Rads Rows And Passes

MaxxxRacer · 11-17-2004, 02:36 PM

To be honest, Ive read way way way too much about rads and I still cant get a deffinite picture on what the rows and the passes are in heatercores and rads in general.. A quick google search didnt gain me much either... So I ask here..

What is meant by passes

What is meant by Rows..

psychofunk · 11-17-2004, 02:48 PM

Rows are refering to the flat tubes/channels (they are sometimes round but if I recall correctly for the rad you are using they are flat) that connect tank to tank in a rad.
Passes refers to how many times the water passes through the rows. So a single pass would be an I and a dual pass would be a U shape path. Or in the case of the round tube type rads that are sans tanks then the shape would be nununun (where the nu is connected, I could'nt figure a nice easy way to diagram it)

bobkoure · 11-17-2004, 02:50 PM

Got one to look at?
The fatter fins that the water passes through are "rows".
If the inlet and the outlet are one one end of the rad/core then the water comes in, goes through half the "rows" to the bottom tank, where it enters the other half the "rows" and flows to the tank with the outlet. That's two-pass - in, down, change direction, return, out.
If the inlet and outlet are attached to the header tanks at opposite ends, then the water comes in the inlet, goes into all the rows, travels to the other tank and exits through the outlet. That's single-pass - in, down, out.
The advantage for single pass is that it has less restriction to the water flow (twice as much cross-sectional area as a same-outside-dimension two-pass). Depending on your flow rate, this may or may not matter much. There's also an interplay between water flow rate and radiator effectiveness, but it's small (I just see slightly different numbers for the same radiator with different pumps, for instance) and I don't understand it that well...

MaxxxRacer · 11-17-2004, 02:58 PM

interesting.. so a tripple pass would be like an "S" shape... where the intake and exhaust for the water would be at oppostie ends...

And the thickness only deals with how wide the rows are correct?

Cathar · 11-17-2004, 03:26 PM

A "row" is like a slice of bread. Imagine that your slice of bread has, say, 12 tubes running along it, or "12 tubes all lined up in a row".

If you put two slices of bread together, you'd have a two-row core. If you put 3 slices of bread together, it'd be a 3-row core.

We'll assume a two-row core in the following example of "pass".

As described above, a single-pass core will have the water flowing down all 24 tubes (two slices of 12 tubes) from one end to the other in a single pass.

A two-pass core will have the water flow down 12 tubes, being 6 tubes on one half of the slice (row), multiplied by two slices (rows). Goes to the other end, gets mixed in a tank, and up the other 12 tubes. Inlet and outlet will therefore be at the same end.

A triple pass would be an S-shaped path. Goes in, down 8 tubes on one side, up the middle 8 tubes, then back down to the 8 tubes on the other side. Inlet and outlet would therefore be at opposite ends.

MaxxxRacer · 11-17-2004, 03:52 PM

Thanks cathar.. was hoping you would explain it..

Just a thought, but im sure ther are more ppl out here than me that dont know this.. possibly ph could make a sticky using cathars post to explain the rads... just a thought...

BillA · 11-17-2004, 05:11 PM

in the rad industry a row of tubes is also referred to as a 'core'
dual core being 2 rows, etc
just to add back a bit of confusion

properly speaking the 'core' is the entire assemblage of tubes and fins, prior to being fitted to the perforated header plates
re-coring a rad is replacing the tubes and fins only

MaxxxRacer · 11-17-2004, 05:53 PM

bill i saw that over at becooling before i asked this question.. so i actually new that one.. lol..

if u recore it, it seems like that is the entire bulk of the rad.. what woudl be the point of that... i would think it woudl be cheaper to just get a new rad... correct me if im wrong..

BillA · 11-22-2004, 09:18 AM

re-coring was common before labor costs exceeded the matl costs,
truck rads are still re-cored as the cost of the headers is quite high

Chew_Toy · 11-22-2004, 09:31 AM

Even for cars that have copper brass construction it is usually cheaper to recore. The newer almuminum radiators that are comon on late model cars it is cheaper to just replace that to fix. A couple months ago I had to replace rads in my 96 and 02 sevilles due to a little stupidness in the driveway and garage and found that there isnt even a cost effective way to replace just one plastic tank on a aluminum radiator.
A few years ago I switched from dual core rads in a couple cars to 4-core rads and there it was cheapest to buy the tanks and core seperately (most stock single/dual core tanks will only accept up to 3-core core usually) and have them assembled for me.

11-17-2004, 02:36 PM	#1
MaxxxRacer Cooling Savant Join Date: Sep 2004 Location: Los Angeles, Ca Posts: 310	Rads Rows And Passes To be honest, Ive read way way way too much about rads and I still cant get a deffinite picture on what the rows and the passes are in heatercores and rads in general.. A quick google search didnt gain me much either... So I ask here.. What is meant by passes What is meant by Rows.. __________________ Excuse me, I believe you have my stapler.

