Gas Saving Tips

[drfabt]

Just don't put to much gas, the deepest the more gas you need.
i got 325 miles with my r18(4drs lx aut) city, and surprisive or lucky i forgot to put gas and i did not have any cells and drove about 15 miles to the next station.

[Tastycakes]

Originally Posted by areben

There seems to be a lot of confusion (all be it an old thread) about modern cars. Modern ECUs shut off the fuel injectors while coasting in gear while above a certain RPM. Every modern car has fuel cut off. Therefore you will save gas going down a hill in an appropriate gear (keeping the RPMS above fuel return--typically 500rpm above rolling idle) versus coasting in neutral. There are no if, ands, or buts. If you feel the need to argue I suggest googleing it first.

To in an attempt to clear up this thread this is false. I have a scangauge like a couple of people on here. It tells me live fuel flow and i cant stress that enough for you non belivers, I CAN SEE LIVE FUEL FLOW AT ANY GIVEN TIME and it uses more gas in gear than in N. And it is accurate to within +-0.1 gallon of fuel over 13 gallons

You telling us this is like telling us that its impossible to fill your tank past half full, even tho i have a gauge that proves you wrong.


Fuel saving tips:

Coast in N
Coast 2-3x longer than what normal people do to stops, in N of course
Stay in the highest gear possible when cruising. Above 30 be in 5th (R18) or 6th (K20) unless you need power
NO V-Tec (pssh, yea right )
Running low octane in your Si will get you less MPG
Running defrost or defrost/feet will turn on the AC compressor



If you have an Si this works nice. Take off from side street stop signs going 1st to 3k rpm then right to 4th gear or take of in 2nd then to 3rd. Seems i can get 24-27 MPG on side streets this way.

All i can think of now

Edit: Some cars may shut off fuel when coasting in gear. I can tell you for a fact the Yaris and Si do not.

[undrgnd]

Give you an E for effort since you're mostly correct.
1. You mean highest gear possible, not lowest.
2. The effect of octane on fuel consumption is not that black and white: Unless you have objective proof, I respectfully disagree that higher octane yields better mileage.
3. The ScanGauge is not that accurate. Even the MFGR only claims 5%. Depending on how you drive, it will be off tank-to-tank. I have seen it be dead on, and I have seen be off by 1/2 gal out of 14.

[Tastycakes]

Originally Posted by undrgnd

Give you an E for effort since you're mostly correct.
1. You mean highest gear possible, not lowest.
2. The effect of octane on fuel consumption is not that black and white: Unless you have objective proof, I respectfully disagree that higher octane yields better mileage.
3. The ScanGauge is not that accurate. Even the MFGR only claims 5%. Depending on how you drive, it will be off tank-to-tank. I have seen it be dead on, and I have seen be off by 1/2 gal out of 14.

LOL yea highest gear, ill edit

I'm not saying higher octane gets better MPG, it gives you the right MPG in the Si. Lower octane in higher compression causes detonation which the computer has to retard the timing (i believe) which turns into less power = less MPG

Depands on the pump. Today i filled up, scangauge said i used 11.2 gallons i put in 11.3 gallons. If i flip flop gas stations i see up to .5 gallons off too at most but if i use the same pump its rarely over 0.2, mostly 0.1 off.

[dextor]

A lot of you are saying there's less fuel going into the pistons when the car is in neutral versus when the car is coasting IN GEAR. Can proponents of this conjecture explain to me why Honda engineers decided to have their engines inject fuel into the cylinders when the momentum of the car, whether be it coasting on a plane or decline, is moving them? Forget about the ScanGauge for a second, the "results" are in, we need a reason! :)

[undrgnd]

Originally Posted by dextor

A lot of you are saying there's less fuel going into the pistons when the car is in neutral versus when the car is coasting IN GEAR. Can proponents of this conjecture explain to me why Honda engineers decided to have their engines inject fuel into the cylinders when the momentum of the car, whether be it coasting on a plane or decline, is moving them? Forget about the ScanGauge for a second, the "results" are in, we need a reason! :)

That's a no brainer. If the fuel is cut off the engine will die. Try that sometime at 65mph going downhill.

[dextor]

Originally Posted by undrgnd

That's a no brainer. If the fuel is cut off the engine will die. Try that sometime at 65mph going downhill.

The engine dies when it gets below a critical RPM. If the car is moving and in gear, the engine is still rotating at a certain rpm, so why would the engine die

[an0malous]

ahhhahaha more idiots.

#1 neutral coasting is illegal and ******* STUPID. stop doing it now.
it saves NOTHING.
#2 when you gear down, your momentum turns your wheels, turns your clutch, turns your crank, makes your pistons move.

what makes you think you need fuel for that to continue happening?

[Tastycakes]

You know, this is all hear say. That it "should" turn fuel down. I know 1 fact. I have a scangauge and it shows fuel flow during engine braking. Seriously show me something w/ good resources that says otherwise. Stop trying to say that thats the way it "should" work so thats the way it does work.

