Best Source and Connection of MP (Manifold Pressure) based on multiple sources

[VELOCITY-XLRG]

Good Afternoon Jeff, Jon and GRT team…

I spoke to Jon last week on this and he asked me to send this email to be sure on best answer.

Reminder: My equipment related to this question is:

Two (2) Lightspeed Engineering Plasma III Electronic Ignitions
Two (2) GRT HXr EFIS
One (1) GRT EX EFIS
One (1) GRT EIS (Remote EIS) with MP Port
One (1) FDS (Flight Data Systems) L2e Adapter (*If needed, I had attached the wiring document for this L2e Adapter in my previous thread) at: https://www.grtavionics.com/forum/viewt ... 6461#p6461


I am getting ready to hook up my Manifold Pressure sources and indications and have the following questions in doing so:

Which of the following is the best and most accurate source of MP for me based on the above equipment
1. EIS?
2. Electronic Ignition(s)?
- Currently, I have the two electronic ignitions with their required MP ports (used to sense and advance the Ignition timing) directly to a port on my engine.
- Can I simply “Tee” off this line and connect it to the Remote EIS Port?
- If not, what do you recommend?
3. I also have the L2e which is capable of sending the Lightspeed Ignitions info directly to the EFIS, etc… but thinking this is not as good as the above connection, (quality of signal wise)?
4. How would I get the MP info to all of my GRT EFIS’s?
- I assume providing to HXr-1 or HXr2 would simply use the data link to provide to the other?
- Is there a way to also get it to my EX?


Thank you!


Gary Ernest
Velocity XLRG
ARB, MI
Email: alpineracing@msn.com
************************************

[VELOCITY-XLRG]

Hey Gary,



1. Either source would be equally accurate and suitable as a manifold pressure sensor source. It'll most likely be easier for you to use the Remote EIS's internal MAP sensor to get the data to your EFIS units, though.

2. Yes, you can connect the EIS MAP sensor by teeing off those lines.

3. The method with most redundancy is to split the EIS's Serial OUT port to a Serial IN port on each EFIS unit. You could wire the EIS to a single EFIS and then feed the data to the other two via the inter-display unit link, but we advise against that because if the one unit wired to the EIS fails, then you lose all of that information and would be, essentially, flying blind.



Hope this helps!



Regards,



Ken