Bump.

With all the new influx of people to GasSavers, thought I'd bring this back to the top.

Interesting read. I'd like to point out something that should be mentioned any time someone speaks of coasting. The transmission needs to be mentioned, manual or auto, and it needs to be mentioned that an auto will be toasted by engine off coasting. It will happen fast enough that car makers put it in their manuals that being towed in neutral, engine off, with the drive wheels on the ground will void the warranty. When the engine isn't running, neither is the tranny pump, so the guts of the trans are moving, but not being lubricated. The effect is the same as running your engine with no oil. Since a lot of new people might be lurking and may not know this, this should be noted in every new post string concerning coasting with the engine off. Manual transmissions are usually bath lubed, meaning the gears are down in the oil, so they get lubed whether the engine is running or not.

Second, on the braking issue. The easiest, cheapest way to address this would be to use a vacuum can with a one way check valve. High performance cars with lopey cams don't build enough vacuum to operate power brakes and stuff, so these cars usually use a simple vacuum can to provide vacuum for the brakes. They are available from Summit Racing for around 50 bucks, and will not interfere with braking operation when the engine is running normally. A vacuum can should provide enough vacuum to operate the brakes 4-6 times engine off before the vacuum is depleted, so long as you have that one way check valve installed. Some cans also have a port for a vacuum gauge on them, so you could install a gauge to tell you when you need to crank the engine to rebuild brake vacuum. You don't have to buy that expensive can though, you can make one so long as you can come up with a sealed cannister with the proper fittings that will stand up to a vacuum.

Slight but important correction to that: IF your manual says don't flat tow, don't EOC. If it says flat towing is ok, EOC'ing is perfectly safe to the driveline.

In response to DRW / rh77 above, I will clarify what they are talking about :) If you have power steering, and you restart the engine, then the power steering will suddenly come back!

The danger is that if you are hanging on to one side of the wheel going around a corner, when the power steering comes on, then the force you are applying will mean you suddenly turn a lot more sharply, lost control, and crash!

The solution is to restart when not turning, or, 'brace' your arm against e.g. the door, so that it won't move when the power steering returns.

I'm one of the biggest eoc'ers/fas'ers around. Its nothing for me to bust off into a eoc.

I sure wish the noobs would get the basics down first. Im seeing away to many noobs going right into the advanced tricks of the trade.

psy

Great thread I have enjoyed it! Using your park brake is not always a great idea. If anyone is behind you, you have no brake lights! So if you do this in traffic it would be a good idea to install a switch in tandem with your brake switch. Also remember 2 other things. 1 if you have rear disc brakes alot of new cars have smaller linings for the park brake. why do I keep calling it a park brake instead of an emergency brake? Because they are built for parking not emergencies. Work in the industry gotta be LEGAL here. 2 if you own a car built after 05 make sure and check that you have brake lights with the key off. For years in the US it was a law that brake lights had to work at all times. Not with the global economy of things. At least for GM, can't speak for other models.
P.S. I love to coast too. 6 miles of my daily commute is coasting. Here in the flat lands one place to remember are freeway exits. They don't call them free for nothing.

Hey, how come no gas log on the Red jelly Bean?

My car stops fine without power assist. Just have to push HARD!

I actually just contacted Ron about this having seen it for myself (why is my mpg going down, the engine is off?) and let him know others were seeing it in their saturns.

It is apparently the saturn pcm publishing that info to the obd port. On the plus side it is putting out a bizzare "61RPM" signal too, so I asked ron if the gph could somehow be "zeroed out" in the scangauge for an obviously wrong rpm reading (i.e. less than 200RPM say).

skewbe -

Someday maybe we'll have programmable scangauges that we can "tune" to the whacky behavior of our PCM/ECUs

CarloSW2

My Cavalier has an automatic transmission, so I always coast in neutral with the engine on - uncalibrated ScanGuage II reporting 0.4 gph. I've got an ~ .2mi coast to my office at 25mph, so I shut the engine off the other day, just to see what the SG would read.

0 gph, 0rpm, 0tps, and 9999mpg. :)

Boy, that felt good. I wish I had a manual trannie, but I have to settle for 150mpg with the engine running.

Thanks for bumpin' the thread, CO