There is a necro bump to a long thread. Haven't heard from Jeffie or Combatpigg for a long time. I made a few turbo heads for the TT .07. They helped a fair bit. One of the three motors I got just would not go well at all. I soldered up the bearings to remove the slop and leaking which helped get a steadier run. How long? IDK. Two of them pretty much equalled the Norvel .074 with the turbo head and some tweaks I read about in another thread a while back.