I see a lot of people who upgrade the radiator and upgrade their fan, but I have a question. Don't all properly tuned cars run at the same tempature? I see guys that have a 400 dollar radiator and I question if that is something I need for my 2nd gen. Can an extra 400 dollars benefit my rx in a better way. I would expect that if you took off the factory fan which means intake modifications and upgrade the rad which changes the cooling characteristic that a TII or even N/A should be tuned for those changes. But like I said shouldn't a 120hp car and a 600hp car run at the same temps. So whats the need for a bigger rad, couldn't that mask a problems for a tuner.

BTW: No need for flamers or smart asses. Its just a question and would like feed back for gains.

 

Bigger HP engines generally generate more heat. More heat means a car needs more cooling capacity is needed. On a stock radiator there is x amount of cooling capacity. That number could be exceeded rather easily. Upgrading the radiator provides a lot more cooling capacity and is also more efficient and not to mention safer.

Its true all cars run at about the same temperature, this is regulated by the thermostat.

You really don't tune according to water temps since they fluctuate about 10-15 degrees and don't greatly affect performance.

The advantages of running an Efan have been covered many times, but basically its not performance based but rather room under the hood. Also, it allows you to adjust the temperature that it kicks on at.

Taking off the stock fan is pointless unless you have an accurate way of activating an Efan. Examples are a standalone with fan output, or a thermostatic control. You also must ensure the fan has a high enough rating for our car (

As long as your thermostat is functioning and your clutch fan is functioning, there is no need to change it.

 

What's been said above is true. The rotary makes a lot of heat, so it needs a lot of cooling.

Taking off the fan and not replacing it with an e-fan will improve airflow through the rad, but it'll overheat unless you're moving at a decent speed (no idling in traffic), so for a street car it's a really bad idea, only race cars can get away with it. The fan only will do anything when you're going slowly, after that it's a restriction to the airflow.

 

Well I just find it odd that changing a radiator size would not require tuning, just as intake, intercooler, and exhaust mods should.

But I do understand what you are saying papiogxl

 

It doesn't require tuning because a properly functioning thermostat compensates for it. The thermostat( from here on refered to as T-stat) opens at a set temperature. When the coolant reaches this temperature the T-stat opens and allows it to flow to the radiator. Once it is cool it starts to close until finally it is closed and it is circulating only in the engine again. As you drive this is constantly happening to keep the engine at a constant temp. With a rad. with more cooling capacity the T-stat may not stay open as long thus still maintaining the proper temp. As long as your T-stat is good you don't have to do any tuning. There comes a point when during continuous hard/high rpm driving when even with the T-stat staying open all the time the stock rad. can't keep the car cool. At this point a radiator with more cooling capacity becomes necesary.

 

Thanks. Now I understand.

 

Yes, but the more power the engine makes, the more waste heat it generates. For your average 4-stroke piston engine only about a quarter of the heat energy released during combustion reaches the flywheel as motive power. About a third goes out the cooling system, another third goes out the exhaust and the rest leaves the engine as radiation. For rotaries it's a little less at the flywheel and a little more waste heat. So the more power you make, the more waste heat the cooling system needs to reject to keep the engine's temp they same. The thermostat regulates how much heat is rejected so that the temp stays within a narrow range.

That's not quite how it works. The thermostat is not an open/shut valve, it gradually opens over a 20degF range (180-200degF for the stock one), so that the hotter the engine gets the faster the coolant flows. In steady-state conditions the thermostat will settle at a particular opening to suit the engine's current output. Even at low loads the thermostat never fully closes until the engine is shut off and allowed to cool.

 

I was aware that it didn't open all at once and probably should have phrased it a little better. I wasn't aware that it didn't fully close until the car was shut off and allowed to cool off. When I think about it it makes sense though.

 

You don't need to upgrade your radiator unless you upgrade your power; it won't run any cooler b/c your thermostat will bypass the radiator when your coolant gets too cool.

When your car is moving it doesn't use the fan. The fan is there for when your car is stopped. The best flowing electric fan "upgrades" move less air than the stock fan, but work well enough to cool a stopped car and are cheaper than a new fan clutch. Lower flowing e-fans cause problems at stop lights and in traffic.