Stop/Start question

[jelt110]

Forgive me please if this is a dumb question, but I have tried finding info on this in the web.

I kind of like the stop/start feature- getting used to it (at first I thought I'd never use it)- it seems pretty smooth- all the complaints i've heard seem to be on the earlier versions/generations...

The question is this: how much more wear on the starter is accumulating? I maybe get 10 cycles on my daily commute. Is it worth it to save 1-2 mpg, which works out to about 1/20th to 1/10th of a gallon ($0.15 to $0.30 cents) per day? 250 days per year commute: so $37-$75 of gas per year, vs how much is a new starter, installed?

It is fun to play with when zipping around is not on the menu- I can't believe how much I like playing with all the toys in this car!

[CatalinP]

10 cycles with S/S enabled versus 1 cycle with it disabled means 10 times the wear, isn't it?

[munge]

Mine does feel clunky when it stops and starts and I wonder if the wear from restarting each time is healthy. I have about 10 miles each way commuting and can easily stop start 20 times.

Is that good for the engine etc? Or is it anticipated and doesn’t cause significant wear?

[diesel733]

per this article it does not wear out the starter because it used a different technology

https://www.greencarreports.com/news...r-cars-starter

[jelt110]

This is great news, right? I can save 25 - 50 gallons of fuel a year on my standard commute, with little more wear to the starter. I figured this would have been addressed- but you know what they say- "trust, but verify".

I am really falling in love with this x5. Next week I may take it out to the country where i did my empirical accel tests with the subaru fxt stage 2+, and see how it compares in acceleration.

Mind you all- I was seriously enamored with the FXT- boxer engine, FADEC turbo with knock sensors-Cobb stg 2 with race tune and a lot of hacking-- I wrang the engine out fairly well while still using it as my go-to fall-back reliable transport.

This x5- i'm leaving it alone for the most part- just an RS racechip.

But: Wow.

[Wavy]

I would imagine anything that repeatedly turns off and on would be susceptible to more wear and tear vs something that stays on for long periods. But when that happens you'll probably be out of warranty so BMW probably doesn't care.

[TOPEC]

the auto start/stop feature engages the starter for a very short duration(maybe half a sec or less) and uses existing fuel in the cylinders to start the car where as if u listen to the starter engage in a full start up event. the starter engages for longer to turn over the car. u can hear the difference if u pay attention during start ups. does it wear put more wear on the starter? yes, but not to the extent of 10 full startups for every 10 start/stop event.

[The Libertine]

Originally Posted by Wavy

I would imagine anything that repeatedly turns off and on would be susceptible to more wear and tear vs something that stays on for long periods. But when that happens you'll probably be out of warranty so BMW probably doesn't care.

That’s where I land in the whole start/stop debate. Not interested in saving a couple of gallons at the expense of wear & tear on the engine and other mechanical components.

[weareweird69]

One other thing to note.... All of the X5's are turbo, gas or diesel. So, when the engine shuts off at a stop.... Guess what else stops. OIL FLOW. So, your turbo is spinning away, or multiple turbos, and after spirited driving, or even a long trip, or going up a hill, or any higher load condition, the turbo is hot, and the oil lubricates the shaft that is spinning. When you stop oil flow on a turbo that isn't properly cooled, you are essentially hurting it. I am not sure if these are bearing, or journal turbos, but either way its not good for either. So, while you're saving a few bucks in fuel. That new turbo is going to cost you a few thousand.

[TOPEC]

the turbos r both water and oil cooled, once the engine shuts off the turbos are still being cooled off by the way of convection via the coolant.

btw, the starter is also beefier than normal

The starter motor must do more in conjunction with the automatic engine start-stop. The starter motor is therefore configured for a significantly higher number (approximately 8 times) of starting operations. The components of the starter motor have been adapted to the higher requirements.

[CatalinP]

The price for a new one is beefier aswell.

[weareweird69]

Originally Posted by TOPEC

the turbos r both water and oil cooled, once the engine shuts off the turbos are still being cooled off by the way of convection via the coolant.

btw, the starter is also beefier than normal

The diesel ones are NOT water cooled.

The Gas ones on the M are, but I am not sure of the non-M.

Either way, the cooling isn't the issue, its the lack of lubrication to the main shaft when the turbo is hot that does the damage.

[alphaod]

The starter is designed for this repeat cycle.

That said I am more concerned about the increased wear due to the lack of oil circulation.

I’d rather pay for more fuel now then more wear due to lack of lubrication when that motor is fired up again and again.

Even those new engines (like new Mercedes straight-6) with the starter integrated into the crankshaft I would be concerned.

If I leased I guess I wouldn’t care, but I buy to own so I care about the long term even if I drive the car very hard.