Question for those running Engine Bridge and IO-390

Getting ready for first engine start on my dual P-Mag, IO-390 equipped RV-14A. I have timed the the PMags for 5* AFTER TDC as the IO-390’s normal advance is 20*. Brad from Pmag tells me i should set up with the jumper in. My understanding is that this will limit the advance to 34* - however the real total advance equates to 34*-5* for a max advance of 29*. Correct?

Question is do I set the maximum advance on the engine bridge to 34* since it is already physically advanced by 5*? I assume so. Also can anyone share their configuration for ADV SHIFT, MAX RPM and ADV LIMIT. In my case i assume i sent up as follows:
ADV SHIFT: 0* (since i already physically set timing 5* ATDC)
MAX RPM: 3050
ADV LIMIT: 34* (giving me max of 29*)

Is my thinking correct? Thanks

MS19087 said:

Getting ready for first engine start on my dual P-Mag, IO-390 equipped RV-14A. I have timed the the PMags for 5* AFTER TDC as the IO-390’s normal advance is 20*. Brad from Pmag tells me i should set up with the jumper in. My understanding is that this will limit the advance to 34* - however the real total advance equates to 34*-5* for a max advance of 29*. Correct?

Click to expand...

Correct on delivered timing.

I know nothing about Engine Bridge.

MS19087 said:

SNIP
Question is do I set the maximum advance on the engine bridge to 34* since it is already physically advanced by 5*? I assume so. Also can anyone share their configuration for ADV SHIFT, MAX RPM and ADV LIMIT. In my case i assume i sent up as follows:
ADV SHIFT: 0* (since i already physically set timing 5* ATDC)
MAX RPM: 3050
ADV LIMIT: 34* (giving me max of 29*)

Is my thinking correct? Thanks

Click to expand...

Like Dan, I have no clue about your engine bridge.

But - set the pMags to 5 degrees ATDC, Jumper in provides the 20-29 degree timing advance that you want for the IO-390 engine. In other words, just do that and fly on.

I run with the same 9 degrees of advance on both the four and six cylinder pMag engines and find it to be exactly what I want.

Carl

Engine Bridge Settings

You will not be using a jumper with the Engine Bridge. The Rx and Tx terminals on the P-Mags connect directly to the Engine Bridge controller.

By adjusting the timing with the Controller you set the advance that you want.

Here is a table showing the offsets that are available. Note that they are only available in 1.4 degree increments. (P-Mag software constraints)
__________________________________________________

Initial
Timing____ Advance_____ Offset (Additive)

19.6_______ -1.4________-7.0 (Recommended Angle Valve Offset)
21.0_______ -1.4________-5.6
22.4_______ -1.4________-4.2
23.8_______ -1.4________-2.8
25.2_______ -1.4________-1.4 (Recommended Parallel Valve Offset)
26.6________ 0.0________ 0.0
28.0________ 1.4________ 1.4
29.4________ 1.4________ 2.8 (Recommended Angle Valve Max Advance: 29.4)
30.8________ 1.4________ 4.2
32.2________ 1.4________ 5.6 (Recommended Parallel Valve Max Advance: 32.2)
33.6________ 1.4________ 7.0
35.0________ 1.4________ 8.4
36.4________ 1.4________ 9.8
37.8________ 1.4________11.2
39.2________ 1.4________12.6
40.6________ 1.4________14.0

Start Delay: 0-2 (0 is preferred to prevent backfire from un-burned fuel.)
Led Mode: Sensor
Pulse/Rev: 2 (Dependent on avionics tachometer display input.)
Rev Limit: 3072 RPM (Recommended Limit) (The next lower setting is 2816 RPM that some use.)
________________________________________________

If you are trying to achieve a 20 degree advance setting you would input an offset of -7.0 on the Engine Bridge setup screen for each P-Mag to get an initial advance of 19.6 degrees. This assumes that the engine and P-Mags are pre-set at 0 degrees TDC.

Read this Post if you would like to understand timing settings better.

Hope this helps get you to your first engine run.

Personally, I would time your mags to TDC and then set the maximum advance you want with the engine Bridge. I belive the P-Mag curve in non-linnier, so I would want it operating based on the actual position, not one with a 5 degree offset.