Who wins this race??? 03 Cobra vs 91 GT

The inlet side of a twin screw can be slightly reshaped and polished, but very minimally. Gains have been proven to be negligible in most cases at best. Twin Screw compressors are very, very sensitive to port timing. A fraction of a millimeter off in any direction can throw off port timing significantly, which can create leak down issues that would have dramatic effects on the units ability to build and maintain internal compression levels. Not to mention chances of elevated ACT’s and premature case/rotor wear. In the end, it may actually end up costing power, rather than creating it. Not to mention the effects it has on blower longevity.

Remember.....Twin Screw blowers are "compressors", not an "air transfer device" like an Eaton. Unlike a Twin Screw where compression takes place between the rotors in the head unit itself, Eaton’s don’t actually compress the air within their lobes at all. Air is actually paddled from the inlet to the outlet and any compression taking place is actually done post discharge port in the lower intake manifold, or the intake runners of the heads themselves. If that weren’t bad enough, unlike the hybrid roots style design the modern Eaton’s are based on, where ACT’s only elevate when the bypass valve closes and blower speed increase, Twin Screws are compressing the air...all of the time...always! This means during idle, putting around town or even cruising down the highway with the bypass valve running wide open. This creates higher cruise temperatures than can often lead to heat soak issues...even with the intercooled kits. Because of this, Eaton’s actually tend to operate at cooler temperatures about 95% of the time they’re in operation.....although some Twin Screw manufacturers would have you believe differently with some of their "creative advertising". Quite frankly, only under wide open throttle do Twin Screws display any more adiabatic efficiency over most OEM style Eaton’s (throw an aftermarket unit like the Magnuson or TVS line up into the mix and it isn’t even close) and even then with the 4th and 5th Generation Eaton’s, the differences are minimal.

This is pretty much why most don’t waste their time porting Twin Screws. Leave the port work to a more forgiving unit like an Eaton. If your buddy wants more airflow than his stock 140AX is putting out, tell him to pony the cabbage on a bigger blower. Porting is not where it’s at!