Engine Mgmt., Fuel, Spark, EGTs, & Air/Fuel Ratios
I just rebuilt a 2.5 turbo block and it has the following upgrades-
T-II turbo
Two piece intake
afpr and large volum fuel rail
aftermarket intercooler with 3 inch piping
vacuum block with compression fittings and hardline vaccum lines(no leaks)
manual boost controller
Blow off valve
52mm...