coasting in neutral w/ a manual...good or bad for the engine - Page 2 - JeepForum.com

Reply
 
LinkBack Thread Tools
post #16 of 74 Old 08-14-2010, 03:02 AM
JustJeepin85
Registered User
2005 TJ Wrangler 
 
Join Date: Aug 2010
Location: Evansville
Posts: 264
Garage
tbh i may be off base here but, if you have a manual you should know what gear you need, so does it really matter if you coast in neutral... i dont find myself doing it all that often id rather lug than have to rev and catch the moter up to the wheels, that is unless im on my bike...

i may be looking at it wrong ive rode street bikes much more then jeepin and had a mustang for years, love the exceleration so sure rev and dump or whatever you wanna call it is hella fun on those, a bit of a waste in jeeps unless truely on trails and need the umf... or maybe im mistaken there too hell seems to work for me...

JustJeepin85 is offline  
Sponsored Links
Advertisement
 
post #17 of 74 Old 08-14-2010, 03:05 AM
JustJeepin85
Registered User
2005 TJ Wrangler 
 
Join Date: Aug 2010
Location: Evansville
Posts: 264
Garage
Quote:
Originally Posted by Sleeperman View Post
I've been driving vehicles with a standard tranny for nearly 40 yrs, and agree totally with Mean Max. Plus, engine-braking is a wonderful thing when trying to time traffic lights!

Here, at 4900 ft above sea level, on pure gas, 15-17 mpg combined city/highway in a 2001 5-speed, 4.0L TJ is easy.
will agree when on the bike engine braking is quite awesome in corners and can be quite a setup for powering out when done... but what does this have to do with a jeep?
JustJeepin85 is offline  
post #18 of 74 Old 08-14-2010, 07:25 AM
Sweeney
Registered User
2006 LJ Wrangler 
 
Join Date: Aug 2006
Location: Spencer, MA
Posts: 1,329
The Toyota engineer is wrong to a degree. Some systems completely cut fuel under compression braking others, like the Jeep, only cut fuel if the rpm is above a certain point. I believe it's 2000rpm on the Jeep. My Audi cuts fuel completely under nearly any deceleration.

I've experimented with my Jeep and a scan tool reading the injector pulse and confirmed my Scan Gauge MPG readings. If I need to apply throttle to maintain speed going down hill then allowing the Jeep to roll in neutral delivers often double the MPG.

Safety; If traveling X mph down hill and I need to emergency stop the I will be disengaging the clutch and jumping on the brakes... effectively rolling in neutral... having it in gear to stop... moot point. If for some reason a situation arises where I need to accelerate after rolling in neutral I think I can afford the 0.250 seconds it takes to select the proper gear and go on my merry way. Chances are that if you were already in gear and needed to accelerate you'd need to select a lower gear anyway.

If you can't handle this sort of operation you should in no way be driving a manual transmission.

The times that I roll in neutral down hill I never feel that I am not in complete control of the vehicle.
Sweeney is offline  
post #19 of 74 Old 08-14-2010, 08:05 AM
redo4x
Registered User
2004 TJ Wrangler 
 
Join Date: Feb 2010
Location: Smithfield
Posts: 244
Try rolling down hill in gear with no gas in the tank and see if the engine still runs. It might use less gas in gear but there is no such thing as a gasoline engine runnin without fuel.
redo4x is offline  
post #20 of 74 Old 08-14-2010, 10:34 AM
WILLY348
Registered User
2003 TJ Wrangler 
 
Join Date: Mar 2007
Location: Snohomish, Washington
Posts: 1,307
I roll in neutral all the time.. theres hills all over the place here in Washington. I do it so much that i know what gear to shift back into when im done rolling down the hill.

2003 Jeep Wrangler Sport: Current Jeep
2006 Jeep Wrangler Unlimited: (Sold and missed!)
2004 Ford Mustang Cobra
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
WILLY348 is offline  
post #21 of 74 Old 08-14-2010, 12:06 PM
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil
Posts: 679
Quote:
Originally Posted by Sweeney View Post
The Toyota engineer is wrong to a degree. Some systems completely cut fuel under compression braking others, like the Jeep, only cut fuel if the rpm is above a certain point. I believe it's 2000rpm on the Jeep. My Audi cuts fuel completely under nearly any deceleration.

