Questions on fabbing custom under cover

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robeats91t

237lbs. of Ballast
Jun 4, 2005
210
0
0
Tampa, FL
A couple years ago I lost my engine under cover on the highway, and ever since I've been thinking of a way to make a better than stock replacement. I've started on a replacement made out of 1/8" sheet aluminum that connects to the front bumper cover using the same bolt pattern as the front lip and runs back to the bulkhead directly in front of the radiator.

The problem with this design is that it is shaped all wrong...the profile of the panel under the car slopes downward going towards the back of the car, and does not promote airflow like I had hoped. (Attached is a pic to show this bad angle...weak PS skills FTL) Logic and my basic understanding of aerodynamics tell me that the panel in its current state promotes front end lift at high speeds, which I'd really like to change. Therefore I'm planning on welding up a duct that will stick out below the stock lip, so long as clearance won't be an issue.

My first question would be, has anyone done anything like this? I'd love to see pics/get tips from anyone that's done something similar.

Also, does the JDM/EDM lip have any vents in the center of the lip? I really don't care about a lip that has ducting anywhere but in the center...I'm just afraid that an effective under panel duct will be too low if it has to stick down below the stock lip to get any decent airflow.

And lastly, I wonder if anyone has any concerns with my material choice/mounting points. I was rather nervous about using a big aluminum panel underneath the car; I kept envisioning it ripping off at high speed and slicing and dicing every bit of Supra on its way out from underneath the car...but in testing it's held up well, and the front lip mounting is pretty solid. I was thinking of reinforcing the mounting with struts that attached to the front bumper support if necessary, but that may be overkill.

Anyways, any thoughts or ideas on this would be appreciated!
 

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inline6

Whistle>Whine
Sep 22, 2005
208
0
16
SoCal
I love the idea, Make it level to the ground by sloping it downward first then flat toward the rear, then add diffusers to create the low pressure zone under the car.

On a side note I got a mint stock undercover chillin in my backyard, makes me wanna put it back on.
 
CTsupra

CTsupra

Supramania Contributor
Mar 31, 2005
1,404
7
38
X: -8102600m Y: 5085800m Lat: 41:41:13N (41.6868
i believe shawndude, a member on both forums, at one point in time was fabbing up and testing a undercover design he came up with. it was rather elaborate if i remember correctly. i don't know if he scrapped the project, or what... try searching both forums for the thread/s.
 
R

robeats91t

237lbs. of Ballast
Jun 4, 2005
210
0
0
Tampa, FL
mrnickleye said:
You can still buy one from the dealer. It's about $150.
Click to expand...

Yeah, originally I just wanted to find a good used one, but shipping on an under cover would be simply rapacious. May as well just walk in to a stealership and buy a new one. Either way though, that's a lot of money; more than I can spend on an undercover.

I've only got about $20 and 2 hours invested in this thing so far, and that $20 covered enough sheet aluminum to make another one if I botch this one.

Plus what's the fun in just buying one that works? :icon_bigg

CtSupra said:
I believe shawndude, a member on both forums, at one point in time was fabbing up and testing a undercover design he came up with. It was rather elaborate if I remember correctly. I don't know if he scrapped the project, or what... try searching both forums for the thread/s.
Click to expand...

I remember reading ShawnDude's findings on the effect on airflow of the under cover; I'll have to research again and see if I can find info on his custom under cover.

Thanks for the info guys!
 
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