Driving 55...can't draft a trucker
 

I'm doing 55 on the right most lane of the freeway and I get passed by truckers lol.

How the heck do hypermilers draft when truckers ususally go about 60-65??

If I stay up to them, it's a matter of RPM.. I'm at 2400 RPMs to 2500 RPMs (just about) at 55. If I go 60, it's at 2800 or 2900?

So which is better, the drafting, or the RPMs?

By the way, I normally do 60, this last trip of about 120 miles roundtrip, I tried sticking to 55. Free way was wide open * if not, I would not have tried, don't want to impede flow of traffic more than I have to. And on the way back, I'm sure I avoided an accident too (van with blown tire rear left tire in the middle lane *people already helping and no one hurt).

New Yaris Sedan 5speed if it matters.

Ok, apart from the fact whether or not you should be drafting and how close I can tell you that drafting say at 60 mph gives you better mpg than driving 55 mph. 65mph I'm unsure about, you would probably still be better of drafting but you'd have to get pretty close and apart from being not very safe, I hate not being able to look ahead and can only draft for shorter periods of time myself.

Same problem here. Though sometimes I can find a motor home or gravel truck poking along at 55. Can't say I really "draft" though; it's more like using them as an excuse for why I'm going slow. :D

I experimented briefly with drafting and it just didn't seem to make any difference. Maybe the VW's slippery enough that the benefit is minimal? But with a really boxy vehicle I can imagine getting sucked along at 60 might be better than 55 on your own.

As far as the Yaris is concerned, the hatchback is on my shortlist of business vehicles to consider. I think Yarii might be undiscovered gems of fuel economy in the right hands. :thumbup::)

Rick

"Yarii" ...nice :)

X2

2500 rpm coasting downhill as opposed to 2500 rpm climbing the same hill...which would use more fuel. RPM is a factor but load is more so a factor and is why drafting works.

I've found so far that P&G is superior to drafting, and drafting is superior to driving at a steady speed. YMMV.

I try and incorporate drafting and P&G. i.e, P&G behind a vehicle (preferably large). Aim so that the closest you come is a few car lengths.

If there are 3 lanes and little traffic, I don't mind going 80kph in a 100 zone. If anyone tailgates me, they know how to pass. If there is slow traffic in the left lane, I will go there. If the traffic is fairly solid and going the speed limit, I P&G around that speed. (I figure if I'm slowing down traffic around peak hour, I'm only increasing the likelihood of gridlock and massive increase in fuel wastage).

Which makes me think... probably one of the biggest things the government could do for fuel economy would be to regulate who can start work at standard hours and prevent gridlock.

Get a ScanGauge and try at 55mph, then try drafting at 60mph, then at 65mph, then see whats best for mpg.

I wouldn't considered drafting unless it gives me a 10-15 mpg increase, not less, because its unsafe, even if its faster.

Because I don't mind takin 10min more on a 50 minutes then not making the it in one piece. FE is one thing, but safety is another, and the last one is higher on my priority list.

So stay alive, don't draft.

And a Yaris sedan is a great car, my mom got one last year, now had put around 8000miles on it. Could do a hypermiller, my mom is doing the EPA. I did drive it for couple undreads of miles and I like it, it handles the bumps REAL good and the engine is powerfull enough, and you have a 5 speed so planty of fun and power. A Yaris is simply a Camry reduce, cheaper, that gets better FE (way better, even than the 4 cylinder), and that is safe.

You could put a 200k miles on it easy...

Sitting back at 55mph lets you choose which truck to draft. When you find one that is going a speed that you like, then get on it! Where I am originally from, people very often drive with less than a single car length between cars, while driving at 70mph. Drafting is just common driving practice in Detroit. Sometimes you wonder if the vehicle in the back is actually being towed.

I personally saw a 10-15mpg increase when drafting in my parents' Lexus 400h, with the speed being anywhere from 60-65.

Drafting will have much more impact on a SUV then a litle car like a civic or a cavalier.

To Bibi, I just ordered a Scan guage II, (anyone want a nice price I can give you the link in a PM--it's from a vw group buy.) So I will definitely be using that.

To Mira, P&G sounds great but from the gas saving sticky, it sounds a bit complicated, don't think I'll try it yet. About traffic, I think I will stick close to slower big cars, either stay infront or behind them. Today, I had cars come rushing around the big rigs, just to get on to my tail. I guess they thought I was ahead because I already passed, not knowing that I was probably the reason why the trucker was slow.

