Pulse and Glide can really work! - Toyota Yaris Forums

Amdkt7 · 05-20-2013, 11:43 AM

This weekend I got stuck on the interstate in stop and go traffic for about ten miles. I was not happy, as I had been averaging nearly 50 mpg so far for the trip up to this point.

However, I settled into short pulses, followed by nice long glides with the clutch in. Some stretches were up hill, which cut into my average, but made up for on the down slopes where only a small bump was needed to restore my speed.

I monitored my instant and average mpg with my new ScanGuage II. I also did not interfere with the traffic flow, if anything I fit right in, with perhaps a bit of a smoothing effect on flow.

The ScanGuage is not calibrated yet, as I have not completed the two fillups required, however it matches the built in Eco-meter by about 4-5%.

My other technique that I am using a lot is to hold my throttle steady (monitoring the TPS reading on the SGII) and allow the road to vary my speed. This only works in light traffic as it can be really annoying to other drivers. Using this technique I brought my average trip to work up a few points despite wind conditions. For the road I drive a TPS reading of 21 seems to work real well.

With the Pulse and Glide approach I would keep my rpms up when accelerating, around 2 to 3K so that I could quickly bump back up to speed, then quick in with the clutch. I love seeing 300+ MPG on the gauge! Even better, when coming in to a forced stop downshifting and seeing 9999 MPG as DFCO kicks in, nice going down a hill where I only need a little engine braking to keep speed down.

MadMax · 05-20-2013, 09:15 PM

Great, you get better fuel economy but you burn out your clutch in a fraction of its normal life...

47_MasoN_47 · 05-20-2013, 09:45 PM

Quote:

Originally Posted by MadMax

Great, you get better fuel economy but you burn out your clutch in a fraction of its normal life...

Yeah I was thinking that sounds horrible for the clutch. Lot of people preach about engine braking and all that jazz on manuals, but IMO brake pads are a heck of a lot cheaper than a clutch. I try to stay off that guy as much as possible.

Bluevitz-rs · 05-21-2013, 07:52 AM

Its fine for the clutch, that's what they're designed for. Hard driving, high RPM shifting and slipping the clutch is what kills them, not letting the clutch out while downshifting or crawling in traffic and coasting. I've driven manual cars all my life.

mr_miles · 05-21-2013, 07:26 PM

Haha, I always engine brake. Partially because of my grandpa teaching me how to drive (he drove truck) and because if i'm sloppy with the OEM one I can upgrade to a lightweight flywheel and new clutch sooner! Not to say that I am beating on it, though. I still rev match and baby it to make it last.

Amdkt7 · 05-22-2013, 09:36 AM

I had 140K miles on my Kia clutch, was still going strong. I always down shift when I need to slow down. I have never known anybody who drove for high FE who did not get a lot of miles out of the clutch. It is the take offs that cause most of the wear on the clutch. Popping in in and out to pulse and glide has almost no wear.

I'm using a mix of techniques on my daily commute. I'm adding more P&G as I learn where it works and where it is better just to hold my throttle steady. I achieved 53 MPG yesterday on the way home which is overall down hill, but with a stiff head wind. I usually have to have at least no wind to do that. This morning I again got 53, and that was no wind, and up to the higher elevation. Most of the trip my average was around 48 mpg, but once I got on top of the plateau I was able to P&G for parts of the remaining 5 miles and my average climbed up to 53.
P&G is very easy on the clutch, and can be fairly easy to do. I do not shut off the engine, except for one traffic light that is red a long time. I use it mostly on gentle downgrades that I cannot simply cost on. It's too much work to do on the level. I generally let my speed drop only about 5 mph, then a snappy pulse back up to speed. I'm still not hitting the throttle very hard on the pulse, generally less then 30 on my TPS reading.
There is no wear on the clutch when disengaging. When I reengage the clutch I am going to bring my engine speed up as I let the clutch out to avoid knocking any of my speed off.
Now, when I down shift I do not speed match as I want to slow the car. That is harder on the clutch, but it still is nothing like the wear that a poor take off on a hill causes.
I expect that the clutch will last as long as I own the car anyway.

47_MasoN_47 · 05-22-2013, 10:51 AM

I've never figured out that rev matching business.

Amdkt7 · 05-22-2013, 10:59 AM

Simply put you try to increase the engine speed so that when you let the clutch out there is no bump. If you get it exactly right the engine speed will not change once the clutch is fully out. Very difficult to do exactly, but close counts, it reduces the slippage of the clutch, or the shock on the drive line components.

With the small size of the Yaris engine it very quickly changes speeds without much shock, there is less momentum due to the reduced mass of the engine.

I hope I answered your question, if you wondered what rev matching means.

