I'm not sure that we've found any "limits" with them yet. The Super Stock guys continue to go faster and faster with them, despite continuing rule changes to slow them down!
Just had a customer report that he got 18.9 MPG with a unit we just set-up for his 455 Pontiac street car. His engine makes over 500hp, and he added a 200-4R overdrive to lower cruise rpm's.
We continue to see folks "jump fence" from shiney gas-guzzling aftermarket carbs to Q-jets, not loosing any power anyplace, and getting a lot more fuel economy for "normal" driving.
I just drove my own car to a local track a couple of weeks ago for "test and tune" night. Made 10 runs, all in the low 7's at 94-95mph, drove it back home. I topped it off with fuel close to the house, made the drive to the track, 10 runs, some cruising around town, and back home on less than 1/4 tank of fuel!......Cliff
