Super_SS

neither am i...i did it on my first car which was manual and i didnt knw how to drive manual at all..so i learned that way and by the time i learned right,the 1st gear sychros was toast

suburbanrobot

well at least you learned before the SS

halfj99

i brake,

the tranny is for shifting
the brakes are for stopping

i like to let each thing do what its best at

if its just to slow down a bit while moving and im at low rpm's (under 2000ish) ill downshift though

YellowG5

Dude, seriously WHO THE HELL TAUGHT YOU HOW TO DRIVE??? THE manual CLEARLY states if you have a Manual Transmission that you should always leave it in the gear you were in when coming to a stop and then pull it out just before coming to a complete stop (around 1200rpm)

And I don't know about you, but If I get rear ended I am ON the BRAKES!!! I had a manual transmission 2004 Pontiac Sunfire with the same drive train combo as this G5 has...Got rear ended while I was coasting to a stop (coasting doesn't mean I'm off to F'in Brake!!! means it is in the gear I started to brake at while my foot is on the brake) The guy was doing 55, I was doing 20 and slowing (foot on brake!) I get hit, and hit the brakes harder, I didn't move any more than if I was in an Auto!

Its called Use your F'in head folks, not be some douche saying 'YOU MUST DRIVE LIKE ME CAUSE I AM BOSS AND I KNOW WHAT THE HELL I'M TALKING ABOUT, AND I WORK FOR A COMPANY THAT WILL FIRE MY ASS IF I'M CAUGHT COASTING!!!'

I in my life have never heard of such a thing, and I have neighbors who have been trucking for 20+ years. They down shift only when they need to, they never use the clutch except for first, and when coming to a stop, them rigs have some really good breaks... And also out on the road, I never hear a truck down shift unless it is to slow down really fast and he switches on the jake brake, even though it is highly illegal to do so in town around here.

message to the disgruntled know it all! Get a life, if someone drives differently, it doesn't mean they are driving wrong, it just means you are pissed off at someone, and have to take your anger out on folks who don't do what you do!!!

PS: Automatics drop to N when you are coming to a stop, and the Torque Converter unlocks...They go back in gear when the tiniest bit of gas is applied! So, N stopping against the law??? Must need to pull over anyone driving an Auto now too, eh?

N8s07SS

THANK YOU. One of very few intelligent posts of the thread.

Wow, I didn't know that when you get knocked out and you're in gear your car will automatically stop. That's an ingenious technology. (sarcasm)

There is no way you can tell me that downshifting does NOT use more fuel than coasting. If you can't figure out why, then I don't think you should be part of this debate. I don't really agree with your other "cons" either, but those are negligible, so I wont argue them.

CobaltVenomSS

iTrader: (2)

this poll/tread is heating up

YellowG5

Why don't people just, Where the hell is that damn smiley when you need it??? Ah, hell, why not just say it then....READ THE F'IN MANUAL???

suburbanrobot

2X

CobaltVenomSS

iTrader: (2)

i put tread u guys see that hahahaha i meant thread obviously

M-Dub

I downshift.... always have always will! Never had any clutch or T/O bearing problems from doing so!

I was always taught not to let the car roll in neutral! So I don't!

YellowG5

If you do what the manual says you won't be in N now will you???

Geezus people! No wonder Dealerships Throw out the warranty on manual transmissions a lot lately...no one reads the manuals. And drives the way they seen some fast and furious freak do it.

b-spot

Nope. The wheels on your car are moving, and therefore your engine is moving. When you put the clutch in, then fuel has to go to the engine to keep it at idle. If your clutch is out, your engine can't stop unless your wheels are stopped.

Just matching the revs wears your throwout bearing. Double clutching is clutch in-shift to neutral-match revs-clutch in-shift to desired gear-clutch out. Sounds like a lot, but once you're used to it you don't even notice you're doing it.

