I have a koyo. I'll make you a deal. Drive the hills in the bay area. You know when its 100 F outside and you are climbing elevation for 3 miles. Let me know how hot your water temps are when your running your ac (hell even if you are not) by the time you get to the top of the hill.

 

My aftermarket temp sensor is also located on the flat frontal spot of the thermostat housing. From my observations, I've noticed about a 5F higher reading on my aftermarket gauge versus my PFC Commander reading. Keep in mind that the filler neck is one of the highest points in the engine, hence the slightly higher readings. Since the computer operates off of the stock sensor, I tend to give more weight to the readings I see on my Commander.

 

One of the biggest items everyone overlooks when talking radiators is the "bung" that collects between the fins.
It is a collection of dust, rubber from tires, pollen, small grains of dirt and sand, insect and plant parts, road grime, etc. It is pretty much glued on to the metal over time from heat. It's impossible to remove. Picking the large stuff out and keeping the fins straight helps, but it is a very small part of the overall equation.

The "bung" ruins the efficiency of the radiator over time. It is insidious and leads almost everyone down other paths when troubleshooting cooling issues. Almost every shade tree mechanic will diagnose the problem as a "clogged" radiator - on the inside. Even though you can still see through the fins they are no longer smooth enough to let air flow cleanly.

The OEM radiator is VERY efficient and light, and except for those damned plastic end tanks works exceptionally well.

 

Yay. Somebody finally got it right. A heat exchanger's primary principle for convective heat transfer is flowrate. So, yes, an aftermarket radiator, in most cases, will not yield any coolant temp decreases. However, more capacity will be beneficial to maintaining a pseudo-steady state temperature ... like during open track sessions.

OTOH, ducting is probably more important than any of the other mentioned concerns. The sides of the radiator are not nearly as efficient as the combined surface area of all the fins. Forcing the air through the radiator is the only way (within reason) to truly achieve significant coolant temp decreases.

Damon, with my Fluidyne running 13psi at Mineral Wells (~95F ambient), I came off my afternoon sessions pushing 117C. That's 242F ..... extremely hot. Once off boost and in a cooldown, the temps dropped quickly to the 100's. Needless to say, I need to duct my radiator and then .... I need a bigger intercooler.

 

I strongly suspect that you could de-"bung" a radiator with condenser coil cleaner... the stuff used on stationary A/C condensers. I've used it on condensers, but never on radiators, although I considered it one time. Only problem is that you might end up eating a hole in the radiator depending on how thin the metal is....anybody want to volunteer?

 

She-it! Granted I run stock boost but I have never, EVER spiked over 230. You should get a duct pronto, maybe that's the difference for me.

 

Looking at it that way doesn't apply. Boiling water, for example absorbs massive amounts of heat before rising above 212F. The situation really has no relation.

The cooling performance of a radiator depends mostly on the length of the piping, velocity of the flow, surface area of the cooling surfaces, inlet water temp, inlet air temp. In the fluidyne, the length of piping and cooling surfaces are larger. All other things being equal (hoses and flow speed), you can expect to get cooler water out the outlet. This will create both lower engine temps and heat removal capacity. I'm willing to bet anyone who didn't see a change changed something else.

Another way to look at it is to put in a water temp gauge, add an aftermarket radiator, and watch the operating and peak temperatures go down. Many have done it before and I'll be doing it shortly (have a temp gauge on the way, and I'll install a miata thermoswitch and later a Fluidyne and note the changes).

Dave

 

dgeesaman - I was already schooled by DamonB. Lesson learned for the day. Many things I didn't initially consider.

 

Ya I started typing it and finished it a long time later (busy day). The point had kinda disappeared

Dave