The injection system is in and operating. Took way longer than expected as the annual inspection ran a little long with a couple issues that needed attention. After some initial engine driven fuel pump configuration issues were resolved the first test flight was conducted today. I am stillgoing over the data to see what the changes are, but here’s what I have seen so far. The engine runs a little rougher at idle than it did with a carburetor. Not bad, not that noticeable, but obvious when comparing data read outs from carbureted to injected. It looks like there is a very narrow power setting band (near idle) where the 5 and 6 cylinder run lean resulting in an egt temp differentialof over 300. The engine now produces a little more than one additional inch of MP at full power than it did when carbureted. At cruise (23 MP, 2400 RPM) the engine has a temp differential of 37. Very smooth. I did not do any serious leaning yet. More to come.
Carb Heat for better fuel atomization?
- Thread starter bubb2
- Start date
skywagon8a
MEMBER
SE Mass MA6
Try running the boost pump on low if you have two settings or just on, if one setting. This is more of an issue in a low wing airplane than a high wing but is a good place to start.
I am very happy with the system. My fuel flow went from about 17 gph (could not get more than 100 degrees rich of peak egt on the leanest cylinder) with the carb, to 14.8 gph with over 125 rich of peak egt on the leanest cylinder. I am now working with GAMI to get all cylinders to peak within 1/2 gph of fuel flow while leaning. As this is a modification to a modification I don't think GAMI had data on an io-520d with o-470j intake system using what is basically a Lycoming io-540 injection system. I am now able to lean the engine lean of peak, with no indication of engine roughness. The five and six nozzles are running a bit too lean. I will be exchanging those GAMI nozzles and expect even better performance. The engine driven fuel pump (Lear Romec R15980B1) also needed a little adjusting (and might need some more) as fuel pressure runs right at idle minimum at 1000 RPM. Not a problem but with the EDM-900 the warning light is a bit annoying.
With moose season around the corner I will be putting the plane through the paces and get a better idea as to whether I get any noticeable improved takeoff performance. More details to come.
With moose season around the corner I will be putting the plane through the paces and get a better idea as to whether I get any noticeable improved takeoff performance. More details to come.
Ah, you must have installed the fuel pump on the accessory drive since you went with the B1. Straight 15980 (no letter suffix) is I believe typical for the fuel pump drive location.
