Engine off coasting?

[Tesla]

Have to ask this question and will probably get jumped on.
Is it really worth it, I'm sure it does save fuel, but what about increasing rear and tear on the vehicle?
It was always said that Taxi Cabs in the old days could easily do 1,000,000km because they were only started and shut down a few times a week, so engine conditions are constant and wear is minimal.
There are many areas that may be negatively affected by starting, even with a hot engine, the biggest loads on any component are initial forces required to bring them in motion, so that goes all the way from starter, belts, pumps, bearings, all the moving parts basically. Every time you stop the engine the oil galleries drain away and it takes a second or so to build up oil pressurse.
Does anyone know of any studies done on longterm effects of repeated engine starting?
I generally only shut down when I think the delay will be longer than 2-3 min.

[cbaber]

What do your roads look like that you can coast for 2-5 minutes? What speeds are we talking about at these distances?

I drive 90% highway for my commute. At most I do about 30 seconds of coasting before I hit below 50 mph. I find that the effort needed to do this just isnt worth it. At speeds above 50 the air resistance is really holding the car back. Even with pumped up tires you need a pretty nice hill just to keep your speed. The wear/tear on the cluth and engine just is not the MPG in my opinion. Just pay close attention to your foot and don't use more pedal than you need. Allow the car to slow down going up hills and gain the speed back when going downhill.

As for city driving I can see the benefits. One time on a 30 mph road I was able to coast for about 1.2 miles of pretty hilly terrain and finally ended up at a stopsign. Probably a good 2-3 minutes of coasting it was pretty cool.

[Diesel_Dave]

Originally Posted by Tesla

Have to ask this question and will probably get jumped on.
Is it really worth it, I'm sure it does save fuel, but what about increasing rear and tear on the vehicle?
It was always said that Taxi Cabs in the old days could easily do 1,000,000km because they were only started and shut down a few times a week, so engine conditions are constant and wear is minimal.
There are many areas that may be negatively affected by starting, even with a hot engine, the biggest loads on any component are initial forces required to bring them in motion, so that goes all the way from starter, belts, pumps, bearings, all the moving parts basically. Every time you stop the engine the oil galleries drain away and it takes a second or so to build up oil pressurse.
Does anyone know of any studies done on longterm effects of repeated engine starting?
I generally only shut down when I think the delay will be longer than 2-3 min.

You big up some very good points. The wear impact of EOC is what concerns me too. I'm sure some work was done on frequent starting and stopping for the Prius and other hybrids, but I have yet to see the data.

[Georgboy]

Diesel Dave what gear do you have in that 11.5 aam axle? 3.42? Us gear vendors overdrive? 3.42 gears would be super beneficial to your setup I believe... I have a 2005 dodge 2500, g56, 5.9 cummins, stock injection pump, lift pump, turbo (he351cw), bigger injectors, south bend 3600 dd clutch, aem brute force intake, 4 inch straight pipe, bully dog triple dog (scary Larry tune), edge ez, .... 551 hp- 1074 lb. Ft. At the wheels.. I have considered running the 3.42 gears....

[Diesel_Dave]

I have 3.73 gears, but I've been looking at swaping them out for 3.42's. Currently all the gearing is bone stock.

[Georgboy]

What rpms do you try to maintain for best fuel economy?

[Georgboy]

Air intake? Performance exhaust? What kind of oil do you run? Another way to lessen your cost per mile is to install a fs2500 bypass filter. I change my oil and engine filter at 20k miles vs 7500 miles. I change the fs2500 filter at 10k miles. I also run Valvoline blue 15w40 premium blue oil and one bottle of Lucas oil stabilizer...

[Diesel_Dave]

We're getting a little off topic here, I'll PM you.

[Sprayed 01]

Ive just started here but I think using the starter is alot easier on things than bump starting over and over again. Seems more natural for the vehicle.

[Georgboy]

It is not bad when you bump start and don't feel the bump... Don't just let (dump) out on the clutch.. Know what gear you need to bump start in so that you don't over rev the engine and ease out on the clutch ....