Other relastic fuel economy goals?

[Cobb]

I havent been able to film it as its difficult to do, but through drafting I have hit 70mpg going 70 mph. I find a big square box trailer works best and you got to stay on top of the slip stream or you will loose it.

Other than that I have slacked off trying to max fuel economy otherwise the cooler weather has lowered it some, but still 48-49mpg is well over the epa and identical to my geo metro.

[Fl_Fyr_Fytr]

Originally Posted by Cobb

I havent been able to film it as its difficult to do, but through drafting I have hit 70mpg going 70 mph. I find a big square box trailer works best and you got to stay on top of the slip stream or you will loose it.

Other than that I have slacked off trying to max fuel economy otherwise the cooler weather has lowered it some, but still 48-49mpg is well over the epa and identical to my geo metro.

Drafting is such an art. I find that there seems to be five different zones behind a truck. As you near 200-300 feet behind the truck you enter zone one and f/e begins to increase slightly. Get closer and you hit some light turbulace which actually lowers fuel economy. Get a little closer and buffeting stops and your numbers jump greatly. Enter zone four and the buffeting becomes serious, shaking the car violenty side to side. Fuel economy seems to be better than zone one but not better than zone three. Finially, zone five appears at about one and a half car lengths and closer. This distance is very dangerous but fuel efficiancy goes through the roof and turbulance is nearly non existant. Truckers also don't really care for you being that close either. Zone three really is the sweet spot and is a good comprimise between fuel efficincy, safty, comfort, and speed.
Personaly, I look for trucks that have the mud flaps that go all the way accross the rear as the slip stream is better and keeps crap from nailing your car.

[euro sport]

Although I don't want to sit here and start a huge debate, I just find it kind of weird reading a fire fighter advocating tailgating. Of course I have no idea if you really are a fire fighter... just going by your screen name. :P

[Fl_Fyr_Fytr]

Originally Posted by euro sport

Although I don't want to sit here and start a huge debate, I just find it kind of weird reading a fire fighter advocating tailgating. Of course I have no idea if you really are a fire fighter... just going by your screen name. :P

Where in my post did you read that I support or even suggest tailgating?! It is a fact that getting closer improves milage and that is all I said. If anything I suggested zone three which is a good 50 feet behind the truck. Maybe you should not read into it what you want and instead read what is written, eh?

[euro sport]

Oh okay.... perhaps I misinterpreted the part where you said zone one was 1-1/2 car lengths behind a truck... and that the other zones were closer. Perhaps you meant to say zone four?

[Fl_Fyr_Fytr]

Yup, your right, it was a typo. Zone five would be the closest whereas I said zone one. My bad. I do not suggest close drafting to anyone and in fact have found that my best best milage was done without drafting at 55mph. While I'm sure that drafting would help those numbers even better, I would be hard up to find a trucker doing 15mph under the speed limit.

[Cobb]

Drafting is driving in the slip stream you are obeying the driver in front of you and working with him or her. Tailgating is riding someones bumper to intemdiate them to go faster or move out of your way.

Myself I find tailgaters will blink their lights and get closure if you slow down vs maintain distant.

I have been drafted and dont care. If you change lanes, slow down or speed up to loose me, I just follow another vehicle.

Yes, I too have notice the zones and love those low profile car trailers that come down to the ground vs the standard semi truck and cargo container.

I find the sweet spot you hear no wind noise.

[nameless00]

Originally Posted by Cobb

Other than that I have slacked off trying to max fuel economy otherwise the cooler weather has lowered it some, but still 48-49mpg is well over the epa and identical to my geo metro.

It's the cold weather we dipped to 1-5 C this past week here and Ive noticed I dropped 5 MPG to 8.. I noticed the engine taking much longer to warm up and gas usage is much higher that when it was warmer. When I took delivery of the I2 it was 12-18C and the first few days of driving the engine warmed up rather quickly so it's noticable.

I'm not looking forward to driving at -40, and I don't imagine the Prius or any car would do well then, it'll be nasty harsh on the batteries, at least it won't be using the starter. My understanding is it takes power from the Hybrid battery to start the engine?

[red1dr]

Originally Posted by Fl_Fyr_Fytr

... and in fact have found that my best best milage was done without drafting at 55mph. While I'm sure that drafting would help those numbers even better....

Ditto here. Apart from the danger, a big problem with drafting is that one is constantly on and off the gas trying to maintain the gap rather than driving efficiently in response to changes in terrain and traffic. Driving slower with an eye to road conditions more than offsets any gains from drafting.

The mpg gain from drafting is less at lower speeds (and the "pocket" is smaller, so one would have to be closer). So even if one could find a truck doing 50-55mph the benefit from drafting it would be less than at higher speeds.

Back in the day I used to roadrace bicycles, and during training often drafted trucks, buses, and motor homes at 50-60mph (not to mention scooters and mopeds at lower speeds, and teammates at lower speeds still). On a bicycle you can actually feel the draft on your body. Less power, so one had to hang no more than 1-2 feet back or the downdraft of air coming off the top of the trailer would make it impossible to stay with the truck. We would ride near the corner of the trailer so we could swing out and around if it slowed suddenly - but still very dangerous.

[Fl_Fyr_Fytr]

Originally Posted by red1dr

Back in the day I used to roadrace bicycles, and during training often drafted trucks, buses, and motor homes at 50-60mph (not to mention scooters and mopeds at lower speeds, and teammates at lower speeds still).

I too used to be a "roadie". I started out BMX and then mountain and finially in the road arena. I was pretty good at drafting other cycles at distances of six inches or so but I never even tried automobiles. I asume by "50-60mph" you are talking about downhill, right? I was considered fast but my best maintainable speeds were in only the 30-35 range (105 / Ultegra mixed parts groups on Schwinn, Giant, and Specialized frames). I think I might have hit 50 once or twice on serious hills but that is a truelly hair-raising experience on tires with a contact surface the width of a quarter and at pressures of 125-130 psi. One small pebble in the road and...

My cycling days ended when a wreckless driver in a mustang used an on-off ramp to get around traffic and hit the left side of my drops when I was at 35mph (I was in the aero bars). While I narrowly (by like 1-2") escaped being hit by a box truck (that the mustang had cut off), I did not escape injury. The cartalidge in my left elbow was torn, my sholder roadrashed nearly to the bone, fractured my collar bone, and broke two ribs. I was wearing a helmet (which may have saved my life as I didn't lose conscienceness for about 30 seconds allowing me to get off the road) and a kevlar suit, both of which failed during the accident. The bike was a total loss ($3k or better) and for more than a year, I couldn't go into the drops or aeros without serious pain in my side. The mustang? He roared off without even pausing and no-one was able to get his tag. The nice man in the truck that nearly hit me as I flew out in the road did stop, called an ambulace, and gave a report to the police. There is a special place in heaven for that man...