As I stated, when your foot is off the throttle and your transmission is in gear it is the wheels turning your engine, not gas. When you put the clutch the car will start feeding gas in again when your RPM's drop to about 1500 so that your engine will stop dropping revs at idle and stay there.

Double clutching means you save money. Less gas. Less brake wear. No added clutch or TO bearing wear.

N8s07SS

I guess I left out the part about matching the revs while in neutral, I thought it was understood. It seems that it would be quite difficult to try to match the revs before you shift, because the minute you let of the gas, the RPMs are already dropping.

So if there's no fuel going into the engine when in gear and deccelerating, does that mean there is no exhaust either? I'm not saying I don't believe you, because you seem to know what you're talking about, but that just seems odd to me.

Maxim_X

LoL @ all of you fast and furious double clutchers have fun, they make synchros for a reason. Double clutching is for trucks, like big trucks, not for cars.



Downshift and rev match, not only is it the least wear on you car, It also sounds hot when the exhaust is crackling.

alleycat58

Then obviously clutch wear is not an issue, because I downshift all the time and I've got 44k and counting (plus learning to drive a manual) on my clutch and it works good as new.

Hmmmm....take your own advice perhaps?


Uh, no. You just gave the reason why in your own argument. There's no reaction time involved with an auto, you need to go and go quickly, it's already on it. If you need to avoid an incident by getting on the gas, you can just hit the gas and go. The reason why neutral coasting or coasting with the clutch in is illegal in a manual is because you don't have that luxury if you're not in the proper gear. The time you have to react is already insanely short, keeping the car in the proper gear allows you to react faster since you don't have to grab a gear on the fly before you can go.

Best explaination so far of why that's a myth:

N8s07SS

If you want to start quoting random people as your proof:

"Perhaps it depends on how the manufacturer set things up. My C5 Vette DIC (Driver Information Center) instantaneous mpg indicator always indicates some fuel is being used even with closed throttle decel on a long grade. My wife's Audi (1.8T) instant. fuel econ. computer hints at no fuel being used in a similar condition with fully closed throttle. Cracking it just the least amount gets it back on the scale around 200 mpg, the upper limit it shows. Both of there cars are throttle-by-wire.

My conclusion is that the GM engine may not completely shut off the fuel during closed throttle decel. I have tried different gears (A4) on long downhill grades, and instant mpg is slightly different in 3 vs 4, but not anywhere near the ratio of the gears.

Some GM automatics with their "fuzzy logic" will downshift to lower gear(s) if you are in a closed throttle decel (coming down a long grade), and the vehicle speed is still increasing. This gives more engine braking, which is a safer thing than coasting at idle with the trans disengaged.

FWIW, if you have a mpg computer, watch instant. mpg during your normal driving, especially before the cold engine gets to normal operating temp. 3-5 mpg. at light acceleration is common with a cold engine, while it will double or better when the engine is warm. Of course letting it warm up without moving gives zero mpg, so driving away moderately right after start is the way to go. Many owners manuals say just that."

"It is the throttle follower, part of DFCO, Deceleration Fuel Cut off. A pain and doesn't work for the good of fuel economy or a good coast down.

If you watch your fuel injector PW, watch it as you decel and count the seconds it takes it from cruise or acceleration to actually bring the injectors to a 0 PW. It doesn't do it much, if ever. I am working on my LT1 to get more agressive DFCO, but it is still a pain to get working right. GM likes this 2.5 second delay before DFCO even starts. So look for that, you are likely fighting the DFCO delay."

"The DFCO has a slew of settings to make it function well.

DFCO Delay
DFCO Enable RPM
DFCO Disable RPM
DFCO Enable MAP
DFCO Disable MAP
DFCO RPM Drop Rate (if the engine drops rpm too fast it will add fuel back)
DFCO Ignition Timing

So with all of this you can do a pretty good job at cutting off the fuel on decel. Unfortunately, GM has it setup so it RARELY ever activates too. So that is pretty bad in my book...."

