Fuel Injection conversion for beginners

[BobTurner]

In case it?s still fuzzy, you need to look at your engine to be sure you have the injection ports (extremely likely that you do). Near the plugs, you should see a threaded hole into the cylinder where the intake manifold attaches. These holes will be filled, either with a primer line, or a brass plug (usually with a square end for a wrench).
As part of the nozzle assemblies, there are small .028? flow-limiting apertures. You can buy these in slightly different sizes (0.0005? increments) to balance all the cylinders, so they will all reach peak egt at exactly the same mixture setting. This will allow you to smoothly operate lean of peak.

[DanH]

Hans, read this:

https://www.danhorton.net/Articles/B...yond%20(1).pdf

[HansR]

Originally Posted by Bevan

Yes.

You will love fuel injection especially if you like to fly LOP.

Bevan

Yes, I always lean very aggressively!

[HansR]

Originally Posted by BobTurner

This will allow you to smoothly operate lean of peak.

Excellent! I do have a problem now that they do not peak at the same time, and furthermore, the no 1 cylinder is significantly cooler than the rest.

[HansR]

Originally Posted by DanH

Hans, read this:

https://www.danhorton.net/Articles/B...yond%20(1).pdf

Excellent! Now I think I am getting a good understanding.

Initially I was very confused, as my reference was car/outbourd EFI systems.

Any idea about the efficiency in aircraft FI vs EFI?

[Bcone1381]

Originally Posted by HansR

Excellent! Now I think I am getting a good understanding.

Initially I was very confused, as my reference was car/outbourd EFI systems.

Any idea about the efficiency in aircraft FI vs EFI?

As you research this question do not neglect to compare the installation simplicity of the Bendix style mechanical FI system, with the EFI. Specifically, Normal Electrical system requirements, backup electrical system requirements, Fuel Return, etc.

[David Carter]

I'm in the middle of this conversion now on my RV-7A O-360, using the Airflow Performance FM-150 kit for the 360, all new fuel lines from TSFlightlines, and Van's mounting kit for the electric fuel pump. I also decided to replace the Van's fuel valve with one from Andair, the fuel lines from the tanks to the valve (TSFlightlines), and the throttle & mixture cables with vernier-assist models from McFarlane.

The AFP FI kit is extremely comprehensive. Call Don at AFP & he will walk you through everything. There are very few if any decisions you need to make on this. Be sure to measure the total distance from the bottom of the sump to the top of the filtered air box so Don can determine the thickness of the spacer required to make up the difference. Otherwise, your FAB inlet will not align properly with the cowl opening.

You can download the AFP installation manual here: https://airflowperformance.com/wp-co...anual-9003.pdf

Assuming your O-360 has the updraft sump, your kit will likely include the control cable bracket kit documented here: https://airflowperformance.com/wp-co...-Cable-Kit.pdf

I also suggest calling Tom at TSFlightlines. His advice has been invaluable on this project.

Finally, regarding mechanical vs. electronic FI: if I was building a plane, I'd build in SDS EFI from the start. That requires a very robust electrical system, and also fuel return lines to each tank & a fuel valve that switches both the supply & return lines. That was just too much for me to bite off in a retrofit installation. Not impossible, but it felt daunting for a non-builder like me.

[HansR]

Originally Posted by Bcone1381

As you research this question do not neglect to compare the installation simplicity of the Bendix style mechanical FI system, with the EFI. Specifically, Normal Electrical system requirements, backup electrical system requirements, Fuel Return, etc.

Right, I have no thoughts of going for the EFI, but is interested in the efficiency in the bendix style FI. Then a comparison with EFI is relevant.

[HansR]

I think I soon can sum up my information to take a decision upon:

In order of price

1. Avstar
2. Airflow performance
3. Precision Airmotive

From what I have found on VAF, Airflow Performance seems to be the most preferred.

Finally, I need to know the maintanance cost for the three:

What is needed in terms of ordinary maintanance, and also scheduled overhaul?
Intervals and costs?

[Northernliving]

Originally Posted by HansR

Hi.


Modifications
What needs to be done to the engine?
Obviously I do not have any holes for injectors.



Thankful for help / HR

Hans, I'm also in the process of replacing an O-360-A4A with a clone injected engine. Assuming you are keeping your sump and vertical intake, one of the challenges you will face is the height difference between the carb and the injection servo. Since you will want to keep your airbox and intake in the same location, you may have to make a spacer. I decided to fabricate a part that included the top of the airbox cover and the spacer. See attached photo of the carb vs injection servo and the new part I'm fabricating to orient the intake in the same position to match the cowl.

Other parts of you will need would be a new high-pressure fuel pump and possibly a new pressure sensor speced to accommodate the higher pressure.

I'll post some more pictures as this progresses.

Brian