Cool. I'll hit them up and see what they say.

It should be stronger correct?

I bet that they have at least a couple of sheets at a discount that have been damaged or scratched. That would be perfect for what you want, as you're going to be scratching and damaging them anyway, amiright?

Yess. And painting them.

I dunno, it could give a nice "living room feel" to the front of your car if you left them plain.

Any reason not to go up to 1/2"? Will the 1/4" be strong enough?

:giggle:

Hard mounted with a steel frame or a well-engineered aluminum frame (stick to steel if you'd prefer to be less OCD about load paths) is the way to go. I've had offs where I ended up in a small boulder field at WSIR, football sized rock took a small chunk out of the splitter. No damage to the frame or the rest of the splitter. Ran the car the rest of the day, went home and bondo-glassed the missing portion and good as new.

I think Moti performed the most unequivocal test of these splitter mounts when he went off into a loose dirt area and the whole front of the car "shoveled" in:

https://www.miataturbo.net/attachmen...ine=1459705771

No damage to the splitter or frame. He came back to the pits with a pile of dirt on the splitter, we all had a good laugh, and then he brushed it all off and ran the rest of the day.

Mind you, there are lots of examples out there of DIY solid splitter mounts that are not strong enough to survive big offs, and even for a well-designed splitter mount, there are some offs where for one factor or another the splitter just doesn't stand a chance, but yes in a nut shell solid mount is the way to go.

Using bamboo is like walking on the moon. You're the pioneer. You're pushing boundaries. I wouldn't pick a thickness until I saw them in person. My guess is that these will be much stronger and more resilient than even birch. If the 5 ply was 3/8", I'd guess that would work.

Sean's splitter was so well documented and easy to remove that I will probably just mimic that. The Z bracket with tabs. I'll have to dig back and see if there were any other supports.

I'm just tired of ripping off bits of my bumper when the GV lip gets ripped off lol.

Any data on "strength" of the sheet? vs "strength" of plywood sheet.

Sean's splitter :bigtu::bigtu::bigtu:

Strength and Durability

Thanks to its unique composition, bamboo is naturally designed for strength…

Unlike wood, bamboo has no rays or knots, allowing it to withstand more stress throughout the length of each stalk.
Bamboo’s sectional anatomy, both as a cane and on a microscopic fiber level, enhances its structural integrity.
The high silica content in bamboo fibers means the material cannot be digested by termites.
Bamboo contains different chemical extractives than hardwood, which make it better suited for gluing.

It's also supposed to have a higher strength to weight ratio than graphite.

I like the sound of it. I'm going to call them tomorrow and pick some brains. They seem somewhat knowledgable.

But I am seeing prices around $130-$150 for a 4x8. Unless I can pick it up for a lot less I might stick to birch. We'll see.

To me the big question is: how flexible is the sheet? I shot them an email this morning but you may get more info by phone. Then again, since this goes down the road of applications it was never originally intended for, you may not get a definitive enough answer without just buying it and getting it in your hands.

If its not horribly expensive I'll buy a sheet.

Current plan is to build a splitter using a frame like sean's, but only have the splitter extend to the front of the GV lip. More of an undertray. I don't have any rear aero so it will more be for protection and some air ducting. Then when I work on rear aero I can just unbolt the smaller one, and put on the bigger one. Or just build another frame and be able to swap small for the street, big for the track.

What's the best way to attach the splitter in the rear? Are the factory undertray mounting locations strong enough.

Those are 6mm holes, they could work, depends on how you design it and where the fulcrum is when pressure is applied to the front edge.

In my experience, those mounting points are strong enough for the aero loads but not strong enough for any kind of impact or off track incident. I lost a splitter that was mounted using those holes.

Cool. Waiting to see some pictures of how seans is mounted.

Here's how I did my last one:

https://www.miataturbo.net/race-prep...9/#post1061231

I don't think I have pics of it but on Sean's we did a similar thing in the rear to what JPreston did in the pic he linked to except we made a steel bracket that attached to the splitter and the bracket slotted above the front subframe lip instead of the splitter itself doing that. That allowed us to run the splitter lower than that point.

Jpreston's is an example of brackets sufficient for an undertray only - no extension forwards of the bumper. You don't need much in that situation. However, it would not hold up well in offs. Dip two off where there's a bit of a drop to the dirt or find yourself straddling big rumble strips.. anything that pressed up on the splitter against the car's weight, and the straps that serve as brackets will likely fold/compress. Although, his is a bit higher than we run ours, so in his situation you might hit the subframe first.. (BTDT)

True. I'll do cables like E suggested, or a much stronger rigid setup on my next attempt. That undertray definitely bottomed out and hit curbs a few times though, and it held up fine.

Thanks for the advice guys. Picked up a 4x8 of 1/2" birch, 8ft of square tube, and a gallon of kilz. I was going to just do an undertray but I don't want to have to do this twice.

Would a front splitter and no rear aero unbalance the car significantly? I plan to make it easily removable, so I could always give it a shot and take it off if its too much. More front grip sounds nice though.

Definitely. I ran my PTE air dam (with the above undertray) without the rear wing once and the car was damn near undriveable. A well-designed splitter would be even worse. You could make other setup changes to work around it but you really need something on the back for good balance.

Thats what I was worried about. Hmmm. Guess I'll just stick to an undertray. Don't think I will have time to sort rear aero out.

SuperMiatas run an airdam with an undertray and need a lexan rear spoiler to balance. To balance anything more than a very small splitter you need a wing.

Hmmm. Good to know. What would you consider a very small splitter. I won't be running an air dam, just a regular NA front end.

