I have a feeling I'll get burned for this... 2 story P-trap?

[pullstart]

I just moved into a new home (new to me). The basement is unfinished and the upstairs shower/tub has a problem. The shower drain is directly in line with the vertical pipe to the basement. Upstairs when the shower's running everything in the access is dry. It's 1-1/2" drain with a kitty wompus loop of 90° elbows for a trap, the top of the trap level with the top of the shower drain. Yeah, it doesn't work that well. There's really no room to build a decent trap below the level of the drain before it goes through the subfloor. In the basement, water's coming from the 2" PVC when it exits the main floor subfloor and dripping off the bottom of a 90° elbow heading towards the main sewer pipe. This vertical drain is only servicing the shower, the sink and toilet have a separate 3" drop.

So... my question after a long winded description. If I cut the drain apart and pull it down into the basement, could I snake a new drain pipe directly to the tub and build a large or series of traps in the basement? My worry is that the velocity of the drop will push any water directly through the trap (reason for asking about more than one)

Now that I wrote the big description, I figured a picture would help. here's what I'm battling. The first and last 90 are touching. The bottom of the top two 90's is level with the bottom of the shower drain. The basement has 9' ceiling with plenty of room to tuck a trap or five. I've got about 6' from the drop to the main drain.

Thanks in advance...

 

[Plumber69]

You need to vent that

 

[Sponsor]

 

[pullstart]

Thanks, I'd like to incorporate a dedicated vent into the new system. Since the vertical pipe needs replacement, might you have any insight to my question?

 

[Stuff]

Maximum drop to a trap is 24"

 

[pullstart]

Thanks @Stuff , That's what I was looking for. I'll see what I can come up with, I appreciate it!

 

[Reach4]

Thanks @Stuff , That's what I was looking for.

Stuff was very perceptive!

 

[hj]

ONLY ONE TRAP IS ALLOWED. If you put in two, or more, it should not drain, but after dropping 10' or so, I suppose NOTHING would stop it from draining, but neither would the extra traps prevent the velocity from emptying the trap. I don't know which way is up in your picture, but it makes no difference, whoever did it was an idiot, NOT a plumber.