Highway Gas Mileage

[tehgyb]

Originally Posted by Sven7

I usually P&EOC from 50-65mph. Best ecomod I've ever made:

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Didn't want to leave the image quoted for space reasons, but jeez man I haven't laughed that hard all day ;P on the other hand is true and probably quite useful huh?

[jousai7]

[QUOTE=Sven7;305366]I usually P&EOC from 50-65mph. Best ecomod I've ever made:

Ive thought about doing that so many times. Ive considered: "follow me for better mpg, or keep speeding"

I try to stay my own pace but I do adjust for semi-truck drivers. I do remember driving a moving van and how hard it could be to maintain speed or getting back when I got cut off or if it was a slow moving vehicle.

[Sven7]

I'm just going to update this quickly if anyone's interested. Since semi's drive 55-60mph anyway you can drive 2-3 seconds behind them and get the same MPG you'd get driving 45-50 by yourself. Effectively better aero and therefore mpg and people are passing the semi anyway. It's a win-win. I do this in my Rabbit and when driving auto transmissions because I can see no good reason not to.

[user removed]

I get the same mileage at 55 on a deserted US Route 60 as I do at 65-70 on the packed I64 east from Richmond to my home near Williamsburg. I think it is a huge mistake to be the "obvious highway cholesterol" on any road.
Personally when you try to engage in "behaviour management" of other drivers, you increase your risk factor exponentially, which is why I try to keep my actions as "stealthy" as possible.
The exception for me is tailgaters. I try to discourage them by appearing to be just incompetent, so they think it's just some half wit old man who can't drive worth a dang.
In the rare instance when I get one who is really stupid. I will either pull off the road, make a turn, or just coast until they get the idea. In one instance that was from 54 MPH down to 20 MPH before the space case decided to pass me in the left lane on an otherwise deserted 4 lane road without any intersection for over a mile.
I guess they were just following me instead of driving themselves. Speed limit was 45.

regards
Mech

[skyking]

I'm with you, and sven. I like to blend in with the trucks. Around here they drive just right.

[SentraSE-R]

You can't fight the laws of physics.





I go my own speed, in the slow lane where the law requires I be. Aveo's lane changing is illegal, as well as unsafe. If other traffic, including tractor-trailers, wants to go faster, that's their problem. As Frank Lee noted, you can never go fast enough to satisfy everyone.

[basjoos]

Originally Posted by SentraSE-R

You can't fight the laws of physics.



.

But you can modify them with effective aeromods to flatten out that drop in mpg with increasing speed (notice the Elantra's line compared to the others). On the Aerocivic, I flattened out that line so much that with my previous non-lean burn, 4 valves per cylinder engine, the improvement in BSFC efficiency as the engine load increased with speed counteracted the increase in wind drag to give me a flat mpg line from 45mph out to 65mph. That is not the case with my current lean burn engine that shows the typical drop in mpg with increasing speed, but it is a very minimal drop compared with most cars.

[F8L]

Another option is to switch tires to the best LRR tire you can find in your size. This could allow you to drive a bit faster when safety is an issue yet still get great gas mileage.

I recently decided to sell my aftermarket 17" wheels and stick with OE 15" wheels for the above reason. I had to hypermile my butt off to get decent mpg with the 17s which meant driving slow on the freeway. With the 15s I can driver faster and maintain mpg or continue to drive slow and gain mpg. A good set of LRR tires gives me this freedom.

[euromodder]

Originally Posted by mcrews

One thing I noted on my cross-country drives.....
Big rigs tend to drive 55mph. I would never 'force' a big rig to pass me because I was doing 52mph.

I've been doing around 85 kph indicated on the motorway lately.
Resulting in a record tank at 4.16 L/100km or 56.5 MPG.
But when a semi starts to catch up, I do accelerate to stay out of its way - on most of our roads, they aren't allowed to overtake, and are limited to 56mph.

The best place to be for MPG, is behind them.
You get the benefit of the draft - yes, even at a safe distance if it's a nice, square rig - and the benefit of the slow, constant speed.

Best of the lot are those who are limited to 85 kph / 53 mph by their employer as a fuel saving measure, instead of the 90kph by law.
These rigs usually have this indicated on the back.

[skyking]

It does go back quite a ways, that beneficial effect. I wonder if a technically savvy guy could make a Cruise control input coupled with a laser rangefinder. Get in behind a good truck, engage. Now if he slows without braking, you still get that safety buffer in case something happens, instead of trusting your eyes only.
If he speeds up past your original set point, oh well. Find a better truck
We have all crept up closer than we wanted in times like that.
Maybe some indicator lights.