SC cams profile dyno charts anyone?

steven c · 11-30-2010, 05:47 AM

I am considering SC grind cams for my pretty much stock 91 3.3 as a mild upgrade during the engine rebuild. I read that the SC cams offer more low and middle power but I am curious to what expense this is gained. Does anyone have dyno charts of the SC cam vs. stock on a 965? Thanks

911st · 11-30-2010, 07:00 AM

Steve,

Not sure the dyno charts are going to help much as a before and after with just a cam change is hard to come by.

Might be something here: Ultimate 930 Dyno Thread!

Also, 911chips.com has a lot of dyno charts on 3.2 Carrera's that use that cam if you want to see its intended TQ curve. However, most re-time them to move them more toward TQ.

From my limited studies the 930 motor seems severely intake port restricted. Probably in improve fuel atomization at low rpm. With CIS delivery rates are changed by raising and lowering pressure at the injector as it has to work at a 100% duty cycle. Thus, at low rpm pressure at the injector is low. On top of that the fuel is contiguously sprayed for two full turns of the crank before air is sucked by the fuel in wait. Poor air and fuel mixing and very low compression can make ignition a challenge.

I personally believe the best way to over come the intake restriction is to open up the ports. This has more potential in increase air flow. Still, many have made a lot of HP through the stock little ports.

As you probably know, SC cams are pretty much the go to cam and even used by the factory on the special turbos over the years. It also seems to be a good match with the stock C2 turbo. Attention needs to be given to spring tension with this mod and the rocker arms should be resurfaced.

Good luck.

911nut · 911nut's Garage

Quote:

Originally Posted by 911st

As you probably know, SC cams are pretty much the go to cam and even used by the factory on the special turbos over the years. It also seems to be a good match with the stock C2 turbo.

Keith, the factory chose to use the 964 cam in the Turbo S and I've never seen anything that states that the Turbo S had anything other than a K27-7200 turbo.

911st · 11-30-2010, 03:17 PM

I believe the cars that ran the C2 cams ran a k27-7006 turbo but I could be wrong.

I also believe this was on the 94 turbos with higher compression and the increased displacement to overcome the drawbacks of a 1 point loss in effective compression ratio over stock and half point over the SC cams.

I could be rusty on this and be wrong however.

The best.