When compared to previous normally aspirated T19, DM's horsepower went through the roof with the new components in T21! Peak power jumped by 30 hp to an outstanding 474 hp at 6,100 rpm but torque fell off down low, so the extra power wasn't a freebie. COMP Cams attributes this to the more-aggressive low-lift ramp profile on the NX274 flat-tappet hydraulic camshaft. The hydraulic roller cam really begins to take over at higher rpms due to its reduced frictional losses. Now it was time to test the EFI set-up.
T22: Installed F.A.S.T. EFI system with Accufab throttle body and 30 lb-hr injectors at 50 psi.
Right away the EFI proved its superiority by adding torque down low and increasing power up top. Although power dropped slightly in the mid-range, which we think we could've got back with more tuning time. We also thought DM might have been a little starved for fuel with small the 30 lb-hr injectors we had originally installed, so we switched them to larger 36 lb-hr injectors and got just a little more top end power, but low end went back down, so we put the 30 pound injectors back in.