P&G on an AT

[Mikeb Yaris]

Is it a mistake to attempt P&G on a car equipped with an AT? If not, what is the best procedure / technique to follow?

[BailOut]

Hello Mike,

You can P&G with a Yaris with an AT but only by going to Neutral with the engine running, not by turning the engine off (the Yaris cannot be flat towed). As an alternative you might want to try Hang Time (see the sticky for it at the top of this sub-forum).

[Mikeb Yaris]

I've been experimenting with hang time (no scan gauge mind you) and I'm not breaking the 43 mpg barrier. I think the subtle throttle position is more than I can master w/o one. I am going to pick one up for Christmas though.

I can pop in and out of neutral pretty easily it seems (no key off), but I don't want to be doing something that people already know is bad for the car - like frequent engagement of the tranny at speed. Do you know anyone successfully pulling this off without damage?

[mark2908]

Hi Mike,
P&G does work with the AT. (in N ICE on)
I've used P&G for 6,000 miles, and so far so good. It works best at slower speeds under 45 mph. Tire pressure seems to make a big difference on glide distances. (My tires are at 50 psi). What I do daily is:

Accelerate with rpm's peaking at about 1,700 rpm to about 35 mph.
Shift to N, and glide down to about 30 mph.
Shift to D, let the AT sync for a second and pulse back to 35 and repeat.

If you do get a ScanGauge for Christmas, watch the current trip mpg readout. The trip average should "ratchet up" after each pulse.
On down hills, or decelerating approaching stops, I stay in gear (foot off the gas) to use Dfco.
I get a lot of "current trips" of 50 + when the lights are timed right. With traffic and frequent stops, it's hard to me to break 42 mpg for a tank. (all city)
There are good P&G descriptions and discussions at cleanmpg.com as well.
Best of luck to you.

Mark

[voodoo22]

P&G means that you're actually turning off the engine while coasting.

AT's can only be P&G'd if they are flat towable. Search that term and you'll find charts listing flat towable cars.

The Yaris can be safely used for N-ICE on gliding as stated above and it can be used for P&G'd at lower speeds on flat roads as per the manual.

[Mikeb Yaris]

Originally Posted by voodoo22

P&G means that you're actually turning off the engine while coasting.

AT's can only be P&G'd if they are flat towable. Search that term and you'll find charts listing flat towable cars.

The Yaris can be safely used for N-ICE on gliding as stated above and it can be used for P&G'd at lower speeds on flat roads as per the manual.

Obviously, since I don't shut down the engine, what I'm doing cannot really be called pulse and glide - and since I accel to 60 and coast in neutral to 50 I'm wasting effort?

Also, what is N-ICE?

I've been doing this for 250 miles. Maybe I'll go ahead and fill up early just to see?

[natethegreat38]

Just curious- what is P&G? lol It is probably something obvious that I just cant think of right now...

[mark2908]

Originally Posted by natethegreat38

Just curious- what is P&G? lol It is probably something obvious that I just cant think of right now...

Pulse and Glide.

[mark2908]

Originally Posted by Mikeb Yaris

Obviously, since I don't shut down the engine, what I'm doing cannot really be called pulse and glide - and since I accel to 60 and coast in neutral to 50 I'm wasting effort?

Also, what is N-ICE?

I've been doing this for 250 miles. Maybe I'll go ahead and fill up early just to see?

"NICE on" is coasting in N at idle... engine on.

Voodoo is right. Technically a P&G glide is done with the engine off. The same principals still apply, but are less efficient because the engine is idling during the glide.

P&G with an AT may truly be NICE on coasting. The same concepts apply to both. There is very little AT specific info on NICE on coasting techniques at YW or at cleanmpg. However, one can learn from the basic concepts of P&G and apply them to NICE on coasting. Sorry to blur the terminology. P&G NICE on should be a term if it isn't.

IMO, at highway speeds, P&G NICE on can be tricky even with a ScanGauge. At speeds over 45 mph, there is more wind resistance, so the frequent accelerations and shorter duration glides, can cost as much as the coasting benefit. Not to say it doesn't work, it does, but it takes more focus.

[Mikeb Yaris]

I worry about killing any benefit with poor acceleration cycles - the scan gauge would certainly help with this as well. It is difficult to be consistent.

[natethegreat38]

Originally Posted by mark2908

Pulse and Glide.

Thanks mark. I am interested and still learning. I have read thoroughly about the DFCO, but this is the first time I have come across P&G

[voodoo22]

Originally Posted by Mikeb Yaris

I worry about killing any benefit with poor acceleration cycles - the scan gauge would certainly help with this as well. It is difficult to be consistent.

I don't have a scan gauge either.

One thing I have found from feel is it's better to go from N back to D a little before the bottom of a hill so you can maintain or even pick up a little more momentum for the next hill in those situation where hills are closely spaced.

I'm sure a scan gauge would help you, but if you tough it out you'll probably find you don't need to spend the $150 on one, instead put that $150 towards gas.

[Mikeb Yaris]

Originally Posted by voodoo22

I'm sure a scan gauge would help you, but if you tough it out you'll probably find you don't need to spend the $150 on one, instead put that $150 towards gas.

That had been my position until I started really enjoying these attempts at better gas mileage. Now, I'm enticed by the "fun" factor of having cool data to play with and try to understand.

So, I filled up and found that my attempts, at least on the surface, aren't paying off. Previously, I had three tanks in a row @ 43 mpg. Then I tried my wife's experiment of driving "normal" and yielded 38. Today, after 325 miles of high speed N-ICE simulated pulse and glide I was only back up to 39 and just barely.

