Make sure glasspacks dont have louversDecember 4 2017 at 10:34 PM
WerbyFord (Login werbyford)
Response to Fairlane exhaust update
or neck down!
Glasspacks are great, for sound (next best thing to open) and power IF:
1. Avoid the kind where the louvers stick out into the airflow
2. Avoid the kind where the core is smaller than the exhaust pipe itself - they neck down inside!
On the H-pipe:
A good low-restriction muffler, like the above or other, will "act" like the end of the pipe, like the end of the collector in open headers. Well ok, not THAT good, but that's what SHOULD happen if the muffler is big enough / loose enough.
So, view the length of exhaust pipe, from headers to muffler, as the "collector" - just kind of a long one, like 4-5 feet.
Kinda long for most drag racing.
An H or X also "acts" like the end of the collector. Again, doesn't do a perfect job but other than open headers, nothing does a perfect job. Advantage of the H or X is you can put it up further so the "effective" collector is shorter, tuned more for the mid-range.