RDXguy

I am a bit surprised to find that when using cruise control and going down a hill, the car does not brake to keep the selected speed. The car just speeds up due to gravity. I presume all of your RDXs act similarly?

My 2011 BMW 335i did apply the brakes to maintain the selected speed.

DWG

The RDX does not apply the brakes.

https://acurazine.com/forums/third-g...ontrol-972694/

Madd Dog

Oddly enough, Acura does not do everything a BMW does. Who’d have thunk it?

My 2008 535 did apply the brakes to maintain cruse control speed.


Otoh, you can’t get torque-vectoring AWD on a comparable BMW at all.

Dthomas2658

My 2011 and 2015 Hyundai Genesis’ both braked to keep the preset speed!

Madd Dog

If there is anything that really needs automatic braking on cruise control, it was that cruise ship in Venice.

hans471

I guess I am the odd one on this as I don't want the cruise to apply brakes on down hills. Why? Well, gas mileage for one reason. I have noted on this car and my previous Honda CR-V's that in hilly regions I did better on gas by driving the car myself than by letting R2 drive it. To accomplish this I let the car speed up on its own (within reason) on the down hill and then give it just enough throttle on the uphill to keep the speed from dropping too much. Cruise controls tend to chop the speed on the downhills only to gas it hard (wasting fuel) on the uphill trying to maintain a set speed. I see 3 to 4 MPG difference between cruise and "me" driving the car in hilly regions (like i have in Kentucky where I live). On the flatland of Indiana or Ohio the cruise does fine on mileage as you don't get all the variations in speed due to altitude changes.

I won't judge a complete car on the merits of one function. I see the vehicle as a total package. Like would I trade my wonderfully performing RDX for a Kia over the operation of a cruise control? Nah! But you might.....

Alias1431

Does the X3 M40i have it?

Midnight Mystery

IKR?

At first, I also thought it was in Venice, LA, lol....

Midnight Mystery

Now doesn't it downshift and engine brake to loose excessive speed?


Suppose you're going down a tall mountain with cruise set at 50 mph, will it speed up to 100 mph just because of gravity?

DHood

I go down a steep grade fairly frequently, so I put the Transmission in Sequential Mode and use the Paddle Shifter to "Engine Brake" the speed. It works very effectively.

horseshoez

iTrader: (2)

Did your 535i apply the brakes, or did it simply downshift the transmission?

mrgold35

Honda used to have Grade Logic Control to hold a lower gear to maintain your speed up or down a hill. I don't think Honda/Acura has that anymore? Might have to do it manually by tapping the paddles a few times on downhill runs to maintain your speed. I had a few MDX loaners with the 9AT and the vehicle would speed up when I hit the paddles to downshift to slow down. I would have to hit the paddles 4-5 times before I would get the braking I needed before hitting a curve. Not sure if the 10AT does the same downshift/acceleration quirk and/or the 2.0T may not have enough engine braking on a 2 ton vehicle to make a difference unless you drop 4-5 gears?

DarkNinja75

Wind resistance will probably slow you before then. I drive a couple different cars for work, and down most grades wind resistance keeps them at 80 or below.

Madd Dog

I think only upper levels have it. It is called Dynamic Performance Control. The lower level cars, like the 3s, mumble around it and use slightly different wording, like ‘intelligent’ and ‘Performance Control’, but it seems to be brake vectoring not torque vectoring.

The X6 has it. The brochures are vague.

I would not trust a salesman to know or say whether a particular car has torque or brake vectoring. I would want to see it in official BMW print. Maybe a monroney sticker?

likerage

If we didnt have this post than we would have the "had to get new brakes at 9k miles" post like what you get on the other manufacturer forums. The systems tend to just ride the brakes causing them to need to be replaced frequently.

Rather have it our way tbh. I hated driving my c43 out of the mountains in cruise control.

Midnight Mystery

Doesn't the ZF-9 and 10AT differ so much (and use newer designs?) That is likely the cause of losing grade logic...

Madd Dog

Both.

I did European delivery, and went from unlimited into a much lower limit. I hit the stalk about 6 or 7 times at -5 each time, and them brakes worked. In day to day driving, the cruise control speed never varied by more than 2 or 3 mph, up or down a hill, regardless of how steep it was.

zroger73

All of the automatic transmissions and DCT's currently used by Honda including the Honda 6AT, ZF 9HP, Honda 10AT, 7-speed DCT, and 8-speed DCT use Grade Logic Control.

