I have a bunch of numbers here for some .25s. They were not all perfect tests, some had mufflers, most don't. I have 3 FX .25s but have not run them yet although two are on planes that may be ready soon. All ran on a MA 8-6 and 10% Riches brew (10, 10, 10) except the GMS which was new and tight, and had 5%. It was 16,000 rpm. with muffler. FP .25 control line carb, 15,400 muffled 16,500 open ex., OS LA .25s 15,500 tight with control line carb, and an rc one 16,300 open ex. The AX .25 17,400 open ex. OS FSR 15,500 and 16,500 muffled and not. OS .20 15,000. Magnum Pro Taiwan .28, 17,400. and the Norvel 16,200 (it had an APC 8-6 because I didn't want drill it.) I think it was muffled. We don't have Westons here, I have a Fox that size, but am not interested to get it going as it needs a drive washer, and well, it's a Fox.