ORIGINAL: buzzingb
The modern Super Tiger engines will run well on 5-15% nitro, no question about it. I seen some on here suggest low nitro for Tigers but it has been my experience with these particular engines (51, 61, 90, 2300) that they will run well on 5-15%. I use 5-10% in the summer months.
I'm with you on the .51 and the .61. I have used both 10 and 15 percent nitro with no problems. Same for my .40 ringed. My .90 has about a half a gallon through it on 10% only. For me an A3 plug seems to work the best. In the air it was hard to tell the difference between the 10 and 15%. Can't remember if the 15% had a higher number on the tach, but I do remember no big increase in performance in the air. General sport flying and 3D/hovering.