In retrospect, I don't think drafting helped me much. First of all, I wasn't close enough-- only about 2 or 3 car lengths behind (too scared to get closer). Second, my car is pretty decent in the aero factor in my humble opinion. I mean it's not a box like a xB or anything and it is low enough already.

Lastly, I don't think there should be any regulations. Maybe instead of or in addition to carbon credits, incentives for companies to stagger start times? -- money talks. Maybe do it by the category? Can't have supervisor's supervising empty plants can we?

I couldn't help but think that I wished I had a 6 speed instead so I can cruise at a lower rpm than in the 5 speed.

And you're right Bibi, I don't think I'll be drafting unless I'm in a caravan of cars.

BIBI, I'd have thought the opposite is true. To me it seems harder to fit a wider vehicle cleanly into the slipstream. The slipstream gets affected by crosswinds and unless you're on a motorcycle (which gets a great boost and way too high pf a risk) it's difficult to find the sweet spot.

But a larger vehicle (SUV) is pushing more wind normally...so the draft makes a big diff

Mythbusters had a 22% (hrmmm... could be wrong, I'm going from memory) aero reduction at 7 car lengths :thumbup: There's no fine line of advantage, it's several shades of gray :D

EDIT: Forgot to mention, I've got some qualitative wool tuft photos attesting to this.

Likely something similar to their increase in FE. 2 additional mpg for an SUV is much more significant percentage wise than 2mpg for basjoos :p

On a Bicycle in a pace line...the second rider uses 10% less energy in a headwind...the third rider uses alomost 20% less energy and the 4th rider 30% less...and that is just bikes.

Let's see the photos! :D

Threaded

I'm actually quite peeved with myself at the moment... I can't seem to find my digital camera (with memory card) - which has more shots at varying distances. They're not particularly useful as stills (they look just like the one's as shown - which is why I only posted one set).... I'm more mad because of other photos on the camera that I haven't put on my computer yet....

Update:


I've been doing the pulse and glide. IT WORKS! Allows me to keep up with the traffic as well and it bumped up my mpg.

Well, getting a scan guage helped a lot.

So instead of a steady 55 or 60, I do the P&G and take advantage of the hills. Still have to get used to drafting. On the occasions when I do hit the sweet spot behind a car/truck/something big. It's like a tractor beam and I've got to train myself not to be quick to the brake pedal. The sweet spots pulls you right in~!

Finallly hit a minor mark: made it to 500 miles on a tank (11.1 total but ususally only fill about 10.2- 10.7)

Thanks guys.

LOL! I live about 80 miles south of downtown Detroit, and Iv been there many times. I know what you are talking about! I remember driving 5 mph over the limit, and getting passed like I was parked, and by MANY cars in a line. They dont call it the Motor City for nothing! FE in rush hour Detroit:eek: traffic must be really difficult!

One of you gassaver electronics gurus needs to design a pulse and glide cruise control, one that continuously pulses above and then glides below a set mph point.

It would make a long road trip much more relaxing if P&G was done automatically. I'm just too lazy to do it on my own when I can just push the button on my cruise control and relax.

Erik, cc (plus) can actually do an okay p&g on my slushbox. Nudge to neutral to glide (that auto disengages the cc), nudge back to gear and tap resume to pulse (the acceleration on the pulse is actually quite optimal). Above lockup speed however, I can't detect any improvement using P&G.

It was funny, I'm in our stick Accord and sensed no load on the tranny while driving at a city speed, so I nudged it into neutral to glide. The cruise was still engaged and I wasn't thinking (no clutch or brake was engaged to disengage the cruise). Luckily it wound up quite slow and the stereo wasn't too loud so that I caught the engine as it not much after it hit 5K... ;)

Personally, I like to draft. My commute is mostly highway, at rush hour. But, oddly enough, finding a good draft can be difficult: The truck going slow in the right lane is getting off at the next exit. The out-of-town semi's go slow, but they don't know where they are going, and keep changing lanes. The local semi's know which lane to be in, but they are going 70mph. And the construction trucks are going slow, but they drop gravel and mud at every bump. I only find a good draft about once per week. :(

Fortunately, rush hour gives me a good corridor effect. I find that i get the same mileage going 65 in the middle lane, flowing with the traffic, as I do going 60mph in the right lane, punching my own hole in the air. Hey, we're all drafting at rush hour :) . At non rush-hour, though, you'll find me going slow in the right lane.

