CVT transmission: "braking" and "maximum braking"

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george.stark

New Member
#1
#1
So I'm looking at buying a 2017 Corolla LE.

As near as I can tell, with the LE I don't get the M setting w/ simulated gear-shifting control with the paddles

I drove one of these as a rental, and noticed the owner's manual has the following definitions for the transmission modes the showed up on the gear shift:



Do the "engine braking" and "maximum engine braking" represent lower gear ratios from the engine to the wheels, like the old 1 and 2 settings? I was hoping to use one of these for when I need an extra boost for merging into traffic.

Or am I better off just flooring the accelerator to get a downshift?
 
Chris Denton

Chris Denton

New Member
#2
#2
My 14 has an “S” and a “B”. When I want some extra umf, I use it like 1 & 2!
But what I’ve noticed, when in “B”, CVT simulates starting off in 2nd gear and will still “”shift”” but at a higher RPM.
(Double quotations around that lol)
If I start from “M”, it only lets the RPM’s go higher and still “”shifts”” itself, but not all the way up(?) If that makes sense. I haven’t been able to test this “M” out completely, I either run out of road or am already going 80.

I think these settings are more of a driver input than anything else. Like giving the CVT a direct command vs an ECU calculated command. The end result is the ECU is still in control!

IMO
 
R

Raymond Rexroad

New Member
#3
#3
It depends on what you mean, or want, by "an extra boost".

S and B do not change the full throttle up-shift RPMs. S and B do change the part-throttle shift points, and that is helpful.

In the same way, S and B change the decelerating shift points. When slowing down, the engine is held at higher engine speeds before shifting down.

In my experience, I haven't found the S mode very useful. The engine RPMs are not high enough during part throttle. For example, I'm holding a speed, and want to "punch it", and the engine must still shift down to get to peak power. I can be cruising along is S mode, and the engine is running in the low to mid 2000 RPM range, and I'd prefer it to be closer to 4000. In S mode, engine braking is there, but weak.

In B mode, the part-throttle RPMs are much higher, sometimes too high for my taste, but the engine braking is much better. I've seen part throttle RPMs close to 5000, which is too high, and I don't often run that high. When driving in stop and go traffic, or even "slow and go" traffic, I do find the B mode useful, because when I lift off of the accelerator, the car slows, sometimes enough so that I don't have to touch the brakes at all.

When I'm driving aggressively, I will use the B mode (I almost never use S mode). Overall, this mode holds the engine very close to where I'd want it - ready to immediately respond to full throttle (no shifting). Sometimes, when slowing for a turn or curve, I'll throw it into B mode, just so when I come out of the curve, the power I want will be ready - again, no shifting after I floor it coming out of the turn.

The other benefit of B mode - is that it is my chosen method to respond to seeing a law enforcement car (if I'm speeding) - and in cruise. B mode turns off cruise, and slows down the car quite quickly, with no brake lights. This is especially helpful when I just passed a state patrol on the side of the road.
 
G

george.stark

New Member
#4
#4
Raymond Rexroad said:
The other benefit of B mode - is that it is my chosen method to respond to seeing a law enforcement car (if I'm speeding) - and in cruise. B mode turns off cruise, and slows down the car quite quickly, with no brake lights. This is especially helpful when I just passed a state patrol on the side of the road.
Click to expand...
So you can be going e.g. 75 and you'll shift from D to B? This is OK for the transmission? I guess it's just more inputs, rather than an actual shift - but it takes getting used to the thought. My prior car was a 2002 Chevy Prism (Corolla with chevy name tags).

ETA: I went with a new 2018 Corolla LE.
 
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Raymond Rexroad

New Member
#5
#5
From the owner's manual:

Use engine braking (downshift) to maintain a safe speed when driving down a steep hill.

Also - this is no different than a CVT with the paddle (steering wheel) shifters. In that case, down shifting is expected, and again, in the owner's manual, indicates that downshifting is OK.
 
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Natron

New Member
#6
#6
Chris Denton said:
My 14 has an “S” and a “B”. When I want some extra umf, I use it like 1 & 2!
But what I’ve noticed, when in “B”, CVT simulates starting off in 2nd gear and will still “”shift”” but at a higher RPM.
(Double quotations around that lol)
If I start from “M”, it only lets the RPM’s go higher and still “”shifts”” itself, but not all the way up(?) If that makes sense. I haven’t been able to test this “M” out completely, I either run out of road or am already going 80.

I think these settings are more of a driver input than anything else. Like giving the CVT a direct command vs an ECU calculated command. The end result is the ECU is still in control!

IMO
Click to expand...
When you typed M, do you mean S?
 
N

Natron

New Member
#7
#7
Raymond Rexroad said:
The other benefit of B mode - is that it is my chosen method to respond to seeing a law enforcement car (if I'm speeding) - and in cruise. B mode turns off cruise, and slows down the car quite quickly, with no brake lights. This is especially helpful when I just passed a state patrol on the side of the road.
Click to expand...
Cops like seeing that you applied the breaks when seeing them, it shows you respect them, which is really important to them. They already know you were speeding, due to their radar.
 
G

george.stark

New Member
#8
#8
Raymond Rexroad said:
S and B do not change the full throttle up-shift RPMs.
Click to expand...
So it sounds like it's just as good to just floor the accelerator when merging onto the faster expressway.

Raymond Rexroad said:
S and B do change the part-throttle shift points, and that is helpful.
....When driving in stop and go traffic, or even "slow and go" traffic, I do find the B mode useful, because when I lift off of the accelerator, the car slows, sometimes enough so that I don't have to touch the brakes at all.
Click to expand...
This sounds useful. I have a lot of "slow and go" or stop and go. Which is better for stop and go or slow and go - engine braking or brake-braking? Certainly it's easier to not be constantly shifting back and forth between gas and brake pedals.

Engine braking requires higher RPM, implying more engine wear and possibly higher fuel consumption, though perhaps the ECU/CPU/? greatly cuts back the fuel in deceleration.

Trading engine wear for braking wear makes a lot of sense in a long steep downhill driving scenario (for which this is apparently intended, based on the owner manual), where the brakes could well overheat - does it make sense in the "slow and go" and stop and go situations?
 
G

george.stark

New Member
#10
#10
Natron said:
That's not how it works. The higher RPMs come from the wheels, not from fuel.
Click to expand...
I was having a flashback, thinking that the higher RPMs would suck more fuel into the engine. Like I'm trapped in the 1970s. :( Though I'm not sure that it worked that way even then.
Natron said:
It does not mean engine wear, but it does mean less brake wear.
Click to expand...
I'd have thought that anything that increased the RPM would increase wear on the engine.

I'll be driving into the city tomorrow so I'll get a chance to try out the B setting.
 
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