dimensioned drawing of front splitter/undertray?
 

So I am finishing up my build and my car did not come with an undertray which I realize will be a problem. I figure if I am going to have to make something, I might as well make it nice and have it be a bumper to rear of front subframe flatbody type panel, maybe have it extend past the bumper to act as a splitter. We get shipped a lot of sheet aluminum at work and have some suppliers who laser cut things for us so I am toying with the idea of slipping a new work order in there somewhere....

Anyone have a dimensioned drawing of a splitter or front underbody tray that would be easy to forward to one of my suppliers?

I realize this may be a far fetched request since most trays/splitters are DIY but figured it was worth a shot.

i think i still have a dwg file that i made from the dimensions of the TDR splitter. I made it into an undertray that should extend to the axles, but i guestimated on all that.

id have to dig it up.

If you get a chance to do that, I would really appreciate it.

BTW, you don't "have to make something." New undertrays are readily available from Mazda for about $60.

Now, if you "want to make something," more power to you.

Ok poor wording I guess. I shoudl have said "If I have to spend money on some sort of undertray, I would rather just go one step further and make it a splitter/flat underbody panel" and work has been slow lately so I am trying to keep myself busy haha

Also I figure with the quantities we buy in, I can prob get a really good deal from our laser cutter. I still need to price it out though.

Maybe you should turn it into a side business?

here:

I don't have dimensions. but it takes no more than 5 minutes. Unless you want to make the front have different radius and longer extensions on the sides.

If you make them cheap enough it could be a good item to sell. I made 3 at once. Knowing they have an unknown life span.

There's no way that goes to the axles and also clears the tires.

i forgot to attach the .dwg file. whoops.

i traced a TDR and made that. I removed the weird wings things and make it one radius.

the rest i guestimated, but one could easily clearance for the wheels.

So the DWG image it does clear the wheels? or are you saying you still had to remove some material to provide clearance?

Could you upload the actual DWG file to open in solidworks?

looks like it would clear the wheels, just won't reach the subframe.

Yeah that was my though. It either goes to just about the back of the radiator and clears the wheels or it goes to the axles like brain says and it'll be intersecting the tires by a couple inches.

So this being my first splitter design, I have limited knowledge so ill spitball some stuff for yall to confirm/deny.

obviously the longer it comes back the better, but i assume the shortest I would want would be AT LEAST to the back of the rad. Then I could add a second square/rectangle piece that joins up with the splitter to continue back any farther?

These are supposed to be relatively strong right? Like I can stand on it without it deforming type strong? We have 2.5mm stuff or for double the price (roughly) we have 5mm. it is slightly more than double because the 5mil stuff comes cladded for brazing, the 2.5 does not. anyone have an idea how thick I would want for 3003 h14 AL to be acceptably strong? I don't think manufacturing would be excited about me standing on/bending one of their sheets out on the shop floor ha.

I talked to purchasing and without disclosing actual pricing, it is pretty inexpensive for a whole sheet of 4x8 AL and I can buy in any size I want smaller than that. So if I can get a decent dim drawing (brains was missing radius dimensions and length it extends back) I can get a quote from one of our cutters/check with a friend who might be able to work this in the CNC for me at his work so this is still sounding cost effective ATM.

Edit: the 5mm comes in 1600x1050mm sheets (german based company.... so 3.44x5.3ft) the 2.5 comes in 4x8 sheet so maybe it would be better to just cut two and sandwich them and add some of that rubber covered metal U channel along the leading edge? assuming that is strong enough even. We pick up coolers that weigh hundreds of pounds using hooks through holes in extended endplates and they only slightly deform. Since I wouldn't be applying a point load like that on any of it, and it would be evenly distributed downforce from vacuum, I don't imagine it deforming any as a splitter.

How are you mounting it is the question.

I was thinking a couple turnbuckles out the mouth of the bumper to the tow hook area, a couple from the frame where the bumper little stabilizer rod things bolt (just that rough area) straight down and a couple bolts to the subframe. I noticed two little holes/tabs just behind the steering rack. If I extend much past there I would have to look for more mounting points, this was just a quick glance around while I was routing my IC piping.

the drawing in blue should look like this when cut out:

https://www.miataturbo.net/attachmen...ine=1378748685

Oh, I was assuming you would want to include the rectangle you drew in that extends from the edge of the splitter/wing shape down to where the corners hit the edges of the 4x4 sheet?

you've forced me to attach the crudest drawing i've ever done in my lifetime.



i didnt mean to attach that second pic, that was when i was figured out what size size I could cut it from. that was supossed to be the .dwg file itself :)

Prob still better than I could have managed. The red top left scribbling is what I was picturing. Looks like you were aiming to come wider than the pivot point of the lower control arm though? Would you not want to be within the width of the pivot location for when you droop on a dip/bump?

