View Single Post
K24madness K24madness is offline
Registered User
 
Join Date: Mar 2009
Posts: 223
While I have zero experience with SC cams into a 930 I can offer perspective why NA grinds have been successful in other applications.

When I hear people ask about cams the biggest piece of missing info is turbine inlet pressure. It’s critical to know the boost to TIP ratio. With that information decisions about overlap and lobe separation angles can be better made. Modern turbos have a lot less back pressure than earlier turbos. Some achieve 1:1 balance. NA OEM cams work pretty well in these applications. It was not unusual (non Porsche) to see 3:1 in older OEM cars.

Even though NA cams work better than stock there’s room for improvements via the custom route. Opening the exhaust valve earlier than NA would helps turbo spool. The upside far outweighs the downside here. OEM cam designs are also centered around smog limits. With more freedom to choose optimized profiles comes great returns. This all seems cheap to me for around $1k when considering the rest of the build costs.

I would also advise caution when using the HP gained as a metric. This can be misleading. The positive personality change can be difficult to quantify but it’s something I hear over and over again. I’ve heard the term “happy engine” used in the past. As I’ve grown older I’ve come to appreciate what that really means. That has become the target of all my street build now.
Old 01-13-2020, 05:39 AM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #16 (permalink)