The plastic tray underneath the RX8..
 

I hit a pothole which I didn't see and the plastic try ripped off. Do I need to get it replaced? What was it for?

You need to replace it and it won't be cheap or easy. It's one peice with the inner fender wells. It is part of the cooling system in that it directs the air into the radiator.

There's a diy on this.

How much would it cost? :\

That must have been one hell of a pot hole....
:(

Mine flew off on the interstate. It was around 150 to replace.

I think the screws holding the tray on have a habit of working themselves loose,at least in my experience. Twice now I've had the dealer check them and the first time some were missing. Second time most of them were loose. I check them periodically and tighten them if needed.

The bottom tray ISN'T one piece with the inner fender well. I know, I've replaced them both after a semi-truck had a tire explode in front of me and damage my undercarriage.

It ain't cheap and it ain't real easy to replace. The snap-lock screws holding the thing in place are expensive too. I think it's something ridiculous like $3.50 a screw. It IS important as it vents air up through the radiator and helps to cool the entire engine cavity. This is important with rotary engines.

Stop by your Mazda Dealership and have the parts department give you a diagram of the parts, plus a price list. They can print one out for you. Keep us posted on your progress.....

Take pics if you have the opportunity.

try searching, been discussed several times before including posting the diagram picture

If you have ever had the front nose off the car it will be sinch to install the bottom tray. There are clips and a few screws.

The tray is for cooling and protecting the A/C condenser and radiator.

A bottom tray is way cheaper than a A/C condenser and radiator.

Those clips are real nice they pop in and are easy to get out once turned half a turn.

Yup, post #14 in the thread at the link below.
https://www.rx8club.com/showthread.p...ght=undercover

I had a similiar mishap with a truck tire recap. My front air dam, bottom plastic tray and one well wheel were broken off. I had a body shop do the repair and it ran about $600, mostly parts. I think the bottom tray was in the neighborhood of $150.

Tray and A/C
 

So I noticed the tray was loose (broke), could that explain why the A/C is not cooling?

No.

No, then what could be causing that problem then, it started a couple days ago. Should I be repaired the tray ASAP? And what could possibly cause the A/C to blow heat?
I should search that, perhaps i'll learn more about my car, and learn to repair it myself. :)

The tray is there to serve more than one purpose but it's primary function is protection. Your AC issues could be a few things, ranging from a pin hole in your condenser from a rock due to no tray, to a faulty HVAC control board. Search is your friend.

And here is the factory FSM:

M A Z D A

It is quite likely that the pothole that took out the tray, took out your AC Condensor. I would get it checked.

I looked at the club vendors and did not see anyone still selling an aluminium one. But, if interested, PM me for a guy in tampa that has one, with fasteners, that can be shipped.