{"id":12831,"date":"2012-05-19T14:37:21","date_gmt":"2012-05-19T19:37:21","guid":{"rendered":"http:\/\/caddyinfo.com\/wordpress\/?p=12831"},"modified":"2012-05-21T19:10:27","modified_gmt":"2012-05-22T00:10:27","slug":"intercooler-hx-testing-changes-in-ambient-temp-vs-iat2","status":"publish","type":"post","link":"http:\/\/www.caddyinfo.com\/wordpress\/intercooler-hx-testing-changes-in-ambient-temp-vs-iat2\/","title":{"rendered":"Intercooler HX Testing: Changes in Ambient Temp vs IAT2"},"content":{"rendered":"

In a water to air heat exchanger cooling system as used on the Cadillac STS-V and CTS-V, ambient air coming into the front of the Cadillac is used to cool the intercooler coolant.\u00a0 The coolant is then pumped through the actual intercooler to cool the air charge entering the manifold.\u00a0 Intuitively we expect changes in ambient air to change the equilibrium point of the intercooler cooling system.\u00a0 This is because the colder the ambient air over the heat exchanger, the better the heat exchanger works and so the lower the expected intercooler temps will be.\u00a0 Today’s test explores to what degree ambient temp changes impact IAT2s.<\/p>\n

The test today and the prior data shown are both for the current intercooler setup:\u00a0 Updated intercooler hoses, retest hot S3TC heat exchanger<\/a><\/p>\n

OEM Heat Exchanger + S3TC additional heat exchanger and hoses.\u00a0 Fluid capacity ~4.6 quarts.<\/p>\n

I experimented with the Mityvac system and repulled a vacuum on the intercooler coolant, pulling coolant along with the vacuum, and refilled it.\u00a0 But the hardware is unchanged.\u00a0 The test is a 20 minute loop at highway speeds, with one or more acceleration runs along the way to demonstrate intercooler heat up and cool down times.\u00a0 These show as spikes on the graph.<\/p>\n

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The graph shows IAT2 temps, which is the incoming air temperature after the supercharger, on a prior test day that averaged 69F ambient temp, and today with 84F ambient temp, or 15F higher.\u00a0 There are 4 lines on this graph.\u00a0 The dark blue is IAT2 today, and the light blue is IAT1, or air coming into the engine intake, today.\u00a0 Dark red is IAT2 on the cooler day, and salmon (pink) is IAT1 on the cooler day.<\/p>\n

What the comparison appears to show is that when ambient temps are 15.3F warmer (avg 84.8F vs 69.5F), air coming into the engine (IAT1) is 15F warmer (avg 94.2F vs 79.2F), and air out of the intercooler is 11.2F warmer (avg 124.7F vs 113.5F).\u00a0 Knowing that ambient temps flow into the intake as IAT1 and on through the supercharger to become IAT2, we might have predicted that a 15F ambient delta would resolve to a 11.2F IAT2 delta.\u00a0 However, that’s why we test, to find out what happens.\u00a0 In general an increase of 1F ambient leads to 1F IAT2 leads to 0.8F IAT2.<\/p>\n

I also note that IAT1 averages 10F above ambient, and IAT2 tends to be 30-32F above IAT1<\/p>\n

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Same trend for this dataset of about 3 sec after acceleration starts to IAT2 begins to rise.<\/p>\n

Let’s think about that for a bit —<\/p>\n\n\n\n\n<\/colgroup>\n\n\n\n\n\n\n\n\n\n\n\n\n\n\n
Item<\/td>\nQty<\/td>\nUnits<\/td>\n<\/tr>\n
Pipe ID<\/td>\n0.75<\/td>\npipe diameter in inches<\/td>\n<\/tr>\n
System loop:<\/td>\n4.00<\/td>\nOEM HX To S3TC<\/td>\n<\/tr>\n
<\/td>\n4.00<\/td>\nS3TC to OEM hookup<\/td>\n<\/tr>\n
<\/td>\n2.00<\/td>\nwidth of OEM HX<\/td>\n<\/tr>\n
<\/td>\n2.17<\/td>\nWidth of S3TC HX<\/td>\n<\/tr>\n
<\/td>\n0.67<\/td>\nhose to factory pipe<\/td>\n<\/tr>\n
<\/td>\n2.50<\/td>\nFactory Piping<\/td>\n<\/tr>\n
<\/td>\n2.50<\/td>\nFactory Piping<\/td>\n<\/tr>\n
Total System Loop:<\/td>\n17.83<\/td>\nFeet long<\/td>\n<\/tr>\n
Obs Circuit<\/td>\n3.20<\/td>\nsec<\/td>\n<\/tr>\n
Result Velocity<\/td>\n5.6<\/td>\nfeet\/second<\/td>\n<\/tr>\n
GPM<\/td>\n7.7<\/td>\ngpm<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n

That if the coolant is doing a 3.2 sec loop through the system, and the system is ~18 feet long, then the fluid must be moving at 5.6 feet\/second, and that the pump must be putting out 7.7 gpm.\u00a0 The pump is rated at 8 gpm against no pressure, so that seems hard to believe. Intercooler cooling system pressure & flow<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"

In a water to air heat exchanger cooling system as used on the Cadillac STS-V and CTS-V, ambient air coming into the front of the Cadillac is used to cool the intercooler coolant.\u00a0 The coolant is then pumped through the … Continue reading →<\/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":[17,718,6],"tags":[],"class_list":["post-12831","post","type-post","status-publish","format-standard","hentry","category-mods","category-intercooler","category-site-info-news"],"_links":{"self":[{"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/posts\/12831","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/comments?post=12831"}],"version-history":[{"count":32,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/posts\/12831\/revisions"}],"predecessor-version":[{"id":12882,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/posts\/12831\/revisions\/12882"}],"wp:attachment":[{"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/media?parent=12831"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/categories?post=12831"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.caddyinfo.com\/wordpress\/wp-json\/wp\/v2\/tags?post=12831"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}