Table of Contents
How do you measure exhaust flange?
To measure such circle measure from the center of one bolt directly across to the center of the other bolt. The Outside Diameter is the measurement of the outside of the Flange or Gasket. The Inside Diameter is the measurement of the inside of the hole of a Flange or Gasket.
How do you determine exhaust header size?
Calculating Pipe Length Look at your camshaft specs and find out how long the exhaust valve opens in degrees at 0.50-inch lift. Subtract this number from 360, then multiply that by 850 (we’ll call this Figure A). If your engine sees mainly street duty, subtract 3 from the rpm at which peak torque occurs.
Is exhaust diameter measured on the inside or outside?
Most exhaust piping is going to be measured using OD dimensions which is outer dimensions of the pipe or the outer diameter. That means if you were to purchase a three-inch pipe—let’s say like the one we have here—the outside diameter of this pipe would actually be three inches.
What is the diameter of the flange?
Diameters and bolt circles for standard ASME B16. 5 flanges – 1/4 to 24 inches – Class 150 to 2500.
| Nominal Pipe Size NPS (inches) | Class 150 | |
|---|---|---|
| Diameter of Flange (inches) | Diameter of Bolt Holes (inches) | |
| 16 | 23-1/2 | 1.12 |
| 18 | 25 | 1.25 |
| 20 | 27-1/2 | 1.25 |
How do you calculate the intake and exhaust volume?
Good Way To Estimate: Take engine RPM x engine displacement, then divide by two. This is the intake volume. Use this same volume of air for the exhaust system, but then correct for thermal expansion (you need to know exhaust temps to figure things out).
How much CFM does a exhaust pipe use?
Exhaust Pipe Size Estimate: A good section of straight pipe will flow about 115 CFM per square inch of area. Here’s a quick table that shows how many CFM each common pipe size will flow, as well as the estimated max horsepower for each pipe size: NOTE: These numbers are just estimates.
How many exhaust pipes do I need for a 400 hp?
NOTE: These numbers are just estimates. All pipes are assumed to be 16 gauge steel. The table above is probably over-estimating pipe size, but you can see that a 400 hp vehicle with a dual exhaust system only needs 2 1/4 – 2 1/2 inch pipes.