Aerodynamics / MPG increase - up 16%

[Excalibrate]

Is anyone actually taking this seriously?!? I have a real hard time believing anyone in a 18000# vehicle is getting 25mpg (I'm not even going to address 37 mpg) let alone one with the aerodynamics of a phone booth. The aerodynamics of a bus are horrible because of the many things listed here (underside drag, frontal area, etc) not to mention the turbulence caused by anything with a straight flat side as well as the trailing turbulent stream of air off the back of the thing. We don't slice throught the wind, we crash broadside into it! Making any kind of serious difference in fuel economy would require a serious redesigning of the entire vehicle more resembling a supository than a brick. If you expect to make any honest experiments you need to broaden you test milage more than 50 miles or so. I bet you would see similar gains (or losses) depending on the day of the week, the temperature, the wind direction and speed of traffic, did your wheels travel the exact same path, etc. This is not a scientific study. A scientist searches for the truth by isolating the variables (say with a wind tunnel) and is able to repeat the numbers over and over to prove the truth. He doesn't guess about anything like how much gas is left. He doesn't try to prove he is right. Put the lawn edging away and focus on a more attainable goal, like adding simulators to make it look a little less ghetto . . .
P.S. Eric, please don't take this too personal. You seem like a very likable inteligent and creative guy and have done some good work on your bus. I just can't keep my big mouth shut sometimes . . .

[Griff]

Originally Posted by Excalibrate

Is anyone actually taking this seriously?!? I have a real hard time believing anyone in a 18000# vehicle is getting 25mpg (I'm not even going to address 37 mpg) let alone one with the aerodynamics of a phone booth. . .

Re-read the post. . .he's talking about his JEEP! But yes, while I agree that there is a LOT of drag on a bus, there is some merit to all of this. Nascar takes a brick and aerodynamicizes it, one can do the same to a bus to a certain extent.

[boojiewoojie]

I was reading a school bus industry magazine yesterday and they had a picture of a modified school bus with a lowered bumper (actually a doubled-up bumper) and covered rear wheel wells on it! Even though the accompaning article didn't mention it, it appeared that they were doing it for aerodynamic reasons. Curious what kind of results they were getting...

[hoser]

Dunno about you guys but 99.999% of my driving is on the interstate, want to improve your aerodynamics follow a semi or another big rig close let them cut the wind, best of all is its free.

[the_experience03]

I'd like to follow those trucks, but I can't keep up with a hot series 60 or C15

[hoser]

Originally Posted by the_experience03

I'd like to follow those trucks, but I can't keep up with a hot series 60 or C15

Their are slow running semis all over the place just look for one, some company's make their drivers run 55 mph

[timecrash]

I was inspired by all this talk....especially since my bus is sucking cash out of my wallet like a Vacuum..so I installed an airdam on my '86 Bluebird with scrap 2x4s and 20 dollars worth of Plastic siding. It looks pretty cool, but you look closely it looks like a hack job. I dont care....as long as it doesnt fall off.

While we're talking Aerodynamics......has anyone thought about streamlining the front of their buses? The windsheild comes up at a 90degree angle tothe hood....but i was considering putting in a giant plastic windshield....or even rebuilding the front. Probably not practical.....but has anyone got any thoughts?

[paul iossi]

look close at a UPS van, they have looked long and hard at fuel economy for at least 20 years, if it pays out over the vehicle life they probably incorporate it into their design.

[the_experience03]

Huh...so my message is under his SN...that's weird.

[Homeskooled]

To keep it simple and respect the aesthetics of a bus, why not cut the bottom off the front bumper, the top off another bumber, and weld the two together to created one large front bumber?

[Redbear]

I expect one of the first things I would do is strip off any extra projections, such as the stop sign, 'eyelids' over the 8-way lights, front convex mirror, etc.

I would think long and hard about it before doing that. I use my convex mirrors more than my regular rearviews.

[baadpuppy]

Originally Posted by Redbear

By the way, I can jump the interstate mileage on the old company SUV from 13 or 14 to 16 mpg by drafting semis at 65 instead of doing 74 in the left lane. That's a 15-20% improvement.

I suspect said semi drivers don't appreciate that, as that increased drag decreases their mileage.

When I bought my bus, my father followed me home with him driving my little toyota corolla. He drafted me the whole way, and the mileage on the car jumped from 35mpg to 48mpg on that trip. Yes, drafting really does make a difference. I have to wonder though if the 8.75mpg in the bus would've been closer to 10mpg if he hadn't been in that spot.

Unfortunately, the huge "ear" mirrors on my bus stick out quite a bit, and provide way too much important visibility for me to consider sacrificing them.

jim

[Redbear]

Huh? What's going on? What happened to my post from last night?

Someone (other than me) replied with part of my post quoted, and their response to me was attributed as being from me. Baadpuppy also quoted from the missing post before it disappeared (or was morphed into the response).

I won't repost about adding a second bumper, or aerodynamics, but I WILL clarify what I meant about removing the front convex mirror. I meant the one out on the fender standing up on octopus arms aimed to look down at the front bumper, not the ones mounted next to the flat mirrors on the right and left sides that let you see traffic.

I currently use 6 mirrors on the company truck, and have used 8 in the past, so I'm not about to remove important ones.