I've experimented with my Jeep and a scan tool reading the injector pulse and confirmed my Scan Gauge MPG readings. If I need to apply throttle to maintain speed going down hill then allowing the Jeep to roll in neutral delivers often double the MPG.

Safety; If traveling X mph down hill and I need to emergency stop the I will be disengaging the clutch and jumping on the brakes... effectively rolling in neutral... having it in gear to stop... moot point. If for some reason a situation arises where I need to accelerate after rolling in neutral I think I can afford the 0.250 seconds...
Ummmm, no It would take longer for the signal to go from your eyes to your brain, to making a decision of what to do. It's more like four to five seconds. In a few situations, by the time you react it's already too late.

I've been driving manual trans for quite a few years, including Super-sport motorcycles. I have yet to meet a single human being that can make an unplanned emergency manoeuvre in less then 1/2 a second that includes having to select a proper gear, throttle position, and body position.

VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
TheHeretic is offline  
post #22 of 74 Old 08-14-2010, 12:19 PM
Rino1425
Registered User
1993 YJ Wrangler 
 
Join Date: Mar 2010
Location: Dayton OH
Posts: 166
I keep it in gear most of the time so i can get back on the gas if i need to, it also helps slow you down when coming to a stop
Rino1425 is offline  
post #23 of 74 Old 08-14-2010, 12:27 PM
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil
Posts: 679
Quote:
Originally Posted by Mean Max View Post
Coasting out of gear or "free-wheeling" is a lousy habit to develop. Should the need to accelerate or decelerate suddenly happen you'll invariably struggle to figure out what gear to be in or how to quickly respond.

You should ALWAYS be in the correct gear for the speed of the vehicle, no exceptions.

Max
I seem to remember reading somewhere in the HTA (Highway Traffic Act [Ontario,Canada]), that it is unlawful to coast in neutral, I assume because of the time it would take to respond to an emergency situation.

VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
TheHeretic is offline  
post #24 of 74 Old 08-14-2010, 12:29 PM
Rino1425
Registered User
1993 YJ Wrangler 
 
Join Date: Mar 2010
Location: Dayton OH
Posts: 166
Quote:
Originally Posted by TheHeretic View Post
I seem to remember reading somewhere in the HTA (Highway Traffic Act [Ontario,Canada]), that it is unlawful to coast in neutral, I assume because of the time it would take to respond to an emergency situation.
I belive that, i bet there are laws against it but they just dont enforce them
Rino1425 is offline  
post #25 of 74 Old 08-14-2010, 12:30 PM
TheHeretic
Kool Kat 4x4
 
TheHeretic's Avatar
2005 TJ Wrangler 
 
Join Date: Sep 2009
Location: Innisfil
Posts: 679
Quote:
Originally Posted by Rino1425 View Post
I belive that, i bet there are laws against it but they just dont enforce them
Kinda hard to enforce

VA3IPB

The only True Professional Mechanic in the Greater Toronto Area for Modified Jeeps, and trucks. If Rock Spyder hasn't seen it before, or done it before, you don't need it.


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.



To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
TheHeretic is offline  
post #26 of 74 Old 08-14-2010, 12:35 PM
Ggg
Registered User
1998 TJ Wrangler 
 
Join Date: Jul 2010
Location: N.IL
Posts: 133
Quote:
Originally Posted by TheHeretic View Post
I seem to remember reading somewhere in the HTA (Highway Traffic Act [Ontario,Canada]), that it is unlawful to coast in neutral, I assume because of the time it would take to respond to an emergency situation.
It is Illegal here in IL and WI, and I too agree with Max.
Ggg is offline  
post #27 of 74 Old 08-14-2010, 12:54 PM
krawler510
Registered User
1999 XJ Cherokee 
 
Join Date: Dec 2007
Location: MD
Posts: 1,832
Who seriously made that law? Seems a bit tough to enforce. Anyway, I'm willing to say that 99% of people respond to emergency situations by slamming on the brakes, even when they should hit the gas.

Do you guys really down shift through all of the gears when slowing down?