05-20-2013, 11:43 AM	#1
Amdkt7 Returning to Toyota Drives: 2013 L 3dr MT Join Date: Mar 2013 Location: Nashville, TN Posts: 154	Pulse and Glide can really work! This weekend I got stuck on the interstate in stop and go traffic for about ten miles. I was not happy, as I had been averaging nearly 50 mpg so far for the trip up to this point. However, I settled into short pulses, followed by nice long glides with the clutch in. Some stretches were up hill, which cut into my average, but made up for on the down slopes where only a small bump was needed to restore my speed. I monitored my instant and average mpg with my new ScanGuage II. I also did not interfere with the traffic flow, if anything I fit right in, with perhaps a bit of a smoothing effect on flow. The ScanGuage is not calibrated yet, as I have not completed the two fillups required, however it matches the built in Eco-meter by about 4-5%. My other technique that I am using a lot is to hold my throttle steady (monitoring the TPS reading on the SGII) and allow the road to vary my speed. This only works in light traffic as it can be really annoying to other drivers. Using this technique I brought my average trip to work up a few points despite wind conditions. For the road I drive a TPS reading of 21 seems to work real well. With the Pulse and Glide approach I would keep my rpms up when accelerating, around 2 to 3K so that I could quickly bump back up to speed, then quick in with the clutch. I love seeing 300+ MPG on the gauge! Even better, when coming in to a forced stop downshifting and seeing 9999 MPG as DFCO kicks in, nice going down a hill where I only need a little engine braking to keep speed down.

05-20-2013, 09:15 PM	#2
MadMax Drives: 2008 Yaris Liftback (Sprocket) Join Date: Oct 2008 Location: San Antonio, Texas! Posts: 2,799	Great, you get better fuel economy but you burn out your clutch in a fraction of its normal life... __________________

05-22-2013, 10:51 AM	#7
47_MasoN_47 What I thought I'd do was View User's Garage Drives: 09 Yaris Sedan Join Date: Aug 2009 Location: Northwest Alabama Posts: 1,140	I've never figured out that rev matching business. __________________ My Nissan Hardbody (D21) 4x4 build log Check out my YouTube channel (mostly shooting) - http://www.youtube.com/user/47MasoN47

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05-21-2013, 07:52 AM	#4
Bluevitz-rs 1NZ-6spd View User's Garage Drives: '05 6-Spd Vitz RS Join Date: Oct 2008 Location: Oshawa, Ontario, Canada Posts: 2,967	Its fine for the clutch, that's what they're designed for. Hard driving, high RPM shifting and slipping the clutch is what kills them, not letting the clutch out while downshifting or crawling in traffic and coasting. I've driven manual cars all my life.

05-22-2013, 09:36 AM	#6
Amdkt7 Returning to Toyota Drives: 2013 L 3dr MT Join Date: Mar 2013 Location: Nashville, TN Posts: 154	I had 140K miles on my Kia clutch, was still going strong. I always down shift when I need to slow down. I have never known anybody who drove for high FE who did not get a lot of miles out of the clutch. It is the take offs that cause most of the wear on the clutch. Popping in in and out to pulse and glide has almost no wear. I'm using a mix of techniques on my daily commute. I'm adding more P&G as I learn where it works and where it is better just to hold my throttle steady. I achieved 53 MPG yesterday on the way home which is overall down hill, but with a stiff head wind. I usually have to have at least no wind to do that. This morning I again got 53, and that was no wind, and up to the higher elevation. Most of the trip my average was around 48 mpg, but once I got on top of the plateau I was able to P&G for parts of the remaining 5 miles and my average climbed up to 53. P&G is very easy on the clutch, and can be fairly easy to do. I do not shut off the engine, except for one traffic light that is red a long time. I use it mostly on gentle downgrades that I cannot simply cost on. It's too much work to do on the level. I generally let my speed drop only about 5 mph, then a snappy pulse back up to speed. I'm still not hitting the throttle very hard on the pulse, generally less then 30 on my TPS reading. There is no wear on the clutch when disengaging. When I reengage the clutch I am going to bring my engine speed up as I let the clutch out to avoid knocking any of my speed off. Now, when I down shift I do not speed match as I want to slow the car. That is harder on the clutch, but it still is nothing like the wear that a poor take off on a hill causes. I expect that the clutch will last as long as I own the car anyway.

05-22-2013, 10:59 AM	#8
Amdkt7 Returning to Toyota Drives: 2013 L 3dr MT Join Date: Mar 2013 Location: Nashville, TN Posts: 154	Simply put you try to increase the engine speed so that when you let the clutch out there is no bump. If you get it exactly right the engine speed will not change once the clutch is fully out. Very difficult to do exactly, but close counts, it reduces the slippage of the clutch, or the shock on the drive line components. With the small size of the Yaris engine it very quickly changes speeds without much shock, there is less momentum due to the reduced mass of the engine. I hope I answered your question, if you wondered what rev matching means.