I recently stated that my 500hp 468 has 2.25" exhaust piping. Duh, I measured the section from the muffler back. Anyway, I got several Emails from guys telling me it should be at least 2.5". Well, rolling around under it tonight playing with trans speedo gears, I noticed that from the header collector to the muffs, it is 2.5". I have two sizes of pipe in the system. Hmmmm...did someone actually know a trick?
It's been 15 years since thermodynamics classes in college, but I remember a formula for gases which goes PV=nRT. Looking at this, we see that volume is proportional to temperature. Comparing the cross sectional areas of the two pipe sizes, it sure looks like the exhaust gases would just have to cool 23% as they travel from the header collector to the output of the muff in order to allow maintain the volumetric flow and velocity (and hence, back pressure) using the smaller tail pipes.
Sooooo...is this correct, am I ok with the smaller tail pipes? Or is there one of those real world parameters which makes the my arguement silly and false?
It's been 15 years since thermodynamics classes in college, but I remember a formula for gases which goes PV=nRT. Looking at this, we see that volume is proportional to temperature. Comparing the cross sectional areas of the two pipe sizes, it sure looks like the exhaust gases would just have to cool 23% as they travel from the header collector to the output of the muff in order to allow maintain the volumetric flow and velocity (and hence, back pressure) using the smaller tail pipes.
Sooooo...is this correct, am I ok with the smaller tail pipes? Or is there one of those real world parameters which makes the my arguement silly and false?