Boat tail mod to my enclosed trailer

[Sulfuric]

I was looking for pictures and I saw the trailer, but I'm more curious about the air dam on the truck. Where did you get the material (rubber I assume)?

[max_frontal_area]

Originally Posted by Braebyrn

I had a nose cone on there last week. Trying to get the data from one to the other. I wish I had it in the trailer, I would have put it on, but its at home.
My tow vehicle is a 2003 GMC with a 2006 Duramax LBZ diesel motor. It has a cap that has a slight angle up. I will have to go over the scales to let you know the weight on the setup. I am so trying to get the best fuel mileage out of this that I drive the people behind me nuts, I'm sure. I don't idle the truck unless I have to, etc.
I just unhooked the trailer and am driving without the trailer and am back up to 21mpg aprox. I have about 1000 miles before I put the trailer back on. Its the best fuel mileage that this motor has gotten. The air dam, side skirts and the bumper opening mods really are helping.

do you have a picture of the nosecone, i saw the semicircular tailcone, your current one being much of improvent!
14000 lbs was my guess. once you add tools, cooler, jacks, hi test... what do you end up with? also which series are you racing in?
in 06 lots of eimssions stuff was added to diesels overherd a buddy telling me to stay away from certain year chevys saying they were real dogs you mighta ended up with one? as to your tow vehicle see what Big Dave is doing he is pretty much the hero on here when it comes to fullsize*s, and of course
Aerohead - the bomb!
a buddy had a 2000 something powersmoke he used some soltron in the fuel and it cured the smoke (it was bad) and improved MPG. then of course there is water injection, does all sorts of good stuff but will mainly keep from melting your motor on the long grades, add some alcohol and you will get a lil extra boost as well. if you dont have a scanguage, get one and learn how to use it, tutorials abound on here. but driving style will be your absolute best bet.

now, to get radical, and this is something i am going to be doing to groovy
as well as one of my rabbits, is an airduct to vent high pressure air from the front of the vehicle (in your case trailer) to the very back, which will exit into the low pressure area behind it - where your tail cone is now. it should work beautifully in conjunction with your stubby cone. its an old boneville trick
used to keep old cars that had round snouts from lifting at high speeds, cept
for us the use is a lil different. the duct inside the trailer could be coroplast
and designed to be colapsible or movable so you dont loose workspace.

"I tried to not use the cruise control and seem to have my right foot fall asleep! Must need more exercise.... I will give it a try and see what happens. Thanks"

you have achieved the desired effect :=)

"I did however notice that the best fuel mileage was when the fuel temperature was around 93. After the outside temperature warmed up and the fuel temp went up to around 120, the fuel mileage began to drop. "

are you sure there were no other factors? diesel doesnt expand that much
when heated therfore energyloss should be negligible, for me preheated diesel
has always burned more completely = better MPG. be aware, ULSD is for the birds when used at roomtemp but once heated it is guranteed to cause damage due to low lubricity. add 1-2% new canola oil to your fuel to prevent
damage when running hot fuel. since you are blocking air in the engine compartment make sure that soe air is allowed to vital components primarily heat exchangers, namely your intercooler. hot air is thin air to your engine!
if you cant get air to it consider a mister, personal comfort misters are great
and produce a fine mist if that is not enough water then go to the finest greenhouse mister you can find. that h2o will help it along a bit if it is starved for cooling air.

[NeilBlanchard]

Edit: this is pretty much what you already did:



I think you might be better off with a truncated pyramid; rather than a half cylinder. Taper it at the maximum angles (15-18 degrees on the top and sides, and 6-8 degrees on the bottom?). If the trailing face is crisply truncated it is much better for the air flow. The curve is better than nothing, but it still has a messy turbulent wake.

[Braebyrn]

Originally Posted by Sulfuric

I was looking for pictures and I saw the trailer, but I'm more curious about the air dam on the truck. Where did you get the material (rubber I assume)?