11-17-2004, 02:48 PM	#2
psychofunk Cooling Savant Join Date: Jan 2003 Location: Los Angeles Posts: 365	Rows are refering to the flat tubes/channels (they are sometimes round but if I recall correctly for the rad you are using they are flat) that connect tank to tank in a rad. Passes refers to how many times the water passes through the rows. So a single pass would be an I and a dual pass would be a U shape path. Or in the case of the round tube type rads that are sans tanks then the shape would be nununun (where the nu is connected, I could'nt figure a nice easy way to diagram it) Last edited by psychofunk; 11-17-2004 at 02:58 PM.

11-17-2004, 02:58 PM	#4
MaxxxRacer Cooling Savant Join Date: Sep 2004 Location: Los Angeles, Ca Posts: 310	interesting.. so a tripple pass would be like an "S" shape... where the intake and exhaust for the water would be at oppostie ends... And the thickness only deals with how wide the rows are correct? __________________ Excuse me, I believe you have my stapler.

11-17-2004, 03:52 PM	#6
MaxxxRacer Cooling Savant Join Date: Sep 2004 Location: Los Angeles, Ca Posts: 310	Thanks cathar.. was hoping you would explain it.. Just a thought, but im sure ther are more ppl out here than me that dont know this.. possibly ph could make a sticky using cathars post to explain the rads... just a thought... __________________ Excuse me, I believe you have my stapler.

11-17-2004, 05:53 PM	#8
MaxxxRacer Cooling Savant Join Date: Sep 2004 Location: Los Angeles, Ca Posts: 310	bill i saw that over at becooling before i asked this question.. so i actually new that one.. lol.. if u recore it, it seems like that is the entire bulk of the rad.. what woudl be the point of that... i would think it woudl be cheaper to just get a new rad... correct me if im wrong.. __________________ Excuse me, I believe you have my stapler.

11-17-2004, 02:50 PM	#3
bobkoure Cooling Savant Join Date: Feb 2003 Location: USA - Boston area Posts: 798	Got one to look at? The fatter fins that the water passes through are "rows". If the inlet and the outlet are one one end of the rad/core then the water comes in, goes through half the "rows" to the bottom tank, where it enters the other half the "rows" and flows to the tank with the outlet. That's two-pass - in, down, change direction, return, out. If the inlet and outlet are attached to the header tanks at opposite ends, then the water comes in the inlet, goes into all the rows, travels to the other tank and exits through the outlet. That's single-pass - in, down, out. The advantage for single pass is that it has less restriction to the water flow (twice as much cross-sectional area as a same-outside-dimension two-pass). Depending on your flow rate, this may or may not matter much. There's also an interplay between water flow rate and radiator effectiveness, but it's small (I just see slightly different numbers for the same radiator with different pumps, for instance) and I don't understand it that well...

11-17-2004, 03:26 PM	#5
Cathar Thermophile Join Date: Sep 2002 Location: Melbourne, Australia Posts: 2,538	A "row" is like a slice of bread. Imagine that your slice of bread has, say, 12 tubes running along it, or "12 tubes all lined up in a row". If you put two slices of bread together, you'd have a two-row core. If you put 3 slices of bread together, it'd be a 3-row core. We'll assume a two-row core in the following example of "pass". As described above, a single-pass core will have the water flowing down all 24 tubes (two slices of 12 tubes) from one end to the other in a single pass. A two-pass core will have the water flow down 12 tubes, being 6 tubes on one half of the slice (row), multiplied by two slices (rows). Goes to the other end, gets mixed in a tank, and up the other 12 tubes. Inlet and outlet will therefore be at the same end. A triple pass would be an S-shaped path. Goes in, down 8 tubes on one side, up the middle 8 tubes, then back down to the 8 tubes on the other side. Inlet and outlet would therefore be at opposite ends.

11-17-2004, 05:11 PM	#7
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	in the rad industry a row of tubes is also referred to as a 'core' dual core being 2 rows, etc just to add back a bit of confusion properly speaking the 'core' is the entire assemblage of tubes and fins, prior to being fitted to the perforated header plates re-coring a rad is replacing the tubes and fins only

11-22-2004, 09:18 AM	#9
BillA CoolingWorks Tech Guy Formerly "Unregistered" Join Date: Dec 2000 Location: Posts: 2,371.493,106 Posts: 4,440	re-coring was common before labor costs exceeded the matl costs, truck rads are still re-cored as the cost of the headers is quite high

11-22-2004, 09:31 AM	#10
Chew_Toy Cooling Savant Join Date: Apr 2004 Location: Wisconsin Posts: 120	Even for cars that have copper brass construction it is usually cheaper to recore. The newer almuminum radiators that are comon on late model cars it is cheaper to just replace that to fix. A couple months ago I had to replace rads in my 96 and 02 sevilles due to a little stupidness in the driveway and garage and found that there isnt even a cost effective way to replace just one plastic tank on a aluminum radiator. A few years ago I switched from dual core rads in a couple cars to 4-core rads and there it was cheapest to buy the tanks and core seperately (most stock single/dual core tanks will only accept up to 3-core core usually) and have them assembled for me.

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