Gas saving myths and tips

Here I clear up some misconceptions about what helps or hurts fuel economy. Having an onboard computer in my vehicle that gives average and real time fuel economy allows for me to see what works, and what doesn't under any circumstance.

Category:

Autos & Vehicles

Tags:

• gas
• fuel
• economy
• oil
• price
• save
• mpg
• efficiency
• gasoline
• premium
• regular
• unleaded

[averagejoeusername]

There exists NO CAR ANYWHERE that gets better MPG at 85 than 65. What "computer" are you using? City MPH is less than hiway only because of braking (stop and go) your logic is terribly flawed. There is NO WAY youre getting 28MPG @85 in a jeep unless its falling off a cliff.

[malignantpoodle]

@averagejoeusername

Simply not true. If a vehicle is designed to get optimum efficiency at a certain speed then it will get less at other speeds. There comes a point with certain vehicles that the amount of energy to obtain a certain speed is less than the amount of energy spent burning fuel at a lower speed for a longer period of time. Your car will get terrible fuel efficiency at 5 mph because at idle it burns more energy than it takes to go 5mph.

[malignantpoodle]

@averagejoeusername City is more because the biggest consumer of energy is ACCELERATION. It has nothing to do with braking. In all actuality, during braking is your best fuel efficiency because you still have velocity due to momentum without burning any energy to maintain that velocity.

But I'm talking about maintaining a speed for a long period of time.

[averagejoeusername]

SO wrong. 85mph better than 65mph? Apparently your car defies the laws of physics. Air resistance is what kills your MPG which increases exponentially with speed. This is why your car cant go 200MPH. City MPG is ONLY less because of braking...your logic is horribly flawed. And there is NO WAY IN HELL you are getting 28MPG at 85 dude. You have proof anywhere?I'm getting 40MPG in a car rated for 24 mixed. You sound credible which makes your post a horrible disservice.

[malignantpoodle]

@averagejoeusername

You talk physics but you completely leave momentum out of the equation. Maintenance energy of velocity is reduced by momentum. This is why objects have inertia. If the momentum is greater than the drag coefficient and is equal to or greater than the energy consumption difference of (in this example) 65 to 85, then fuel efficiency would go up. For your logic to hold true, the slower an object travels the greater a distance it will travel and this just isn't the case.

[big92fs]

True on the air conditioning, but the engine is not actually producing more power is adding stress to the engine taking power away from it. To be exact about 30-45HP loss of power.

[malignantpoodle]

@big92fs

The engine has to produce more energy for less distance traveled.

[Dotchetter]

- So the point is, as you said, it depends on the vehicle. REALLY.

The transmisson, differential gear ratio, transfercase ratio, in case of a 4WD vehicle, and on and on.

What I'm trying to say is that guys with Jeeps or cars with high compression, low rpm engines tend to achieve their cruising speeds at higher speeds than other cars, therefore the increased mileage and this is NOT true for any other conventional engine due to their lower cruising speeds, gear ratio in diff and tranny.

[Dotchetter]

Hey, I liked this vid.

Some good tips. What I really comprehended was that you're driving a Grand Cherokee, which I also do. Now my Jeep's got the 5.9 V8, and when I heard what you said that 60mph gets worse mileage than 85, I instantly thought about my Ford that I had, with a simple 4cyl engine. The mileage differed ALOT depending on cruising speed, due to the higher RPM in the weak engine. Jeeps tend to use V8s or inline 6's which are powerful engines that gets cruising rpm at high speeds.

[Dotchetter]

Hey, I liked this vid.

Some good tips. What I really comprehended was that you're driving a Grand Cherokee, which I also do. Now my Jeep's got the 5.9 V8, and when I heard what you said that 60mph gets worse mileage than 85, I instantly thought about my Ford that I had, with a simple 4cyl engine. The mileage differed ALOT depending on cruising speed, due to the higher RPM in the weak engine. Jeeps tend to use V8s or inline 6's which are powerful engines that gets cruising rpm at high speeds.

[ononsual]

Different cars achieve max mpg at different speeds.

As mentioned, dozens of variables at play.

No need for high octane unless engine knocks from pre-ignition.

Careful...knock can damage engine.