# Koyo R1977 Radiator Installation



## lshadoff (Nov 26, 2002)

Yesterday I installed the radiator. It is designed to prevent overheating in high horsepower SR20-powered cars in extreme conditions such as track racing. A technical description by Mike Kojima is here.

It is double the thickness of the Nissan Motorsports radiator.









You can see the installation here.

Lew


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## James (Apr 29, 2002)

That thing is a monster! 

On the radiator fans, I think the models with air conditioning had two fans no? Are you going to install some slim fans on there?


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## lshadoff (Nov 26, 2002)

James said:


> That thing is a monster!
> 
> On the radiator fans, I think the models with air conditioning had two fans no? Are you going to install some slim fans on there?


The stock driver's side fan fits.









Lew


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## James (Apr 29, 2002)

So then that's a no for a fan for the other side?


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## lshadoff (Nov 26, 2002)

James said:


> So then that's a no for a fan for the other side?


It doesn't fit. It just barely fit with the Nissan Motorsports radiator. The turbo is in the way. The HotShot turbo kit has a bottom-mount turbo. Perhaps with a different configuration, the passenger side fan would fit.

I haven't read of any turbo SR20 B13 or B14 car using the stock fans. Everyone has used slim fans, either in front or behind the Koyo radiator. I was fully expecting to have to mount a fan in front of the radiator and had prepped it for mounting the passenger side fan in front. I tested the fans and found they would run backwards if the power and ground leads were swapped.

Lew


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## NotAnotherHonda (Aug 7, 2003)

hell yea lew....time for slim fans though


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## lshadoff (Nov 26, 2002)

NotAnotherHonda said:


> hell yea lew....time for slim fans though


Why? The stock fan should be more than adequate.

Lew


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## Johnny-wonk (Jan 28, 2003)

There are a few guys running stock fans with a T25 setup. On a B13 I think though. 

How are you liking the radiator so far? Mine will be here Wednesday. Do you feel any differenc from the motor running cooler?


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## lshadoff (Nov 26, 2002)

Johnny-wonk said:


> There are a few guys running stock fans with a T25 setup. On a B13 I think though.
> 
> How are you liking the radiator so far? Mine will be here Wednesday. Do you feel any differenc from the motor running cooler?


The engine doesn't run cooler, the temperature is controlled by the thermostat. If you want your engine to run cooler, get a lower temperature thermostat.

I never had an overheating problem in normal driving with the old radiator, only on the track. That is why I installed the radiator.

Lew


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## Johnny-wonk (Jan 28, 2003)

lshadoff said:


> The engine doesn't run cooler, the temperature is controlled by the thermostat. If you want your engine to run cooler, get a lower temperature thermostat.
> 
> I never had an overheating problem in normal driving with the old radiator, only on the track. That is why I installed the radiator.
> 
> Lew



They both help keep the car running cooler. But all the thermostat does is keep the car from heating up as fast. It wil still heat up to normal temps. The Koyo actually makes the car run cooler period when your in motion...


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## lshadoff (Nov 26, 2002)

Johnny-wonk said:


> They both help keep the car running cooler. But all the thermostat does is keep the car from heating up as fast. It wil still heat up to normal temps. The Koyo actually makes the car run cooler period when your in motion...


The thermostat keeps the engine at a constant temperature (that's the definition of a thermostat). The thermostat actually makes a car heat up faster because there is no circulation of coolant through the radiator when the thermostat is closed. When the coolant temperature approaches the thermostat set temperature, the thermostat opens, allowing coolant to flow through the radiator. The thermostat opens and closes, changing the flow through the radiator so that the coolant temperature stays constant. 

For example, if you are driving along and the temperature of the coolant falls below the thermostat set temperature, the thermostat closes, reducing the flow of coolant to the radiator. The coolant heats back up because of the reduced flow through the radiator. When it reaches the thermostat set temperature, the thermostat opens allowing more coolant through the radiator.

Check out How a Thermostat Works.

According to the temperature gauge in my car, it runs at the same temperature as it did before I installed the Koyo radiator.

Lew


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## Ninety-Nine SE-L (May 5, 2002)

Yes, the koyo is one schweet radiator, I got one on mine too:

















About the fans, if you have AC, you MUST have 2 fans. The koyo has mounting holes for the stock fans, but I ran into a clearence problem with the pass. fan. Even though I'm N/A, the clearence between my hotshot header and the Koyo was too small.

