Transmission wear from P&G (pulse and glide)?

[edwin]

"By my estimation, clutching had to occur anyhow to get into neutral."

really ? I have been effortlessly and smoothly going from 4th or 5th gear to
neutral without the clutch for over 30 years since I learned the trick. I have never had a problem with the trans or replaced a clutch.

[EcoCivic]

Originally Posted by edwin

"By my estimation, clutching had to occur anyhow to get into neutral."

really ? I have been effortlessly and smoothly going from 4th or 5th gear to
neutral without the clutch for over 30 years since I learned the trick. I have never had a problem with the trans or replaced a clutch.

On my car the best technique for shifting to neutral without the clutch is release throttle completely, wait about half a second, then quickly pull it into neutral. If you get it right, it feels no different than using the clutch since the drivetrain is unloaded.

As always, don't use force. If it doesn't want to come out of gear, try again or just use the clutch. As long as you don't force it I don't see how you could cause any damage with this method.

[EcoCivic]

I tried engine off coasting for the first time today and didn't see any MPG gains. My average for today was 49.2 MPG which is typical for my daily 50 mile commute. I don't like the way the transmission feels going back into gear with the engine off either. Instead of effortlessly sliding into gear like when the RPMs are matched, it resists for a second while the synchros speed up the input shaft/clutch similar to how downshifting from 5th to 2nd at 45+ MPH without doubling clutching feels. I can't see how repeatedly doing this every day wouldn't take its toll on the transmission over the years so I'll stick to leaving the engine idling when I coast.

For the sake of discussion, what is the best way do go back into gear from 0 RPM while in motion to minimize synchronizer wear? Is it better to use light pressure over a longer period of time until it goes in or is it better to use a little force to quickly get it back into gear to minimize the amount of time the synchros are slipping for? I suspect the best compromise would be to use a moderate amount of force to get back into gear relatively quickly but without jamming it in?

[Gasoline Fumes]

What gear and what speed? I bump start in the highest gear I can. I think cranking speed is around 300 RPM, so you don't need the engine to spin very fast to start it.

[EcoCivic]

Originally Posted by Gasoline Fumes

What gear and what speed? I bump start in the highest gear I can. I think cranking speed is around 300 RPM, so you don't need the engine to spin very fast to start it.

Always used 5th gear to start it. When I was using pulse and glide I was usually bump starting it at between 40 and 50 MPH so around 1600-2000 RPM. When coasting to a stop with the engine off, I'd put it in 5th to start it once I'm down to around 15-20 MPH although I'm sure it would have started a bit lower than that. As you said, the engine doesn't have to spin very fast to start.

[Gasoline Fumes]

Originally Posted by EcoCivic

Always used 5th gear to start it. When I was using pulse and glide I was usually bump starting it at between 40 and 50 MPH so around 1600-2000 RPM. When coasting to a stop with the engine off, I'd put it in 5th to start it once I'm down to around 15-20 MPH although I'm sure it would have started a bit lower than that. As you said, the engine doesn't have to spin very fast to start.

That might be a bit fast for bump starting. If I'm doing pulse and glide, 40-50 MPH is usually where I'd be shutting the engine off, not starting it. That could be why you didn't see an improvement in MPG too. I think it works better at lower speeds. I usually only coast to stops and downhill if it's not so steep that I need to brake. I tried a constant P&G in my old Civic and didn't see an improvement either. It might work better on overpowered cars, or at very low speeds.

[EcoCivic]

Originally Posted by Gasoline Fumes

That might be a bit fast for bump starting. If I'm doing pulse and glide, 40-50 MPH is usually where I'd be shutting the engine off, not starting it. That could be why you didn't see an improvement in MPG too. I think it works better at lower speeds. I usually only coast to stops and downhill if it's not so steep that I need to brake. I tried a constant P&G in my old Civic and didn't see an improvement either. It might work better on overpowered cars, or at very low speeds.

I think you are right. My car coasts way better at lower speeds. Only problem is most of my driving is on rural 2 lane highways with 55 MPH speed limits. When there's no traffic low speeds is no problem, but when there's traffic behind me I try to stay within around 5 MPH of the speed limit when possible and keep speed variations gradual and to a minimum which often means having to step on it going down hill to keep from losing too much speed.

Pulse and glide definitely works for this car though. My best tank (49.6 MPG calculated manually) was accomplished by maintaining a steady 45-50 MPH up hill and on flat ground, driving without brakes, and coasting down every little hill even though most aren't steep enough to not lose speed on the way down.

When I manually calculate on fillups, I normally get around 45-47 MPG depending on traffic conditions, so something must be working well since that's on par with or better than the majority of 7th gen Civic hybrids from the data I've seen on Fuelly but with way better simplicity and performance. I'm hoping replacing my failing o2 sensor, getting a proper alignment, and finishing a couple small aero mods can get me close to or over 50 MPG. We will see

[SDMCF]

Originally Posted by EcoCivic

For the sake of discussion, what is the best way do go back into gear from 0 RPM while in motion to minimize synchronizer wear? Is it better to use light pressure over a longer period of time until it goes in or is it better to use a little force to quickly get it back into gear to minimize the amount of time the synchros are slipping for? I suspect the best compromise would be to use a moderate amount of force to get back into gear relatively quickly but without jamming it in?

I always raise the clutch until it just bites enough to get the engine spinning a little. Then depress the clutch a bit before raising it fully. This produces a smoother start because the engine speeds up more when I depress the clutch so when I raise it again the engine is already at a higher speed.
Also, as others have said, use top gear - or the highest gear you can at the speed you are travelling.

[EcoCivic]

Originally Posted by SDMCF

I always raise the clutch until it just bites enough to get the engine spinning a little. Then depress the clutch a bit before raising it fully. This produces a smoother start because the engine speeds up more when I depress the clutch so when I raise it again the engine is already at a higher speed.
Also, as others have said, use top gear - or the highest gear you can at the speed you are travelling.

Great tip, thanks! I just gently lifted the clutch to the bite point until it started then released it but your method sounds like it would work better.

[freebeard]

Originally Posted by SDMCF

I always raise the clutch until it just bites enough to get the engine spinning a little. Then depress the clutch a bit before raising it fully.

AKA, double clutching.

Double clutch
Technique
Double-clutching is a method of shifting gears used primarily for vehicles with an unsynchronized manual transmission, such as commercial trucks and specialty vehicles.Wikipedia