899 ci HD/SI Giving me Fits

Hi all. I am new to the forum and appreciate any feedback or expertise that can be relayed regarding my H’bird situation. I have a 899 ci HD and a 997 c SI that came with my used rig I bought. I believe all electronic installs were done by Cabelas when the rig was bought new.
Now, 2 years into owning this boat, I became unsatisfied with the side/down imaging detail and sharpness that the 899 si/hd was displaying. I am running the 997 in the front and it runs off the universal sonar on the Minn Kota fine in 2d. But, no having the cash for a new Mega unit, I decided to call Humminbird customer service. They explained that my 899 ci/hd was running off a compact 455 khtz transducer – so I asked if a 800 khtz HD transducer would help the resolution and sharpness? She said yes, and I ordered a nearly $200 HD SI transducer for that unit.
I installed the new one as instructed and as close as possible to where the compact mount was. I have since been on the water two times and the 2d is fine (the same as it was before running off compact) and I believe the side imaging provides more clarity on the 800 signal. BUT, the down imaging is terrible. It is a super faint screen and does show bottom, but nothing resembling fish or structure marks. I have it set on hi def transducer and have tried both 455 and 800 kilohertz frequencies both. I have tried every imaginable color pallete and down imaging enhancement sensivity and contract imaginable. Still terrible reading on the down imaging. I have tried a direct connect to the unit(s) to rule out a problem with y cable and watched every You Tube video applicable on the subject. I have it set on 200/83 as well.
I have even tried lowering/raising the transducer on the mount and adjusting the angle.
Any ideas as what to possibly try next would be appreciated? Lastly, the 899 SI HD should have the capacity to get better resolution with the HD/SI transducer – right?

-Green1

How deep of water do you usually fish in. The stronger transducer will likely provide minimal improvements in shallow water.

Thanks for reply ‘Dave. I have tried in 5 ft to 35 ft. The reading and visuals do not improve with increased depth at narrow, medium or wide beam settings and all kinds of different enhancements.
Thinking of selling my 997 c and 899 HD SI and getting 1 mega SI unit if I can…

Down imaging is garbage.
Throw it in a barrel and pay someone to get rid of it!

You’d be best to ignore it was ever invented and start focusing on the SI.
That’s my opinion only. Go to views, and turn Down Imaging to OFF! Then focus on SI as down will never show you something side isn’t already showing you in better detail and a larger breadth to boot. Down is basically less info…Like buying 8′ of 2×4 and using 12″ of it. SI is raw data whereas DI is software manipulated garbage.

Sounds like you got improvement from the Compact SI to the HDSI in regards to Side imaging. You should expect that.

Ignore Youtube for a minute:

Go seek some additional information from BBC BOARDS Humminbird section. You’ll get to speak directly with humminbird staff if you don’t find the answers your looking for (and sign up). IDO isn’t a great resource for Bird info, at least not in comparison to the wealth found on BBC. CHeck em out. You won’t be disappointed. Even if you choose to upgrade, learn about it there.

Feel free to post a picture of what you have got and aren’t happy with.