Racecarzz08

i dont know if anyone else does this other than me. but i noticed when in sport mode if your going a little faster than you expected and you downshift the car automatically kind of pulls back without you stepping on the break..and kinds of helps you if you need to make a quick stop from higher speeds. question is does anyone else do this? or does anyone know if this can mess up the tranny or do any harm? im not to familiar with CVTs

ambystom01

iTrader: (7)

No, it's not OK in a manual and it sure as hell isn't OK in a CVT.

xgangsthashytex

well this is my first time owening a car but i do that do but that's like the only way i know how to i have to down shift to go slower if not will ****ing get into accident cuz it picks up very slow catching up speed i dont know what amby talking about does she or him own a cvt?

Racecarzz08

^ no i dont think he ever has i just thinks hes known for being knowledgeable about cars..

imo i cant really see how you can compare a CVT to a MT when theyre 100% different since the CVT is just a belt what harm is downshifting doing to the tranny?

DJ Brett B

iTrader: (12)

Wear and tear on tranny components/clutch/CVT and even engine (since you will be downshifting into higher rpms) are definitely a lot more expensive and harder on your car than using the brakes to slow it down and replacing brake pads/rotors when they wear out. Think about it....

ambystom01

iTrader: (7)

^This, downshifting and using the engine/transmission to brake is harder on those components. Think it through logically, what force is used to slow the car? Friction. What does friction do? Produces heat. Would you rather replace your brake pads at 100$ a pop or your engine and transmission at several thousand a pop?

nunyas

iTrader: (2)

20+ years of driving manual transmissions, downshifting, and engine braking down LONG down hill straights to maintain constant speed without using brakes, and I have yet to have a engine or transmission blow out on me because of it...

That's just my experience...

I would not do it with a CVT though. I just don't trust a belt to be able to handle the forces in reverse...

evo_soul

Downshifting is safe, you will only encounter problems in situations where you transmission is overheating. The CVT is much more advanced than other transmissions. The Transmission controller and Engine ECU would work together to ensure that everything is all systems go during accelleration and deceleration.

expanding this idea further. there are very sensitive sensors that monitor any type of slippage or problems with the CVT belt. The transmission is a highly pressurized system just to operate, how it runs doesnt really add more stress. The ECU will not allow you to do anything that will harm it. This is why it doesnt allow you to even rev the engine above 3250 RPM.

The are further protections all the way thru your drivetrain that prevents high stress situations, etc. TQ converter and its engagement and disengagment. Downshift to your hearts content. But if your car tells you to slow down. pull over and let it idle. This happens is rare situations. But more likely if your engine is BOOSTED and you are running in D mod.

Your Engine is more likely to fail than your transmission, even your engine is pretty unlikely to frag itself with constant downshifting. Its a pretty bullet proof system in normal OEM spec. There are studies that say CVTs are more reliable.

Hope that helps

Bladed

It's safe to do it on the CVT. It won't let you downshift when it's bad for the car. There are parameters built into the CVT ecu that allow you to downshift safely. Try cruising at 60mph and downshifting as much as u can, it'll probably not go under 3rd gear. When its no longer safe or healthy to downshift it won't let you. The car will beep at you and stay in the current gear. I downshift all the time when passing a car or when slowing down for a stop sign or hill. No problems so far.

Edit: nvm, Evosoul beat me to it with a much better explanation lol

ambystom01

iTrader: (7)

There is a difference between staying in a lower gear to maintain a constant speed and using a downshift to slow the vehicle.

kalpakiotis

iTrader: (1)

physics would disagree with you. both situations you are dissipating energy through the transmission back into the engine.

meckert

iTrader: (11)

The bigger issue here is that you risk having your rear brakes lock up at downshift while breaking hard " to avoid and accident" and you loose directional control... just dont do it.

ambystom01

iTrader: (7)

Except in one situation you're actively using the clutch and transmission to slow the vehicle while in the other you're simply limiting the speed of the vehicle using the inertia of the system. Downshifting to slow down is hard on the drivetrain.

absolute

if ur going 50mph
and u want to slow down a bit shifting 1 gear down is fine
but if ur talking about serious engine braking...like down to second and skyrocketing ur rpms to slow ur car down...then yea ur an idoit =P

but i always downshift when im slowing down...like heel-toe braking..as long as ur rev matching u shud be fine

and yea on MT's if u put ur gear into netural and only use ur brakes on a downhill...if its a long downhill by the end of the hill and u really need to stop, ur brakes might over heat and actually malfunction....i was in hong kong last year....an accident like that happened to a small van 16 seater van....driver put it in neutral for a LONG stretch of downhill....and by the end tehre was a turn where he had to brake...his brakes were over heated and he slammed the side of the bus vs a wall and killed 5 people onboard

Webman

So, what you're saying is, slowing forces is hard on the drivetrain, but acceleration forces aren't? I'm pretty sure any forces put on the drivetrain through slowing, are much lesser than through acceleration.