Is shifting into neutral and using breaks bad?
08-03-2007, 09:11 AM
#21
Originally Posted by SladeX
brakes are cheaper and easier to replace, if you've done a clutch change, you will appreciate this statement all the more.
I'd only downshift for road racing. I have no problem downshifting myself, can do it on a whim and I do usually when I know the light is going to change soon or if I am coming off the highway. If I know I'm going to stop for awhile, I'll just use all brakes. In an emergency stop or panic stop, I leave it in gear to just below idle regardless of gear and then slam the clutch in and bump to neutral.
As far as mpg goes, your right foot dominates that department, go easy and you will save, and well you know how hard that is in a car like this...
I'd only downshift for road racing. I have no problem downshifting myself, can do it on a whim and I do usually when I know the light is going to change soon or if I am coming off the highway. If I know I'm going to stop for awhile, I'll just use all brakes. In an emergency stop or panic stop, I leave it in gear to just below idle regardless of gear and then slam the clutch in and bump to neutral.
As far as mpg goes, your right foot dominates that department, go easy and you will save, and well you know how hard that is in a car like this...
lol, thats all im saying.. its not something to avoid, its just part of driving... as for the wear.. well, its no more wear then you upshifting.. and far less wear then starting from a stop.
on a emergency/panic stop its always two feet in... dont worry about shifting until you're off the brake.
and yea.. MPG depends more on your throttle usage then anything else.. i remember a couple years ago, it rained for a week straight.. i gained 5mpg just because i didnt floor it all week.
08-03-2007, 09:18 AM
#22
Originally Posted by MrDude_1
i was logging the injector pulsewidth for injector #7 with a PIC controller (#7 was just easiest to wire neatly, no other significance)
it was for this project i was working on, that i have yet to finish.. its pretty neat.. i wanted an accurate-ish MPG reading, but i wanted it to be universal, so i was logging values like RPM and injector pulsewidth.... of course its made stupidly difficult by the fact that the fuel pressure on a stock LS1 is not manifold pressure referenced... so i had to copy the table from HPtuners....
look at post #7 here: https://ls1tech.com/usa/showthread.php?t=314371
i have logged it before in HPtuners, but to be honest, i never really paid enough attention to remember off the top of my head if it logged zero or not... although if its anything like the earlier GMECMs, it skips the min injector constant if its in full cutoff... but like i said before, i wouldnt surprised if they changed that. we're talking a 20+ year span of firmware diffs.. lol
it was for this project i was working on, that i have yet to finish.. its pretty neat.. i wanted an accurate-ish MPG reading, but i wanted it to be universal, so i was logging values like RPM and injector pulsewidth.... of course its made stupidly difficult by the fact that the fuel pressure on a stock LS1 is not manifold pressure referenced... so i had to copy the table from HPtuners....
look at post #7 here: https://ls1tech.com/usa/showthread.php?t=314371
i have logged it before in HPtuners, but to be honest, i never really paid enough attention to remember off the top of my head if it logged zero or not... although if its anything like the earlier GMECMs, it skips the min injector constant if its in full cutoff... but like i said before, i wouldnt surprised if they changed that. we're talking a 20+ year span of firmware diffs.. lol
Looks good to me! Never been a PIC person though. I guess I like pain cause I have always used TI.
08-03-2007, 10:13 AM
#23
TECH Fanatic
This thread is kinda funny. Asking if it is O.K. to use just the brakes to stop your car is like asking if it is O.K. to use just the engine to accelerate the car. Brakes are cheap, so don't sweat it as stated above.
08-03-2007, 12:00 PM
#25
Originally Posted by 2002_Z28_Six_Speed
Brakes are meant to be serviced. Check the service schedule for our cars. Clutches don't even appear on there.
you also wont find a service procedure that includes a DMM and duct tape...
i know some of you know this but... when you downshift, the clutch doesnt magically become a hard-to-service brake... its not slipping. its not wearing. its just there, transferring less power back then it normally transfers under a moderate cruise.
08-03-2007, 12:13 PM
#26
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This again! You have much more control of your car with with the clutch engaged than you do when disengaged. There is nothing wrong with slowing down by downshifting and it doesn't introduce abnormal wear to your clutch for crying out loud. If you think it's a good idea to drive without using engine breaking, try it on ice some time and see how well that works (how about going down a hill?). And no, I'm not talking about screaming to redline every time you downshift, I'm talking about normal driving. It's the drag launches and power shifting that wear out clutches and transmissions in a hurry. Enjoy driving the car the way it was meant to be driven.