Brain: Looks like it is still a second sizing picture instead of a DWG

Just double checking, you never actually made a part from this file correct?

the aim would have been to use the exisiting undertray mounting holes and be within the pivot area.

I don't have a drawing, but I do have a coroplast undertray that you can use as a template to get the drawings... I use the existing undertray's mount points on the subframe and the bumper (ie just before the oil pan, and bolts directly to 5 bolt holes on the bumper).

Is bolting to the bumper structurally sound enough for a splitter? I was under the impression any deflection in the splitter would drastically reduce effectiveness. Granted This will be the only aero on my car so far so it may not matter much but if I am going to bother with it at all, I would like to know it has potential to do something. I have seen turnbuckles used before, is that overkill?

I would prefer the splitter be the rigid point to use to mount an airdam to, rather than use the bumper/airdam as a mount point for the splitter.

But I would like to come out and see what you have done just to see.
What part of Raleigh are you in?

definitely not structurally sound. Just saying that as a reference for length. I use it more as a smooth undertray (I also hold it in place from the top, but its not relevant to this). You would need to extend it for it to be splitter. Turn buckles are definitely a good idea I think.

I am in the brier creek area.

The bumper + turn buckles is ok, but will stretch your bumper skin a bit even if you keep it under 70mph

Wouldn't the turnbuckles be preventing any downward deflection?

Yeah near the turn buckles. My splitter even with the big braces still flexes down and scrapes the surface especially with the extra bumps and grip of the nebraska concrete.

What material is yours made from?

1/4 birch plywood. V2 wont have the bracing put will be 1/2" ply instead.

Seems like the Brain does not want to part with his .dwg file.

But if you have solidworks (or autocad if memory serves me), you can take the image Brain posted in Post #7 and add it to a sketch. Scale it correctly per the dimensions in the image. Create your new dimensioned sketch overtop of the image, just like Brain did initially. Then you can post your .dwg for everyone else.

Looks like scott just put a bunch of points along the picture and added a spline connecting the dots. You should be able to define a few arcs that are tangent to each other if you want an actual dimensioned drawing. Maybe the front arc, corner arc, side arc, make the part symmetric about the center, etc.

But yeah, for plywood, using a quickie spline would be more than adequate.

I actually drew a vector file in illustrator and exported the file as a dwg, then imported it into solidworks.

I have an ems in email if that works, forgot to upload the dwg last night.

I have CAD experience from my previous job but I don't have it on my computer at work, we have a design group that models all of our designs for us and I was trying to avoid "wasting" too much of their time for a personal project which is why I was hoping to just get a complete file to submit for a pricing quote. I will have to see if I can find a designer with a light work load/interest in cars that I can trade a ride in my car for some CAD work I guess.

Scott, I'll take whatever you have. It is a start at least

does this work?

the 'f' is .ems? Emachineshop proprietary file?

eMachineShop CAD Design File.

I think I was trying to use it on some site that would cut the ABS and ship it...this was YEARS ago. I just searched my mail and found it. I do have the DWG file at home, I just chose the wrong file it attach earlier here. I just need to remember to do it when I'm home.

although, you could do what Tim said, since it is to scale.

yeah that's what I'm doing now, because...well I don't know.

I will see if we can open an EMS file. And yeah I know I could, but "I" in this case means bugging a designer to do me a favor when I can just wait for the DWG file from you later. I am finally enjoying driving my car now, so I am not in a huge rush to start on a new project. Mostly just checking pricing and practicality of doing it this way for now.

If you remember to upload the DWG when you are home that would be great

See do something like this:

boobies.
https://www.miataturbo.net/attachmen...1&d=1378820425

https://www.miataturbo.net/attachmen...1&d=1378820425

Tim,

Care to upload the DWG file for the not boobies version? I can send that directly to the supplier to get a quote...so seriously no boobies because I don't have a way to open it myself to verify, I am trusting you...

bwahahaa ahhh god ok. let me see what I can add. I'll upload the .dwg soon.

you can email it to me if that is easier, Ill pm you my email

:bowrofl: This will me good. :party:

this is on my to do list. Damn that looks good. I need to read up on aerodynamic theory when I run out of misc miata projects.

