Exhaust pipe size for horsepower. How much power can a 3 mandrel exhaust flow before it becomes too much of a restriction. But what if your engine is putting out more than the numbers shown in the table. The 1-58 inch pipe was choking the system and i dont care if Datsun said it would support 150 HP it was restricting the flow. On early carbureted engines pipe size was very critical. Our motor is 400 hp at the flywheel we need an exhaust size larger than 3. Buz The size of your exhaust system pipes should be matched to the power of your engine. The greater the exhaust volume the greater the optimal exhaust size.
Determine the correct diameter of exhaust pipe you should use on your car by consulting a general guide for pipe sizing. Put a 35 or 4 on then post. It is a common practice to size the first length of primary to as close to the exhaust valve diameter as is reasonably available. A good section of straight pipe will flow about 115 CFM per square inch of area. The 2 hp levels will of course work fine with a smaller system but will not make max hp in most cases. Was wondering what the horsepower flow is for each different exhaust size. If the pipe is too large the back pressure is less and if it is too small the exhaust fumes will not exit properly.
That pipe diameter would be most appropriate for a 200-250hp applications IMHO based upon what Ive heard from expert and seen on the dyno. To strike a balance between low back pressure and high gas flow velocity you need the correct pipe size. It tells you the proper pipe diameter based on your vehicles engine size and horsepower. Let us assume we have a motor making 400 flywheel horsepower and wed like a single pipe exhaust.
So here is an example. To strike a balance between low back pressure and high gas flow velocity you need the correct pipe size. A 3 single exhaust is good for about 340 crank horsepower. A good section of straight pipe will flow about 115 CFM per square inch of area. Typical exhaust pipes are 18ga.