A running pictorial of my new project B9R from BBI
#70
07-28-2009 | 01:46 AM
Teamspeed Junior Member
Joined: Jul 2008
Posts: 77
Here's the a little technical background regarding the pistons going in your build, along with a few images
BBI has been working closely with MAHLE, the manufacture of stock Porsche pistons, to come up with a solution for high hp 3.8Ls. MAHLE spared no expense in creating these custom forged pistons for us. They went all out on these as you can tell from the images below.
These pistons lower the compression ratio from 9.0:1 to 8.5:1. Lowering the compression lowers combustion pressure, prevents pinging, detonation, and knocking. These characteristics allow you to effectively and safely run higher boost.
There are 3 types of coating on these pistons.
-The top layer has a heat reflective coating that helps keep heat in the combustion chamber.
-The top ring land/groove has been hard anodized for strength. The top ring land has also been relocated down from the top of the piston, away from the heat. This piston ring is the compression ring.
-The piston skirts have been dry filmed to further reduce friction against the cylinders.
All of the piston rings are motorsport style, and completely hand gapped.
The piston pin has also been modified to 21mm from 23mm, thus lowering the weight. The piston pin is coated in Diamond like Carbon (DLC). As implied by their name, DLC, the value of such coatings accrues from their ability to provide some of the properties of diamonds. The primary desirable qualities are strength, wear resistance, and slickness (low coefficient of friction).
