Our latest product - The Header-Y - completes the connection between our new merged-collector headers for the 16v motors and the stock or Borla Performance Exhaust. Dyno tests show a 21 lb/ft increase in torque at the tire in addition to the increase from a performance exhaust and cat delete.
www.928motorsports.com/parts/headerypipe.php
It is always hard to answer the question: "How much HP will I get from Headers on my 928?". Because headers are never installed alone, it is difficult to attribute what HP came from the headers and what HP came from the cat-delete or the rest of the exhaust upgrade.
But - a little while ago I had a customer deliver a nice 1984 928 5-speed to me that already had a Borla cat-back system and a Motorsport Y-pipe on it. No cat.
So our "baseline" (shown below) already shows the gain over a stock 1984 4.7L as a result of those mods. (stock is 234 at the motor, and this car did 242 at the motor).
Then we replaced the Y-pipe with our new merged-collector headers and Y-Pipe and got another 9 HP and 25 lb/ft of torque at the motor. Nice! Sounds great too.
The Header-Y is made from all 304 Stainless.
