Pulse & Glide or In 5th Gear

[fairdinkumfrankies]

My 2010 Yaris Auto does not glide in gear. I have not been willing to place it in neutral at high speeds. The 2011 Fiesta six speed auto-manual glides in gear very well. I have had tank averages of 42mpg mixed with the Yaris and 48mpg with the Fiesta. I tend to run 60mph on the highway slowing to 55 up hills and maintaining 60/65 going down. We did not get manuals because my wife drives both cars. The Fiesta is the MPG champ by far but the Yaris is the king around town.

[mcbota]

Today, I have made a trip with my car, mostly on roads which passes through villages, so , one way I drive almost steady with 70 kph, in fifth gear, and the route back, I have made pulse and glide, 80/60 kph, in fourth gear, the consumption, one way was, 3.8 l/100km, and back 2.9 l/100 km; is this a good method, the clutch isnt affected too much, will be no problem with it? It was the first time when I tried this method!

[oldtamiyaphile]

Originally Posted by mcbota

Today, I have made a trip with my car, mostly on roads which passes through villages, so , one way I drive almost steady with 70 kph, in fifth gear, and the route back, I have made pulse and glide, 80/60 kph, in fourth gear, the consumption, one way was, 3.8 l/100km, and back 2.9 l/100 km; is this a good method, the clutch isnt affected too much, will be no problem with it? It was the first time when I tried this method!

Since your car is a diesel with little engine braking, try pulse and glide IN GEAR. It's a lot less work and gives me roughly 15% improvement.

Your 25% improvement is huge, I feel other factors were involved (tail wind or elevation differences, or P&G fooling the OEM display as with my Fiat), but yes P&G really works. The gearbox & clutch will be OK as long as you rev match before shifting back into gear. I'd also suggest shifting into neutral without using the clutch, just back off until the gear lever is easy to shift out (works better on some cars than others).

But IMO this is really a petrol car technique. For my TDI both methods give the same result, so I'm using the easier method.

[mcbota]

Coasting in gear, on flat roads, isnt so useful for my car, so for this reason I have tried coasting in neutral. Maybe, on the going road, the speed wasnt so constant, and on the return trip, I started P&G, even from the beginning, the engine being warm already. Maybe most of you have not this istuation, but here, on the ”national roads”, not highway, you cannot speed more than 70, so I choose to make 80/60 kph pulse and glide. Usually, the revs in neutral are at idle, and when I shift back in gear, I use the clutch and put in 4 gear, to have the optimal speed! My fear is, because of , on-off clutch, to not appears excessive wear of the clutch!

[mikeyjd]

Originally Posted by mcbota

Coasting in gear, on flat roads, isnt so useful for my car, so for this reason I have tried coasting in neutral. Maybe, on the going road, the speed wasnt so constant, and on the return trip, I started P&G, even from the beginning, the engine being warm already. Maybe most of you have not this istuation, but here, on the ”national roads”, not highway, you cannot speed more than 70, so I choose to make 80/60 kph pulse and glide. Usually, the revs in neutral are at idle, and when I shift back in gear, I use the clutch and put in 4 gear, to have the optimal speed! My fear is, because of , on-off clutch, to not appears excessive wear of the clutch!

It's always better to coast in neutral. You can do on/off pulse and glide without hurting the clutch, but it does take a little practice initially. It would be better economy if you were able to do the 80/60 pulse in 5th gear rather than 4th.

[mcbota]

Originally Posted by mikeyjd

if you were able to do the 80/60 pulse in 5th gear rather than 4th.

At 60kph the rpm when I put in fifth gear, seems to be too low, and for this reason I have tried with fourth gear. I will try with fifth gear, and in city probably, iwill try to make 60/40 kph with fourth gear. I was thinking that can be an optimal load for the gears!

[oldtamiyaphile]

4th is probably right at BSFC. It's 80km/h not 80mph

[mikeyjd]

Originally Posted by oldtamiyaphile

4th is probably right at BSFC. It's 80km/h not 80mph

I'm always in 5th by 50km/h (30mph), you must have some really tall gears.

[mcbota]

Originally Posted by mikeyjd

I'm always in 5th by 50km/h (30mph), you must have some really tall gears.

When I am cruising I am the same, 5th at 50 kph, but when I have to shift, 60kph seems better for 4th gear; and for sure I drive at low rpm, but I do not like to force the engine. shifting, when the revs are too low!

[serialk11r]

Originally Posted by oldtamiyaphile

Since your car is a diesel with little engine braking, try pulse and glide IN GEAR. It's a lot less work and gives me roughly 15% improvement.

I feel like this would depend on the car and the speed you're going. If your engine speed in gear is high enough compared to idle the in gear coast could be slowing you down a lot, wiping out any gain from the "pulse". Engine braking is primarily due to mechanical friction not pumping, easy way to test this out is step on the throttle in a cable throttle car with engine off; the engine braking is reduced, but only very slightly.