This can be verified by reading the powertrain press releases or viewing the transmission description of operation in the service information (subscription required).

Here's the powertrain press release for the 2019 RDX:

"Sequential SportShift 10-Speed Automatic Transmission with Paddle Shifters

• Electronic shift-by-wire gear selector
• Sequential SportShift automatic transmission allows semi-manual operation
• Steering wheel-mounted paddle shifters
• Cooperative control between Drive-by-Wire throttle and transmission
• Advanced shift-hold control limits upshifts during spirited driving
• Grade Logic Control reduces gear "hunting" on various road gradients"

https://hondanews.com/acura-automobi...kit-powertrain

Honda's CVT's don't have or need Grade Logic Control since there are no "gears to hunt between". Most of them, however, have Honda's G-Design shift logic which is intended to emulate the feel of a stepped automatic transmission while negating some of the benefits of a continuously variable transmission in order to make the powertrain feel more "natural".

samiam_68

^^ This. Tiny engines in big heavy vehicles are not very useful for engine braking.

horseshoez

iTrader: (2)

Compared to the 340 in my 1970 Challenger, even modern I6 and V6 engines don't provide much useful engine braking. In the Challenger I could actually chirp the rear tires when downshifting.

stevesTL

Actually I find it annoying Acura doesn’t use engine braking to maintain speed when going down a steep incline. It is a nice thing to have and why it doesn’t work I have no idea. Because it does have it already!
When using ACC and you come upon another vehicle it maintains the speed using this method including when you are behind another car going down a hill. So not having it always maintain speed doesn’t make sense.

zroger73

On each of the 11 Hondas I've owned since 2006 - including the 2019 RDX I had, the transmission will downshift to take advantage of engine braking during cruise control operation if the vehicle exceeds the set speed by more than a few MPH.

JB in AZ

Yes, I find that my RDX does this as well, but my previous 18 CR-V did not, as it has a CVT.

Midnight Mystery

CVT's cant...


Not that this means much, but it makes a point!

zroger73

1. In this video, he stated he rented a Ford Focus with a CVT. The Focus has never had a CVT! The first and second generations offered a traditional automatic transmission. The third generation offered a 6-speed dual clutch (automatic) transmission - this transmission had some problems, but it was a completely different design than a CVT. In the comments, he wrote, "...meant to say I rented a Ford Fusion not Focus..." The Fusion doesn't have a CVT, either! The Fusion Hybrid has an "E-CVT", but that, too, is a completely different type of transmission than a CVT.

2. I used to watch Scotty Kilmer's channel regularly until I caught on to his misinformation and extreme bias. The last video of his I watched was one that contained reasons to avoid a Honda Ridgeline. It was full of incorrect information.

3. CVT's most definitely allow for engine braking. The one in my 2016 Honda CR-V Touring did! The owner's manual for the 2016 CR-V even explains this:

JB in AZ

I agree with everything you said about this "carnival barker" He is very annoying and, as you said, often presents incorrect information...I'm not sue whey people even watch/listen to him.

The issue being discussed, I believe here (please correct me if I am wrong) is engine braking using cruise control while on a downgrade.

It is true that most CVTs offer a "Low" option, I don't believe that most drivers will use the LOW position on a CVT to keep the speed close to the CC set speed...while a normal geared transmission will downshift automatically in many cars, the 19 RDX included, from my experience. I was recently on a long 6% downgrade and the vehicle speed never went more than 5 mph over the set speed.

Midnight Mystery

Thanks for sharing!

The Honda Ridgeline video was BS... He said they have "massive engine problems"...

That's one of the oldest and most tried and true engines still in production!

However, I feel he has a point about CVT's even though he was wrong about the facts about the car...

But I already am lead to believe Honda has one of, if not the best, CVT out there, so.........

Madd Dog

Both my wife’s Accord’s CVT and my RDX do use grade logic control, and you see the revs go up in the CVT and in the RDX. It is just not producing enough engine braking to keep the set speed, and will often go 5mph over. If ACC is active on the RDX, it will brake when the speed of the other car calls for it.

Popping the left paddle a couple or three times usually gets me the results I am looking for.