Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post - Mismatched trailer and tow vehicle..help me move

sparksnsaaben · 08-02-2011, 10:54 AM

Hello aerodynamicists and trailer owners. Due to some bad stuff, I'm moving from Colorado to Florida. I just purchased a trailer that has the volume and weight capacity that I need.

However, I experience a massive amount of drag at interstate speeds. The tow vehicle is a 1997 SAAB 9000 CSE with a turbocharged 2.3l engine. At speeds below 50 to 60 mph, I can barely notice it behind me. At 75 mph I can maintain speed in 5th gear with close to maximum boost. At 90 mph I can maintain speed in 4th gear at maximum boost. During those tests, trailer stability and engine temperature were excellent. Without a trailer 30+ mpg is easily achievable at 80 mph. The vehicle has a manual transmission and I feel confident that it will not suffer adverse effects by pushing it to it's limits as they sit in current form.

I am an ASE certified Master Auto Technician that has pushed these engines and drive-trains much further than what my current problem is. These cars have brakes and handling capabilities similar to a truck's.

I don't want to run my engine that hard for 2000 miles. Also, I believe that with some aerodynamic modification, I can greatly improve my fuel mileage.

From the research that I've done, it seems like my biggest disadvantage is the difference in my car's height versus the flat surface of the trailer.

My spoiler is at 3'7", my car roof is at 4'10", the trailer is roof 8' tall with it's current tongue weight.

I believe that adding a "nose" to the trailer made out of 2x4s and OSB will greatly reduce my drag. My car is also a few feet narrower than the trailer. I have two weeks for preparation, but only a narrow window of time for the trip.

What minimum height should I build my aerodynamic "nose"? What is the best shape, one plane, three planes, etc.? I am also considering adding a "boat tail" if that would result in a significant fuel savings. As of right now I believe that fixing the front aerodynamic disparity is the only thing required to meet the law of diminishing returns.

A picture of the rig can be found at (sorry, I don't have enough posts to provide an unbroken link) :
imgur
.com/5QjkL

Thanks.

08-02-2011, 10:54 AM	#1 (permalink)
sparksnsaaben EcoModding Lurker Join Date: Aug 2011 Location: Colorado to Florida Posts: 4 Thanks: 8 Thanked 0 Times in 0 Posts	Mismatched trailer and tow vehicle..help me move Hello aerodynamicists and trailer owners. Due to some bad stuff, I'm moving from Colorado to Florida. I just purchased a trailer that has the volume and weight capacity that I need. However, I experience a massive amount of drag at interstate speeds. The tow vehicle is a 1997 SAAB 9000 CSE with a turbocharged 2.3l engine. At speeds below 50 to 60 mph, I can barely notice it behind me. At 75 mph I can maintain speed in 5th gear with close to maximum boost. At 90 mph I can maintain speed in 4th gear at maximum boost. During those tests, trailer stability and engine temperature were excellent. Without a trailer 30+ mpg is easily achievable at 80 mph. The vehicle has a manual transmission and I feel confident that it will not suffer adverse effects by pushing it to it's limits as they sit in current form. I am an ASE certified Master Auto Technician that has pushed these engines and drive-trains much further than what my current problem is. These cars have brakes and handling capabilities similar to a truck's. I don't want to run my engine that hard for 2000 miles. Also, I believe that with some aerodynamic modification, I can greatly improve my fuel mileage. From the research that I've done, it seems like my biggest disadvantage is the difference in my car's height versus the flat surface of the trailer. My spoiler is at 3'7", my car roof is at 4'10", the trailer is roof 8' tall with it's current tongue weight. I believe that adding a "nose" to the trailer made out of 2x4s and OSB will greatly reduce my drag. My car is also a few feet narrower than the trailer. I have two weeks for preparation, but only a narrow window of time for the trip. What minimum height should I build my aerodynamic "nose"? What is the best shape, one plane, three planes, etc.? I am also considering adding a "boat tail" if that would result in a significant fuel savings. As of right now I believe that fixing the front aerodynamic disparity is the only thing required to meet the law of diminishing returns. A picture of the rig can be found at (sorry, I don't have enough posts to provide an unbroken link) : imgur .com/5QjkL Thanks.