RE: Super Tigre GS-45 ABC Readings
Downunder has modified several of his engines, to obtain more power when using 0% nitro. This has been done, by raising the compression.
Iâ€™m also not using nitro, and tried it myself:
Out of the box, the Super Tigre GS 45 has a clearance of 0,6 mm from the piston to the head â€“ simply measured with a piece of solder, and the engine turned one time over the top dead centre. In the top of the cylinder, there is a cab of 0.25 mm from the inside to the outside. My theory is that some of the effect from the explosion therefore is going outside instead of downside and pressing down the piston. A friend of my took the â€śoutsideâ€ť ring of, and there bye lowered the cab with .25 mm. Now the total cab is 0.35 mm.
Tested on bench using 9/8 APC prop, Rossi 4 plug, 0% nitro, 3% castor, 15% Aerosynth2, stock muffler.
Max RPM: 12400
HP (Only on my test stand): 1,27
Max RPM: 13200
HP (Only on my test stand): 1,67
Now, thatâ€™s something!!! An increase of 800 RPM and a HP-increase of 24%!!!
If I can get some 0,05 mm shims, Iâ€™ll try to make a more accurate modification.
When using the stock muffler I could measure a little decrease in torque, if the muffler was pushed as closed towards the engine as possible, than the opposite.