what do custom tuners address? with the ecu they can adjust timing and air - fuel ratios at given rpms ,and can adjust rpm limits but what else can they touch ? to effect performance?

 

Redline. Most all of the 200+ HP club is hitting their high number at elevated rpm's.

 

Yeah, but it's more than hitting 200+, they're hitting 220+. If I raised my redline from 7000 current to 7500, I wouldn't be over 200 whp on the Mustang or Dyna-Pack machines.

 

Timing advance, fueling, torque limiter, VE (volumetric efficiency), rpm limiter.

It's mostly in knowing how the car reacts to difference changes and using those to affect the change you want. Sometimes it seems like it voodoo (this coming from someone who write software that others thing is voodoo).