CSDP

I'm taking an EFI course currently and we have made it past calculating duration from cam cards. But now we are supposed to be estimating IVO, IVC, EVO, and EVC based off of modifications. For example an LS3 with heads/cam, LT with out cats, cold air intake, 6 speed, 3.42 gears, daily driver, 3200-6200 RPM, 11.0:1 CR.

I suppose my brain is just stuck. I just don't understand how much it should actually move EVC and IVO the amount that it does?

My instructor estimated a value of 5 for both IVO and EVC after the above modifications. I'd like to understand how he got there.

G Atsma

I would ask him. Sounds rather arbitrary when it actually depends on how much anything is modified and which engine, head design, etc.

ChopperDoc

Real world numbers are all that really matter. Mechanically nothing changes unless you have VVT or something changing that event. Dynamic numbers are estimates at best… so… like I said, real world is all that matters.