Trying to figure out underbus plumbing

[Whiskey.Wilderness]

So due to how our undercarriage is laid out we put our grey tank on the passenger side, our sink and shower are on the drivers side so we are trying to figure out how exactly to run the plumbing underneath the bus to the grey tank.
Anyone else with a international 3800 dog nose (ours is a 2001) with a similar setup who can share some advice on how you did it and what you used?

[TheHubbardBus]

I think it might help if you clarify your question a bit. "How you did it" is pretty broad. Are you not sure of what slope to use? Not sure how to mount the tank? Having troubles routing piping? Unsure of the proper size?

[turf]

i crossed the drain over underneath my bus to the the tank.

key for it all working, for me, was that my waste tank is low.

i came straight down from my sink to the bottom rail of the frame. clamped a 2x4 on the opposite frame rail to get my drop, and hung a pipe across the bus.

my cross over is just in front of the rear wheels, and i put a metal tube over it for a heat shield from the exhaust, but that probably wasn't needed.

my waste tank inlet is a few inches beneath my frame rail. the crossover ties to the shower drain hepvo and then into the 3" waste pipe from the toilet.

[Whiskey.Wilderness]

Yeah more about routing. Do we need a specific angle from the drains into the plumbing to help with draining. Our grey tank is actually a rv black tank that mounts underneath right against the baffles so trying to figure out how we route it all

[TheHubbardBus]

Gotcha.

You have to have a slope on all drain pipes. The minimum standard is usually 1/4" per foot. You can (and probably should, if possible) exceed this minimum depending on the space you have available, considering your bus isn't a house and getting it parked 'absolutely level' might not be easily achievable. FWIW we're aiming for 1/2" / foot if not more.

Note you can have too much slope - which can result in blockages formed by the liquids all draining off the solids to rapidly to keep things moving as a unit - but I think in your case getting enough slope will be more likely an issue.