{"id":315,"date":"2017-10-05T08:45:40","date_gmt":"2017-10-05T13:45:40","guid":{"rendered":"http:\/\/performancetrends.com\/blog\/?p=315"},"modified":"2017-10-05T08:54:15","modified_gmt":"2017-10-05T13:54:15","slug":"besides-cfm-flow-what-can-you-measure-on-a-flow-bench","status":"publish","type":"post","link":"https:\/\/performancetrends.com\/blog\/?p=315","title":{"rendered":"Besides CFM Flow, what can you measure on a Flow Bench?"},"content":{"rendered":"

Our Port\u00a0Flow Analyzer<\/a> for flow bench testing has several features for making several measurements of cylinder head performance. \u00a0For head flow, pretty much anything that improves CFM flow improves the HP\u00a0potential of the head. But after measuring CFM, there are several other\u00a0measurements which can give better insight into one particular head runs\u00a0well on the dyno or the track, and another head with equal or sometimes even\u00a0less flow can run much stronger. These are the hard earned “black arts” of\u00a0head porting which many engine builders are reluctant to share. Questions\u00a0these engine builders are looking to answer include:<\/p>\n

1) Have you given up too much port velocity for improving CFM flow? This\u00a0is pretty much dictated by port volume. An engine with too much port volume\u00a0has low velocities and will not make good torque at midrange RPM. There are\u00a0many simplistic “rules of thumb” on this, but the best way to know if you\u00a0have too much port volume is with a sophisticated engine simulation program\u00a0like Engine Analyzer Pro<\/a>.<\/p>\n

\"Engine
Engine Analyzer Pro<\/figcaption><\/figure>\n

It can read\u00a0our Port Flow Analyzer<\/a> files which contain both CFM flow and port volumes\u00a0and tell you how the head will likely perform at various RPMs. A particular\u00a0head may have too much port volume for a smaller CID or shorter runners, but\u00a0at a different RPM, runner length, cam, etc., it may run real strong. A\u00a0simulation program will let you investigate all these trade offs.<\/p>\n

\"Engine
Engine Analyzer Pro graphs of intake tuning pressures at intake valve closing<\/figcaption><\/figure>\n

 <\/p>\n

2) Where is the port velocity highest? This is called “port mapping” and
\nuses velocity probes<\/a> to construct a map of high and low velocity areas.
\nThere is little universal agreement about how a port map should look. But
\nif the port maps are different between a good and bad head, it gives you
\ninsight on where to look. Pitot tubes are the standard method, but are
\nquite large and bulky for measuring intake flow, where they must have a 180
\ndeg bend so the tip faces the incoming flow. They are hard to get into
\ntight spaces, or into small or short ports. We have our Mini Intake tubes,
\nwhich are better, but still relatively large. This year we have developed
\nour Electronic Velocity Probe<\/a> which are MUCH smaller and a big leap forward
\nin technology.<\/p>\n

\"Port
Port Velocity probes<\/figcaption><\/figure>\n

 <\/p>\n

\"Velocity
Velocity Probing an Intake Port<\/figcaption><\/figure>\n

 <\/p>\n

3) Are we using all of the valve to allow flow, or is all the flow going
\nthrough just the back half of the valve? To know this, you need to measure
\nflow velocity around the entire edge of the valve. Ideally you will see
\nabout the same velocity around all 360 degrees of the valve’s head. If you
\nfind low velocity areas, that tells you you could better use the entire
\nvalve flow area if you got more flow into that area. The Plus version of
\nthe Electronic Velocity Probe<\/a> lets you mount just the tip close to the edge
\nof your valve. You can now rotate the valve at a particular lift and find
\n“lazy” low velocity areas.<\/p>\n

\"Valve
Valve Curtain Area Velocity Probe<\/figcaption><\/figure>\n

 <\/p>\n

\"Valve
Valve Curtain Area Flow Velocity Graph<\/figcaption><\/figure>\n

 <\/p>\n

4) What happens to the mixture once the air enters the chamber? These\u00a0measurements are called Swirl <\/a>and Tumble <\/a>measurements. Swirl is typically measured on 2 valve heads and Tumble on 4 valve\u00a0heads.<\/p>\n

\"In
In Cylinder Swirl Definition<\/figcaption><\/figure>\n

 <\/p>\n

\"In
In Cylinder Tumble Definition<\/figcaption><\/figure>\n

Again, every head porter has their own theories on what works on\u00a0their particular heads. However, on race motors it is clear you do NOT go\u00a0for maximum swirl or tumble. At high RPM there is so much motion due to
\nsquish and piston motion, that added motion tends to throw the fuel out on\u00a0the walls. Some engine builders will actually design for the minimum swirl.<\/p>\n

\"USB
USB Swirl Meter<\/a><\/figcaption><\/figure>\n

 <\/p>\n

\"Tumble
Tumble Fixture<\/a><\/figcaption><\/figure>\n","protected":false},"excerpt":{"rendered":"

Our Port\u00a0Flow Analyzer for flow bench testing has several features for making several measurements of cylinder head performance. \u00a0For head flow, pretty much anything that improves CFM flow improves the HP\u00a0potential of the head. But after measuring CFM, there are several other\u00a0measurements which can give better insight into one particular head runs\u00a0well on the dyno … <\/p>\n

Continue reading “Besides CFM Flow, what can you measure on a Flow Bench?”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[93,98,95,94,96,97],"_links":{"self":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/315"}],"collection":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=315"}],"version-history":[{"count":4,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/315\/revisions"}],"predecessor-version":[{"id":332,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/315\/revisions\/332"}],"wp:attachment":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=315"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=315"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=315"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}