Yea, I'd like to know what's going on with that engine for sure.CGT wrote: ↑Thu Jan 18, 2018 10:06 amIt's always fun to me to try vacuum on the dyno. The results are sometimes really inconsistent. There is one particular motor (Randy knows about) that has an allergy to vacuum. . It should really respond to it in theory, but is hard headed and doesn't. It tends to pick up the same amount of power that it takes to spin the vacuum pump
It's been tried 3, maybe 4 times on it, belt on nothing, belt off nothing, and one time with small oil pan, still nothing.
Tommy Boy picked up 15 HP with the same pump on it and similar vacuum. (15"-16")
Be interesting to raise oil pressure on it and see if vacuum still had the same results.
Guess if I figure it out I can repeat it on others and save money on vacuum pumps.