Originally Posted by jpnovak (Post 9910235)

The Thrust curves are calculated from the torque (dyno) curve. Torque (ft-lbs) is converted for each gear ratio into thrust (lbs). The gear ratio gives you the distance traveled per revolution to cancel the (ft) component. The RPM component is also converted to speed using the gear ratio. Its a relatively simple conversion and exceptionally useful.

Originally Posted by Trakrat (Post 9901393)

ok.. I'm looking at changing my cam profile to change the characteristics of my stock engine. I've been told that a different cam profile can move the power curve up or down the RPM scale. I've read that a 911 S cam profile from the earlier years will give my 3.2 a smoother curve (the question is, why would a smoother power curve be beneficial?)

I'm struggling to understand what to choose... in that, I'm struggling to properly communicate what I want because I'm confused as to what exactly I want.

So help me understand how changes to a camshaft can do this.

I know a camshaft just opens and closes the valves... and I understand that the lift and duration are what you are changing, along with the overlap.

But what I don't understand is HOW the different changes actually effect the engine's performance.
The chamber can only hold so much air and fuel, and the piston can compress only so far... so how does the valve change the performance characteristic?

I've been to dozens of websites that show diagrams that look like I'm trying to understand the gravitational mass of a black hole while calculating its impact on tachyon waves through dark matter.
My point is... understanding the diagrams doesn't help me to choose the right profile (or keep from choosing the wrong one).

So when I call Webcams (or whoever), what am I needing to know I want, and how do I communicate that in a way that doesn't make the person on the other end of the conversation think I'm an idiot?? :confused::(

Originally Posted by mikedsilva (Post 10830975)

What did you end up choosing?

Originally Posted by Trakrat (Post 10847070)

I've narrowed it down to S cams and 964 cams.

I'm leaning to 964 cams because a few shops say that this is a GREAT starting point for me, and once i am used to how the engine responds... I'll have a better understanding what I want changed by communicating that I am starting with 964 but want to change 'this' or 'that' in the engine characteristics.

I've still got a long ways away to get this engine built... just now finally putting in the time and money to get this completed.

Originally Posted by Trackrash (Post 10847088)

What personality do you want from your motor? What intake will you use? What RPM will you want your motor to produce power?

Originally Posted by Trakrat (Post 10847565)

A torquey motor that pulls hard. are you talking about the intake manifold? or the air intake? Intake manifold will stay the same... no change to fuel system either. But I would like to switch to an aftermarket, performance air intake (haven't been able to find one).

I'd like my motor to produce power at all RPMs.... I guess I don't understand your question. I don't want to have to redline the thing to reach its power peak, that's just putting too much stress on the motor. But at the same time, I don't want to lose power with another 2k rpm left in the gear.

Originally Posted by Trackrash (Post 10847717)

So, how much you can increase your performance beyond a mild 964 cam upgrade, depends on a piston and intake system upgrade.

There is a great section in Bruce Anderson's Porsche 911 Performance Handbook on upping the performance of the 3.2s using stock internals and more.

Originally Posted by Trakrat (Post 10849007)

Thanks... I have that book and have browsed it many times.
Without getting too custom in my engine build, I am going with 3.4 Moritz style P&C setup. (best for single ignition due to the piston design w/ a lower 9.8 compression)

It sounds like the 964 cams is the best choice to improve performance at a conservative level then?