[70 eliminator]

i am weldin up a alu rad core and adding tanks . its a single 1.5 inch core this should equal a 3 core coper brass i am wondering what the down side is to a double pass system it may make it eaisy to make coolers and such fit as well as clear my inter cooler i can make it conventional or double and cant see the downside .

i could route hor hose to upper section ans lower section would be getting better cooler air this might drop temp better but i am not sure of best fdesign ..

any heat exchanger gurus

[karnage]

Double pass should/will cool better.

[70 eliminator]

is this a general rule?? seems more makers would have used this

[70 eliminator]

so i need to check out thermodynamics books darn...

[Asimov]

Just because it makes more sense/power, car companies don't go in for "make the most power" they go in for "make it last till warrenty is up."

[Reeve]

I don't think a dual pass system will work as well. It will have twice the flow rate through the core and should not cool as well. Its just like an intercooler you get better cooling with runing two cores in paralell not inline.

[Hemi]

theoretically a double pass design will cool more effectively if areas and thicknesses are kept equal and the first pass is the rear of the radiator and the second pass is the front (where incoming air hits first).

[slcooper]

Reeve is correct I believe. The major heat transfer occurs when the temp gradient is greatest, ie in the region of the radiator where coolant enters. Adding a second section (double pass) just increases drag which slows down flow but is not efficient at heat transfer. Better to use the doubled surface area in parallel to reduce drag and increase heat transfer.

[Jon Dell Blair]

Quoted from: Stewart Components

Double pass radiators require 16x more pressure to flow the same volume of coolant through them, as compared to a single pass radiator. Triple pass radiators require 64x more pressure to maintain the same volume. Automotive water pumps are a centrifugal design, not positive displacement, so with a double pass radiator, the pressure is doubled and flow is reduced by approximately 33%. Modern radiator designs, using wide/thin cross sections tubes, seldom benefit from multiple pass configurations.

[70 eliminator]

rather than having a front\back config i intended to have the upper section be first pass on merk this is lower air flow area . the lower section would be higher flow area and would cool better . i remember most volkswagons are double pass but i also remember them using about 1\2" round tubes instead osf flat tubes :pat: i guess this helps with pressure :thumbup: . if i had a more modern impeller design i might try double pass . but to lower volume seems to be a bad idea . also big back pressure dosent appeal :eek:

i guess i will make it conventional!!

unless there are any more good arguments for going double??? :headscratch: