Double trap toilet issue

[Inna]

Looking at Toto Aquia vs Sloan flushmate toilets to improve flushing in a double trap set-up, any advice is highly appreciated:

I'm renovating my bathroom in a prewar apartment building and the old plumbing set-up has a trap (as pictured). With the toilet's trap that makes it a double trap and the new low flow 1.28g toilet or the older 1.6g toilet from another bathroom can't cope. The old toilet was thrown away early on in the remodel but I presume it was a high flow one. I would like to try a stronger flush toilet before trying to cut the plumbing trap, which would be difficult, expensive and might require cutting into the stack of the building (as per two plumbers).

Also it's a bit of a tight space so I'd like to keep the toilet length less than 27-28".

I hope the toilet with a strong 1.6g flush would help. Any suggestions on which toilet to get? Looking at Toto Aquia (a bit shorter than the other Toto lines at 27.5", has 1.6g flush option) or a Flushmate system toilet.

Thank you for any advice!

 

[Cacher_Chick]

Toilets are made to flush into an empty drain line.

If you have your building gutted as shown in the photo, it would be the perfect to to bring the plumbing up to today's standards.

 

[Sponsor]

 

[Jadnashua]

I don't think any modern low-flow toilet would work reliably with the second trap in the line.

 

[hj]

The old toilet must have been a "hopper" type, possibly cast iron, from the looks of the piping. Even an old 6.0 gpf toilet would have a hard time flushing through two traps.