These quotes are all from LS1Tech

Nice try Alleycat and Witt.

I guess the best way to determine the truth to this is do what the first guy said, and reset your DIC's MPG while your doing this coasting/downshifting and see what it reads as your instantaneous MPG. Then you will know the truth. All cars are different, so what someone know about one car is not necessarily true about all.

Also, could someone please find me a written law that states coasting to be illegal. That is the dumbest thing I've ever heard on this site. When was the last time you heard of someone getting a ticket for coasting. Come on people, use common sense.

Witt

I take it you never owned a wideband UEGO sensor or ever modified an EFI computer before.

BTW, what random person did I quote?

alleycat58

LMAO, will we now? Is that why if you start the car at a top of a hill, reset the DIC, and coast it reads 99.9 MPG????? I'd rather trust a gauge that reads what's ACTUALLY going on fuel wise (wideband) rather than a gauge that displays an arbitrary (and easily inaccurate) calculation.

BTW:

Indiana - illegal to coast in neutral going down a hill
IC 9-21-8-44
Coasting in neutral when traveling upon a down grade; prohibition
Sec. 44. (a) A person who drives a motor vehicle may not coast with the gears of the vehicle in neutral when traveling upon a down grade.
(b) A person who drives a commercial motor vehicle may not coast with the clutch disengaged when traveling upon a down grade.

Ditto for Tennessee:
Coasting Prohibited
The driver of any motor vehicle traveling on a downgrade
shall not coast with the transmission of the vehicle in neutral.
Vehicles shall not coast with the clutch disengaged.

Same for California:
I 21710 Coasting, in neutral on downgrade.

Same with Texas - where you also get points on your license:
§ 545.406. COASTING. (a) An operator moving on a
downgrade may not coast with the gears or transmission of the
vehicle in neutral.

Colorado prohibits coasting at ANY time:
WARNING--Allowing your vehicle to coast in neutral is against state law
(42-4-1009, CRS, Coasting prohibited).

Pennsylvania it is considered driving in an unsafe manner (not being in control of a motor vehicle) if you "coast" for more than the length of the vehicle:
Unsafe coasting occurs when your vehicle is out of gear (clutch depressed or gearshift in neutral) for more than the length of your vehicle.

Cliff's Notes: It's illegal in EVERY state to coast down a hill, other states you've just got to check the laws. Or it could be like it is here and be an unsafe driving ticket, because it's just that......unsafe.

HighPSI_LowCC_Speed

double-clutching is a waste of time with modern tranny/synchros...just single-clutch rev-match (using heel-toe braking if slowing down)

BWAHAHAHAHAH...zero gas....HERE IS THE ANSWER TO THIS, YOU F-ING IDIOTS:

YES, it takes a tad bit more gas to downshift/brake than coast/brake because the engine uses more gas at higher rpm REGARDLESS OF THROTTLE POSITION. Because you are rev-matching to higher rpm upon down-shifting, you are using more gas. End of story.

Not to mention illegal as aforementioned.

I think you were dropped one too many times on your head as a baby.

See previous quote/response...

djt81185

Actually the auto tranny remains in gear at all times. What is does is reduce trans line pressure to 0 as to not bog the motor. When reapply throttle the trans pressure is brought back up and ur moving again. This is easily see in hpt when logging a 2.4 auto ss

It does..DFCO works and happens A LOT on these cars. Get a wideband in ur car and go for a drive rev to what ever rpm u feel like and left off and let it coast...in a few seconds the car will go lean then on my wideband reads air meaning that 0 fuel is being used in the motor. There is a 2mile long hill on my drive home from work...when I crest the hill i downshift to 4th and let it coast the whole way down. I do 55mph with my wideband showing AIR the entire time...and when i log the fueling is 0

Double clutching is still valid it does reduce the wear on synchros by using the clutch (a wear item) to spin up the gear shaft to the next gears desired speed instead of using ur synchros (a hard, metallic, expensive to replace part)

Corvette DFCO is disabled from the factory...you can see it in a HPT file...Its called deceleration fuel cutoff...it does what its called...cuts off fuel while ur decelerating teh engine/car

First part...see above about trans and synchros

2nd part It takes less gas to zing the engine up a gear then then have no fuel running thru it then it does to sit at a 14.7 idle until u come to a stop...DFCO does work on these cars so ur whole point is now counterproven

Btw using no fuel is more environmentally friendly then idling...u coasting bastards are killing the rainforests and driving illegally

Dan

b-spot

Read the thread, you're wrong on all of this.