08-03-2007, 01:11 PM
#28
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Think about it this way. An auto still wants to push while your slowing down/stopped. In a manual car putting it in neutral will actually allow you to use less braking b/c you aren't trying to stop a car that's still in gear. Even though an auto is made to stay in gear and is able to roll to a stop, putting a manual in nuetral takes all the pushing force out of stopping.
08-03-2007, 05:59 PM
#30
Originally Posted by MrDude_1
you also wont find a service procedure that includes a DMM and duct tape...
Haha. You would be suprised how far something like a multimeter gets you. I only pull an oscope or LCR meter off the shelf once in a blue moon.
What model PIC did you use? Are you saying that you used a loop of wire around the injector wires and feed it into the PIC to get an estimate of the injector pulsewidth? Sounds like a good project.
08-06-2007, 07:41 AM
#32
Originally Posted by ddnspider
uh,it adds tranny wear and engine wear assuming u dont perfectly match revs
DAMMIT! were IS that slapface smilie?!!?!
Originally Posted by 2002_Z28_Six_Speed
Haha. You would be suprised how far something like a multimeter gets you. I only pull an oscope or LCR meter off the shelf once in a blue moon.
What model PIC did you use? Are you saying that you used a loop of wire around the injector wires and feed it into the PIC to get an estimate of the injector pulsewidth? Sounds like a good project.
What model PIC did you use? Are you saying that you used a loop of wire around the injector wires and feed it into the PIC to get an estimate of the injector pulsewidth? Sounds like a good project.
as far as that project.. geeze its been awhile.. i think it was a PIC16C84..... im horrible about the names of everything, i have to look it all up as i go along..
basically it was a simple optical isolator circuit... triggered off everytime the ECM grounded the injector... the pic kept track of the length of time, and when asked, it sent back the current average of the last 3 or 5 pulses (i forget the number i ended up with)
it really ended up being a nightmare, i was just trying to do to much stuff.. i could make a MPG display, but then i run into timing issues if i try to have it do other things in the background as well.
eventually i just dropped it and havent gone back to it yet.
i do have a newer idea though, based off the same concepts and stuff i learned from the first project...
imagine a cheap, simple USB circuit that can measure things.. say have one setup for RPM.. another for oil pressure/water temp... another for the injector, maybe even axle speed or clutch speed, etc... since they're USB, you could daisy chain them together, or only use the one you want.. and plug them all into a cheap pocketPC handheld... giving you a pretty full color touch screen display.. with all the data in there.. plus you can now log it.
although i donno when id get around to messing with this stuff again.. my social life is a little bigger then it used to be..
08-06-2007, 12:00 PM
#33
this was already discussed in another 10 page thread that it does assuming u dont match revs...ie it wears out the synchros.and u dont need a slap smiley....i can just give u a 
and just so u know they already make something like what your saying.only its OBD2 port instead of usb aeroforce scan gauge.and now theres some Hawk thing that does the same thing.
and just so u know they already make something like what your saying.only its OBD2 port instead of usb aeroforce scan gauge.and now theres some Hawk thing that does the same thing.
08-06-2007, 12:14 PM
#34
Originally Posted by ddnspider
this was already discussed in another 10 page thread that it does assuming u dont match revs...ie it wears out the synchros.and u dont need a slap smiley....i can just give u a
unless you have something truly useful to add, and not a just a reply to me, why dont you just not hit that reply button.
Originally Posted by ddnspider
and just so u know they already make something like what your saying.only its OBD2 port instead of usb aeroforce scan gauge.and now theres some Hawk thing that does the same thing.
we're talking about designing and building our own ones as small projects.
we're not talking about buying a ODBII scanner... if you count the laptop software based one ive already built one.. (ELM chip setup for GMODBII-> serial + some C# based COM software.... btw C# sucks for COM ports.. no native support.. ugh.)
08-06-2007, 01:30 PM
#35
Originally Posted by MrDude_1
yea, well it only takes 1 uninformed idiot to drag out something stupid to 10 pages.. i mean look. i already replied to you twice.
unless you have something truly useful to add, and not a just a reply to me, why dont you just not hit that reply button.
lol, no ****. they've made different scan tools for decades.
we're talking about designing and building our own ones as small projects.
we're not talking about buying a ODBII scanner... if you count the laptop software based one ive already built one.. (ELM chip setup for GMODBII-> serial + some C# based COM software.... btw C# sucks for COM ports.. no native support.. ugh.)
unless you have something truly useful to add, and not a just a reply to me, why dont you just not hit that reply button.
lol, no ****. they've made different scan tools for decades.
we're talking about designing and building our own ones as small projects.
we're not talking about buying a ODBII scanner... if you count the laptop software based one ive already built one.. (ELM chip setup for GMODBII-> serial + some C# based COM software.... btw C# sucks for COM ports.. no native support.. ugh.)
