Hard evidence of underbelly pan cooling abilities?
 

I was just wondering if any one had any hard evidence of the underbelly pan really making a difference in temps. Can anyone explain how exactly it works. Any personal experiences or stories help too. Also, any one that has any experiences of the underbelly pan not making a difference speak up. I just want to see both sides of the arguement. Thanks for the time, Evan

The underpan "seals" against the bottom side of the radiator. It prevents air from shooting past the radiator and out the bottom of the car. It may also help aerodynamics. There is ZERO reason not to run one.

there isn't an argument because it's a simple subject. the radiator is tilted FORWARD at the top, therefor it NEEDS the underpan to force the air through it without the fans being on. if it's not there, you will still have some air flow through it, but not nearly as much. don't remove it.

in regards to evidence...I don't think its that difficult...with no underbelly air can escape around the radiator....

that's why you see threads about sealing and ducting the radiator so much...

as for hard evidence...

I think I posted in an old thread before my current rebuild with it off and on....nothing else changed....and there was a dramatic difference in coolant temps.

Why don't you take it off and see for yourself?


It doesn't take a rocket scientist to see that while Mazda took pain to remove ounces from various components, they purposely stuck a 10 lb piece of plastic under a car for some reason that you can't fathom?

And what is there to this "arguments"? It works or it doesn't, having an argument for or against doesn't do shit.

Do you even have an FD?

Just imagine without the underbelly pan when the air hits the radiator instead of going through it, it will just slide downwards off the radiator, hence radiator not getting air through it = chances of overheating, but with the underbelly pan on, the air will be trapped and will have no place to go other than through the radiator, hence it will cool down your water temps.

Aerodynamic wise, it lets the air flow under the car rather than upwards the engine bay and lifting the front end of the car.

i'm sure it helps quite a bit, but i've had my fd for 2 years and it's never once gotten hot enough to worry about without it. it didn't have one on it when i bought it. it's had a fmic for about a year and a half and it's never even seen 100*C

I've got the Greddy 2 row FMIC with the koyo radiator and cannot stop overheating. Underbelly pan on or off. Yes, I understand its usefulness with the stock radiator setup but with a FMIC it's near verticle so I wanted to see some other peoples opinions. I've searched and found people say how much of a MUST it is, but it seems like a fair share of people drive around without them and have no problems. What kind of temp difference have you guys seen?

Do I own an FD...hmmm, yes, but believe it or not I'm a normal person that doesn't know every little detail about it. I'm simply asking about this because there seemed to have been no answer other than word of mouth.

you have to work on your own ducting with a FMIC, this is a given. you need your fans to come on much sooner also.

Do people mod the stock underbelly pan if they are running an aftermarket front bumper? Do yourself a favor and replace the stock thermosensor with one from a miata

I would suspect other issues. I've been running a Greddy 2 row FMIC with Koyo for over 2 years and never had any problems with the underbelly on. My fans are set to kick on at 95c. Do you have a PFC? If so you might want to adjust your fans. If not, you might want to look into a PFC or manual fan switch.

i think your problem will be solved by when you duct (enclose) the entire thing...my friend ran that intercooler with a stock radiator...no overheating..

It's really simple to prove. Remove the undertray and drive around in hot weather. Report back with what you find...

Actually one of our club members down here drove around without it for a couple of days because it was inadvertently left off of the car. He noticed the difference immediately and he was very concerned, until he figured out what the problem was.


Petros

i run no underbelly w/ greddy fmic/koyo

200F all day long

That's probably b/c you've the fans set up to run constantly via PFC, right?

What other modifications do you have done to your car? I also have the Greddy FMIC and koyo, but along with the fan mod, I don't worry about engine threatening temps. Ducting your radiator, using that underbelly tray, and even a vented hood are all ways of combating high temps. Consider WI as well.

I've got the VIS "KS" hood, and 2 10" fans running always by switch. I'm getting a new set of stock fans, hopefully that will do the trick. Thanks for all the feedback and help everyone.

I run V-Mount and have no underbelly pan :p: but that's one of the benefits of a v-mount...

-DC

I need a new underbelly pan, the passenger side 'wing' i guess is the best way to call it, is missing.