Did a search, found lots of undertrays that include a splitter and/or extend rearward of the axle. Thats not what Im looking for.

NASA TT rules state that:
And

My plastic undertray is a little worse for wear, not to mention a PITA to get off. Along with doing a radiator shroud to help with cooling, is it worth my time to bother with an undertray? I cant have a splitter nor canards to cut airflow in front of the wheels. So, my question becomes, is it worth the effort?

For reference, here is the Beatrush panel:


According to NASA rules, Id have to stop approximately where the first line of bolts are, just aft of that actually. A well thought out design could easily come under the control arms too I guess, right?

 

Mine stops right behind the first line of bolts and covers more of the wheel wells... but its also part of a splitter, so I have no idea how much effect the under tray would have by itself.

 

Bump, anyone? I picked up a big sheet of aluminum this weekend when I finished the cage, I just dont know if its worth the time spent fabricating the undertray...

 

I do not know how much downforce that one will generate compared to an all-out plywood splitter. I am guessing less, maybe a lot less. It should help with cooling (radiator flow).

 

I bought some aluminum from Lowes and made one almost identical to the Beatrush except it stops at the first two rear bolts. I made one in cardboard first, then cut the aluminum off the carboard template. Definitely made fitting it a lot easier.

 

i made mine similar to the beatrush and i feel the difference. i also know there is a positive effect as my mpg went up and my steering feels planted at 65mph+. i doubt you will feel a difference if its a foot shorter. its just not as ideal.

 

That one looks pretty good but I'm cheap and I'd make my own.

 

Does the one in the OP replace the plastic belly pan? Does it come with shrouding for the sides as well?

 

Really. Adding this to my list of things to do then.

 

Yes, the cooling is one reason I want at least something under there. Now granted, Im not running a turbo setup, but even so, Ill take any benefit I can get.

Yes. As far as shrouding, to what are you referring? Shrouding along the control arms? If so, yes, I would probably do something like that. My plastic undertray is pretty much shot.

Edit: This is getting pretty close, minus the splitter portion.
http://forum.miata.net/vb/showpost.p...&postcount=496

 

Subbing for win and fabrication pics when you get this going.
I think gdmorr is asking about the vertical portions of the belly pan, the parts we get to drill big *** holes in for IC tube. My guess is no on the Beatrush, I see no where for it to attach.

Rev9 sells this thing, check it out:
http://rev9autosport.com/nb/engine/b...nderpanel.html



Yeah, I see no sides. They would be pretty easy to build though

 

Are the sides actually necessary?

I'm tempted to just go buy a large sheet of aluminum, and copy their general design with tweaks to support my build (I'd just buy it from them direct if I could, but it's not possible with my IC setup)

 

---- it, Im gonna do it. Ill put it on my to-do list after I shake the car down in May. Next track day would be June, so I should be able to compare then.

 

This thread has inspired me. I'm waiting for election season to get into full swing so I can steal some coroplast

 

I've got an idea for potential splitter material-buy an office chair poly mat and cut to size-it's thin and somewhat flexible and not very expensive.

 

"somewhat flexible" is the exact opposite of what you want a splitter to be.

 

Thanks, I wasn't aware of that.

 

Yeah, I am referring to the sides that the IC piping would usually go through. I would think they are as beneficial as having the bottom.

Reason I ask is I want to know if I can use just my splitter and not worry about the "thermal suicide" by not having the oem piece in - which has sides.

 

It might be bad for a splitter, but would it be alright for a undertray? If Im thinking of the same stuff its also pretty heavy. What would be a better material. Al or plywood?

 

For an undertray? Aluminum.

For a splitter? Plywood as it will be much stiffer than a thin sheet of aluminum. For example, I am 170 lbs and can stand on my wood splitter no problem.