My thoughts are two-fold. 1) Wind resistance between 50-60 mph slows the vehicle too quickly for significant benefit and probably hinders efficient pulse. and 2) There just no doubt in my mind that my pulse cycles were not as efficient as they could/ought to be. I was trying to, by intuition, discern an efficient acceleration rate but how in the world can I think I even know what kind of positive pressure on the accelerator is called for without something to measure that by?

So, I'm back to simple use of moderate acceleration, moderate speed and DFCO whenever possible.

We just hit a cold snap so I think I better check my tires today too...

What a great hobby!

[mark2908]

Hi Mike,
Sorry your results were not what you hoped for. You may get better results
driving 55 instead of pulsing from 60 to 50. My numbers are going down with colder temps. Could that be part of it too?
This is my first winter with car, but from what I've read it is pretty typical for winter mpg's to go down for multiple reasons.
My 6 mile commute mpg's have gone down by 3 to 5 mpg with morning temps in the 40's.

Here's one trick I use with acceleration. (once warm) Accelerate slightly faster at first, but back off the throttle right away and get the transmission to shift up, accelerating in higher gears at engine speeds not far above idle.

For highway speeds, (as Bailout suggested) Hang Time is a good technique and can be felt without a Scangauge. On a level stretch, at 55 mph slowly back off the throttle until your speed starts to drop. Take note of the position of your foot. Try the same thing again but don't go quite as far. See how far you can back off the throttle without slowing, then hold it there. That's it. It's a small move, but once you find it it's always there.
It is a fun hobby. Cheers

[Mikeb Yaris]

Originally Posted by mark2908

Hi Mike,

For highway speeds, (as Bailout suggested) Hang Time is a good technique and can be felt without a Scangauge. On a level stretch, at 55 mph slowly back off the throttle until your speed starts to drop. Take note of the position of your foot. Try the same thing again but don't go quite as far. See how far you can back off the throttle without slowing, then hold it there. That's it. It's a small move, but once you find it it's always there.
It is a fun hobby. Cheers

I have some nerve damage on my right side and so determining precise foot position / angle is pretty tough for me along with knowing with certainty that once I find a position I think is right, keeping it there. I DO try it sometimes though - with some if not little success. I'm hoping that if my good wife purchases me a scan gauge as a gadget, i'll be able to find the sweet spot with the throttle position indicator so that I have a number to look at rather than a feel. I believe my acceleration rate is inconsistent for the same reasons, so real life fuel flow or mpg readout will give me digital targets rather than physical ones.

This tank I've been doing a little bit of p&g in town at low speeds. I'm surprised at how far I can coast between pulses, so I'm still hopeful.

The good thing about doing this as a hobby is that you can remember that you're just learning and experimenting - no life and death on success here! But the competitive side of me wants bragging rights for success! I keep wanting to put a sign in my window with my average mpg's on it!

re: Winter - we've had a couple of cool days here, but nothing requiring a coat. I think one morning it was down to 30, but came back up to 60. 70 today so I have doubts whether the cool weather is enough to be hurting me yet - unless they've changed the gas formulation for the season. How can I find that out?

[mark2908]

Originally Posted by Mikeb Yaris

I have some nerve damage on my right side and so determining precise foot position / angle is pretty tough for me along with knowing with certainty that once I find a position I think is right, keeping it there. I DO try it sometimes though - with some if not little success. I'm hoping that if my good wife purchases me a scan gauge as a gadget, i'll be able to find the sweet spot with the throttle position indicator so that I have a number to look at rather than a feel. I believe my acceleration rate is inconsistent for the same reasons, so real life fuel flow or mpg readout will give me digital targets rather than physical ones.

This tank I've been doing a little bit of p&g in town at low speeds. I'm surprised at how far I can coast between pulses, so I'm still hopeful.

The good thing about doing this as a hobby is that you can remember that you're just learning and experimenting - no life and death on success here! But the competitive side of me wants bragging rights for success! I keep wanting to put a sign in my window with my average mpg's on it!

re: Winter - we've had a couple of cool days here, but nothing requiring a coat. I think one morning it was down to 30, but came back up to 60. 70 today so I have doubts whether the cool weather is enough to be hurting me yet - unless they've changed the gas formulation for the season. How can I find that out?

It is amazing how far you can coast on each acceleration phase. I try to keep my foot off the gas as much as I can. (N or DFCO)
Don't forget DFCO... Read Bailout's Sticky on that if you haven't already. For off ramps, down hills, and decelerations approaching stops, leave it in gear with your foot off the gas. The computer will cut the fuel to the injectors. Less (0) fuel is used.

I don't know about winter formulations. However the cold weather does make a big difference. Cold engine warm up is far longer at 45 degrees than at 70. The shorter the trip, the harder the FE hit. Temp swings have been wide here so I've been comparing morning temps from the 70's to the 40's on the same tank of gas. Winter gas aside, just the longer warm up phase on my 6 mile commute, has been interesting to watch. An unarguable drop, relative to the morning temps.

Take care.

[Mikeb Yaris]

Mark,

Yes, I'm a big fan of DFCO. In fact, because of the use of it, I've become quite a fan of the Yaris' gated shifter. I coast in D until the tach approaches 1K rpm, the pop left into 3 and sometimes if I still have a distance to go I'll drop on down to 2. Then I idle at stops in N. So, the pattern D - 3 - D - N is very easy and sure. Straight shifters are a bit goofy because it is so easy to pass up the selection you want.

Last night I was driving my wife's Durango (her computer has her averaging 11 mpg) and tried it - I was all over the place and it really pissed her off!

I have a thirty mile commute and rarely if every do short shots across town. I HAVE noticed though, with morning temps around 55 - 60, that it takes quite a distance for the cold eng light to go off. Plus, when cold it does not like to shift up - that's quite annoying.