Thread: 9.5:1 vs 8.5:1

Same answer; timing. The 8.5:1 ECU will have more timing than the 9.5:1 engine will be happy with. You might be able to get away with it by lowering the base timing 3 degrees or so.

Wouldn't a Calum still be a better choice over that? What is the compression on your DE+T?

Calum ECU is always a better choice over stock ECU.

""Wouldn't a Calum still be a better choice over that? What is the compression on your DE+T?""

its a usdm sr20de+t with a compression ratio of 9:5:1. The calum ecu is set for compression ratio of 8:5:1

Burn 9.5:1 bin on your chips. Calum got this program.