As to safety, I feel much safer following a semi at one trailer-length, than I think those folks in the left lane are: going 70mph, one car-length apart.

The scenario where everyone is driving faster benefits you regardless, every time a vehicle passes it helps pull you along a little bit.

Be careful doing this, but perhaps a minor adjustment in your lane position might enhance the effect, which is to say I think the closer you get to the car passing the better, but I wouldn't get no closer than say the center of your lane.
I think if you were riding near center it would be better for mpg than ridge riding when cars are passing, but I'm not sure, it may not benefit at all too.

......................
The rest of this refers to other types of drafting:
The inherent problem with long-term drafting is that the tailgater has to constantly re-adjust their speed to keep from hitting my trailer, not to mention safety factors and my own dislike against the practice, the numerous speed adjustments will waste at least as much fuel as the drafting saves, so it rules this out.

The minimum following distance is 2 seconds, now I am 100% certain that by the time drivers enforce this there is no way they can draft at the same time.
I don't want to scare anyone nor is this a dare, but don't ride bumper :p

So I think this only applies for a slow down glide, say for instance you're coming in faster than I am driving so you decide to stay off ICE until you've regained a NON tailgating distance, so you coast in behind me to benefit from the tailwind until such time that you have to re-enable ICE. In this scenario you could stand to gain some free distance from the tactic, and this is likely the only tailgating most drivers would tolerate, so long the drafters do fall back in relatively short order.

It's rare that I can find a vehicle to draft.
But sometimes I do, and I go with it till it doesn't work any more.

I like buses and other vehicles where their back end goes lower to the ground than the typical 18-wheeler. When I can find such going a decent speed, of course. I figure the drafting effect is better when the lead vehicle's body reaches close to the ground, like mine does.

I just watched the Mythbusters on drafting and gas saving - they keep saying throughout the entire show that it is dangerous (but not why it is) and they got some significant fuel savings until they got within 2 feet of the tailer and then it got less savings. I think the wind tunnel test of the model car and box was very interesting when they actually measured the force change on the model car. The real world test was with a Dodge Charger wagon (baseline 32mpg at 55mph!) and a new low drag Freightliner truck. One reason for the poor mileage at 2 feet was from the constant gas pedal movement to maintain the 2 foot distance. They did see savings as far back as 7 car lengths 21% in the wind tunnel test at 55mph so you can realize even more savings at higher speed.

While drafting a truck from a safe distance may give minimal results, the space between you and the truck ahead can provide more room to pulse and glide between 55 and 65mph. A lot of trucks either have speed limiting devices or drive at 60mph by choice to save fuel. Watching the traffic coming from behind, gliding when distant and closing the gap between you and the truck when traffic is coming closer. This keeps most from diving in front of you just to have to pass the truck seconds later. Also the traffic coming from behind will see the truck easier than your small car and will change lanes to pass earlier and not try to force you to go faster by tailgating ( as it's not going to work on the truck anyway). This also works with the big truck behind you as the other traffic has already changed lanes and wouldn't bother getting back into a limited space behind a slower car( most people just want to remain in one lane as long as they can).

Truckers basically don't like cars behind them, in front of them, beside them or anywhere else. They believe the roads were made to haul freight only and everyone else is trespassing.

Hateful,

truck drivers do not like other vehicles around them because the Smith System(truck driver training) dictates it. WHEN POSSIBLE, we are taught to keep a cushion(open space) around our large mass in case of emergency braking/manuevering. "leave yourself an out" is the short version.

at high speeds this is vitale, obviously. at low speeds it is not always possible and difficult, but not as imperative.

if passenger vehicle drivers REALLY knew how difficult it is to stop/manuever such a large vehicle, maybe there would be more courtesy extended to us.
i tell people there is no such thing as a minor collision involving a truck.

interestingly enough, my company now makes, ANY employee that drives ANY vehicle at work, take the smith system. imagine making this mandatory for all drivers(with periodic retesting)...could prevent many collisions and/or traffic jams.

"Curb Weight: 68000 "

Like crashing into 10 SUVs!

Depends on which side you are on. If you're crashing into the truck, no.... But if the truck is crashing into you, then yes.. Also I realize this is an old thread and I don't care.



BUMP