I have a champion 4 1.28 gallon. I see you can buy the 1.6 tank, can you install the 1.6 without any issues? I have been told you can and I have been told you can not. Has anyone done this with success?

i they have reworked the bowl to flush with 1.28G and you use a tank with 1.6G, you may get something like a double flush??
my answer is' i don't know'..

A double flush only happens when the incoming water is too slow and the siphon breaks before the tank is emptied, the difference in water is only a little over a quart, so I highly doubt that it could double flush at all. The extra water should flow in just as fast as the first 1.28 gallons, and the siphon should continue as normal.

Flush the toilet, then pour in the difference as the water is running out of the tank. See what happens.

Poor the water in the bowl or tank

Hmmmm....Let's see....You're considering buying a tank that holds more water than what you have now. I think if you pour it in the tank, it might show you whether there might be a problem with the bowl design and the additional water.

Ok, so i can just adjust the float to allow more water into the tank and see what happens?
Correct?

No...It will go down the overflow. Put the .32 gallons in a pitcher, and pour it in as the water is dropping in the tank.

I don't want to sound stupid, but I don't no anything about plumbing, if i flush the toliet and add .32 to the tank as it is filling up won't it just shut off at that 1.28 like it is designed to?

You should absolutely not attempt this yourself. Call a plumber.

Call a plumber because your suggestion makes no common sense at all.

I'll attempt to explain. There was a question as to whether the bowl design (flush characteristics) would accomodate the 1.6 gpf tank. If you remove the tank cover, then have a pitcher with .32 gallons in it. Flush the toilet with one hand, and simultaneously begin pouring the .32 gallons into the tank. You have just flushed with 1.6 gallons, and you can evaluate the performance.

You are correct master5d, you would pour the water into the BOWL,AND Paul's answer made no sense. If you pour it into the tank it will still only allow 1.28 gallons into the bowl.

You would pour into the tank, not the bowl.

The tank holds more than just 1.28 gallons, so adding more water to the tank during the flush is doing nothing.

Wow...This has turned into an adventure, and it seemed so simple.Swim...I guess it has some type of new flapper technology that knows when 1.28 gallons have gone into the bowl?

Aren't all tanks marked with a fill line?

I thought your suggestion was pretty straightforward Paul…

Thanks KC. It seemed simple enough to me.

I was hoping to find someone who new the answer from experience. I do appriate all your replies, let me tell you what I found. The flapper sits about 3 to 4 inches above the bottom of the tank bottom. There is equal amount of water below the flapper as there is above the flapper. When you flush only half the water above the flapper is used. So if i hold the handle down a second longer it uses all the water above the flapper which appears to be the 1.6 or greater amount of water i desire for a flush. So I would assume a 1.6 tank would work, but why spend the money if all I have to do is hold the handle down 1 second longer. Thank you all for your replies.

Or install a fluidmaster replacement flush valve and bullseye super flapper. The tank will empty every time and you don't need to hold it down.