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2003-2009 Nissan 350Z

HUGE DEBATE! Coast in NEUTRAL

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Old Jul 10, 2007 | 09:33 PM
  #21  
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Originally Posted by PM-Performance
One question. . . . WHO CARES? Are people going to roll down hills in nuetral all the time to save gas if this is the case?
You should, and so should everyone else who is energy conscious. Yes, there are people who coast down every hill in neutral because they mistakenly think it saves gas. If every commuter drove more efficiently, gas usage/demand would go down, and guess what that would do to gas prices?
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Old Jul 10, 2007 | 09:45 PM
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Originally Posted by roast
You should, and so should everyone else who is energy conscious. Yes, there are people who coast down every hill in neutral because they mistakenly think it saves gas. If every commuter drove more efficiently, gas usage/demand would go down, and guess what that would do to gas prices?
I coast on big hills like cajon pass , and baker grade. Now for you part above , i agree , i also think if they times traffic lights properly it would help a lot on gas too. To bad gas is taxed a lot , why would they want to cut down on fuel use. State and federal have nothing to gain , only lose.
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Old Jul 10, 2007 | 10:19 PM
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Originally Posted by terrasmak
I coast on big hills like cajon pass , and baker grade. Now for you part above , i agree , i also think if they times traffic lights properly it would help a lot on gas too. To bad gas is taxed a lot , why would they want to cut down on fuel use. State and federal have nothing to gain , only lose.
Why would you coast?

As far as timing lights, it depends on the city that operates the lights, and there are other factors to be considered. Overall flow of traffic, safety, etc.

As far as cutting down on fuel use - everyone on this planet has something to gain. Who cares though, right? I sound like al gore.
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Old Jul 10, 2007 | 10:51 PM
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Originally Posted by roast
Why would you coast?

As far as timing lights, it depends on the city that operates the lights, and there are other factors to be considered. Overall flow of traffic, safety, etc.

As far as cutting down on fuel use - everyone on this planet has something to gain. Who cares though, right? I sound like al gore.
Cause its about 16 miles long of not needing to hit the gas. Everybody has something to gain , correct , but the government has a lot of money to lose. What is actually more important to them ???? I'll bet $$$$$$$$
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Old Jul 10, 2007 | 11:43 PM
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Originally Posted by roast
You should, and so should everyone else who is energy conscious. Yes, there are people who coast down every hill in neutral because they mistakenly think it saves gas. If every commuter drove more efficiently, gas usage/demand would go down, and guess what that would do to gas prices?

I've had my '07 Z for about 1 1/2 months now and while going through my 1200 mile break in period, I figured I might as well try to see how good of gas mileage I could get. Over the course of 4 tanks my gas mileage has ranged from 22.8 and 27.6 with mixed driving. I have tried different driving styles (i.e., slow acceleration, slowing the car by down shifting, cruising in different gears and RPMS, etc). I have always found that I get the best gas mileage when I coast, in neutral, down the many hills going and coming home from work. There are some areas that I can coast for about a mile without losing much speed. With the engine RPM's dropping to about 500-750 when it is put into neutral, I can watch my MPG increase the longer I coast. If I coast while in 6th gear it slows my car down much earlier and I have to get back into the throttle sooner.
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Old Jul 10, 2007 | 11:55 PM
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Originally Posted by ragecaj
I've had my '07 Z for about 1 1/2 months now and while going through my 1200 mile break in period, I figured I might as well try to see how good of gas mileage I could get. Over the course of 4 tanks my gas mileage has ranged from 22.8 and 27.6 with mixed driving. I have tried different driving styles (i.e., slow acceleration, slowing the car by down shifting, cruising in different gears and RPMS, etc). I have always found that I get the best gas mileage when I coast, in neutral, down the many hills going and coming home from work. There are some areas that I can coast for about a mile without losing much speed. With the engine RPM's dropping to about 500-750 when it is put into neutral, I can watch my MPG increase the longer I coast. If I coast while in 6th gear it slows my car down much earlier and I have to get back into the throttle sooner.
You should try driving normally. Your MPG will improve.

6th gear is overdrive. Engine braking is not exactly strong in 6th gear unless you're doing 159mph..... any amount of throttle you have to apply to keep your speed up in 6th going downhill will not be as much as it takes to keep the engine idling the whole time.
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Old Jul 11, 2007 | 12:50 AM
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Originally Posted by roast
You should try driving normally. Your MPG will improve.

6th gear is overdrive. Engine braking is not exactly strong in 6th gear unless you're doing 159mph..... any amount of throttle you have to apply to keep your speed up in 6th going downhill will not be as much as it takes to keep the engine idling the whole time.
I have tried it both ways and have visibly watched my gas mileage increase while coasting in neutral. My mileage does increase while cruising in 6th, but not as quickly. I know that 6th gear does not slow down the vehicle a substantial amount, but it does slow the vehicle down much more quickly than having it in neutral (again, I have tried coasting both ways).

I guess I'm not understanding the logic of the last part of the statement. I use less gas when I coast in neutral. Although the engine is using gas to keep it idling, I do not have to add additional fuel by pushing on the accelerator peddle. Because of the gear slowing down the vehicle sooner, I have to get into the accelerator sooner to maintain a certain speed.
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Old Jul 11, 2007 | 02:47 AM
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Thanks, everyone; I'm going to keep this thread subscribed, but I feel I can get more at this point from the discussion by observing than contributing; I've already said everything I had to say in the other thread, and some of you are now providing concrete proof that I was right. I really appreciate that.

