[911nut]

[QUOTE]Originally posted by mperkins
The CIS system is also less agressive in that the fuel distributor is smog-friendly (I believe it offers less potential volume) where as the Euro unit is idential to that of the MBZ 450SEL and 911Turbo fuel distributor and can be set to run a little meaner =i.e. rich.

CIS fuel distributors vary according to calibration requirements but I don't think you'd notice the difference if you put a Euro fuel distributor on a U.S. motor, even a Lambda CIS distributor (if the O2 sensor was disconnected and the mixture is set richer).


In 1980 the USA cars received an increase in the compression ratio to 9.3:1 and retained the 95mm pistons. They also introduced a Llamda/Oxygen sensor for the catalytic-converter which enabled Porsche to do away with the smog
pump.

Actually, the lambda sensor allowed the use of a 3-way catalytic converter. The lambda system continously varies the fuel pressure in the fuel distributor which keeps the air/fuel ratio at 14.7/1. A cat won't function properly at any other air/fuel ratio. This air/fuel ratio is good for economy but you get more torque at a 12.5/1 air/fuel ratio.

However, in the interest of smog compliance and maintaining an acceptable Corporate Average Fuel Economy -as
the required by our Federal Goverernment (or pay bigass penalties) Porsche elected to REDUCE the port size to 35mm intake and 34mm exhaust.

Reducing the intake runner diameter increases air velocity at low rpm, which enhances low speed driveability. It has no effect on emissions or economy.

The horsepower was rated the same at 180hp.

Who really knows what the HP figures actually are? Porsche (as well as all manufacturers) are notorious for understating HP figures. I'd be willing to bet that the US motor is more like 190 HP and the Euro motor is 200-210 HP.