Try Coasting - Fuel Economy, Hypermiling, EcoModding News and Forum

michaellawre · 12-03-2009, 01:32 PM

I have found that coasting even short distances as well as on hills has added many miles to each tank of gas. I have frequently added as many as 100 miles to each tank of gas.

I also coast on any grades and try to watch ahead for red lights. If you stay aware of the flow of traffic and the grades in the road you can coast and save from the reduced RPM's by disengaging the transmission from the motor in Drive to Neutral. It also reduces wear on the brakes too!

Happy Motoring and Coasting!!!

runbyu1 · 12-03-2009, 02:21 PM

Amen, I think this is the single biggest way to save gas...

mchlbk · 12-03-2009, 03:55 PM

I'm a little worried about what this does to the transmission in the long run, though?

Rainh2o · 12-03-2009, 08:00 PM

Being a manual I wouldnt think it would cause any harm since you shift out of gear at stops, and if like me, I shift into neutral and release the clutch, that way im not ridding the clutch bearing, then when the light turns green, i just shift into first...

JonnyG · 12-03-2009, 09:46 PM

The issue of shifting in and out of gear with an automatic transmission is heavily debated. A bunch of different arguments can be seen here: Does going into neutral wear down tranny?

rmay635703 · 12-03-2009, 10:22 PM

Quote:

Originally Posted by JonnyG

The issue of shifting in and out of gear with an automatic transmission is heavily debated. A bunch of different arguments can be seen here: Does going into neutral wear down tranny?

The answer is simple, it depends on what car and what transmission.

The buick I drive clutches out of gear when you let off the pedal in 4th and goes to idle rates, My TDI jetta shuts off the injectors and remains locked up so I would estimate would wear differently in neutral than in D engine braking?

rgathright · 12-04-2009, 09:16 AM

Quote:

Originally Posted by michaellawre

I have found that coasting even short distances as well as on hills has added many miles to each tank of gas. I have frequently added as many as 100 miles to each tank of gas.

I also coast on any grades and try to watch ahead for red lights. If you stay aware of the flow of traffic and the grades in the road you can coast and save from the reduced RPM's by disengaging the transmission from the motor in Drive to Neutral. It also reduces wear on the brakes too!

Happy Motoring and Coasting!!!

Coasting works on my Honda Accord as well. I usually coast to work when I get off the interstate. A good suspension is key as well since you may be banking hard on some long turns that you would normally brake on. I develop a route and pick the right speed to coast through many attempts.

Another consideration when coasting frequently is weight. Lighten the load of your vehicle as much as possible by removing those golf clubs and other junk in your vehicle.

Old Mechanic · 12-04-2009, 09:34 AM

Coasting in my VX and Echo.

Pulse at 25 MPG.

Glide at 50 MPH while the engine is idling (EOC would be better but it is labor intensive and accelerates wear on components).

Echo at .19 GPH at idle, 50/.19=263 MPG
VX at .15 GPH at idle, 50/.15=333 MPG

Engine off is infinite MPG.

I tried a tank in the Echo using EOC. The mileage went from 53 to 56 MPG for that tank.
If I wanted to shut off and bump start several hundred times for every tank of fuel, then I could get 3 more MPG.

If there were more significant grades here or my average speeds were lower than 35-38 MPH then the difference would be greater.

In the VX shutting the engine off means you lose Lean burn for over 30 seconds on the restart. Extreme engine off coasting can also cause your 02 sensor to go out of closed loop and in even more severe cases your engine can cool off to the point where warm up fuel enrichment becomes an issue.

regards
Mech

instarx · 12-04-2009, 10:32 AM

Quote:

Originally Posted by rgathright

Another consideration when coasting frequently is weight. Lighten the load of your vehicle as much as possible by removing those golf clubs and other junk in your vehicle.

I think added weight improves coasting efficiency. My old 1-ton van would coast forever in neutral, but my Volvo wagon doesn't go nearly as far. It makes sense tht the more mass the vehicle has the harder it is for friction and wind resistance (or anything for that matter) to slow it down. Which is why it is against the rules to add weights to Olympic bobsleds.

Of course you would lose way too much when not coasting for it to help in the real world.

thatguitarguy · 12-04-2009, 11:29 AM

I've experimented a little with EOC in my van, and I don't think it's worth the risk. My van appears to have DFCO, so I'm not using up fuel when going down the steep hills, and I have important things like power steering and power brakes available as needed, and I get the braking of the engine. With the engine off and in neutral, the steering is extremely stiff, the vehicle accelerates too fast, and terminal speed is way above the speed limit, and you only get a few stabs at the brake before you deplete your vacuum storage. So I'm going down a steep long mountainside, picking up speed, very unresponsive steering and brakes... Not for me. I will be trying it more in the Metro though.