View Single Post
RarlyL8 RarlyL8 is online now
Crotchety Old Bastard
 
RarlyL8's Avatar
 
Join Date: Jan 2000
Location: Huntsville, AL
Posts: 13,558
Garage
I do appreciate the support. Building shorty headers would've been much easier and cheaper.
The equal length portion of my design was spawned from my experience with the SSI based 930 system and the high-end systems such as Mode. In a nut shell these are the points I considered:

> The torque gained by an equal length system on an otherwise a stock engine is small when compared to the baseline of all systems. Headers only add ~15WHP to a stock engine so any increase by definition will be small.
> Short tube headers will give you that 15HP bump using the cheapest least complex design. Great from a business standpoint.
> Old racecars use shorty headers. They do not operate off boost and will never see a daily work commute. Getting the exhaust to the turbo fast is their function.
> Headers on a turbo engine are enablers. They allow other modifications to work optimally. The better the header design the more potential for optimal performance.
> Optimal performance (to me) does not mean the most horsepower but rather the most broad torque band.
> Street cars spend 90%+ of the time off boost and need as much torque below threshold as possible to enhance driveability and driving pleasure.
> Driveability improvement comes from a complex combination of the right components working perfectly together in a high state of tune. Headers are but one piece of this formula. Anything less than the perfect compromise in a header design will take away from the desired result.

That last point was/is my main focus. All headers make more power than the stock system. Equal length headers have the potential to give back even more in torque which translates to driveability and more usable power. How much more depends on the engine build and tune.
__________________
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8
Old 01-13-2010, 06:13 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #86 (permalink)