many people that does this because they're not as skilled) it's worse than our auto downshifting." That, is about me comparing my manual driving to our auto tranny.

Is that understandable or do I have to rewrite
If there's points that I'm wrong, sorry but as I've said my knowledge is limited and you can learn something new everyday so, correct me if there's anything.

JeffTsai

iTrader: (1)

The way I drive my car...some of you guys would be shocked that it still holds up

And yes you can revmatch on this transmission. You just have to do it manually like in a manual car. It's not like the new cars that will blip the throttle automaticall for you. I have a turbo on my car and in my testing...letting the auto trans downshift and stall up to build boost is much more effective than revving up then downshifting.

I'll try to get some videos when I get a chance.