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Old November 19th, 2019, 10:14   #11
Certified Volkswagen Nut Vendor
oilhammer's Avatar
Join Date: Dec 2001
Location: St Louis
Fuel Economy: fantastic

Here is my take:

if they had actually let hybrid technology spill over into non-hybrid vehicles, specifically ditching the conventional starter and alternator, and going to an integrated motor/generator (even if this motor was just for restarting the engine and not actually MOVING the car), this would work much better.

But instead, they are just essentially using software on existing components. It varies model to model, manufacturer to manufacturer. Some simply use a higher rated battery (usually an AGM type) that can withstand the more frequent ups and downs of voltage. Remember, when the engine is not running, all the electrical consumers are working off the battery AND that battery still must be able to restart the engine. These consumers vary, but can be quite substantial, more than a car without stop/start, because they do things like hill holding (runs the ABS motor to hold pressure on the brakes).

There are a few that use a slightly higher rated duty cycle starter as well. But I know of exactly NONE of them that use a strengthened flywheel, although there are some that do some fancy trickery with the cam phasing and throttle to reduce the cranking load on an engine that is already warmed up.

I personally do not like it, I find it annoying and I can most certainly tell the delay in taking off from a stop, although it probably isn't any different than working the clutch on a manual transmission car but I just do not expect it when driving something with only two pedals.

But the biggest thing is, the starters... the normal failure mode of most starters is (drum roll... ) they DO NOT CRANK! And when do you find out when your starter dies? Well, normally it is when you go to start your car, and where do you have your car when you go to start it? The place you PARKED IT. But now, we have cars "parked" at traffic lights. So yes, now the starter can suddenly die and strand the vehicle in the middle of the street. We've already seen this happen.

GM actually has their software so in tune that when your stop/start GM car dies suddenly, OnStar is already on it. So when you are sitting in the middle of the street with people honking at you, they are already calling your car to tell you a tow truck has been dispatched. Pretty clever. What would even be more clever? Just letting the engine run for 30 seconds.

It is something that has been granted greenie points so the manufacturers have an incentive to have it, because it *could* possibly save *some* fuel. But we figured out on the F150 that the fuel savings as estimated by Ford will essentially be eaten up by the higher battery cost alone under most conditions. I do think some people may see some fuel savings, depending on the type of traffic conditions you encounter. And most of these systems are still not very good at toggling HVAC duties with the engine operation. The Malibu I had to drive for a bit most certainly had its A/C output take a steaming dump as soon as the engine shut off. So much so, that I found that if you place the car in N, the system switches off, and lets the engine keep running. Go figure.

We have had several Kia Souls in here with dead starters already, and a couple F150s and some various GM vehicles, the most recent was a Traverse.
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