I've got 2 vehicles with California emissions TBI engines, a '91 305 in a Caprice wagon and a '94 350 in a 1500 truck. I'm working on upgrading the performance of both using tips from this forum.

When looking at ECM chips from some of the big suppliers (Jet and Hyperchip) I noticed that they list different chips for the California and non-California versions of these engines.

Does anybody know what is actually different on the Cal and non-Cal versions of these engines? The '94 350 was rated at less HP (195), does anybody know what the rating of the California '91 L03/305 was?

Can I use a non-California ECM chip on these engines or do I have to go with a California chip?

Thanks,

Paul T.

 

The California/Federal emissions engines had very little different. In fact the engines themself were IDENTICAL. The difference is that most california vehicles had an emissions air pump (federal cars too) while most federal pickups were without.

The difference is the timing advance and fuel tables run in the chips.

 

If you need to pass Cali emssions, then start with Cali calibrations. And be careful of what areas are changed for fuel & SA. As Fast355 mentioned there are major differences in those areas between Fed & Cali cals.

The California calibrations typically run less timing (up to 10 deg less in areas on a '92 TBI Camaro). Along with running a slightly richer AFR (while in closed loop).

RBob.