A "crappy" problem
 

So after a lot of figuring, I'm still having a problem with black tank placement. I would like to drop the toilet straight into the tank, but that would put it overtop of the diff and driveshaft. Not only is there not enough room for both, But in the event of a driveshaft failure it would spray "stuff" all over the underside of the truck and anything nearby.
So How much plumbing can I use to connect the toilet to the tank. All of my campers have had a straight shot, but I have seen some that were not.
Anyone have any experience with this?
Thanks, Steve

No direct experience with a long horizontal run, but my suspicion is it would not work with the very small amount of water used to "flush" an rv toilet, it really only works because it drops straight down. A home toilet uses a ton of water to flush everything down the pipe runs. My suspicion is you would just have constant plugs in the horizontal pipe.

Is it possible to do something creative like a small tank under the toilet and a macerator pump through a smaller pipe to your black tank? I know a lot of campers that have two bathrooms use an arrangement like that to empty the rear tank into the main tank so as to be able to dump all tanks through a single dump valve. You could also check blizzardnd's build thread, it seems to me he used a macerator pump setup on his rig.

I would agree with Hot Rod. When building my conversion I had run into the same problem. Every where I wanted to put the toilet ended up over a tire. I finally decided to build a custom tank and put it in between the tires. The only way I would attempt to not put the toiled over the tank would be using a boat toilet. I think those work with vacuum or air assist?

man it seems much more likely that you'll have a tire blow out than a driveshaft failure.

The picture I took is with the air bags dumped so there is more room when running down the road but yes there is a risk there.... More reason to keep good rubber on their! It is also built of .125" stainless steel so should stand up to any debris hitting it, but you are right, any kind of tire blowout could be bad to say the least!

What kind of ceiling height do you have in your unit? How about raising the floor in the bathroom with the black tank under the bathroom floor? They make those things in all sorts of shapes and sizes.

That was my initial thought, just place the tank (or small tank as suggested) at main floor level. Bathroom is actually raised a step or so as it is above the tank. This would help put a good downward flow to the main tank or drain, to minimize clogs.

Well the problem resolved itself. I found a great deal on a 36 in hex shower. The resulting shuffle put the toilet right where I needed it. Now I need big enough grey tanks for the wife to enjoy the massive shower :)