Header design
(Hooker makes 1-5/8" headers with 2-1/2" collectors for trucks but not cars.) |
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I guess all we can do is create our headers properly or reconfigure existing units to work as they should and not give ourselves tuning headaches. When big name header manufacturers say equal length, they must be talking out their collectors. | I guess all we can do is create our headers properly or reconfigure existing units to work as they should and not give ourselves tuning headaches. When big name header manufacturers say equal length, they must be talking out their collectors. | ||
| − | Now we get to the collector - ever see a header with 1 5/8" primaries that had a 2 1/2" collector? | + | Now we get to the collector - ever see a car header with 1 5/8" primaries that had a 2 1/2" collector? Hooker makes them for trucks, but you don't see them for cars. But that is the optimum diameter for most street headers. Run that right into a 2 1/2" exhaust and you have a sweet system with lots of torque where you need it, and better fuel economy to boot. The collector should have a smooth, gentle shape from the four tube area down to the final diameter to keep things moving smoothly. |
While we are on the subject, I see the proliferation of 3" exhaust systems out there. If you have very healthy big block, are running a blower, some turbo, or have a ton of nitrous, you go boy! About the only street application of the monster 3" diameter pipe is when you count on having an engine with large gobs of top-end power. Otherwise, velocity is king in exhaust and 3" is probably too big to keep the speed of the gases up in the exhaust, and there goes that bottom end torque again! Many recommend either 2 1/4" or 2 1/2" diameter pipe for street V-8's. | While we are on the subject, I see the proliferation of 3" exhaust systems out there. If you have very healthy big block, are running a blower, some turbo, or have a ton of nitrous, you go boy! About the only street application of the monster 3" diameter pipe is when you count on having an engine with large gobs of top-end power. Otherwise, velocity is king in exhaust and 3" is probably too big to keep the speed of the gases up in the exhaust, and there goes that bottom end torque again! Many recommend either 2 1/4" or 2 1/2" diameter pipe for street V-8's. | ||
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