If the cost is minimal to process a second, I would be interested rigid. Depends on how happy you made your CAD guy... probably should give him the boobies version to be safe in that regard.

the boobies make for a great place to stand for testing mounts.

I smell group buy, except I'm sure shipping would be cost prohibitive :bang:

So true.

I cannot upload/attach .dwg or .dxf. Brain?

Put it in a .rar or .zip.

yeah duh, ok. :bigtu:

If anyone makes one and there's a problem, or wants to let us know where the mounting holes should be or whatever, I can update the solidworks model.

Methinks the plotter here at the office will get a workout today. Hopfully I can print this 1:1 and use it as a template :party:

Thanks gays! :makeout:

Edit: LOL! Won't be printing that on one sheet...

hey now you can use this:

https://www.miataturbo.net/attachmen...tter_sheet-jpg

I guess it wouldnt matter for printing it as a template, but for my purposes I would need center points for the radius circles, and the wheel cut defined as well. I talked to a designer during lunch though and he seemed interested in helping so I will have him do that part for me.

Thanks a lot Tim this is a great start. And luckily I happen to have an Eassembly viewer so I could verify no boobies...

E02K if you print it out could you let us know about the location of the subframe holes just in front of the steering rack, those would be easy to add in to cut or punch and would hardly affect price. I will have to talk to the laser cutter but I would imagine they could cut a stack of material potentially at once reducing cost some. But I think the main cost will be material/shipping, not the actual cutting but I will get back to yall on that.

Edit: I guess if there is a potential interest in buying these, I should get some opinions. How far should we look to extend the leading edge, from what I understand this leading edge will be flush with the edge of the bumper correct? I talked to the designer about offsetting the radius bends and keeping them tangent but I figured 2 or 3 inches. would do yall think?

I need to screw with it in DraftSight until I can get it to fit on a single sheet. It's been probably a decade since I touched this stuff.

Timmeh: Thanks for the drawing!

Brain: Thanks for the alignment image, that helps. We have a 36" roll in there currently so the 4'x3' looks do-able.

Mr Bigglesworth: I'll let you know what I come up with. I have several huge sheets of coroplast in the barn from the last election, so I may be able to get out in front of this pretty easily. I just wish I had access to a lift.

4x3 JUSTTTTTTTTT fits. but that assumes you make only a 2-3" splitter. I forgot how far I made it extend.

I did this back in like 2007. That7guy bought a TDR splitter, I traced it crudely before he installed it and then I tried to transfer that to a digital file so it might be close but probably not perfect. I think I might have gone out and taken a few of my own measurements to get it closer; I honestly dont remember.

Oh this is already extended? I can just get them to make me a PDF drawing and ill get it submitted for a quote.

EDIT: Tim: can I get the actual model file? then we can pull center point dims for the radius and get some dims for the wheel cutout area.

You can get everything you need off the .dwg or .dxf in the .zip file above, using any number of free 2D cad or cam softwares.

The wheel cutout areas I did as 1/4 of an ellipse because that was faster, matched scott's profile, and I have real work to do today. So...yeah, there is no arc centerpoint or radius dimension for that.

Any CNC software can take either the .dwg or .dxf profile and make some code, regardless of the shapes or dimensions on your paper. Does your guy type out the program manually? :dunno:

No I was just talking with the designer and we both figured we would need those dims. The way we typically submit parts for quotes is with PDF of a fully dimensioned drawing. If they are just taking our PDF and making a DWG file, I guess I can save them a step by sending them the DWG file. I guess we don't do that so that our files stay ours, and theirs stay theirs? I dunno. Big companies with red tape...

I wasn't quite sure how that process worked.

So I found out my friend has access to a CNC at his work, so I am having him cut me out that DWG in some coroplast for me to test clearance of wheels and locate the subframe mounting holes. I will share my findings with yall so we can update the DWG if needed for anyone else who wants to print it out in the future.

Coroplast is a good choice, it should be lighter and stiffer than the aluminum sheet the OP was talking about. Wait you are the op.

Ha yeah thats me...

You think the coroplast will be stronger than AL? I didnt expect it to work very well as a splitter, maybe as an undertray?

I planned on doubling the 2.5AL material by riveting it together/sandwiching it with some adhesive