[the_experience03]

In my opinion that one IS an important one, but to each their own. I have them on both sides with one set up to look across the front and the other is set to look down the side of the bus. The big rearview on the side gets the long distance stuff, but the convex one keeps the Camrys from disappearing into the blind spot.

[Redbear]

My sixth mirror (or eighth, when I had both convex and wedges stuck to the outside mirrors) serves as an "anti-Camry" blind spot mirror. When I used a van, I mounted a second rear view mirror inside above the standard one in the center. This mirror aimed down and sideways out through the window in the sliding side cargo door. In the SUV, I simply leave the passenger's sun visor down, and have removed its cover and defeated the vanity light. This visor/mirror aims down out the passenger's door window instead.

[somewhereinusa]

I'd like to keep this post alive, on the aerodynamics side. I think that an air dam of some sort in front would definitely be of value, and I'm going to build something to give it a try.I like the double bumper idea, or even maybe triple. If I could afford it, I'd try to put a Texas bumper on it.https://www.texaschromeshop.com/webs...log2/40992.jpg
I also think that some sort of side skirting will help and to start I'm going to get everything at least as low as the belly boxes. Wheel base length is somewhat of a problem for ground clearance. Noticed the semi trailers lately? They are all sporting some sort of skirt. (Mainly because California said they have to) but it is because of fuel mileage. Do the math, if you gain 1/4 mpg with fuel at $3.00 a gallon and you drive 120,000 miles a year. It's quite a chunk of change. I know that none of us is going to drive our skoolies even half of that a year, but every little bit helps.

I do know that this helps, because I have them on my tractor. Not the trailer because I pull a flatbed. http://www.airtab.com/main.html
Not aerodynamic but this also works http://www.airtab.com/main.html

You may want to change your driving habits. In my truck I found that every 5 mph over 55 decreased my mileage by .5 mpg. Increase your tire pressure to the maximum recommended it may ride a little harder, but it saves on both fuel and tires. Pay attention to what is way far ahead, you can see over the top of those suckers so do it. Try to avoid using your brakes, If a light changes ahead, start slowing down now by getting off of the fuel, try to judge just how fast you need to be going to just get there without stopping. It takes a LO-O-O-OT less fuel to accelerate 20 to 55 than 0 to 55.
Just my 2 cents worth, but what do I know, I've only driven a million+ miles. By the way THIS truck only has 1.4 million miles on it.

[lornaschinske]

RE: Drafting...

I would love to take a shotgun and shoot those idiots who draft behind me in the Class C. I can't see them unless I catch a glimpse of their car antennas. It's dangerous. What happens if they stop "quickly". Drafting puts you too close to see what is going on up ahead of the vehicle you are following. If I ever pull into a place and have some idiot who had been drafting me pull in to, I will definitely tell them a thing or two. Coming out west (the only long trip we have made with the bus) we had several morons squeeze between the bus (David driving in the lead pulling my Jeep) and the Class C (one almost took my front bumper off... I couldn't see their taillights!) and between the Class C and my Daughter who was following and pulling the food cart. It was worse around the bigger cities. If one of us had slung a tire, some moron drafting us would have gotten all the debris. Up side to traveling so slow was that most of the idiots didn't want to travel as slow as we were, so they didn't draft for long.

Like the sign in the back window of the bus says..."If you can't see my mirrors, then I can't see you".

[somewhereinusa]

Not only that it pulls down your fuel mileage. Happens all the time in the semi, sometimes turning on your four ways will back them off at least for a bit. Slowing down sometimes will work, but much of the time they just slow down too. I think that most of the time, they aren't really tailgating for the pull, they just have their head up their ---- and have no idea of anything outside of that sphere that is only 6 inches bigger than they are.

[lapeer20m]

When this thread was originally started five years ago, i didn't think much about mpg mods on a skoolie.

Since then i've owned a couple of VW diesel cars and become kind of a mpg dork. I consistently average more than 50 mpg per tank in my 1999 Jetta. My personal best was 55 mpg, which worked out to over 830 miles between fuel stops (with 1.5 gallons left in the fuel tank)

I think there can be great value in improving the mpg of a bus. Obviously driving style and speed is a big factor, as well as not letting the bus idle excessively. (it is important to let a turbo cool down, especially when getting off at a rest stop)

Besides a double bumper/bumper skirt, and possibly cleaning up the under-body of the bus, other mods i would like to try:

purchasing a bus with good highway gears (4.10 or better)
Replacing all fluids with synthetic
Replacing mirrors with video camera's
Possible lower side skirts
Emphasis on lightweight construction
Limited Roof obstructions

[Ryan Grimm]

Originally Posted by hoser

Dunno about you guys but 99.999% of my driving is on the interstate, want to improve your aerodynamics follow a semi or another big rig close let them cut the wind, best of all is its free.

MYTHBUSTERS spent some time doing just that, drafting behind a big rig to see what kind of mileage improvements they could get. By the time they got to RIGHT BEHIND the trailer by some 5 or so feet, the increase in mileage was on the order of over 40%....perhaps even higher.
Indeed, they did a series of tests, following at several different distances, and reporting the mileage increases as they got closer.
Now, I do not recommend getting THAT close, but I remember my dad driving the '69 LTD Country Squire wagon with the travel trailer behind it on trips, and getting substantial mileage.....we were about 75 or so feet back.

DO NOT NASCAR DRAFT A SEMI.

'nuff said.