Originally Posted by
Pondus
That's a lot of engine modification, I'm not going to take it that far myself. One of my FA-450's have 0 runtime, and the other reportedly only have 5 or 6 flights in addition to break in on the ground so it is in very good condition, I feel it would be silly to swap out all six cylinders assemblies when they are in this condition. I am going to limit myself to ignition and induction mods, I had a look at mounting a 180 carb but as that is a bit more than a bolt on job I think I'll leave it for now. Maybe just swap out the choke plate assembly with a velocity stack from a 150, that should bolt right up. I may also swap out the throttle barrel for a 150 barrel, it looks like saito added a brass bush in the 450 throttle barrel to reduce the bore from 10mm to 9mm, so it can either be bored out or swapped out for a 150 barrel that is 10mm bore as far as I know.
I think they spec the carburetor as 9.4mm on the FA-450R3.
Going to the 10 mm carb might not sound like a big difference, but it will have about 14% more cross sectional area so it would definitely give you a boost when coupled W/the induction mods.
To go to the bigger 11mm & 12mm carburetors you would need to machine for the 14mm gland nut then modify an FA-180 manifold which in itself is quite a chore. Given that you are not going W/the FA-180 pots & boosting compression, it probably wouldn't gain you anything.
A well tuned FA-450R3 W/ the Ray English induction mod & CDI/glow fuel will make lots of power. Probably in the neighborhood of 8 HP on 15% nitro. More if you want to tip more nitro into it. A little less if you want to go straight methanol/oil mix. I think on straight methanol it will make as much power as the Ray English modded FG-84R3.