08-06-2007, 01:52 PM
#36
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ddnSpider is correct on the wear issue.
Downshift does cause clutch wear. Period. It may not be significatn, but it does. Anytime the clutch is engaged/disengaged, the clutch surface slips on the PP and flywheel. This slipping (however minimal) DOES cause wear. But is it going to significantly decrease the life of your clutch if you downshift??-No.
Downshift does cause clutch wear. Period. It may not be significatn, but it does. Anytime the clutch is engaged/disengaged, the clutch surface slips on the PP and flywheel. This slipping (however minimal) DOES cause wear. But is it going to significantly decrease the life of your clutch if you downshift??-No.
08-06-2007, 09:29 PM
#37
Originally Posted by Pewter02WS6
Think about it this way. An auto still wants to push while your slowing down/stopped. In a manual car putting it in neutral will actually allow you to use less braking b/c you aren't trying to stop a car that's still in gear. Even though an auto is made to stay in gear and is able to roll to a stop, putting a manual in nuetral takes all the pushing force out of stopping.
When the throttle is closed, the engine wants to return to it's idle speed, it doesn't want to be higher than it...when you properly downshift, you bring the engine above it's idle speed, and then the throttle is closed...thus it wants to come back to idle...the more gears you downshift, the more mechanical advantage the engine has over the mass of the car, and the easier it is for it to return to idle (which results in slowing down the car)...if you don't downshift, and do keep it in gear...once the RPM is low enough, the engine won't want to slow down anymore and THEN it will be opposing the brakes (but the brakes in any LS1 car are FAR stronger than the LS1 is at idle with the throttle closed).
I believe part of the reason why some states say it's illegal to be in neutral in a stick shift car at a red light is that it takes longer for you to react to an emergency situation and move the car out of the way...granted it may not be the best thing for the throwout bearing...but I've never worn one out in over 200K miles in 3 T56 cars. Also, then the vehicle is slowing down, if you're in the appropriate gear for accelerating again...you have significantly more control of the vehicle than if it's in neutral, or if you're holding the clutch pedal in and the car is in a totally innapropriate gear.
IF you downshift properly (using the gas pedal between gears) you're NOT going to cause the clutch to wear out prematurely at all. Don't expect it to mean you won't need to use your brakes ever...you still will, and you'll still wear them out...but I just had my STOCK 96 Camaro clutch out of my LT1 Caprice (yes I said Caprice, all 4400 pounds of it with a T56 conversion) that has over 75K miles worth of me downshifting it EVERY TIME I stop the car...and it still looks fine...looks like it'd last another 75K miles of the same driving if not more.
08-06-2007, 09:52 PM
#38
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I rev-match and downshift most of my anticipated stops. Usually go down to 2nd or 3rd, its nice so im ready to take off again if a light turns green or something gets in my way i can floor it and go around it.
If you cant handle the downshift rev match, i would leave it in gear and apply brakes until your rpms get close to 1000 then clutch in and shift to neutral (while continuing to give brake).
If you cant handle the downshift rev match, i would leave it in gear and apply brakes until your rpms get close to 1000 then clutch in and shift to neutral (while continuing to give brake).
08-07-2007, 07:53 AM
#40
Originally Posted by Mike454SS
I believe part of the reason why some states say it's illegal to be in neutral in a stick shift car at a red light is that it takes longer for you to react to an emergency situation and move the car out of the way...granted it may not be the best thing for the throwout bearing...but I've never worn one out in over 200K miles in 3 T56 cars. Also, then the vehicle is slowing down, if you're in the appropriate gear for accelerating again...you have significantly more control of the vehicle than if it's in neutral, or if you're holding the clutch pedal in and the car is in a totally innapropriate gear.
it has ZERO effect on the throwout bearing, since you're leaving it in gear (NOT riding the pedal)
and yes..you DO have significantly more control of the vehicle... provided you know how to drive to begin with. im still amazed at the number of people who think they can drive a "performance car" and then fail to throttle around a corner... (no not "slide", or "drift" im talking about just using the throttle to make the car turn smoothly and normally around a normal corner)