Apoligies

 

[QUOTE]Originally posted by Nathan
[B] If you have a 160° thermostat, I do not care how big the radiator is, the engine water temp is not going to get below 160°. Now if the radiator is too small and cannot cool the water to 160° then you may need a larger radiator. The need for the larger radiator is based upon the demands of the cooling system. Simply installing a larger radiator will not make the stock car operate any better.

 

exactly teh

I am not saying it does not have its benefits. But keeping temps lower is NOT one of them

 

What is the point of having a radiator that holds more coolant than the engine cooling system requires? Wouldn't this be the most efficient volume, as there is only so much surface area that can be exposed to moving air? Am I missing something? I would think that a better design would use the same volume of coolant, but offer more surface area to incoming air so that it cools faster.

 

If keeping temps lower is NOT the radiators function please enlighten me as to what job is it supposed to do.

The thermostats job is to assist the motor to reach its opperating temp as quickly as possible & then maintain the lowest opperating range temp, it plays no part in maintaing escalating temps.

 

I remember my brother putting bag's of ice infront of his intake when he would dyno his car... hehehe

 

You have most certainly missed the point.

You state that there is only so much surface area that can be exposed to the moving air, but then say the better design would be to offer more surface area to incoming air.

That is exactly what the the upgraded radiator does, its a lot thicker & therefore offers more surface area. A consequence of this larger surface area is increased capacity

 

No, I mean more radiator/fin surface area per incoming air area than is currently available. Can't you increase the fin surface area without increasing the coolant volume? I agree that the upgraded radiator has more surface area since it is larger, but given relatively the same surface area exposed to incoming air, wouldn't it take longer to cool a larger volume of water?

 

Keeping to the stock radiators frontal area's size & thickness there is no way you can increase the fin area without decreasing the water area, afterall a radiator is only made up top & bottom tank & cooling core.
The larger the core area the greater the heat exchange.
Now you either make a phisically larger radiator or you keep to the stock diamensions & make it a lot thicker & given that there's not a lot of room under the hood of the modern motor vehicle thats the way its done.
Sure you have more coolant but this is where the thermostat comes into play in letting the motor reach its opperating temp in exactly the same time as the lesser amont of coolant that the stock system employs

 

And of course to get the most out of a 160 Thermostat, you need the computer to kick on the fan(s) earlier.

 

Increasing the fin area is not so important as increasing the contact area between water and air. The fins are there to disturb the coolant and cause more of it to come into contact with the air. Plus, I'm not so worried about the engine warming up cause I live in Florida. I just think that since the incoming air area is limited, you would want to limit the volume to an efficient amount so that the coolant cools faster. The water in the engine's cooling system can only absorb so much heat before it needs to be circulated or cycled with the radiator cooled water . As long as the radiator can hold the volume of coolant around the engine, the faster the cycle the cooler the engine. Assuming that the thermostat knows when to cycle.

 

Damn this sounds like a thermodynamics problem to me!

 

There is a lot of missunderstanding here

THE FIN IS THE CONTACT AREA FOR THE AIR, they are not there to disturb the coolant.

THE WATER NEVER COMES INTO CONTACT WITH THE AIR, the water goes through the tubes & heat is conducted out to the fins where the air cools the fins

The reason that radiator cores are made copper or more recently alluminium is because these elements are very good conducters of heat. For the very same reason pots & pans are made of alluminium or copper bottomed stainless steel.

THE THERMOSTAT DOES NOT HAVE TO ASSUME. It opens to let the coolant flow into the radiator when is reaches its opperating temp. In Florida it would be open all of the time after warm up. In the northen winters it may be closed the majority of the time

The only way the coolant can cool faster is by having a bigger heat exchange, not by having less coolant.

Any heavy duty internal combustion engine, weather it be in a race car, truck, or machinery will always have more coolant & a bigger heat exchanger than a light duty engine.

 

Yeah you are right there is a lot of misunderstanding here.

Quote from howstuffworks.com:

Radiator
A radiator is a type of heat exchanger. It is designed to transfer heat from the hot coolant that flows through it to the air blown through it by the fan.

Most modern cars use aluminum radiators. These radiators are made by brazing thin aluminum fins to flattened aluminum tubes. The coolant flows from the inlet to the outlet through many tubes mounted in a parallel arrangement. The fins conduct the heat from the tubes and transfer it to the air flowing through the radiator.

The tubes sometimes have a type of fin inserted into them called a turbulator, which increases the turbulence of the fluid flowing through the tubes. If the fluid flowed very smoothly through the tubes, only the fluid actually touching the tubes would be cooled directly. The amount of heat transferred to the tubes from the fluid running through them depends on the difference in temperature between the tube and the fluid touching it. So if the fluid that is in contact with the tube cools down quickly, less heat will be transferred. By creating turbulence inside the tube, all of the fluid mixes together, keeping the temperature of the fluid touching the tubes up so that more heat can be extracted, and all of the fluid inside the tube is used effectively.

So before you get all CAPS on me, do your homework first. There are two types of fins! I'm not saying that you need less coolant...you just need the right amount of coolant. I'm sure that the nissan engineers did their homework and found out what is the efficient amount of coolant. I never said that the thermostat assumes anything. Please reread my previous posts.

 

Really?

Dude, you're reading too much into my posts. It sounds like you need to start a thread titled "Who wants to argue?" I will let you have the last word cause I don't like where this is going.


I'm outta here.

 

I bought a Blitz aluminum radiator. Box is light (about 30-35lbs). We'll see how it fits when it is installed next month. Should I get the lower temp. thermo, to start flowing coolant sooner? I was not really concerned with lowering temp., more with just getting my FI to keep up with Houston 90-100 degree weather better...

 

why is it just for 6 speeds?

 

ARC has a nice radiator

$$$$$$$$$$$$$$$$$

 

I don't know for certain but I'll take a guess and say the 5AT has a transmission cooler built into the radiator assembly so removing the stock rad you'd lose the trans cooler as well.

 

Oh my, oh my...first of all, unless you're running forced induction or road racing your Z (which most of you aren't) you shouldn't even think about replacing the OEM radiator unless you want the bling factor of a polished piece. The OEM piece with the stock radiator should be more than capable of beating on your street car in 100 degree weather.

That being said, for those who actually might NEED a radiator upgrade, the radiator should have a larger coolant capacity, and preferably be made of or coated with somethinig that dissapates heat better than the OEM piece. The upgraded radiator won't keep the engine cooler, it will simply be more efficient. The increase in coolant should mean that it will take longer to boil over which is really important for track-cars that are at full throttle for many laps at a time in hot weather. Think about it, what is going to boil sooner on your stove, a quart of water in a smaller pot or a gallon of water in a larger pot. Mmmmmm, who wants pasta