Say bye to hypermiling at average 65+ mph?

Below about 45 MPH, the engine turns off when not under load, above 45 it has to rotate to protect MG1. That will change how to hypermile.

Also at 65+ most of your energy is pushing air, so better aerodynamics would be an important hypermiling technique.

 

1) Keep your tires inflated. Max PSI in front, Max PSI - 2 PSI in rear.

2) Drive as slow as you can while being "safe" on the road. If you can drive closer to 65 mph rather than 70 mph, drive 65 mph. If you can reduce it to 63 mph and not be run over, drive 63 mph. Speed kills mpgs much worse than people realize.

3) Don't grill block unless you have a way to measure your engine temperature. The mpg savings aren't worth it if you burn out your inverter prematurely. Grill blocking helps a lot during warmup, especially on cold days.

4) During warm weather (when you'd have the A/C on), try to park in the shade with the windows cracked to keep the ambient temperature in the car down. Get a windshield screen to reflect the light/heat. Your interior will absorb the heat of the car (equilibrium), so even if you roll down the windows to let the hot air out, the interior (seats, carpet, etc) will warm the air up again. By keeping in the shade, you keep the overall car temperature down which will allow you to minimize A/C usage. You may be able to get by with just the fan blowing ambient air.

Good luck!

 

I second Codyroo's comments.

You'll still glide when traffic ahead is slowing, in stop & crawl, and when going down a good grade. But in general, wind will kill your speed so quick that the reacceleration is not worth it at freeway speeds.

Use DWL and DWB.

 

If you're still going to be in SoCal, good luck driving anywhere near the speed limit for that 65 mile commute unless you drive in off-hours.

 

I'd like to add the following....

5) Reduce your aerodyname profile/drag: keep you windows rolled up and your sunroof closed when your are going over 55 mph. Any exterior attachments like a bike/ski rack should be removed. Removing any excess weight/cargo can help too.

6) Design your trips so that the route longer than 7 miles/60 minutes. Short trips kill the mpgs. Long trips increase the mpgs.

7) pick routes with very smooth road surfaces and stay away from road construction. Smooth roads allow easier glides. Rough road surfaces, snow, icy roads, and rain can cause the Prius' mpgs to drop.

8) the Prius can get 55mph fuel efficiency when driving 65mph if there is a tail wind of greater than 10mph .

9) there are two hypermiling techniques that work as speeds greater than 65 mph.
a. The first is drafting. In drafting, a vehicle hides behind another vehicle's wake. By being directly behind the lead vehicle, most of the wind resistance can be avoided. By being behind on either side of the lead vehicle, a significant port of the wind resistance can be avoided. Here in DC, its not uncommon to se SUV draft/tailgate really close behind another vehicle just to save gasoline. However, they have have to get really close to save fuel this way.
b. The other hypermiling technique is called Driving with Load (DWL) which means speeding up on the downhills and slowing down on the uphills ( this is an old 18 wheeler trick to conserve fuel). It's easier to do at low speeds -- as your speed increase DWL sessions become harder and hard to do.

10) If you are in Orange County, California - I don't think it will get cold enough for a long enough time down to effect your vehicle's overall MPGs. If you're living in a Smog prone metro area - you probably can only get 10% ethanol gas - if you see 15% ethanol gas - don't buy it even if its cheaper - the more ethanol that's in your gasoline the lower your MPGs will be

 

E10 has 3% less energy than E0, so you will get 3% poorer mileage, but if E10 is more than 3% cheaper, you are saving money as well as petroleum.

For E15, 5% is your breakeven point.

 

great input...I think drafting at a relatively safe distance is possible, but you would need to do it over an extended period of time to see any measureable difference. My first long road trip is coming up...so cannot wait to find out! I can sense just a bit of drag lifted off the car when in someone else's wake much more than any other car I have ever driven (which for the most part were all larger than the Pri)

 

Increasing trip distance in order to increase mpg defeats the real purpose of hypermiling. It is better to minimize total fuel use, even if it means a lower mpg 'score'.

Father Wayne gets very annoyed when the terms 'hypermiling' and 'drafting' appear in the same paragraph. To many people, and the trucking industry, and nearly all law enforcement, 'drafting' refers to a specific, illegal, and deadly practice that gives other hypermilers a bad reputation. Don't do it.

While drafting will save some fuel when you do it, it saves a lot more fuel after you die, because then you won't need any fuel at all. Drafting also hands over control of your vehicle to the driver in front, preventing you from applying other techniques that are actually more effective.

If you do take advantage of another vehicle's slipstream at a safe distance and position, please use a different word to describe it.

 

I do not draft.
I stay in the right lane until the last moment when passing. It may take miles <G>
When being passed I tuck to the left of my lane as they 'cut in front of me'.

But I never draft!

Not drafting can be worth 3 MPG.

 

what do you mean?

 

I am saying that without following too closely, you can still improve your Mileage via reducing airflow over your car.

(By the way, drafting a prius is just silly, since they have wonderful aerodynamics, they do not leave much air still going freeway speeds in their wake. If you must follow too closely, at least draft something cubical)

 

that is why I said at a relative safe distance, no one said anything about following too closely. And who said anything about drafting behing a Prius? That is like the blind leading the blind. I pick the biggest gas drinker on the road to get behind in which case they are punching the largest hole in the air.

 

You can still utilize hyper mailing techniques well above 65mph. One technique I find very helpful is to glide down the other side of overpasses. With good LRR tires I can maintain or even lose a little speed going up one side then glide down the other side. In my case this is only realistic with the 15" tires but if the overpass is steep enough I can do it with the 17" tires. This also applies to hills.

 

Off-hours isn't any better. People still blast through on- and off-ramps at 85+ so good luck not to get run over.

 

wow...way different than South Texas. Down here...70 is considered fast. I find it quite easy to be in the flow of traffic and in many cases above it. It has its Pros and Cons.

 

OMG, hypermiling and drafting are totally obnoxious, and give Prius drivers a bad (or should I say, worse) reputation than they have already.

Please don't.

 

I don't like following big trucks. They kick up debris, that mess up the paint.

 

The point is that the draft dissipates quickly, so there isn't much draft advantage unless you're following REALLY closely. Mythbusters did an episode on this, and the real advantage is at 10 feet or so as I recall. At 70mph you're going 100 feet per second, so even the minimum 2 second following spacing puts you 200 feet back (roughly 13 Prius lengths).

Besides being really tiring and damaging your paint, as Jimbo points out you actually get POORER mpg than you would on your own. Because you constantly have to accel/decel to adjust your position, which wastes gas, and because it's hard to see the road ahead you can't react to hills, packs of slower traffic, etc. (There's also the issue of not being able to see and avoid debris on the road, like truck tire treads).

I tried close drafting in my old car (with a Scangauge on it) and could see that I got worse mpg doing it than I did by simply backing off 5mph and letting the trucks do their thing.

As Jimbo says, you can get "scraps" of draft as you come up to pass trucks or as trucks go by you and pull in ahead. That helps, especially if there are strong headwinds.

There's more to gain by simply driving a bit slower and trying to maintain constant speed (cruise control may help at first).

EDIT: I found the Mythbusters data:

55mph control: 32mpg
100ft: 35.5mpg, 11% improvement
50ft: 38.5mpg, 20%
20ft: 40.5mpg, 27%
10ft: 44.5mpg, 39%
2ft: 41mpg, 29%

At 70 mph 200 feet is the minimum safe distance (2 seconds), so the effect would be even less, except that at 70mph the draft would extend a bit further back than at 55mph.

The dropoff at 2 feet vs 10 feet was thought be from having to constantly adjust speed to avoid a collision.