I think this topic is worthy of a new thread. I've copied the following discussion from a previous thread. My max spool rpm is currently set at 2750 rpm with my Vanos Spool Inlet / Exhaust table values overlapping (equaling) the moving warm VANOS Inlet / Exhaust table values at 2750 rpm. I currently have lean spool enabled for my stock turbo / OEM catted DP exhaust setup. Right now I have no cowl or engine cover on to help hear spool up and diagnose operation of my Forge Diverter Valves. [SIDEBAR: I had a lot of fluttering on the yellow springs when shifting 3rd-4th WOT. I added a shim to each one to tense the Yellow springs a bit more with no real improvement. I then went up to the blue springs (23-30 psi) and they seem to hold pressure better and release the pressure more crisply.] During lean spool up I hear lots of swooshing / filling the intake at a Lambda target of about 16.0... So I'm wondering: 1. Maybe I'm better off reducing my max spool RPM and eliminating lean spool? The theory being that I'd need less air spooling richer and thus achieving faster spool up to hit the max part of the torque curve sooner (at a lower RPM) if I disable lean spool. 2. But on the other hand, lean spool is intended to generate hotter exhaust gas which is intended to speed up the spool process. 3. I think it was Brad or RSL on the other forum who recommended the VANOS / spool strategy I mentioned above to generate nice amounts of torque below spool max rpm. Is this strategy still considered to be sound? Any thoughts on whether or not to use lean spool for stock turbos / stock exhaust setups running 93 octane and 23 psi?