The Stovebolt Site Forums The Shop Area The HiPo Shop Benefit to enclosing the drivetrain like today's trucks?

Y'all have seen material added to tractor trailers and cars (underside) - diverting wind at hwy speeds to smooth out air flow turbulence. It must work if they add it to the rigs. Its also my impression that this helps cars. Does anyone have experience with adding this to the underside of our trucks to save 1-2mpg? It would also protect them from the elements like this crap they put down on the roads for salt on the east coast..

I don't see the harm in it, It should help protect stuff from road debris and salt and whatnot if done correctly. I don't see it doing much as far as fuel economy goes, our trucks were not designed with aerodynamics in mind and it shows, although it done right I suppose it could do a little 1-2mpg like you said.

I may try a before and after once I get my truck running and consistent.

I may try that down the road on my 62' just to see what happens

I see the pros and cons. But for me, water and dirt get where water and dirt want to get and it’s a PITA to wash when it’s all covered up. I like being able to get my pressure washer right up my truck’s skirt when I’m washing it.

I will start by saying I'm not completely sure what you are talking about. But if it's what I imagine, I would be very careful about anything that would cover the exhaust system. If you ever had an exhaust leak, and the gasses could somehow collect under the vehicle, a rich running engine condition combined with a spark could be a big problem. More like a big BOOM! Do the big car makers cover the exhaust system when skinning the bottom of the vehicle?

A smooth belly pan can be a lot of fun. I used to "toboggan " over snow drifts as much as 50' wide and any depth with my Corvair. A farm tractor came in handy when speed needed to ski across was miscalculated.

Back in the ‘30s it was a common practice to install sheet metal pans from the frame to close to the engine pan. I assume this was to keep mud/water out of the engine bay. As more reliable ignition systems came along the pans went away. My 1939 Dodge Business Coupe has them.

Just a thought. Keep in mind you may be trapping heat on your rotating parts.

The cars I have seen do cover the exhaust but I totally agree with the comments to think safety first.. maybe twice before modding. Good points. I was thinking of going just past the cab and leaving it open for it to "vent " at the back somewhere.. None of it "air tight".. but better than what it is.

What are you planning on experimenting with? If it's your 38, I don't really see the point. First off, the draft tube needs air acrossed it to function properly. Secondly, the the pre-war trucks are about as aerodynamic as it gets with there smooth body lines.

On a pickup, maybe an under bumper spoiler and some skirting under the running boards may help, but I can't see a significant increase in economy.

If you do something like this, please share. I'm always impressed with the innovation and thinking outside of the box that happens here.

This guy is a great source for auto aerodynamics that normal people can understand. Here is a belly pan video.

How much do you actually plan on driving your truck? The OTR trucks and trailers you see with the aerodynamic kits are rigs that see hundreds of thousands of miles a year of interstate highway cruising. For rigs that get 10-15 (guess??) mpg of expensive diesel, the single digit improvement in MPG is real money to them. It may not be worth the expense, effort and ugliness on an occasional use antique.

Is fuel efficiency that critical here?

John, you're wildly optimistic on the mpg of the OTR trucks. More like 6-7 mpg is the average, so anything that they can do to eke out even another 1/2 mpg (stuff like trailer skirts, and cab fairings) pays back. I have to agree that for a Stovebolt, it's not going to help much.

Even reducing splash (most stay off the roads with their babies when it rains, right) probably isn't much help, as it makes it harder to wash the crud that would still get above the splash shields.

Kevin -- you are correct. I was making a (conservative) SWAG. In my own work experience driving the 359 Pete with the big cam Cummins ... we don't even bother figuring out the MPG. I just fill the tank everytime I drive it as we don't trust the fuel gauge ... But that 50-plus gallon tank runs down alarmingly fast.