For those that are curious, proof that drafting does make a HUGE difference... - GreenHybrid

jlambeth · #1 (**permalink**) 06-19-2006, 10:37 AM

Kind of interesting to me anyway. My route runs from Redlands, CA to Monrovia CA via I-10, 57, 210 and is approximately 52 miles. I made two different runs, one with drafting and one without on different days with similar weather stats. Elevation change is from 1100' at Redlands to 560' at Monrovia therefore my chances of achieving the same mileage going back are zero.

Without drafting - 54.0 mpg
With drafting - 67.7 mpg

That is slightly over a 25% increase in mpg. I was drafting probably 70% of the time. I did drive in the granny/trucker lanes the entire way resisting the siren song of the HOV, no small test of character.

Jesse

mmrmnhrm · #2 (**permalink**) 06-19-2006, 12:52 PM

I've never been a doubter of drafting, having done it mroe than a couple times in my old car during the fall rut. What I'm curious about is if anyone's had success in "surfing", placing the front edge of a large vehicle's shock wave in your draft point.

s2ktaxi · #3 (**permalink**) 06-19-2006, 04:46 PM

Accept for the safety factor of tailgating

, drifting is quite effective at improving gas mileage, in my MDX, I used to go from a 24-25mpg at best to about 30-32 just by drafting about 20 ft behind a semi.

Eskrimast1 · #4 (**permalink**) 06-19-2006, 07:35 PM

Quote:

Originally Posted by jlambeth

That is slightly over a 25% increase in mpg. I was drafting probably 70% of the time.

My results are similar: 20%+ increase in mileage, depending on the speed of the big rig, 60MPH and 5 car lengths behind the rig. I've seen less dramatic improvements from drafting smaller vehicles too, such as slow moving minivans and SUVs.

Anahymbrid · #5 (**permalink**) 06-19-2006, 09:37 PM

Quote:

Originally Posted by Eskrimast1

60MPH and 5 car lengths behind the rig.

Is that enough for drafting? If so, it's not really tailgating or dangerous! If I remember my driver's education courses (from 30 years ago!), the rule of thumb was one car length for every 10 mph. Five at 60 is close enough.

The only REAL issues, then, are visibility (hard to see what's up ahead with a big rig in your face!), and rocks kicked up from all those tires.

It's a gamble. Better mileage... chips in windshield.

jlambeth · #6 (**permalink**) 06-19-2006, 11:06 PM

I don't actually draft, other than today. It was about 3-5 car lengths on average from what I remember. Oh, the a/c was also on full blast as well.

Can't see very well at all behind these trucks which I do not like at all. Though, I am fairly sure that I can react and brake more quickly than the truck can brake. Though those tires are unbelievably weak for braking.

Jesse

Eskrimast1 · #7 (**permalink**) 06-20-2006, 02:45 AM

Like Jesse, I don't typically draft. On the rare occasion that I do draft (long business trips during off peak traffic hours on interstates), I typically pick a big rig with mud flaps, a FedEx delivery truck (or equivalent), or a slow moving Expedition/Suburban (hard to find). I don't really look to draft every single time I get on the freeway, but if the conditions are right and I'm not in a hurry, I'll make an effort to. I personally don't have the patience to draft for an entire tank.

If you just want to experiment, try drafting a minivan or large SUV.

Combine this technique to the extent you feel comfortable with DWL and DWB, and you have a highly effective hypermiling strategy.

mickster · #8 (**permalink**) 06-20-2006, 06:39 AM

Unfortunately on the Long Island Expressway (which is neither express and barely a way...but it is on Long Island) is an incredibly unsafe place to draft. There is a 100% chance you will get a rock hitting your car or windshield (the roads are a mess) and there is a 90% chance another tractor trailer will run into you trying to draft the big-rig up ahead. Then there is an 85% chance someone else will hit you if you are between two rigs because they want that space...

Suffice to say, the LIE (as we all call it) is a joke for driving---and I do the so-called "reverse commute." At least until March (hopefully they renew it) I can drive in the HOV lane where I might get tailgated if I'm only doing 65....

Mr. Kite · #9 (**permalink**) 06-20-2006, 07:39 AM

Quote:

Originally Posted by Eskrimast1

Like Jesse, I don't typically draft. On the rare occasion that I do draft (long business trips during off peak traffic hours on interstates), I typically pick a big rig with mud flaps, a FedEx delivery truck (or equivalent), or a slow moving Expedition/Suburban (hard to find). I don't really look to draft every single time I get on the freeway, but if the conditions are right and I'm not in a hurry, I'll make an effort to. I personally don't have the patience to draft for an entire tank.

If you just want to experiment, try drafting a minivan or large SUV.

Combine this technique to the extent you feel comfortable with DWL and DWB, and you have a highly effective hypermiling strategy.

How closely would you be following these minivans or SUVs?

birchman2 · #10 (**permalink**) 06-20-2006, 07:57 AM

I don't think there is any dispute that drafting will increase FE. NASCAR proves this and has for years just like slowing down increases FE.