All,

With the addition of my custom ic piping and begi #3 intercooler i was able to easily trim the splash guard for nice fitment but the mouth not so much as way too much had to be cut away and when in place blocked off the bottom 4 or so cooling rows for the intercooler.

The plan: The plan at this point is with some very thin gauge aluminum sheet metal to make the mouth where it originally mounts but to then to bend down underneath the intercooler and be mounted to the front mount holes of the splash shield.

The questions:

1. I assume that the mouth is just as important to cooling as the splash shield to direct airflow the best. Is this the case or should I not even bother with the mouth as is not that important?

2. Assuming I do go through with this should I try to not only build a mouth for the bottom but for the sides and top of the ic area as well? I would like to get away without doing the sides and top as there are less (easy or obvious) mounting positions for it and the sides will be even harder.

3. Searching fabricating miata mouths and similar searches did not land the answers I am looking for or to see others similar solutions so to anyone else who has experience in this so would you please comment or chime in with ideas or personal experience as that would be greatly appreciated?

If i do go through with this and to whatever capacity i do it, I plan on following up with pictures and such to help others in a similar situation as me in the future 😊

​​​​​​I thank everyone for their input in advance!

 

I have the same intercooler, is your car a NA or NB?

I wouldn't think the mouth is as important. Just as long as you have ducting to contain the pressure that hits the intercooler. Having the splash guard will help with this. Use some cardboard to mock up how you can keep it sealed around the edges of the mouth.

A quick search gave me these two threads.

https://www.miataturbo.net/race-prep...-setups-57670/

https://www.miataturbo.net/general-m...w-37262/page2/

 

It is a NA, begi 3 ic, and supermiata crossflow. Thankyou for the threads as you found what I couldn't. Im thinking (at least for now) to just go with the bottom to keep air from just hitting the ic and going straight underneath the car.

I also feel like (at this time with my current setup will be running 230ish whp) this should be sufficient as I went a little overkill with my cooling with the 949 crossflow and mt coolant rr. However, the car is retaining AC and that big ic blocking most of everything leads me to believe i atleast need to fab something up for the bottom. The car is not tracked only Street and light autox, live in PA. Thoughts?

 

You want to completely seal the mouth to the heat exchanger stack, bottom, top and sides. Heat exchangers work on pressure differential, not aerodynamics like I think you're imagining. You could put the radiator out in free air and it would actually cool better if you built a box to contain high pressure air from simply falling off the sides.

Take a look at my build thread for some ideas on how to do your ducting. Your biggest problem will be sealing the intercooler to the a/c condenser, without doing that air will simply bypass it. At the same time you do need to leave some air space in front so you get adequate flow to the rest of the radiator that isn't right in front of your intercooler. Rule of thumb is 1/4 to 1/3 duct opening per heat exchanger area.