Re-starting by 'putting into gear'

Skezza
Posts: 2
Joined: Wed Aug 12, 2015 9:06 am

Re-starting by 'putting into gear'

Postby Skezza » Wed Aug 12, 2015 9:14 am

Hi,
First post, hope you guys can help.
I drive a Lupo SDI and currently average 69MPG every week (+ or - 1MPG). I wouldn't say I'm a strict or committed hyper-miler, I follow the rules fairly loosely but naturally I'm always looking for advice to improve.

A friend of mine is a more committed hyper-miler and does this stop/start lark while moving, as in, on a hill, he will routinely stop the car and use gravity (aided by the footbrake) to move in some cases for several miles. Now, when I tried this, I found it hard work because I would drop the car into neutral and then re-start the car by turning the key, powering the starter motor and then moving into gear. Now, my friend will coast for a while before putting the car into gear while still moving and then lifting his foot off the clutch which naturally restarts the car. No need for the starter motor and certainly appears a bit smoother and more pleasant. That said, this feels wrong to me, he's convinced that's there no real wear to any components other than the clutch and that it would be the same amount of wear as usual gear changes. Isn't there going to be wear to the synchromesh etc?

Is he right? is that what everyone does? He did claim that he learnt this technique from a hypermiling website but no website I've read recommends it.

Thoughts?

Thanks guys

User avatar
frv
Moderator
Posts: 3926
Joined: Wed Sep 03, 2008 11:09 am

Re: Re-starting by 'putting into gear'

Postby frv » Wed Aug 12, 2015 11:51 am

Hi Skezza and welcome to the forum. The Lupo SDI is capable of some amazing mpg, 69 is pretty good for modest hypermiling :D

In my old car I used to restart it over 20mph by a dropping it into gear from Neutral (I pretty much always put it in 'N' when coasting with the engine off to reduce wear on the throwout bearing) do a quick lift of the clutch pedal in 6th gear and back down again (i.e. just enough) to restart the engine and then put it in the actual gear I want to use - for example I might bump start in 6th and then select 3rd if I'm only doing 20mph. If I'm travelling at speed I use rev matching to reduce wear on the clutch.
I would have thought just lifting the clutch pedal to restart the engine would cause more wear, particularly at higher speeds as there would be no rev matching and therefore more clutch slipping and/or potentially jerky restarts.
In my wife's Honda Jazz, it will bump start in 5th at much lower speeds than my diesel did.

I also used key starting at slower speeds and this works fine too.
'15 Audi A3 Sportback SE CoD S-Tronic - 5+ year average 55+mpg
Image

(Retired) '06 Honda FR-V 2.2 i-CTDi - Best/longest tank: 67.92mpg (+51.6%) / 815.5 miles.

Skezza
Posts: 2
Joined: Wed Aug 12, 2015 9:06 am

Re: Re-starting by 'putting into gear'

Postby Skezza » Wed Aug 12, 2015 12:07 pm

Hi Skezza and welcome to the forum. The Lupo SDI is capable of some amazing mpg, 69 is pretty good for modest hypermiling :D

In my old car I used to restart it over 20mph by a dropping it into gear from Neutral (I pretty much always put it in 'N' when coasting with the engine off to reduce wear on the throwout bearing) do a quick lift of the clutch pedal in 6th gear and back down again (i.e. just enough) to restart the engine and then put it in the actual gear I want to use - for example I might bump start in 6th and then select 3rd if I'm only doing 20mph. If I'm travelling at speed I use rev matching to reduce wear on the clutch.
I would have thought just lifting the clutch pedal to restart the engine would cause more wear, particularly at higher speeds as there would be no rev matching and therefore more clutch slipping and/or potentially jerky restarts.
In my wife's Honda Jazz, it will bump start in 5th at much lower speeds than my diesel did.

I also used key starting at slower speeds and this works fine too.
The best I got out of my Lupo is actually 79MPG, but it was committed, and bloody hard work :P I know some people can do that every week, but I just found it really tough. I was happy to take 69MPG as a compromise. Plus I run on veg a lot of the time which means my equivalent MPG is about 95MPG. It's a good car for the old reliability though, 149k miles on the clock and it's still running strong.

So what would you consider a higher speed? The Lupo can comfortably sit in 5th at 30mph but bump starting at that speed, I'd be more likely to opt for 3rd or 4th? Are you saying if I did adopt this technique, it'd be easier on the clutch to put it into 6th the quickly change down? Do you bring the clutch out quickly or slowly?

To be fair to him, he doesn't tend to do it at higher speeds at all, usually at low speeds, often below 30MPH just when he's running out of momentum.

User avatar
frv
Moderator
Posts: 3926
Joined: Wed Sep 03, 2008 11:09 am

Re: Re-starting by 'putting into gear'

Postby frv » Wed Aug 12, 2015 8:24 pm

The simple answer is yes, bump in top gear then select the gear you actually want.
Bump quickly then slower when rev matching in gear you actually need.
'15 Audi A3 Sportback SE CoD S-Tronic - 5+ year average 55+mpg
Image

(Retired) '06 Honda FR-V 2.2 i-CTDi - Best/longest tank: 67.92mpg (+51.6%) / 815.5 miles.

Who is online

Users browsing this forum: No registered users and 2 guests