"Drafting" experiment... 50 mpg to 65 mpg, easy!

Escalade_on_22s · 04-16-2005, 01:05 AM

I commute on a weekly basis from Las Vegas to Ridgecrest, CA (235 mi) and decided to run a little "drafting" test tonight.

I typically set the cruise at 65 and achieve about 49 mpg per trip. Tonight I got behind a 18 wheeler running 70-75 and followed him for about 175 miles or so on I-15. I was inside his wind vortex following at about 25 ft or closer (not recommended but mildly amusing). My MFD average went from 44.5 MPG outside of Bartsow (at 65 mph), to 63.5 MPG (at 70-75) by the time we got to Tropicana - and it's an uphill run.

I couldn't believe how many 5 minute segments of 99.9 MPG I saw. The battery was 10 bars full green the majority of the way and the motor was generating instead of producing for minutes on end. Several times (at speeds up to 72 mph) the car went into "super-golfcart" mode where the electric motor was providing the sole source of power. I imagine you could achieve better than 75 mpg traveling cross-country using this technique.

I think I'll get at least 650 miles out of this tank, but I don't recommend following that close... just wanted to see what would happen. Also, a fella in a maroon '05 Prius tagged along in the train for the last 30 miles or so... the first Prius I've seen in a long time.

mtc1234 · 04-16-2005, 07:59 AM

At one point several years ago, I was thinking about getting a Honda Insight. The newsgroup I monitored discussed several techniques like that. They also noticed mpg improvements by positioning themselves on the crest of the air flow disturbance. I think the guy who wrote about it referred to it as surfing.

Ray Moore · 04-16-2005, 08:50 AM

It works. I stay back about one second and get results of around 52 MPG at 77 mph.

BTW get ready to be scolded by others. Scolding yourself first won't help.

V8Cobrakid · 04-16-2005, 10:22 AM

I used to do this all the time when on 101. The only drawback is that if the highway isn't clean, you be getting little rock chips in the very front part of your car and not know it. You can hear little pebbles when they hit the hood, b ut not the lower front area. my car is pretty chipped up

DaveinOlyWA · 04-16-2005, 10:26 AM

great results!!... try drafting in a F-150... you will double your mileage. and in isolated areas, drafting behind a professional driver is not as dangerous or difficult as driving with idiots under any circumstances imho.

**efusco** · 04-16-2005, 10:33 AM

Quote:

It works. I stay back about one second and get results of around 52 MPG at 77 mph.

BTW get ready to be scolded by others. Scolding yourself first won't help.

1 second at 77mph!! Not with my family in the car...that's what, 112 ft. following distance, your reaction time is practically 'nil'. And if it's a semi or large enough SUV to get a decent draft off of there's no way you can see around it to help anticipate problems.

Just last week I took care of a 19y/o who drove his car under the back end of a semi. His friend in the car died and they were still trying to extracate the body 4 hours after the accident. The patient I took care of took over 30 minutes to extricate. His face was fractured in too many places to count and he had serious brain damage.....he was wearing a seat belt and had an air bag.

My understanding is that a 2 second following distance is adequate to benefit from a draft, and I use that sometimes, but please folks consider risks and benefits and driving conditions before ever trying this. A few pennies saved is just not worth the risks....and they are very very real risks.

jayman · 04-16-2005, 11:28 AM

Quote:

Just last week I took care of a 19y/o who drove his car under the back end of a semi. His friend in the car died and they were still trying to extracate the body 4 hours after the accident.

Evan:

I suppose the neat thing about your line of work is that on an almost daily basis you get to see Darwinism in action.

Jay

xevious · 04-16-2005, 01:20 PM

The best way to do this is to mount a HV battery-powered electromagnet to the front bumper or your Prius. On the highway, creep up behind a large truck until your front bumper is almost touching the rear bumper of the truck, then engage the electromagnet.

**TonyPSchaefer** · 04-16-2005, 01:59 PM

I have tried drafting on a few occassions. My adult ADD doesn't allow me to stare at the back of semis for very long.

Booooooorrrrrrriiinnngggg

DaveinOlyWA · 04-16-2005, 02:08 PM

well i dont recommend drafting to anyone... but i realize that a truck will not be able to stop faster i do so that a following distance of one second will be good enough.

obviously i will be paying extra attention to what the truck is doing and i dont do it when others are in the car not so much out of concern for their well-being. its more like, i dont want to listen to them b**ing about my driving.

