Engine braking with the PowerBoost

[Calson]

With the GM trucks the diesel exhaust brake is not only standard but it works in tandem with the grade descent control so exhaust braking is coordinated exceptionally well with the transmission.

Sponsored

 

[thudnblunder]

Did pretty good in Yosemite. My trip average from the Bay Area out and back was about 24.2 mpg. Engine braking used to kick in when the battery was fully charged. It was pretty seamless. I didn’t have to lock out any gears.

Blue Cruise in stop go highway traffic is so helpful.

 

[HammaMan]

Don't let the truck fool you, it uses the brakes with cruise control....

Yes, it's regen'n, but it's also engaging the rotors too

 

[mbouck3]

Fascinating stuff that I will not often experience in the flatlands. Amazing vehicle!

central fl. resident but I may drive to the Rockies just to experience it. Well maybe to get to some livable temps also.

 

[SuperRaptor]

It depends on the vehicle. With my GM 2500 truck using the manual transmission setting would disable grade control completely and not a smart thing to do. Wth my 2022 F-150 it came with the hill descent control feature that is activated with a push of a button on the dash and then the + and - buttons on the steering wheel. If the system overheats and shuts off then you are back to using the brakes.

The engine braking from its diesel engine was exceptional but with a gas engine the "braking" is nowhere near as effective and not something to rely upon.

Modern trucks have disc brakes at all four wheels and brake fade is not the problem it was with enclosed drum brakes.

Most drivers do not have a clue as to how to drive in the mountains and will brake too late and lock up the steering and then try to compensate. Ego driven drivers are the worst as they will drive faster than their limited skill can manage and have no knowledge of chassis loading going into a turn.

Hill Descent Control is for slow speed maneuvering and is using the brakes/abs system to keep you going slow on uneven terrain. If memory serves me correct it's 12 mph.

And diesels without an exhaust brake aren't really that effective at compression braking either.

While you can use the generator system to create additional drag like someone else has pointed out when your battery is topped off it stops creating the drag and you're back at square one. Keeping the loads under control and properly working trailer brakes is key like you mentioned.

 

[Calson]

I had a 3700 lb load in the bed of my truck and did a descent of 4,000 feet over a distance of 15 miles on a winding mountain road and never touched the brakes and the exhaust brake and grade control kept the speed at 25-30 mph the entire time. Most of the time I did not use the truck's exhaust brake as it was overkill unless I was towing a heavy trailer. But how effective the exhaust brake is depends on the truck. GM in tests had the best back in 2011 when I bought the truck and Ford had the worst at that time.

Ford's hill descent control will actively keep the speed below 20 mph but over that speed it still functions but cannot be used alone to maintain the truck's speed. It is not meant for general use as with a diesel exhaust brake. It does help where ABS brakes can cause problems as on dirt or gravel roads. On these surfaces I wish there was a way to disable the ABS brake system entirely.

 

[Oxford_Powerboost]

Don't let the truck fool you, it uses the brakes with cruise control....

Yes, it's regen'n, but it's also engaging the rotors too

Agreed. This is the main reason I opted not to use adaptive cruise in stop and go traffic. I can be much more efficient using regen with my foot

 

[HammaMan]

Agreed. This is the main reason I opted not to use adaptive cruise in stop and go traffic. I can be much more efficient using regen with my foot

Adaptive cruise in traffic is good, but when you're approaching stopped vehicles, it's not smart enough to understand that it's time to start slowing much earlier. In slow moving traffic however I let it do its thing.

 

[thudnblunder]

On that note, do you guys here clicking from the engine bay as it starts to apply brakes? I'll try to get a recording. It's not loud, but I can hear a click everytime the brakes are applied. Almost like a relay.

 

[Bob Violence]

On that note, do you guys here clicking from the engine bay as it starts to apply brakes? I'll try to get a recording. It's not loud, but I can hear a click everytime the brakes are applied. Almost like a relay.

Yep. My PB is the "noisiest" vehicle I've ever owned. There is always some clicking, whirring, whining, etc going on. It's all a normal part of the PB experience I suppose.

 

[Snakebitten]

Yep. My PB is the "noisiest" vehicle I've ever owned. There is always some clicking, whirring, whining, etc going on. It's all a normal part of the PB experience I suppose.

I would have agreed with you while I owned my 2021 Platinum Powerboost. And note that in 50 weeks of ownership I did NOT have any issue requiring a visit to the dealership.

However, my 2022 is a quieter drivetrain. Considerably. Especially with the windows up, in EV mode driving down my gravel road it's dead quiet other than the tire crunching.

And based on some PIDs I monitor, I'm surprised at the amount of variation between the two trucks. Nothing serious of consequence, but this truck has a happier combustion chamber regarding things like timing and knock.

 

[Bob Violence]

I would have agreed with you while I owned my 2021 Platinum Powerboost. And note that in 50 weeks of ownership I did NOT have any issue requiring a visit to the dealership.

However, my 2022 is a quieter drivetrain. Considerably. Especially with the windows up, in EV mode driving down my gravel road it's dead quiet other than the tire crunching.

And based on some PIDs I monitor, I'm surprised at the amount of variation between the two trucks. Nothing serious of consequence, but this truck has a happier combustion chamber regarding things like timing and knock.

I am at almost 1 year of ownership on my 2021 PB, and no visits to the dealer for anything other than recalls and maintenance.

For clarity, my drivetrain is as quiet as I would expect a modern ICE to be. There just seems to be a lot of other "doo-hickies" and "thing-a-ma-jigs" on the PB that make themselves heard.

 

[Snakebitten]

I am at almost 1 year of ownership on my 2021 PB, and no visits to the dealer for anything other than recalls and maintenance.

For clarity, my drivetrain is as quiet as I would expect a modern ICE to be. There just seems to be a lot of other "doo-hickies" and "thing-a-ma-jigs" on the PB that make themselves heard.

Yea, note I mentioned "with my windows up".

And it's true that if I open my door inside the barn where any sound is amplified off the metal walls, I DO hear all the various Powerboost systems necessary to support the ICE being off. The electric brake boost when I put pressure on the brake pedal.
The electric transmission fluid pump if I take it out of park. The fans if I crank up the AC demand......

Lots of amazing Hybrid related components that produce sound. But I swear that the 2022 is a quieter version of all those sounds. I don't think it's necessarily anything to do with model year but rather I didn't get one of the loud auxiliary pumps or vacuum pumps or.....

I think I'm just fortunate and got a good sample. Very happy with it so far.

 

[Atlee]

Yea, note I mentioned "with my windows up".

And it's true that if I open my door inside the barn where any sound is amplified off the metal walls, I DO hear all the various Powerboost systems necessary to support the ICE being off. The electric brake boost when I put pressure on the brake pedal.
The electric transmission fluid pump if I take it out of park. The fans if I crank up the AC demand......

Lots of amazing Hybrid related components that produce sound. But I swear that the 2022 is a quieter version of all those sounds. I don't think it's necessarily anything to do with model year but rather I didn't get one of the loud auxiliary pumps or vacuum pumps or.....

I think I'm just fortunate and got a good sample. Very happy with it so far.

I find my MY22 is quiet also. Window up, and I can't hear the noise it's supposed to make if in electric drive going forward. And the backwards beeping isn't nearly as loud as many MY21 owners talked about.

I do get an almost rumbling sound when the ICE is running.

 

[BRDVPRA]

As far as the noise,, I am at 80K ish miles now. I have noticed that when I turn the truck on and it is running the AC without the ICE it is much more noisy than it was when I first got it. I have seen a few other posts on it too.

Sponsored