'The early bird may get the worm, but the second mouse gets the cheese.'
krawler510 is offline  
post #28 of 74 Old 08-14-2010, 01:59 PM
Sweeney
Registered User
2006 LJ Wrangler 
 
Join Date: Aug 2006
Location: Spencer, MA
Posts: 1,329
Quote:
Originally Posted by TheHeretic View Post
Ummmm, no It would take longer for the signal to go from your eyes to your brain, to making a decision of what to do. It's more like four to five seconds. In a few situations, by the time you react it's already too late.

I've been driving manual trans for quite a few years, including Super-sport motorcycles. I have yet to meet a single human being that can make an unplanned emergency manoeuvre in less then 1/2 a second that includes having to select a proper gear, throttle position, and body position.
Ummmm, yes. It may take four or five seconds to react after a few pints of single malt but if you are the least bit attentive, and relatively healthy your reaction times should be measured in milliseconds. Yes, that includes sensing and reacting.
If it takes more than 250 ms for your brain to register what your eyes sense you better get to a neurologist.
Yes, there is a law in MA that states you must always have your vehicle in gear when moving. There is also a law in MA that states you can legally shoot a person for tampering with your lobster pods and it is still against the law to have sex in any position but missionary.
The vast majority of laws are ridiculous at best and often absurd.
Now remember, coasting in neutral is perfectly safe when employed in the appropriate situation. What is dangerous is drivers who don't know what those appropriate situations are.
BTW, I too have been driving manual shift vehicles for a few years... 30 to be exact... from a WWII deuce and a half (first thing I ever drove) to 500whp BMWs to Jeeps, a CAT D11 high drive and a Link Belt excavator. I've drag raced, rock crawled, river crossed and driven rallys on snow and ice covered roads.
Also remember, just because you've been doing something for a long time does not mean you've been doing it well or correctly.
Sweeney is offline  
post #29 of 74 Old 08-14-2010, 03:48 PM
BlueFlame
Registered User
 
BlueFlame's Avatar
2003 TJ Wrangler 
 
Join Date: Mar 2006
Location: Oregon USA
Posts: 8,396
Just like with any manual trans shifting/operation question - it's situation dependant.
Coasting in gear or in neutral should use the same amount of fuel - either way the throttle is closed - when the throttle butterfly closes the fuel is reduced accordingly. (I seriously doubt fuel rate ever goes to zero...)

But, coasting in gear using engine braking is good when you're needing to slow down soon, and coasting either out of gear or with clutch depressed is clearly better when you Don't need to slow down. None of these hurts a thing. (carnucks case is extreme, and sounds like it was caused by a maintenance issue and not the actual coasting...)

I agree that being aware of what gear to be in is important, but that's just a part of driving properly. I haven't had any problems figuring out what gear to shift into after coasting, or finding that gear, in 30 years or so....


To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
|
To view links or images in signatures your post count must be 10 or greater. You currently have 0 posts.
BlueFlame is offline  
post #30 of 74 Old 08-14-2010, 04:00 PM
wushaw
Rockin jeep
 
wushaw's Avatar
2000 TJ Wrangler 
 
Join Date: Jan 2007
Location: Texas
Posts: 8,165
Quote:
Originally Posted by krawler510 View Post
Who seriously made that law? Seems a bit tough to enforce. Anyway, I'm willing to say that 99% of people respond to emergency situations by slamming on the brakes, even when they should hit the gas.

Do you guys really down shift through all of the gears when slowing down?
Not all, it all depends upon the situation.
wushaw is offline  
Reply

Tags
better economy , better mileage , coasting , driving , in gear , manual , miles per gallon , mpg , neutral

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the JeepForum.com forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid e-mail address for yourself.



Email Address:
OR

Log-in









Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



Similar Threads
Thread Thread Starter Jeep Forums Replies Last Post
Installing a neutral safety switch for remote start? 2003 manual 4.0. TheMightyGoat TJ Wrangler Technical Forum 34 12-05-2010 04:16 PM
Click/ gargle noise when i drop the clutch in Neutral or when turning off in neutral JJeeper09 TJ Wrangler Technical Forum 1 08-11-2010 10:50 PM
Noise from left wheel while coasting in neutral mudsmorefun YJ Wrangler Technical Forum 4 11-14-2009 08:05 PM
Coasting in Neutral BM20 TJ Wrangler Technical Forum 41 07-10-2008 05:47 PM
Squeak in Manual Tranny when in Neutral newjob1975 JK Wrangler Technical Forum 8 04-11-2007 08:09 PM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome