http://www.gami.com/GAMI makes fuel injectors for TCM and Lycoming engines. They claim that their fuel injectors will modify the fuel flow to more evenly balance the fuel/air mixtures between cylinders and thus make the engine run smoother at leaner mixtures. GAMIjectors work by having different sized injectors for different cylinders. See articles on http://www.avweb.comAvweb discussing the old ROP (rich of peak) vs. LOP (lean of peak) arguments.
On the GAMI web site, they show that they sell injectors for IO-550’s, but not the -N model. I called GAMI and here’s what I found:
- The -N model has a “tuned induction system” which is supposed to balance the air to the cylinders, which TCM hoped would achieve the same result as the GAMI approach.
- GAMI claims that there are still significant inblances in the fuel/air mixture between cylinders in tuned induction engines.
- GAMI does not have approval for their injectors in the tuned induction TCM engines, but hopes to have it by this fall. They have a lot of hurdles to jump over. They hope to get blanket approval for all a/c using the IO-550-N, but may have to go plane-by-plane in the process.
- When it is available, the six-injector set will be $800.
- The process will be:
a. The a/c must have an engine monitor
b. The owner runs the “GAMI leaning test”, described on their web site, and sends the results to GAMI.
c. GAMI sends injectors to the owner which are supposed to correct the specific imbalances in the particular engine.
I am generally wary of engine add-ons, but I find the technical arguments on Avweb compelling. I also fly a Bonanza with GAMIjectors and it is the smoothest-running engine I’ve every flown behind. Could be coincidence, of course. I don’t think the GAMInjectors would hurt, however. GAMI claims they have sold over 7,000 injector sets.
PS. Cirrus called again today to say that the delivery date they gave me two days ago was too optimistic and that #30 will be ready June 4th. They’ve been very nice and I understand that these things cannot be predicted perfectly. I don’t want them to rush. However, they said that there wasn’t any particular problem with #30, just that production flow wasn’t quite what they wanted.
They said that they had built two days of padding into their schedule. I suggested that in the future, they build more like 10 days into their schedules. That’s only 10 a/c they’d have to hangar on average at current production rates. Much better to call up a future owner and say “we got it done three days early, in case you want to come out sooner” than to say what they’ve said to us twice in the last two weeks.