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Keywords: radiator, OEM dimension, koyo radiator, race radiator

Okay guys, I know that some people have been searching for this info as well as me. So, here is what I found and compiled.

Koyo offers two upgrades for my cars (NX2000 and Classic). There are the big version and the race version. Most Koyo distributors that sell Koyo radiators to typical parts stores or mechanics will not even have the part number for the race version on file.

The upgraded street version of Koyo is numbered: 1405 or C1405. I think other manufacturers also utilize the same part number. The number is pretty much standardized.
The dimension is

Core: 12_5/8 x 25_1/2 x 1_1/4
TH: 1_7/8 x 26_1/4
BH: 1_7/8 x 26_1/4
inlet/outlet: 1_3/8
Rows: 2

I have seen the radiator myself, and it is slightly beefier than my NX radiator. And it is made of aluminium. It came with all the necessary adaptors. direct drop-in. Places like Autotech By Beck sells it around 200+ dollars. (626-584-0522) Personally, I think it is a much better buy than the Nismo radiator because of the size and price.

Okay, and for the racers, there is a race version of Koyo radiator. As I mentioned earlier, it is not listed in the typical radiator database. This one is about 3 inch thick. Full aluminium construction. It is made in Indonesia. The part number is 1440-R. Places like Absolute Radiator or Intensed Motorsport sells it for about 350+shipping.

http://www.absoluteradiator.com/TheStore/scpages/KoyoGroupBuy.html is the cheapest price I found.

This is also a direct replacement.

Boonie

Originally posted by Booniewillow
Core: 12_5/8 x 25_1/2 x 1_1/4
TH: 1_7/8 x 26_1/4
BH: 1_7/8 x 26_1/4
inlet/outlet: 1_3/8
Rows: 2

Silly question, but what is TH and BH?

I could probably take pics of my Koyo Radiator installed in my NX later tonight. It's a direct-fit, double-row, and about 2" thick! I'm too lazy to take it off the car and take more detailed pics of it, though.

As promised, here are the pics of that big Koyo radiator in my NX.

http://www.imagestation.com/picture/sraid33/pbed45ed2a0fef8c2dffadfc1c722a342/fd3b8db7.jpg

http://www.imagestation.com/picture/sraid33/p7d7c6b52c547e6bd7ffcf0c6bc1b3ae2/fd3b8dad.jpg

http://www.imagestation.com/picture/sraid33/pba3f50fa621b16901f038c64704a92f5/fd3b8da0.jpg

Originally posted by Calum
Silly question, but what is TH and BH?

I think that is a very good question. I am not sure myself either. I think it is the TOP and BOTTOM dimension for the end headers/housings/reservoirs.

Boonie

PS: Thanks Andy for the pictures!

Originally posted by Booniewillow
Koyo offers two upgrades for my cars (NX2000 and Classic). There are the big version and the race version.

Is there any reason why this would not fit a b14? I would think it would but want to be sure.

Originally posted by 98sr20ve
Is there any reason why this would not fit a b14? I would think it would but want to be sure.

Yes... There is a reason... Because B14's suck!!! :D J/K! Seriously, though... Yes it should fit.

Is the Koyo thicker than the Nismo radiator? Is it better at cooling? I would get one if it is. I will move the Nismo to the Classic and put the Koyo on the race car.

Originally posted by nj1266
Is the Koyo thicker than the Nismo radiator? Is it better at cooling? I would get one if it is. I will move the Nismo to the Classic and put the Koyo on the race car.

Let's not forget that there are two versions of the Koyo radiator for our cars. There is one with plastic endtanks that is 1.25" thick as mentioned in Boonie's original post. Then there is the one that I have that is all-aluminium and is just a tad over 2" thick, and it's double-row. The Nissan Motorsports radiator, IIRC, is about 1 inch thick.

Originally posted by RollcageSR20
Let's not forget that there are two versions of the Koyo radiator for our cars. There is one with plastic endtanks that is 1.25" thick as mentioned in Boonie's original post. Then there is the one that I have that is all-aluminium and is just a tad over 2" thick, and it's double-row. The Nissan Motorsports radiator, IIRC, is about 1 inch thick.
Sorry, I was referring to the all aluminum race radiator. I will have to measure my Nismo radiator and see the thickness, if it is 1 inch, then I am getting the Koyo for sure. My race car can always use a bigger radiator.

BTW, Boonie thanks for all the info and thanks for the pics Andrew.

