Poor flushing after replacing toilet discharge elbows

[Theodore]

Hello.
In the process of finishing the basement ceiling, I replaced the 1st floor toilet's 4" diameter long sweep 90deg elbow with a 4" short sweep elbow to get the pipe to stay between the ceiling joists/above the ceiling. Shortly after (not sure if immediate or a few months) the toilet has been difficult to flush, typically requiring more than one flush. This has been the case for 2+years now, so not likely a clog. This is an older toilet, not a modern water-saver. I've attached two scaled drawings of the current orientation. The toilet is near an exterior wall, so immediately after the first 90, I had to turn down with another 90 to meet the main house drain (with vent, trap, etc.)

Is the poor toilet function definitely my fault due to poor choice in the short sweep elbow?
Is this a typical issue when such an elbow is introduced?
Will a different/modern toilet help?
Advice appreciated.

 

[Reach4]

Will a different/modern toilet help?

Probably. A new nice-flushing toilet would a big improvement over an old one.

I am wondering if a 45 closet flange and a 45 on the pipe could have done it.

 

[Sponsor]

 

[Terry]

The trapways on most are about 2"
I don't think the 3" bends are the issue.

 

[hj]

The 3" elbows are not the problem, but the lack of a vent could be causing the toilet to be "air bound" so it cannot flush properly.

 

[Theodore]

Was thinking about the statement on venting. I have redrawn my previous and current sketches to be more accurate.
Please take a look and tell me what you think.
And, whether anyone believes there can be a way to improve this situation (ideally without tearing it apart).

 

[Reach4]

Unless there is some local law to the contrary, get rid of that trap on the right of your drawings. It could be that it was required in the past, but is no longer required. It should not be required by modern plumbing standards AFAIK.

 

[Theodore]

Unless there is some local law to the contrary, get rid of that trap on the right of your drawings. It could be that it was required in the past, but is no longer required. It should not be required by modern plumbing standards AFAIK.

Agreed, and if major plumbing work is in my future, I'll get rid of it. State code no longer requires.

Do you think the change in toilet plumbing may have caused a venting issue and hence flushing issue with this first floor toilet? From what I've read on the plumbing code, I've a 4" diameter drain and I'm close enough to even the house vent that I don't believe I need venting behind this fixture. But would appreciate guidance.

Note: the drawing I provided is to-scale, so it's a realistic reflection of size/dimensions/distances. I took no "artistic license" in this.

Thanks!

 

[Terry]

Once it's a vent, it stays a vent up through the roof.
Once it's a waste pipe, it stays a waste pipe.
You can't combine a waste from an upstairs bath and use it as a vent for the downstairs bath.

 

[WorthFlorida]

If I’m correct you had this problem started sometime after the change about two years ago. If your toilet is before the 1.6 gal flush requirement became law, 1994, about 3+ gallons is used per flushed. The old configuration looks like it was a straight drop at least below the joist, 10-12 inches. That allowed the column of water to get some movement before being redirected and helped with the siphon effect. Now the water column almost immediately takes a bend and slows up the whole process for maybe three gallons of water.

If you have the first generation of low volume toilets, an American brand, they all performed poorly. Another slight chance is something at least 2” is stuck at the outlet end of the toilet, maybe a kids toy, makeup mirror, etc.

As suggested above changing to a new toilet probably will help. I have a Toto 1.28 gal unit and works 100% of the time but I wouldn’t rule out venting issues.. The old setup the vent was at the first bend, now it is a foot or two below the second bend. I believe a vent should be at the waste line before going down to the main. If you look at Terry’s picture, every toilet is vented at or before going vertical.