TV modifications to increase gas mileage

There are small things you can do to
increase mileage like maintaining proper tire inflation, eliminating wind drag, minimize use of air conditioning, coasting on inclines, keeping speeds below 65 mph, eliminate travel in mountain areas, etc.  But the cold hard facts about towing a larger and heavier trailer like a 320 or 400 T@B is that once you hook onto one of these trailers your mileage is going to drop dramatically.   You might as well realize that fuel costs are going to go up and your wallet is going to be a lot lighter when you reach your destination.  I hear a lot of miraculous claims of outstanding gas mileage, etc. but the reality is that wind drag, added load weight and gravity play a big role in dramatically lowering mileage rates on long cross-country trips.  

I have a cold air intake on my Tundra 5.7l which I believe helps with power and perhaps MPG (sounds good too).   I agree that the best method to maximise MPG is a light foot and anticipating hills and stops as mentioned above. 

Our 15 y/o 3.3L 6cyl Sienna van dropped from 22mpg to 14 towing our 320S, which is probably typical.

We try to always go down hill. Roads that go south seem to work to. No really keeping speed at 60 mph or less works best for us although I rarely do.

Speed and aerodynamics are the biggest things you can manipulate with our trailers.  I’m never in much of a hurry so I stay under 58mph.   If I push it past this mileage really drops.  I also pull with a truck.  With a topper it pulls so much easier than without.  Without the topper it feels like I’m pulling a brick wall.

So to the point of improving gas mileage and performance with intakes and tuning...yes and no. Intakes improve air flow through the mass air sensor. In theory the extra flow can result in the MAS sending more fuel to the motor...giving a performance boost...most re-sellers offering these are very careful to downplay the actual performance effect as it is typically less than 2 or 3 percent, if anything. More intake airflow without improving the rest of the flow tuning (intake, headers, exhaust) will always provide superficial results. Most modern motors are already tuned to optimize the intake and airflow so these "tuning tricks" are less effective now than they were on older motors where a K&N intake would make a noticeable difference. They do sound better...the boost you might achieve may be more audible than measurable. If you do use one of these intake kits you end up with a filter that you will need to clean and re-oil. 
Next, making wholesale tuning changes by re-mapping the motors computer (ECU) is a known method for improving performance and increasing HP...it may or may not improve gas mileage, usually not. Tuning is generally focussed upon HP. Most tuning voids warranties so you need to really think through this before you try it. And, it's pricey.
The best advice is to buy the right TV with the needed HP and drive it carefully with a light foot. Don't pile things on the roof that increase drag (those kayaks and bikes are not helping the MPG). 

@Sharon_is_SAM there are definitely aero improvement devices that help. Look at a modern aero semi truck, lots of aero stuff and some of the new ones are near and above 10 MPG loaded, makes most Tab TV look pathetic when you look at size and HP.

One of our brainiac members has posted air flow charts in the past.  Who was that...@MuttonChops?

Maybe if we get @MuttonChops together with our 3D printer member, they can create an air deflector that we can all buy and they can retire!

If you Google RV trailer air deflectors you find a lot of info claiming they are not worth the money except one.  It has been reviewed by many, and claims are that it works. 

Sharon_is_SAM said:

Maybe if we get @MuttonChops together with our 3D printer member, they can create an air deflector that we can all buy and they can retire!

jrhamel said:

Thanks for all the ideas. We did our maiden voyage this past weekend. We drove about 300 miles from Madison to Minocqua. On the way up I drove 65 mph and got about 10 mpg. After starting this post and using some of the ideas stated in the post I got about 14 mpg. I drove 60 mph and coasted when I could on down grades and anticipated stops.
Again thanks for the help, love this site.

@TabberJohn - that is why I thought it may work for a minivan.  
“Semi-truck studies have shown a deflector must be mounted far back on the cab close to the trailer to work.”