Double clutching is not necessary by any means, but still does save wear. Your throwout bearing is an unlubricated part, so reving a lot with your clutch in is a bad idea.

chipsgt

I am not opinionated one way or another on this topic. I know what works for me, and I have never been at fault in an accident.
I have also in 3 manuals never had to replace a clutch nor have I had slippage issues.
So I am going to stick with what I have been doing.

I have this question though, and I am not being an ass about it, so please dont take this the wrong way all of you pro-downshifters.

But, for those using the gas saving argument, but are mimicing the actions of an automatic drive train, how would that save you gas?

I was under the impression that manuals got better gas mileage because of the fact that you can coast in neutral.

Those that said the engine uses no gas when you down shift, are just wrong.
If you are going 50 mph, and down shift, but are completely out of gas, your engine isnt going to run on magic. If your RPM's are above anything but 0, you are using gas.

Also, I dont know about other states, but I know when I lived in New Mexico that there were signs on the highway prohibiting trucks from using the engine to slow down.
Just a thought.

I dont advocate coasting in neutral, because most accident situations (in my experiance) can be avoided by being on the gas, but I also dont subscribe to down shifting being better than braking. I say a good mix of the two and smart driving are the keys to success here.

djt81185

IN neutral the car is idling so its make emissions and burning gas

In coast down it is using 0 fuel until u reapply the accelerator...that is how u save gas

light'bolt

Hmmm.,, this so far has been quite informative. I've been neutral coasting for so long that I'm wondering why it really is not enforced. At least I've never been ticketed for coasting downhill, but speeding, inspection, registration, proof of insurance, failure to stop, exhibition of acceleration, not using turn signal, failure to yeild, etc... but never coasting.

This really is a helpful site, thanks everyone

N8s07SS

No, you are the random person being quoted.

And chipsgt, best post of the thread. I still feel funny about this whole thread, because I am not a "coaster" Although I do it sometimes, generally I am downshifting, but spend a little longer in neutral than just going straight to the next lowest gear. Basically a slow downshift. Whatever, I just like debating I guess.

As for the laws posted about it being illegal, I noticed that all specifically note that it is illegal ONLY WHEN GOING DOWN HILLS, nothing about regular flat roads. No **** it's dangerous to coast down a hill. Jesus. No one's arguing that. It can't be that horribly dangerous if it's not enforced either. Has anyone ever heard of someone getting a ticket for coasting?

Really?!? You trust an aftermarket gauge that works for any car over the COMPUTER THAT CONTROLS YOUR OWN VEHICLE? Not saying the widebands are inaccurate, but all you people think the technology in the DIC is a joke, and it's so inaccurate. Yeah, GM's engineers probably don't know what they're doing and have access to less advanced technology than the people who make wideband gauges. Good call.

The 99.99 MPG is an instantaneous readout, it's saying that is what mileage you are getting at that moment. Obviously it cannot sustain that, because of gravity, wind resistance, etc. If you think the DIC is inaccurate, then you should think anything that connects to your car is inaccurate, because they are both connected to the ECU. Haven't you seen those guys that can sqeeze like 100 MPG out of a typically 30 MPG car. Someone posted it on here a while back, but I couldn't find them. I can guarantee you they are doing more coasting than downshifting.

No one has yet to provide a response to the post about the directions in the owner's manual. Why would GM say that is the preferred method?