typer161

whats the highest compression i can run all motor on pump gas

Scott_Tucker

16:1

riceburner700

depends on combustion chamber/head design and define pump gas. e85 is considered pump gas as well

typer161

going for a ls/vtec with a b16 head

Scott_Tucker

The truth of the matter is that static compression ratio alone never determines whether you can run pump gas. It's static compression ratio together with intake valve closing point that determines the effective compression ratio. The effective ratio is far more important that the static ratio and on an aluminum head/iron block engine is usually about 8.5:1. You can have an engine with a 16:1 static compression ratio and still have an 8.5:1 effective compression ratio but the intake valves would have to close so late that a large portion of the air/fuel charge would be forced back out the intake at low rpm.