And did the guy above me just say coasting in neutral is illegal, LMAO that got me a good laugh. If it saves nothing why can i average 30 MPG w/ mostly city driving in an Si if i do this? (if i lay off vtec that is )

[dextor]

Originally Posted by Tastycakes

You know, this is all hear say. That it "should" turn fuel down. I know 1 fact. I have a scangauge and it shows fuel flow during engine braking. Seriously show me something w/ good resources that says otherwise. Stop trying to say that thats the way it "should" work so thats the way it does work.

And did the guy above me just say coasting in neutral is illegal, LMAO that got me a good laugh. If it saves nothing why can i average 30 MPG w/ mostly city driving in an Si if i do this? (if i lay off vtec that is )

Just wondernig, how does ScanGuage work?

[Tastycakes]

I just emailed em w/ a couple of questions about this. It hooks up to the OBDII port and reads info from there. Go to http://scangauge.com for more info.

[an0malous]

Originally Posted by Tastycakes

You know, this is all hear say. That it "should" turn fuel down. I know 1 fact. I have a scangauge and it shows fuel flow during engine braking. Seriously show me something w/ good resources that says otherwise. Stop trying to say that thats the way it "should" work so thats the way it does work.

And did the guy above me just say coasting in neutral is illegal, LMAO that got me a good laugh. If it saves nothing why can i average 30 MPG w/ mostly city driving in an Si if i do this? (if i lay off vtec that is )

technically the law states that its illegal when done on grades....
http://legis.state.sd.us/statutes/Di...tatute=32-24-2 just the first link i grabbed. not sure which exact states its illegal in...but its in most.
But the reason its illegal is, you have less control of your vehicle, its far more dangerous in an accident, you cant stop nearly as fast.
not a laughing matter. its flat out stupid.

Even the scangauge won't tell you if you are in fuel cutoff during engine braking.
What it does show is that you go into open loop, and under many circumstances that means no fuel.

i could go get som HPtuners logs that show fuel cutoff?
Have a look around. its not new technology. its been around a good while.
Its called DFCO. Decelleration Fuel Cut Off.

[Tastycakes]

Ok, i'm an ass Got an email back from scangauge.com

Mike,

Some vehicles shut off the injectors when coasting in gear but still report the use of fuel as if they were still operating. I believe this is the case for your Honda. The amount of fuel difference in a tank of fuel is not much because the fuel flow rate is so low and the time you are doing it over a tank of fuel is not high.

We are looking at a way to determine if this is happening using a combination of the throttle position and open/closed loop. If you watch the open/closed loop when coasting, it will usually go to open loop if the injectors shut off.

(this parts about the laptop interface)
We are still working on the interface. It grew in complexity and we hit some problems we didn't anticipate. I will send you an email when it is completed.

Ron

I guess the computer still reports fuel use for some reason, my bad lol. Anywho.....

About the illegal part, i mean cmon. You think a cop is going to give me a ticket for popping it into neutral 100 ft before a stop light? That page is about down hill which i do agree with. If your going down a long hill yea you should be in gear cause if you brakes glaze over (old drum brakes and trucks have this problem) then you cant stop.

And have you ever seen a sign that says "engine braking prohibited"? I have.

[an0malous]

thats to cut down noise.
truck engine braking or "jake brakes"
are very loud.

did you notice its always coming into populated areas when you see that sign :)

[LoverOfCivics]

Originally Posted by Tastycakes

Ok, i'm an ass Got an email back from scangauge.com



I guess the computer still reports fuel use for some reason, my bad lol. Anywho.....

About the illegal part, i mean cmon. You think a cop is going to give me a ticket for popping it into neutral 100 ft before a stop light? That page is about down hill which i do agree with. If your going down a long hill yea you should be in gear cause if you brakes glaze over (old drum brakes and trucks have this problem) then you cant stop.

And have you ever seen a sign that says "engine braking prohibited"? I have.

No when your in an accident they can pull it up and see that you were in neutral

[Tastycakes]

Originally Posted by LoverOfCivics

No when your in an accident they can pull it up and see that you were in neutral

LOL, is this guy serious?

[Johnbro]

^^what does he mean pull it up. ya and they can tell what color shoes you were wearing to by the tread pattern left of the gas pedal, but only the las vegas csi's....

[Tastycakes]

Originally Posted by Johnbro

^^what does he mean pull it up.

The OBDII comp stores the last 5 seconds of info before a crash (something like that). They can look at throttle, if the brakes were on, speed ect.

But once again i seriously doubt they'd care if the car was in neutral. It can in no way cause an accident. Like the cops gonna say, you were in neutral, you get the ticket.

[LoverOfCivics]

they can always tell what foot your using to drive too wow you guys take things to seriously

[leonphelpss11]

I still don't understand it. Is it better to slow down using ur gear or just pop it into neutral