I was running only 1 stock fan for quite awhile and unless I was moving, I could not turn on my AC. Sitting still, my AC would blow hot air and my temp needle would go up, I almost overheated 2x. I finally raised the money for some slim fans. I mounted them as pushers just because I like to keep my engine bay as empty and simple as possible. I still need to make some shrouds for the fans tho b/c not all the air is going straight into the fins.

here's some other pix:
fans:








backside:


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## lshadoff (Nov 26, 2002)

That's good to know. I removed the AC from my car, so I don't think there will be a problem using one stock fan.

Lew


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## Johnny-wonk (Jan 28, 2003)

lshadoff said:


> The thermostat keeps the engine at a constant temperature (that's the definition of a thermostat). The thermostat actually makes a car heat up faster because there is no circulation of coolant through the radiator when the thermostat is closed. When the coolant temperature approaches the thermostat set temperature, the thermostat opens, allowing coolant to flow through the radiator. The thermostat opens and closes, changing the flow through the radiator so that the coolant temperature stays constant.
> 
> For example, if you are driving along and the temperature of the coolant falls below the thermostat set temperature, the thermostat closes, reducing the flow of coolant to the radiator. The coolant heats back up because of the reduced flow through the radiator. When it reaches the thermostat set temperature, the thermostat opens allowing more coolant through the radiator.
> 
> ...



So you have an aftermarket water temp gauge? or is it the stock one your refering to?

Also why does your radiator look so dented up? Did you buy it new from Koyo and it came like that?


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## lshadoff (Nov 26, 2002)

Johnny-wonk said:


> So you have an aftermarket water temp gauge? or is it the stock one your refering to?


It's the stock one.


Johnny-wonk said:


> Also why does your radiator look so dented up? Did you buy it new from Koyo and it came like that?


It was new in the factory box. I had to slide the fan against the radiator to get it in place. It was a close fit. In the process, it bent some of the fins.

Lew


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## Ninety-Nine SE-L (May 5, 2002)

yea, bent fins is something you really can't help, I got tons of bent fins on mine. I try to bend them back with a tiny screwdriver, but it never looks the same. The problem with not having fans in the back is that nothing is protecting the radiator. Whenever I'm working in the engine bay, there's a good chance at messing up the fins. 

In fact, I was tigntening a bolt one time and the ratchet came loose, my hand hit the fins hard. Not only did I bend a bunch of fins, but it sliced up my pinky bad. Little chunks of skin were still stuck in the fins as I grabbed some paper towels and packing tape for my hand


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## lshadoff (Nov 26, 2002)

There is a tool for fixing this, a Fin Straightener.

Lew


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## Johnny-wonk (Jan 28, 2003)

Lshadoff- get ant aftermarket water temp gauge and put your stock radiator back in, watch the temps, and then put the Koyo in and watch the temps. You will see the diffrence. The stock gauge doesnt move until the engine is way hot, or way cold. It sucks! Ive got a Nissport water adaptor and Autometer gauge on the way also. Cause I want to see the temp diffrence between my stock 2 core and the Koyo.

I see you guys have these fins that are bent. But what Im asking is did it come like that new? Cause ill be pretty pissed if my Brand new raiator has bent fins!


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## lshadoff (Nov 26, 2002)

Johnny-wonk said:


> Lshadoff- get ant aftermarket water temp gauge and put your stock radiator back in, watch the temps, and then put the Koyo in and watch the temps. You will see the diffrence. The stock gauge doesnt move until the engine is way hot, or way cold. It sucks! Ive got a Nissport water adaptor and Autometer gauge on the way also. Cause I want to see the temp diffrence between my stock 2 core and the Koyo.


In other words, you don't believe a word I wrote. Hm.



Johnny-wonk said:


> I see you guys have these fins that are bent. But what Im asking is did it come like that new? Cause ill be pretty pissed if my Brand new raiator has bent fins!


The radiator was new in an unopened factory carton and it looked new. The fins were protected by cardboard in the carton, they were straight, and the tank was shiny. The outlets were round with no dents. But in case you still don't know:

*THE FINS WERE STRAIGHT*

Lew


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## Ninety-Nine SE-L (May 5, 2002)

So, you're asking him to remove his koyo, reinstall the stocker, rebleed the system, take temps, reinstall the koyo, rebleed the system and take temps yet again?

If you don't know what the thermostat does, it prevents water from passing through the radiator when the car is cold, it regulates the temperature in the engine trying to keep it at a constant 'warm' temperature.

You don't want your temps to be under 180*F. The whole point of the cooling system is not just to cool the block as much as possible, but to keep the block at a constant temperature no matter what the conditions are. If the engine is too cold, carbon deposits will build up in the cylinder, if it's too hot, it hurts the integrity of the metals and fluids that make up the engine.

