CODFISH or Pulse and Glide?

[diamondlarry]

Is this to fast a speed to do this? (Should I try Pulse and Glide?)

No, it's not too fast. That is roughly the speed I have used occasionally. In fact, when I made a highway trip a couple of weeks ago, I would speed up to 60 then coast(engine off) down to 50 then bump-start and start over again.

Should I be able to coast farther than I am? (Is something dragging me down?)

That does seem like a very short coasting distance. I think my coasting times are actually longer than what it takes to get up to speed. I would check your air in the tires and make sure you don't have any brakes dragging.

Should I coast to an even slower speed before speeding up?

That speed seems about about right.

Should I speed back up quickly or slowly?

I've found that somewhere around 1/2 throttle seems to be about right for accelerating.

Any other technique suggestions? (I'm costing to stoplights trying not to stop, turning it off when I do stop, driving the speedlimit etc.)

Sounds like you are on the right track. Keep practicing and good luck.

[MetroMPG]

Originally Posted by Kraig

I noticed it does seem to slow down pretty quickly from 55 but if I'm in town it seems to coast fairly far.

Our cars are very light, so they slow down faster at higher speeds due to relatively low momentum. Aero drag kicks their butts when you take away the power. That's why the car decelerates more gradually and coasts noticibly longer at lower speeds.

Don't worry about what to call the technique. It's a fine distinction, and it doesn't matter a heck of a lot.

As far as BSFC, you'd probably be safe accelerating at about 1/2 throttle in the range of 2500 RPM, +/- 300 RPM.

But that only applies if you don't have a stop or slow-down immediately after accelerating - but you probably know that already. Try to avoid accelerating into any situation that requires you to get on the brakes. Coast in N to burn off your speed instead, if you can.

[GasSavers_Kraig]

Thanks for the replies! I'll check tire pressure and make sure I don't have any brakes dragging etc. I'd like to be able to get to 60 mpg with technique before starting to make any mods to the car. I guess I really need to save up for a SuperMid and get a tach.

[MetroMPG]

My first Firefly had sticky front calipers (corrosion on the piston - wouldn't retract smoothly). The car would come to a very slight but noticible STOP when coasting down to zero in neutral. I changed them, and that fixed it, but I suspect even a mechanic wouldn't have said the drag was serious, or even a problem.

Once your tire pressure is up, you should be able to push the car VERY easily with one hand on a level smooth surface. When coasting to zero, it should glide to a practically imperceptible stop, no "lurch" or jerk at the end.

[GasSavers_Kraig]

Thanks again.

[Silveredwings]

Oh, and I thought was normal for my brakes to throb like a trans-warp drive set to overload. Next you're going to tell me my tire tread is too worn when the steel belts make sparks on the road going around corners.

[Peakster]

Well instead of making a new thread, I thought I'd hijack this one

During my last fillup with the scangauge in use, I was codfishing like mad all over town, turning off the engine at virtually every available coast (that was 5 seconds or more). When I went to fill the tank, the Scangauge displayed that I used 3.8 gallons, but it took 4.3 to fill!

That combined with less-than-aspiring 52mpg I began to wonder if codfishing makes any sense in a city like mine where there are virtually no hills at all. I can only coast with the engine off for a mere 2 or 3 city blocks at most before coming to a stoplight, so is it even worth it to shut off my engine while coasting those short distances? Keep in mind that it's winter time here with lots of snow so my coasting distances have diminished. How many seconds of codfishing should be a minimum for best effect for FE?

[GasSavers_James]

Pulse and glide and codfishing is best done in the summertime. When you turn off the car in the winter, it is sometimes so cold that the engine has cooled off by the time you restart. I would not shut the engine off until you have driven for at least 10 minutes when it is below 20 deg F out. I think you might as well continue to warm up the oil, coolant, etc and leave it idling most of the time during winter. I would still coast at any given opportunity.
In the winter aerodynamic drag is greater, and since your car is very light and not very aerodynamic, the slower you go the better your economy will be (to a certain point).

You might also want to make sure your car idles at the right speed once it is warmed up. If it idles high it will use a lot more fuel while coasting (w engine running of course).

[GasSavers_James]

I notice that my father's 06 HCH II does not autostop until everything is warmed up--usually 5-10 minutes after starting. If that car does that, probably the engineers figured it wasnt worth the extra wear and tear of cold startups to save a little bit of fuel.

[Peakster]

What about when the engine is fully warmed up? How long should the engine be shut off to offset the extra fuel required to bump-start and/or key-start the car?

My Geo uses 0.1gph (800rpm) when it's warmed up and idling at a stop. When the car is rolling during a coast with the engine on, the car uses 0.2gph (1250-1300rpm). Is it normal for the ICE to idle higher when the car is in motion?