That looks awfully tight with just an NA header... what kind of clearance would you get with a turbo? Even with slimmer fans it still looks like it would be real tight

Nice information. Now I have at least one question. What does it all mean? I've compared the size of the Koyo with a Modine. The TH/BH of the Koyo is bigger. The Koyo is aluminum, the modine is not.

So, what does this all mean for how well a radiator will work? Does one set of numbers indicate how well the coolant flows? What determines heat dissipation? What advantages/disadvantages to using one type of metal over another?

My best guess is that the two radiators are very similar. The extra thickness helps keep the fluid cooler, while the rows and larger tubing help flow rate and heat dissipation. But... by how much?

Anyway, this has turned into too many questions. I have more, but I'll stop now.


Later,
Mark

Originally posted by RollcageSR20
Let's not forget that there are two versions of the Koyo radiator for our cars. There is one with plastic endtanks that is 1.25" thick as mentioned in Boonie's original post. Then there is the one that I have that is all-aluminium and is just a tad over 2" thick, and it's double-row. The Nissan Motorsports radiator, IIRC, is about 1 inch thick.

What is the part number for the one you have in the picture. Is that the race one or is it the other one. What is the difference between the 1405 or C1405 or are they the same. I want that one you have in your picture.

What determines heat dissipation?

surface area (more is better)
coefficient of heat of the exchanger material
temperature differential between hot and cold side (higher is better)
flow rate (more is better)


What advantages/disadvantages to using one type of metal over another?

See item 2 above. Also, cost of material and cost of forming said material.

Aaahhh, I knew Bruce would get to this eventually.

So, what determines flow rate, volume/channels? I understand the temperature differential, higher being better... I'm going to guess that the Aluminum does this better.

End question: Which serves the car better, then, the Koyo Aluminum or the Modine? Or, in other words, which does a better job for the engine or works better? Of course now I'm thinking that "works better" is relative... depends on what you want to do with it.

Oh well, just trying to get some ideas to help make a decision.

Thanks,
Mark

Flow rate will be determined by pressure drop across exchanger and motive pressure. I don't know either of these but they could be measured relatively easily with the proper equipment. Lots of people seem to be able to measure pressure drop across turbo intercoolers, so a radiator should be simple since they are both fin/tube heat exchangers.

Thermal conductivity of (pure) aluminum is 2.37 W/cm K (watts per centimeter ºKelvin), silver is 4.3, copper is 4 and gold is 3.2. Apparently copper is more expensive than aluminum and softer, too. Obviously, the same holds for gold and silver. Beryllium TC is 2 but it's pretty much used in alloying and high-temp applications; calcium TC matches Be but, of course, wouldn't make a suitable exchanger material since it dissolves in water. Tungsten is the only other element with a thermal conductivity higher than 1.5; I don't know what prevents its use as exchanger material. Scarcity? Hard to work, like titanium?

Andrew, why do you have only one fan? Clearence or no A/C or both?

Which one is pictured, the Big radiator, or the Racing version? Which do you think would be Ideal for turbo use, but still daily driven?

Item#: MO 2251

Price: $ 209.00
tax and shipping not included

Usually ships in 24 hours.


Attributes:
Attributes: Radiator
Make: Nissan
Core Size: 12 5/8'' x 25 1/2'' x 1 1/4'' (2 Row)
Inlet Header Size: 1 3/4'' x 26''
Outlet Header Size: 1 3/4'' x 26''
Inlet Connector Size: 1 1/8'' or 1 3/8'' Right
Outlet Connector Size: 1 1/8'' or 1 3/8'' Left
Type of Mount: Top and Bottom Pin
Oil Cooler: 7 3/4'' w/ Adaptors
Comments: Brass tanks/copper-brass core. Replaces OE w/ plastic tanks/aluminum core.

Modine Radiator

Core: 12 5/8 x 25 1/2 x 1 1/4(2 rows)
Inlet Header: 1 3/4 x 26
Outlet Header: 1 3/4 x 26
Inlet Conn: 1 1/8 or 1 3/8 right
Outlet Conn: 1 1/8 or 1 3/8 left

Don't know about an oil cooler or hose, tank is metal instead of the OEM plastic.

93Blackbird(Carlos), here in Tampa, is selling these for $188 plus shipping. Also comes with a Z radiator cap.

His thread is over in the "For Sale" section. If you have any questions, he's been answering quite a few.

Of course, despite the finding out how a radiator works(well, at least more information) and what makes a better radiator, I still don't have a definitive answer on which works better... the Koyo or the Modine... and why.

Later,
Mark