I noticed a nice strong pull from mid range all the way to redline. I tried ½ oz the first tank noticed it right away, 2nd tank 1oz and she didn't like it (really wanted to stumble and idle ruff in low rpm's). Then every tank since then has been 1/2oz. 20/50w both holes (going to run 20/60w next go around), I live in Arizona, straight velocity stack intake and full header/exhaust. My first few tanks where also done with the airbox still on and factory exhaust with a second hole drilled in it.