So running WOT is the most efficient for the engine...

[wirelessenabled]

Get a diesel. WOT all the time:thumbsup:

 

[JCH13]

i often pop my tranny into neutral and coast for a ways to a stop. dunno if it helps mileage, but figured it couldnt hurt compared to maintaining speed up to the point where you need to brake firmly like most do.

Neutral coasting can hurt. Some cars, like my two, fuel-cut under deceleration. Burning no gas is infintely better milage than idling an engine

 

[Bignate603]

Get a diesel. WOT all the time:thumbsup:

You need a throttle to be able to run WOT

 

[HeXen]

Neutral coasting can hurt. Some cars, like my two, fuel-cut under deceleration. Burning no gas is infintely better milage than idling an engine

i don't think mine cuts the fuel. i got a cheapazz 05 civic, base model.

 

[overst33r]

Neutral coasting can hurt. Some cars, like my two, fuel-cut under deceleration. Burning no gas is infintely better milage than idling an engine

Yes but you can coast farther in Neutral. Either way, it's a minute difference. 1-2mpg at best. Not worth the safety issue IMO.

i don't think mine cuts the fuel. i got a cheapazz 05 civic, base model.

It does. My sister has the same car. Coast in gear at low RPMs between 1-2000RPM so you minimize engine braking, but still use zero gas.

 

[Shawn]

I didn't think coasting in neutral is legal.

 

[HeXen]

I didn't think coasting in neutral is legal.

not sure what the reason would be unless your a dumbass who can't brake or shift back into D when necessary
But no different than holding in a clutch and coasting for whatever distance. keep your hand on the shifter and you can go from N to D as fast or faster than you could shift a gear.
i just pop it in and out, theres no danger...actually you can stop easier and faster in N cause theres no torque at the wheel.
it seems to help on icy roads too where the drive wheels don't have power moving them, N allows to freespin yet i can still tap the brake lightly as needed and slow down much better as apposed to have a gear ratio hold a speed.
cause i'm sure no one with a stick hits ice and downshifts or not push the clutch when sliding on ice.

but thats me. i've never been in a single accident so far as of 19 years now, its my experience so guys can think whatever ya wants.

 

[alpineranger]

It's sort of like a jet engine. Yeah it's the most efficient thing there is when you need 55,000 lbs of thrust, but you wouldn't put one in a Prius to get maximum MPG.

That's what a prius does. It decouples the normal direct relationship between engine speed and road speed, and uses the engine merely to provide power when it's input is needed. When the engine is running, it operates in it's most efficient range (efficient as in high BSFC), with a moderately high RPM and at effectively full throttle.

 

[JCH13]

That's what a prius does. It decouples the normal direct relationship between engine speed and road speed, and uses the engine merely to provide power when it's input is needed. When the engine is running, it operates in it's most efficient range (efficient as in high BSFC), with a moderately high RPM and at effectively full throttle.

The issue is that a jet turbine uses nearly the same amount of fuel to idle as it does at full power. It's something like 80-90% of peak fuel consumption at idle, I can double-check with a guy I work with that used to design jet engines for Pratt&Whitney. If you need lots of power all the time they're great, but they are terrible for automobiles.

 

[Bignate603]

The issue is that a jet turbine uses nearly the same amount of fuel to idle as it does at full power. It's something like 80-90% of peak fuel consumption at idle, I can double-check with a guy I work with that used to design jet engines for Pratt&Whitney. If you need lots of power all the time they're great, but they are terrible for automobiles.

It's not as bad as you're saying but that is one of the drawbacks of turbines. They are much less efficient at lower loads.

 

[Howard]

Yes but you can coast farther in Neutral.

I didn't think this could be a benefit to anyone.

 

[TakeNoPrisoners]

Don't coast with the engine idling. It just burns extra gas and you need to bother with shifting which is something I avoid in an automatic.

I don't see why you just don't engine brake.

 

[LTC8K6]

The issue is that a jet turbine uses nearly the same amount of fuel to idle as it does at full power. It's something like 80-90% of peak fuel consumption at idle, I can double-check with a guy I work with that used to design jet engines for Pratt&Whitney. If you need lots of power all the time they're great, but they are terrible for automobiles.

I don't think so. Fuel use at idle is very low relative to full power as far as I know with a turbine.

Chrysler had a turbine powered car.

 

[Bignate603]

I don't think so. Fuel use at idle is very low relative to full power as far as I know with a turbine.

Chrysler had a turbine powered car.

There's a shred of truth in what he said but it's not nearly as bad as he's saying. Turbines like to be run at specific conditions, if you operate outside those conditions the specific fuel consumption really suffers. If you need good efficiency over a wide operating range a diesel will be better.

Ford also looked at turbine engines (don't think it made it ever made it into a car, but I know somebody that worked on the project) and a company also looked at diesel powered semi trucks. Nobody has been able to make one that can compete with piston engines yet though.

 

[JCH13]

There's a shred of truth in what he said but it's not nearly as bad as he's saying. Turbines like to be run at specific conditions, if you operate outside those conditions the specific fuel consumption really suffers. If you need good efficiency over a wide operating range a diesel will be better.

Ford also looked at turbine engines (don't think it made it ever made it into a car, but I know somebody that worked on the project) and a company also looked at diesel powered semi trucks. Nobody has been able to make one that can compete with piston engines yet though.

I don't think so. Fuel use at idle is very low relative to full power as far as I know with a turbine.

Chrysler had a turbine powered car.

You guys are right, I was mistaken. I was thinking of idle RPM vs full-load RPM, which are much closer to each other than in a reciprocating piston engine. This does cause turbine engines to really suck down fuel when idling. I don't think it's as bad as 80%, but I believe it is significantly worse than a typical car.


That's what I get for trying to think after my brain shut off

 

[LTC8K6]

IIRC, to use a poor example, the Abrams tank supposedly burns 10GPH at idle and about 60GPH at full tilt. So about 6 times as much.

One thing that skews the numbers when you look at aircraft is that they burn a lot more fuel in the thicker air down low, and a lot less up high in the thin stuff.

 

[Bignate603]

IIRC, to use a poor example, the Abrams tank supposedly burns 10GPH at idle and about 60GPH at full tilt. So about 6 times as much.

One thing that skews the numbers when you look at aircraft is that they burn a lot more fuel in the thicker air down low, and a lot less up high in the thin stuff.

The Abrams actually is a really good example. One of the chief complaints on that tank is high idle fuel consumption, much higher than a diesel of comparable size. It's design is closer to what you would see in a car, with a recuperator to get more efficiency. A recuperator is typically too heavy for applications that fly but in things that stay on the ground they're less sensitive to weight. More weight still hurts your efficiency for the vehicle, but not nearly as much as it does for something that has to fly.

 

[jhu]

Does that mean that in order to get the best fuel mileage, I should be accelerating WOT (ie. balls to the wall, accelerating as fast as I can) up to my intended speed and then just shift to my highest gear and cruise?

Say I want to cruise at 50mph. I start at 1st, floor it and redline it to 30mph, then shift to 2nd and floor it to 50mph, then shift directly into 5th and cruise? That would be the most fuel efficient way to drive?

Actually, it'd be 3/4 throttle so your engine doesn't enter open loop in the highest gear you can get away with such that the engine is at its lowest bsfc/hp.