AT not rev matching?

[Bergen23]

Tried searching for this and couldn't really find anything. Apologies in advance for anything that isn't proper terminology, learning as I go along here.

So, I understand the AT rev matches on downshifts. Coming from driving a manual, I used to downshift quite often when I would come to a stop or slow down. Normally, I get the nice throttle blip when I pull the paddle to downshift. I've noticed that after driving for a while (today I was driving about an hour and a half, and this happened around the hour mark) the car doesn't really rev match and it becomes sluggish when down shifting. After playing around with different combinations of driving modes (sport, sport vsc, track off, in D and in M) nothing really changed for me.

Anyone have a solution for this?

[N1rve]

Originally Posted by Bergen23

Tried searching for this and couldn't really find anything. Apologies in advance for anything that isn't proper terminology, learning as I go along here.

So, I understand the AT rev matches on downshifts. Coming from driving a manual, I used to downshift quite often when I would come to a stop or slow down. Normally, I get the nice throttle blip when I pull the paddle to downshift. I've noticed that after driving for a while (today I was driving about an hour and a half, and this happened around the hour mark) the car doesn't really rev match and it becomes sluggish when down shifting. After playing around with different combinations of driving modes (sport, sport vsc, track off, in D and in M) nothing really changed for me.

Anyone have a solution for this?

What RPM and gear are you currently in when you do this?

[Bergen23]

Originally Posted by N1rve

What RPM and gear are you currently in when you do this?

Been through the range from 6 down to 1. RPMs between 2k to 5k. What happens is, when I pull the paddle, the RPM drops down, the engine/trans hesitate, then it downshifts without the cool throttle blip.

[navanodd]

Weird. I've noticed similar behavior, but only when the trans is cold and leaving the torque converter unlocked. Does it seem like your torque converter is locking?

[Bergen23]

Originally Posted by navanodd

Weird. I've noticed similar behavior, but only when the trans is cold and leaving the torque converter unlocked. Does it seem like your torque converter is locking?

I honestly don't know what that feels like. Best I can describe it is hesitation with a lazy downshift once the RPMs settle

[navanodd]

You can tell if your torque converter is unlocked by increasing/decreasing the throttle briefly and seeing if the engine RPMs change a bit without any corresponding change in speed.


The torque converter is a fluid coupling and acts sort of like a partially engaged clutch when not locked. When the torque converter is locked, there is no slipping and the entire drivetrain feels much more responsive. Normal operation (warmed up) for the FRS is for the torque converter to lock after the shift from 1st to 2nd. It only unlocks otherwise when slowing down at low engine speed.

[whataboutbob]

If the downshift is going to over rev the motor, it will queue it and make the shift when it is safe, otherwise it will make the shift very quickly after inputs. In full auto mode, if you hit the brakes really hard and slow the car down a lot, it'll do the cool blip down shift.

[feldy]

3 years come may and I have never seen this issue. As far as the que goes. I can actually plan my runs around it for autocross. For the times I need to get back into first that is. Other people who drive the car thats not used to it gets frustrated when they cant shift into first.

[Bergen23]

Originally Posted by whataboutbob

If the downshift is going to over rev the motor, it will queue it and make the shift when it is safe, otherwise it will make the shift very quickly after inputs. In full auto mode, if you hit the brakes really hard and slow the car down a lot, it'll do the cool blip down shift.

That's not the issue here. I'm not going to over rev. The engine just seems like its lazy and doesn't want to make a quick downshift.

[aa_chow]

I have experienced what you said twice, both times are longer spirited drives. It stops rev matching without throttle, but seems under throttle. Back to normal after restarting the car. Anyone else can chime in?

[Bergen23]

Originally Posted by aa_chow

I have experienced what you said twice, both times are longer spirited drives. It stops rev matching without throttle, but seems under throttle. Back to normal after restarting the car. Anyone else can chime in?

I've now found its correlated to cruise control. Verified in my own car, and a brand new 2016 on the dealers lot.

[redmoon]

I have also experienced the same thing with at times the downshifts don't rev match. Bergen23, can you explain your findings on how it is correlated to the cruise control and whether you have a solution. Thanks bud.

[aa_chow]

Originally Posted by Bergen23

I've now found its correlated to cruise control. Verified in my own car, and a brand new 2016 on the dealers lot.

Please explain!

[Bergen23]

No idea how it's correlated. But after around 400km driven this weekend on my car, I had zero rev matching issues, except after using cruise control at speeds over 80kmh. It's clear that this is an electronics problem and not mechanical.

Just glad that I found where the problem starts. I was planning on leaving my car at the dealers for the day, but they wanted me to raise my suspension and switch back to stock wheels and tires and I had zero desire on doing that, so I won't be finding the solution to this.