Without a thermostat, the engine temps would fluxuate too wildly. When you're at a red light your water temp would climb over 200*F, when you begin to move, the engine would suddenly cool to 150. This constant cooling and heating would eventually fatigue the metal structure very fast and lead to fracture/failure of the materials.

Think of it this way. Upgrading your radiator is like upgrading your brakes. The biggest, baddest brake setup will not slow your car any faster, the biggest, baddest radiator will not cool your car any better. On both of these, you will not see or feel any difference between their stock counterpart until you take the car to a roadcourse and make them do what they were designed to do.

My car sees plenty of track which makes my upgrades pay off.


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## Ninety-Nine SE-L (May 5, 2002)

oh, one thing to add. You have an NX2000. The stock radiator core on an NX2000 is significantly thicker than any stock SE-R radiator. Check out the difference:


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## Johnny-wonk (Jan 28, 2003)

lshadoff- I asked if the fins were strait when the radiator came new and this is how you replied: It was new in the factory box. I had to slide the fan against the radiator to get it in place. It was a close fit. In the process, it bent some of the fins. Did you mean to put a comma after "It was" in the first sentence? Or maybe did you mean to begin the sentence with they were, ...?

Where in there does it say that it didnt come new with the bent fins? If anything your first sentence led me to assume that it was INDEED dented when it came to you. I never *assume* anything. All you had to do was say no when it came new it wasnt dented like it is now. Strait to the point. 

As for the Radiator. Obviously if you have a stock temp gauge that basically reads Cold, warm and hot its not going to show a temp change. What I was saying about switching the radiators back out was only a hypothetical situation (No I didnt ask him to do it)...But if it didnt keep your water temps cooler (which in turn keeps the motor cooler) it wouldnt be an upgrade would it?

Ninety-Nine SE-L- Yeah I know that I have the 2 core radiator. Its significatly bigger than the SE-R Radiator for a good reason. We only have one opening in the front of the NX instead of the 2 the SE-R has. So the NX radiator being bigger is only better if its in an SE-R. On a road coarse the stock NX radiator isnt going to cut it.


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## lshadoff (Nov 26, 2002)

Johnny-wonk said:


> As for the Radiator. Obviously if you have a stock temp gauge that basically reads Cold, warm and hot its not going to show a temp change. What I was saying about switching the radiators back out was only a hypothetical situation (No I didnt ask him to do it)...But if it didnt keep your water temps cooler (which in turn keeps the motor cooler) it wouldnt be an upgrade would it?


Your temperature gauge must work differently from mine. When the coolant gets hot the needle goes up. When the coolant gets cooler, the needle goes down smoothly. It doesn't jump from off-scale cold to mid-scale, to hot. My gauge did not show one needle's width difference going from the Nissan Motorsports radiator to the Koyo radiator. Just as it didn't move one needle's width going from the stock radiator to the Nissan Motorsports radiator. That's because the thermostat regulates the coolant temperature.

When I had my car on the track with the stock radiator, the gauge gave me plenty of warning that it was getting hot. The gauge started to rise after about 5 laps at the Dallas Motorsports Ranch track. It rose slowly over two laps until it approached the red zone. I backed off, and it slowly returned to normal over four or five laps. That doesn't seem like your gauge behaves. Perhaps yours is faulty.

Lew


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## wes (Apr 30, 2002)

Johnny-wonk said:


> lshadoff- I asked if the fins were strait when the radiator came new and this is how you replied: It was new in the factory box. I had to slide the fan against the radiator to get it in place. It was a close fit. In the process, it bent some of the fins. Did you mean to put a comma after "It was" in the first sentence? Or maybe did you mean to begin the sentence with they were, ...?
> 
> Where in there does it say that it didnt come new with the bent fins? If anything your first sentence led me to assume that it was INDEED dented when it came to you. I never *assume* anything. All you had to do was say no when it came new it wasnt dented like it is now. Strait to the point.
> 
> ...



Lew's post mad eperfect sense to me. Anyway I have the KOYO and notied a HUGE difference in how long it takes the fans to come on. Under idle my stock fans would come on (196 degrees, GA16 motor) within 3 minutes. Now with the koyo it takes at least 15 minutes of the car idling with the hood closed for the fans to come on. I have the EBAY fans mounted as pushers and it cools the car down to 186 degrees within 10 seconds. The stockers took about 45 seconds to do teh same thing.


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