<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by ERIC JORDAN:
Joseph,
To answer your question it is important to remember that forced
induction systems are not as dependent on cylinder scavenging
as NA applications. Forced induction systems need relatively large (1.75") primaries healthy collectors and and about 3" duals to avoid significant restriction. The 1.63" tubes that are so helpful in building area under the curve on normally aspirated motors is a detriment to you.
<HR></BLOCKQUOTE>Hello Eric -
Your theory is well spoken, however, it's a different scenario for Joseph's car. I've already been in this predicament MANY times. The addition of headers to Joseph's car in it's present form will most certainly present other issues that will need attention.
Sometimes it becomes a little difficult to explain with limited time via computer the exact details of my objective. I'll try to skim the surface with some detail....
As you know, the B.S.F.C. _Brake Specific Fuel Consumption_ (how much fuel you are using per horsepower per hour) on a forced induction application is generally higher than an NA application. In most cases a naturally aspirated engine will have a B.S.F.C of .50. This means that the engine will use .50 lbs. of fuel per hour for each horsepower it produces. Supercharged engines will want to be at .55 - .60 lbs. per hour or higher. Brake specific should be .45 to .50 for naturally aspirated engines ,55 - .60 for supercharged engines, and .60 to .65 for turbocharged engines. Joseph's car will most definitely encounter fuel related issues (in it's present form) with just the addition of headers, he's pretty much limited with the fuel system/computer he currently has. I would prefer to see him upgrade his current fuel/computer system (for the same or lesser cost of an entire exhaust system) to maintain adequate fuel delivery and computer control. Once again, he will make more, safer power, with the "upgrade" than just the addition of headers.
Thanks for the input,
Doug