More than ever confusion

[adventurenali92]

Start liking it; everyone is doing it. The only reason it's not in the Tahoe yet is that the drivetrain tech is old and they probably haven't gotten around to upgrading the starter mechanism to withstand the use. 100% chance that feature will be in the next generation.

And, if it's like any of the other GM cars I get as rentals that have the ASS function now (Malibus and Impalas mostly) - it can't be disabled!

Why would anyone want that feature? I can’t imagine it saves a lot of fuel?

 

[Rdr854]

Why would anyone want that feature? I can’t imagine it saves a lot of fuel?

The theory is two fold. First, when you are sitting ata traffic light or stuck in traffic and not moving, you are not wasting fuel. Second, because the motor shuts off when you are not moving, vehicle emissions are reduced, which means less smog and pollution.

 

[cardude2000]

Why would anyone want that feature? I can’t imagine it saves a lot of fuel?

Apparently it saves ~10%. More if you are in an urban/heavy traffic area.

 

[adventurenali92]

The theory is two fold. First, when you are sitting ata traffic light or stuck in traffic and not moving, you are not wasting fuel. Second, because the motor shuts off when you are not moving, vehicle emissions are reduced, which means less smog and pollution.

Wouldn’t you burn that same fuel that you’re not using while stopped in order for the engine to start back up?

 

[cardude2000]

Wouldn’t you burn that same fuel that you’re not using while stopped in order for the engine to start back up?

No. Not in a modern engine that is already warmed up.

 

[WillCO]

Why would anyone want that feature? I can’t imagine it saves a lot of fuel?

It's more a benefit for the car company. Using broad assumptions on how the ASS systems will work in the real world, they can credit better fuel economy versus the CAFE standards.

I've had it in a BMW and it's in my wife's Mercedes. In both, there was a big button to defeat it. I always do. It's disturbing to feel your engine die at a light; I always very briefly think it's stalled.

 

[cardude2000]

It's more a benefit for the car company. Using broad assumptions on how the ASS systems will work in the real world, they can credit better fuel economy versus the CAFE standards.

I've had it in a BMW and it's in my wife's Mercedes. In both, there was a big button to defeat it. I always do. It's disturbing to feel your engine die at a light; I always very briefly think it's stalled.

According to this it doesn’t really play into EPA estimates

https://www.edmunds.com/car-reviews/features/do-stop-start-systems-really-save-fuel.html

Agree though on how annoying they generally are though. Some cars it’s really pronounced and others not even noticeable.


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[GTNator]

According to this it doesn’t really play into EPA estimates

https://www.edmunds.com/car-reviews/features/do-stop-start-systems-really-save-fuel.html

Agree though on how annoying they generally are though. Some cars it’s really pronounced and others not even noticeable.


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I noticed you were gone for a few months. Nice to have you back, appreciate the varied points of view and differing opinions you sometimes bring. Keeps the forum smart in my opinion.


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[orchidcrazy]

I think it is mostly for CAFE standards. I drove a Chevy Cruz during a college visit in a town on a grid - engine shut down at every stop, every block. Was very surprised to see the gas that thing ate when starting and stopping as it did and I tell you, it was freaking annoying! Car ran great on the freeway when it could just run. I rented 3 different vehicles during 3 visits to that same town for the same 3 days flying in/out of the same airport. While we didn't drive the exact same route or the exact same distance, the Cruz got the worst gas mileage in the same area. I rented a Passat and a BMW SUV the other two trips.

 

[swathdiver]

I noticed you were gone for a few months. Nice to have you back, appreciate the varied points of view and differing opinions you sometimes bring. Keeps the forum smart in my opinion.

He's back because of good behavior!

A purpose built system like that used on the Hybrid Tahoe and Toyota Prius is far more durable and problem free than one adapted using an existing transmission and a big starter in the same place as a truck not originally designed for it.