964 engine rebuild 11.3:1 compression

[john_colasante]

Originally posted by ChrisBennet

IMO, I don't think any racing body is going to accept a motor with 9 points higher compression (than a truly stock motor) as "stock".
-Chris

I would think if you built the motor to the spec you are legal.

[ChrisBennet]

Originally posted by john_colasante
I would think if you built the motor to the spec you are legal.

Yes, that true but you have to comply with all the specs - not just the compression ratio one.

In this case we are talking about ignoring all the other specs to get a desired compression ratio. There is a spec for the cylinder height for example. You can't just lop off whatever you want.

I don't know if PCA stock rules allow machining of any components short of resurfacing the heads.

I don't know how the factory arrives at their compression ratio (does anyone?) but they are obviously using a different method.

-Chris

[john_colasante]

Originally posted by ChrisBennet

I don't know if PCA stock rules allow machining of any components short of resurfacing the heads.

PCA stock rules say machining for balance purposes only.

Still, I think 11.3:1 MUST be achieved for maximum "stock" performance. Would race gas be required? I guess so.

[ChrisBennet]

Originally posted by john_colasante
PCA stock rules say machining for balance purposes only.

Still, I think 11.3:1 MUST be achieved for maximum "stock" performance. Would race gas be required? I guess so.

Maybe they are already 11.3:1 - using the Porsche compression measuring method.

If there is any question, one could simply ask the PCA Race rules guy. I think we both know what he would say.
-Chris