-Ed
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Old Jul 11, 2007 | 03:48 AM
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only coast in neutral when you see the boys. they might give you a exhahust ticket
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Old Jul 11, 2007 | 04:05 AM
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All modern crs have a de-cel fuel cutoff strtegy. It is a mandatory emission control feature required by EPA to prevent unburned hydrocarbons from being discharged into the when you lift off of the throttle. There is a contact on the throttle body that initiates the fuel shut off sequence.

Many years ago,I had to have the fuel cut-off valve replaced on my '87 Nissan hardbody. Also had the fuel cut-off switch replaced on a '95 626.

So it doesn't matter whether you coast in neutral, or enginge-brake.

Even my current lawn mower (with an OHV engine) has a de-cel switch and a fuel cut-off valve. (and it has a carburetor!)

bill

Last edited by bailey bill; Jul 11, 2007 at 04:11 AM.
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Old Jul 11, 2007 | 04:20 AM
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I think we did this before. It was more of a Do I coast to a stop debate? Inexperienced drivers do all sorts of dumb and unnecessary stuff. With more experience, drivers will unlearn poor techniques.
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Old Jul 11, 2007 | 05:29 AM
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Originally Posted by infiniteracing
Actually any time your engine is on, it's using gas.
+1 ... that's a fact...
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Old Jul 11, 2007 | 05:45 AM
  #33  
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Have you not read anything in this thread? I posted quotes out of Nissan patents stating that fuel is cut off to the engine while it is running when certain conditions are met.
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Old Jul 11, 2007 | 06:17 AM
  #34  
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Originally Posted by ragecaj
I've had my '07 Z for about 1 1/2 months now and while going through my 1200 mile break in period, I figured I might as well try to see how good of gas mileage I could get. Over the course of 4 tanks my gas mileage has ranged from 22.8 and 27.6 with mixed driving. I have tried different driving styles (i.e., slow acceleration, slowing the car by down shifting, cruising in different gears and RPMS, etc). I have always found that I get the best gas mileage when I coast, in neutral, down the many hills going and coming home from work. There are some areas that I can coast for about a mile without losing much speed. With the engine RPM's dropping to about 500-750 when it is put into neutral, I can watch my MPG increase the longer I coast. If I coast while in 6th gear it slows my car down much earlier and I have to get back into the throttle sooner.
I understand what your saying and it makes sense. If you are on a long enough downward slope that staying in gear, off-throttle, slows you down to the point of having to stay on the gas to keep going, you will expend more fuel than coasting in neutral. Sounds dangerous though—not having any throttle control when traveling at those speeds.
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Old Jul 11, 2007 | 06:23 AM
  #35  
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Two more things:

Coasting=In neutral, engine idling, at speed, letting momentum/gravity do the work of moving the car forward. You can't "coast" in gear...that's engine braking.

One more test for those who don't believe there is 100% fuel cut off when in-gear, off-throttle i.e. engine braking. Engine brake in 2nd until you reach 1200-1500rpm, you can actually feel the fuel kick back on to keep the engine from stalling.
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Old Jul 11, 2007 | 06:33 AM
  #36  
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I think you all need to get a moped or a hybrid! However, if you want to get the best mpg possible, turn the engine off while going down a steep hill...
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Old Jul 11, 2007 | 06:38 AM
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Originally Posted by infiniteracing
If your coasting at 3000 rpms you are using more gas than if you put it in neutral and it sits at 1200 rpms



If you're using no gas at all, then how does your engine maintain rpms? Actually any time your engine is on, it's using gas.

All electronically controlled fuel injected engines work like this. pressing down on the gas does not directly reflect how much gas goes in the cylinders. It's mandated by the computer and how many rpms your at. Fuel hasn't been directly linked to the "gas pedal" since carburetors, which is why old muscle cars have a tendency to cut out if you go wide open throttle and then lift all the way off the gas.
As the posts, while I was away support, in fact you are wrong and I am right. Touche'
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Old Jul 11, 2007 | 06:41 AM
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I have to agree with the hybrid comment. To be honest when I bought my Z the MPG was the last thing I worried about. I love my car and I can honestly say it has NOTHING to do with how good or bad my gas mileage is. I knew coming in that it wasn't going to be great and to be honest when I'm having the most fun in my it's the times when my MPG gets really crappy anyway.
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Old Jul 11, 2007 | 06:57 AM
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i just put it in neutral, open my door, exit the car, move to the rear and push it. it saves me a ton of gas.

Last edited by FleckDZ; Jul 11, 2007 at 07:16 AM.
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Old Jul 11, 2007 | 07:04 AM
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Originally Posted by roast
You should, and so should everyone else who is energy conscious. Yes, there are people who coast down every hill in neutral because they mistakenly think it saves gas. If every commuter drove more efficiently, gas usage/demand would go down, and guess what that would do to gas prices?

So people buy higher HP sports cars with decent sized engines to be energy concious? What world do you live in man?
Gas prices wont go down either. Dont assume, you do not work for an oil yard or the govnt.

also, most cars do shut off the injectors when you let off the gas. I have shown this by driving around with a wideband in all my cars. Once you let off the gas, the injectors shut off per say because the Wideband will show AIR or LEAN,
Take it for what you want.
I dont care either way. i will not put the car in neutral to save gas. I dont care about saving gas. I drive the car hard when I drive it because. . . . . Its what I bought it for. If you want something good on gas, but a commuter car that is more enviro concious
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