I’m just off the phone to Sarasota Avionics. I wanted to order an Insight G4. They said “the juice isn’t worth the squeeze” and to look at the other brands instead. They say they sell 10:1 JPI equipment versus the smaller brands.
The Garmin unit is expensive and would mean taking down the headliner to change the fuel senders for me.
William, did you look at the EI CGR30-P?
It has the standard round form factor and is certified as primary instrumentation. I have one in my Super Cub and it replaces all electrical and engine gauges, and the Tacho, as well as adding other features like fuel flow, EGT, CHT, and Carb Temp.
Just found this on a US site, relevant to replacing a KI256:
A single GI-275 needs a backup attitude indicator as part of the install. That could be your existing AI (though the vacuum system needs to stay in that case), a second GI-275, a G5 or something else that meets the requirement as a backup system. An electric horizon without a battery backup does not meet that requirement.
One needs to always remember this. For certified aircraft, there will never be an electric replacement for a KI256 unless it has a backup.
If you already have an electric T&B you can replace the KI256 with an Aspen E5 and you are good to go.
Neil wrote:
William, did you look at the EI CGR30-P? It has the standard round form factor and is certified as primary instrumentation. I have one in my Super Cub and it replaces all electrical and engine gauges, and the Tacho, as well as adding other features like fuel flow, EGT, CHT, and Carb Temp.
Good choice. I just finished diagnosing and replacing a broken old-timey 70s style six-pack style oil pressure gauge in my plane, after previously having screwed around a while to get a tachometer that’s accurate to better than 30 rpm in cruise. I’m tempted to get two CGR-30s to replace the entire engine instrument six-pack, plus the tach, fuel flow totalizer, manifold pressure and fuel pressure gauges. The best thing about the idea is that you can also replace the original resistive float-type fuel senders and the whole thing is STC’d for my plane. God knows if anybody has actually ever installed it in the type but who cares, the details can be worked out. Imagine having semi-accurate fuel gauges. The only problem is probably $7K hardware expense and a lot of effort including removing the wings and fuel tanks etc. and wiring the whole thing up. This is on my list for after an upcoming $30K minor rental remodel, and after the last rental mortgage is paid off 
BTW the best conventional analog tach I could come up with is a newly overhauled AC Delco unit from the 60s (Lock Haven Air Parts did the overhaul). It looks automotive and cheaply made but it works OK. Anything analog that’s new, available today and not a crazy price is junk by comparison.
Actually, the EI fuel gauges are said to be as accurate as the CIES ones, which means “very accurate”, not “semi-accurate”. At least as reported by fellow Mooney pilots. Thread drift off. Is the GI-275 EIS certified for your plane?
No fuel measurement system for long skinny tanks that uses four float style gauges is going to provide perfect info, but something that’s close and which I personally calibrate is certainly more accurate than uncalibrated resistive gauges with lots of connectors.
I’m not buying anything Garmin any more unless there is no other choice. My plane is not in any case on the Garmin GI-275 EIS AML.
This video shows a dual GI275 installation. It’s interesting. There is a great deal to understand…
I am still looking for a solid state alternative to the gyro that is required for the STEC55X . Any ideas?
