Cams in a 3.2

[ROWSC]

I understand the need for mild cams in a CIS engine. What if I swapped to a 3.2 engine with DME? Can these be made more aggressive or is it still best to scrap the factory injection?

[Joe Bob]

It depends on what you want to do.....

The 964 cam in the CIS 3.0 is a great upgrade. I did it with my 914/6.

The 3.2 is a whole different ball game, my choice would be to pay a few extra bucks and go for a 3.6.....

[Bill Verburg]

All 3.2 and 3.6 use a mechanical "barn door" to measure the volume of air injested by the engine. All of these systems are very sensitive to the strong pulses set up in the intake manifold due to valve events and the fact that air has mass(momentum). The larger the engine the more extreme the duration and timing of the valve events can be, the 964 cams have greater duration and initiation angles as a result. There is still a limit.

The mass air flow sensor(hot wire) of the 993 is an improvement for this reason. It is less sensitive to the intake pulsation but there is still a limit.

Even carbs and mechanicly injection are sensitive to this phenomena(though less so).
Cars with wild full race cams often have a very lumpy high speed idle and do not respond well to low speed partial throttle inputs.

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Bill Verburg
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