Port Flow /wet Vs Dry

Grumpy · Jan 18, 2021

a great, many people seem to place a great deal of credence in the advertised dry flow numbers advertised with most aftermarket and there's a strong,
but there's hardly directly mathematically reliable ,
linier relationship between port flow rates and power produced.
you can,t just buy the largest port heads available and drop those on your short block without matching the compression, displacement, cam timing and fuel/air ratio to the intended power band.
theres plenty of people doing research in this area so it pays to read a great deal and use other peoples research before throwing money into a build that may not be ideal.
a few hours research will allow you to find a nearly ideal combo.

The concept of port matching an intake manifold to a head is to ensure the flow of air to the cylinder is as big, smooth, and efficient as possible for maximum power. By ensuring the mating surfaces of the intake manifold and head have holes that match perfectly will help air flow through the engine.

Port Matching - Intake & Head Porting - Tech - How To - Circle Track

A tech article on match porting your intake manifold and heads. Find all the details inside Circle Track Magazine

www.motortrend.com

some heads just seem to operate more effectively than the flow numbers might suggest, and factors like dynamic compression, engine stroke to bore ratio, port cross sectional area, octane of the fuel used, fuel/air ratio, and valve size in relation to port volume do have a pronounced effect on the results you'll see.
you can be rather sure that your never going to reach peak power until your valves lift exceeds about .30 of the valve diameter, your engine compression it maximizing the fuels octane limitations and your exhaust system scavenging and drive train gearing is close to ideal in the power band or rpm range your trying to use,
as a general rule you can expect average pump gas to have an octane limitation that limits street cars to use about a 8:1 dynamic compression
and they generally produce the best torque with fuel/air ratios close to 12.5:1
there's a lot of threads on this web site with links to the math and formulas that will prove useful , in narrowing down any combos potential sweet points if you do some research
but you'll generally want to keep the port velocity rather high as it helps keep the fuel atomized and in suspension for more effective combustion.
higher compression and larger displacement generally helps boost results
power adders like nitrous or turbos are looked at as CHEATING by some old school builders but I've always thought they were advantageous if your wallet would allow the potential cost.

http://garage.grumpysperformance.co...-calculators-and-basic-math.10705/#post-72061

http://garage.grumpysperformance.co...-potential-dream-bbc-combos.14607/#post-93690

http://www.wallaceracing.com/Calculators.htm

http://garage.grumpysperformance.com/index.php?threads/calculating-ideal-port-size.624/#post-8692

http://www.csgnetwork.com/automotiveconverters.html