It is rubber and it is conveyor belt material. It is about 1/4 inch thick and I think should go lower to the ground, but that is the cheapest stuff they had. It was around $25. to do the air dam and side skirts. I am getting the best fuel mileage ever without the trailer right now. Yeah!

[Braebyrn]

Originally Posted by max_frontal_area

do you have a picture of the nosecone, i saw the semicircular tailcone, your current one being much of improvent!
14000 lbs was my guess. once you add tools, cooler, jacks, hi test... what do you end up with? also which series are you racing in?
in 06 lots of eimssions stuff was added to diesels overherd a buddy telling me to stay away from certain year chevys saying they were real dogs you mighta ended up with one? as to your tow vehicle see what Big Dave is doing he is pretty much the hero on here when it comes to fullsize*s, and of course
Aerohead - the bomb!

I only have a picture of the frame under the coroplast. I am not racing but rather helping a couple of friends out with their cars and one that I sold. It is more of a challange to see what the best fuel mileage I can get. I was disabled in a couple of car wrecks caused by others and have limited use of my body. I was told by the Dr. to keep active and don't sit on the couch.
I am very slow physically and mentally, so it takes a few times to get things right.

Back to the engine, it had the emissions stuff on their that was on the 2006 model engine, but I had it taken off and the 03 good stuff put on it. It has definately picked up in power and fuel mileage (22 mpg with no trailer).

I like your idea of the water/meth injection. That might happen someday on my setup.

Rick

[Braebyrn]

Originally Posted by max_frontal_area

now, to get radical, and this is something i am going to be doing to groovy
as well as one of my rabbits, is an airduct to vent high pressure air from the front of the vehicle (in your case trailer) to the very back, which will exit into the low pressure area behind it - where your tail cone is now. it should work beautifully in conjunction with your stubby cone. its an old boneville trick
used to keep old cars that had round snouts from lifting at high speeds, cept
for us the use is a lil different. the duct inside the trailer could be coroplast
and designed to be colapsible or movable so you dont loose workspace.

I wonder about the air behind the truck and between the trailer.? If I put scoops to pull the air in and then drop it out behind the truck? I was thinking about that drag.

[max_frontal_area]

Originally Posted by Braebyrn

I wonder about the air behind the truck and between the trailer.? If I put scoops to pull the air in and then drop it out behind the truck? I was thinking about that drag.

sorry i didnt make myself clear, you make an opening at the front of the trailer
where you had your nosecone, all that air trying to push your trailer back will now go inside the trailer into a duct that channels that air to the very back through a hole in the center of the loading door/ramp (which is cool since you are dealing with cars, which tires will ride alongside the hole during loading and unloading) and into the middle of your tailcone which would have to have an exit for the ducted air to go.
now comes the cool part. the ducted air as well as the naturally flowing air from the sides top and bottom flow around towards the center and converge
with the ducted air. and this is what is really slick about it, if this setup is done properly the outside "airs" will help pull along the ducted air and vice versa! this is known as augmentation and the formula 1 crowd uses this phenomenon all day long.

punch a coupa hows in ya trailer?! may seem radical - yes it is, but you will driver father between fillups and perhaps even start a trend!

[max_frontal_area]

can you send a few pictures of your truck so we can get an idea of how it is clad and see the cap/wing...

[Frank Lee]

Ducted air is not slick.

If you have room to spare inside for a duct, you are better off chopping the top or reducing the interior volume by whatever means.

Ducting = more skin friction.

Ducting = more exposure to x-winds vs. smaller envelope.

Ducting = more weight.

[Braebyrn]

Originally Posted by max_frontal_area

can you send a few pictures of your truck so we can get an idea of how it is clad and see the cap/wing...

Its dark right now, but I will tomorrow when I get a chance. Don't know when I will get internet, but I will post when I can. I don't have a wing on the cap. Should, but don't.......yet.