04-16-2005, 01:05 AM	#1
Escalade_on_22s Join Date: Apr 2005 Location: Las Vegas, NV Posts: 70 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	"Drafting" experiment... 50 mpg to 65 mpg, easy! I commute on a weekly basis from Las Vegas to Ridgecrest, CA (235 mi) and decided to run a little "drafting" test tonight. I typically set the cruise at 65 and achieve about 49 mpg per trip. Tonight I got behind a 18 wheeler running 70-75 and followed him for about 175 miles or so on I-15. I was inside his wind vortex following at about 25 ft or closer (not recommended but mildly amusing). My MFD average went from 44.5 MPG outside of Bartsow (at 65 mph), to 63.5 MPG (at 70-75) by the time we got to Tropicana - and it's an uphill run. I couldn't believe how many 5 minute segments of 99.9 MPG I saw. The battery was 10 bars full green the majority of the way and the motor was generating instead of producing for minutes on end. Several times (at speeds up to 72 mph) the car went into "super-golfcart" mode where the electric motor was providing the sole source of power. I imagine you could achieve better than 75 mpg traveling cross-country using this technique. I think I'll get at least 650 miles out of this tank, but I don't recommend following that close... just wanted to see what would happen. Also, a fella in a maroon '05 Prius tagged along in the train for the last 30 miles or so... the first Prius I've seen in a long time. __________________ LT Bryan "Donny" Rex USN Test and Evaluation, VX-9

04-16-2005, 07:59 AM	#2
mtc1234 Member Join Date: Mar 2005 Location: Laurel, MD Posts: 39 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	Re: "Drafting" experiment... 50 mpg to 65 mpg, eas At one point several years ago, I was thinking about getting a Honda Insight. The newsgroup I monitored discussed several techniques like that. They also noticed mpg improvements by positioning themselves on the crest of the air flow disturbance. I think the guy who wrote about it referred to it as surfing.

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04-16-2005, 08:50 AM	#3
Ray Moore Senior Member Join Date: Mar 2004 Location: Texas Hill Country Posts: 820 My Car: 2004 Prius Model: Package: #9 Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	It works. I stay back about one second and get results of around 52 MPG at 77 mph. BTW get ready to be scolded by others. Scolding yourself first won't help.

04-16-2005, 10:22 AM	#4
V8Cobrakid Senior Member Join Date: Jun 2004 Location: s.f. bay area Posts: 2,946 My Car: 2004 Prius Model: N/A Package: #9 Thanks: 10 Thanked 26 Times in 25 Posts Friends: 5	I used to do this all the time when on 101. The only drawback is that if the highway isn't clean, you be getting little rock chips in the very front part of your car and not know it. You can hear little pebbles when they hit the hood, b ut not the lower front area. my car is pretty chipped up

04-16-2005, 10:26 AM	#5
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,823 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 39 Thanked 188 Times in 161 Posts Friends: 12	great results!!... try drafting in a F-150... you will double your mileage. and in isolated areas, drafting behind a professional driver is not as dangerous or difficult as driving with idiots under any circumstances imho.

04-16-2005, 01:20 PM	#8
xevious Join Date: Jan 2004 Location: Oregon Posts: 187 My Car: Model: Package: Thanks: 0 Thanked 0 Times in 0 Posts Friends: 0	The best way to do this is to mount a HV battery-powered electromagnet to the front bumper or your Prius. On the highway, creep up behind a large truck until your front bumper is almost touching the rear bumper of the truck, then engage the electromagnet.

04-16-2005, 01:59 PM	#9
TonyPSchaefer Your Friendly Moderator Join Date: May 2004 Location: Far-North Chicagoland Posts: 11,200 My Car: 2004 Prius Model: Package: #9 Thanks: 58 Thanked 306 Times in 190 Posts Friends: 27	I have tried drafting on a few occassions. My adult ADD doesn't allow me to stare at the back of semis for very long. Booooooorrrrrrriiinnngggg

04-16-2005, 02:08 PM	#10
DaveinOlyWA 3rd Time was Solariffic!! Join Date: Apr 2004 Location: South Puget Sound, WA Posts: 12,823 My Car: 2010 Prius Model: IV Package: Solar Roof Thanks: 39 Thanked 188 Times in 161 Posts Friends: 12	well i dont recommend drafting to anyone... but i realize that a truck will not be able to stop faster i do so that a following distance of one second will be good enough. obviously i will be paying extra attention to what the truck is doing and i dont do it when others are in the car not so much out of concern for their well-being. its more like, i dont want to listen to them b**ing about my driving.