105 MPG coast - Page 3

diamondlarry · 06-20-2007, 04:51 PM

Quote:

Originally Posted by popimp

Question about the P&G, or pulse and coast I guess. If I did the method of speeding up to 60 and using the coast function of the cruise control to drop to 55 then cruise back to 60, would this be the same as turning off the cruise then getting the speed back to 60 manually?

I haven't used cruise control much in the past but, from what I remember, most CC's try to get back up to speed as quick as possible which means they may "push" the pedal harder than what you might do manually. Many people say that your foot can get better FE than CC but it's a WHOLE bunch more effort to do it yourself.
Edit: I just checked out your garage. Nice choice of lubricant and filters.

I'm using the 0W-20 in the Prius.

minic6 · 06-20-2007, 04:51 PM

Shutting of the O2 can cause a problem with your emmisions if your trying to be green.

diamondlarry · 06-20-2007, 05:00 PM

Quote:

Originally Posted by minic6

Shutting of the O2 can cause a problem with your emmisions if your trying to be green.

Which by the way, is why I never went there.

savoF3 · 06-20-2007, 05:04 PM

Quote:

Originally Posted by popimp

Question about the P&G, or pulse and coast I guess. If I did the method of speeding up to 60 and using the coast function of the cruise control to drop to 55 then cruise back to 60, would this be the same as turning off the cruise then getting the speed back to 60 manually?

What diamondlarry said, plus "coast" on the cruise control will coast in gear. It'll drop fast from 60 to 55.

ffvben · 06-20-2007, 06:01 PM

Quote:

Originally Posted by popimp

I'm trying. We're probably going to New Orleans this weekend. About 70 miles from Biloxi. What would be the most effecient speed on a 70 mph I-10?

I think 15mph under the max speed limit is safe (this might be a law - you can get a ticket for driving to slow, causing a hazard) or you'll have to turn your flashers on as do big trucks do going up hills. this way someone doing 85-90 mph will see you and have a chance to slow down or change lanes vs you might get rear ended without flashers. or have one of those big dump trucks with the crash zone cushion following you

GasSavers_rGS · 06-20-2007, 06:51 PM

Quote:

Originally Posted by savoF3

At highway speeds I've been seeing negative value to trying to pulse and coast, though. The drag brings it down too fast. Let us know if you get some good comparative data and what your secret is to pulsing a minivan.

savoF3,

The return leg was late at night so I was fatigued before the leg began. So I was just pulse and coasting not only to try to increase my mpg but the more important reason was to help keep my mind awake and alert to prevent boredom induced falling asleep at the wheel. Man, pulse and coasting does utilize more of your attention and therefore brainpower to drive. Fortunately, by returning back to familiar road sections near home helped me perk back up due to "home sweet home" emotions so I stopped pulse and coasting at that point.

GasSavers_rGS · 06-20-2007, 07:14 PM

Quote:

Originally Posted by popimp

Question about the P&G, or pulse and coast I guess. If I did the method of speeding up to 60 and using the coast function of the cruise control to drop to 55 then cruise back to 60, would this be the same as turning off the cruise then getting the speed back to 60 manually?

popimp,

Purely from a technique comparison they would be different since you're doing different things in each technique.

So with the first technique, you're basically cruise controlled at 60 mph then push the [coast] button down to 55 mph then re-engage cruise control so it automatically accelerates back up to 60 mph. Am I understanding the technique correctly? If so, based on "gut instinct" since I don't have a ScanGuage, the "automatic acceleration from 55 mph to 60 mph" is probably going to involve an RPM spike to like 2500 rpm, achieve 60mph then RPMs drop back to the appropriate RPM for 60 mph. So since it's probably going to spike, I would recommend against this technique.

Now from a pure no cruise control technique, this may result in spending too much time with your eyeballs inside the car by looking at the tachometer and the speedometer to see if the RPMs are low and the speedometer is bouncing between 55 mph and 60 mph. That would probably distract you from safety of driving by looking outside the windshield for other traffic. Increasing fuel economy and saving fuel expense is one thing, but unless you're the only car on the road, you could also "fuel efficiently collide" with another car. So like the first technique, I'd recommend against it.

What I did was to smoothly and slowly accelerate up to 55 mph then set the cruise control. Then, on the flats and gentle downhills, I would add like an extra 100~200 RPM to help nudge the speed up to 60 mph. Then once it reached 60 mph, I took my foot off the accelerator and disengaged the cruise control so that my RPMs dropped as low and fast as possible. However, at around 57 mph or so I re-engage the cruise control so that the tachometer pops up from 1500 RPM to 1800 RPM instead of spiking to like 2500 RPM had I re-engaged the cruise control at or below 55 mph. YMMV for your 2006 model. When "brain overload" happened, I just temporarily discontined pulse and gliding and just sat at 55 mph with cruise control.

I hope this helps.