Maybe I'll start decent sized and bring my battery powered jigsaw to the track. Cut off splitter material until it balances :D

My GV lip + under tray and hood vent was balanced with a CoT wing at -2*.

https://www.miataturbo.net/attachmen...ine=1459801402

https://www.miataturbo.net/attachmen...ine=1459801402

Hmmm, I'm probably underestimating what a splitter will do for front aero. I'll read through the thread again.

For those thinking of bamboo, I considered it a year or so ago and found a local exotic hardwoods place and they had about 60 sheets of 1/4" stuff, I think it had 3 plys, definately not 5 ply. They basically wanted to give them away at $20 per 4x8 sheet, they had apparently been sitting for a long time because some rich guy ordered them but didn't get them exactly on the day he was promised, so cancelled on them and refused to pay. They weren't stored very well so they had some waviness.

Unfortunately, they were not stiff at all. They were pretty flimsy. This is just 1 data point though, it could have been because of weak glue or because the storage conditions, or many other factors. It was very pretty though!

If you look up stiffness values for bamboo, it should make a great material for a splitter, not sure why the stuff I found sucked. :dunno:

Edit: just remembered the stuff I found was horizontal layout. I think vertical would be more stiff.

That bamboo place got back to me saying their 5-ply stuff had been laid up incorrectly and was pretty flexible. They say the 1/4" stuff is "pretty rigid", so apparently 5ply =/= 1/4"

I'd still check it out. Ryan, you've seen the aluminum tray under the front end of my Catfish, right? It bolts to the front bodywork and then is connected under the steering rack with the two M6 nuts that are sitting there. Have you guys considered doing this for your cars, and then just making an edge splitter that extends from the front of the car?
https://www.miataturbo.net/attachmen...ine=1459825432


The big part stays under the bodywork, and the small splitter can be removed somewhat easily


https://www.miataturbo.net/attachmen...ine=1459825432

I was thinking about something like that. Couldnt come up with a great way to connect the plywood together off the top of my head.

I'd consider aluminum under the bodywork and wood/tegris/other for the splitter. It seems like you guys could come up with something removable in a couple of days, the way you work. :)

Did some more searching today in the name of science.

1/4" bamboo plywood can come in single ply, 3 ply, and 5 ply. I found out that 3/8" thickness is pretty rare.

Aside from that, it can come in a horizontal layout or vertical layout. Keep in mind the layup can also be optimized for being stiff along the length or the width, just like any plywood and also composites. Cool stuff, but it's pretty expensive right now and not many places have it.

I may be having deja vu but I'd swear you and I have had this conversation before.. you're just messing with me now aren't you? ;)

Aluminum isn't a popular splitter material. I'm a BIG fan of aluminum in general, but I don't like it for this application... You have to go way too thick (heavy) to get the rigidity you need.
0.125" thick (rough guess) aluminum at ~1.75 lbs per sq. ft. doesn't win any weight contests, and that's still not nearly rigid enough at that thickness to extend very far beyond the bumper without additional supports. I'm not doing the stand/bounce test on a 0.125" aluminum splitter edge...

Re: removable extension, I've thought about it before, but the answer has always come down to it just adds unnecessary weight. You have to overlap the two layers a considerable amount to get enough rigidity in the layer that extends outwards of the bumper, and all of that double-thickness is twice the weight of what you'd have had there if it was one piece. And again, now you need a substantial amount more support along the outer edge than you would've needed if it was all one continuous piece - we can run more than 6" of extension beyond the airdam without any support at all.

My current splitter transitions to half thickness in all the portion behind the bumper. At ~0.75 lbs per sq. ft. that is hard to beat without going composite.

How do you transition from 1/4 to bigger?

Not really 100% DIY since I bought the diffuser off a buddy but whatever.

Dollars spent: $180 (diffuser, paint, and splitter rods)
Hours spent: 20-25
How effective: 2
Materials used: Paint, l-brackets, u-bolts, windlace, edge trim, splitter rods, and diffuser
Tracks tested on: None but will be tested at Thunderhill this weekend
Race/TT class built for: Just HPDE, nothing serious yet

https://www.miataturbo.net/attachmen...ine=1461046999

Love the Lotus diffuser's look on the Miata. Had one on mine many moons ago. Good exhaust setup to make use of the existing center hole as well.

Thanks man, I'm pretty excited with how it turned out. We'll see how well it performs on the track this weekend.

only thing I don't like about the Lotus diffusers is their outer channels are pretty much worthless due to tire squirt contaminating the airflow.

What's tire squirt? As in the air that's being directed off the tires?

it is the turbulent air that is a result of the rotating tire moving through it. There is a way to fix it though, and that would be to add a fence to the outside edge of the channels that extends forward.

https://www.miataturbo.net/attachmen...ine=1461181744

A fence? What do you mean? Sorry for my lack of knowledge, I'm basically clueless when it comes to aero. I'm assuming I just make some sort of an extension on the outter sides to kind of block out the turbulence?

correct, extend the outside fin further downward and forward.

Right on, I'm assuming just riveting a sheet of aluminum should work fine?

yup

:bigtu:

just spotted on facebook
https://www.facebook.com/Backyardcivics/
https://www.miataturbo.net/attachmen...ine=1461307958

https://www.miataturbo.net/attachmen...ine=1461307958

https://www.miataturbo.net/attachmen...ine=1461307958

Wow that looks great, if only I had enough power to fully utilize all that down force.

Going to suck when you bend that up going 4 off.

That was my first thought. I try and build in a weak point for those occasions, and when I look again at that design, I think the weak point is the lower part attached to the splitter, where the round hole is. Just unbolt, apply a BFH, and it should straighten enough to work ok if not win a beauty contest.

Ouch that's a good point, I didn't even think about that.

needs more center/frontal support.

Almost finished my aero setup for this year! Should try it tomorrow to see if I need a center brace for the spoiler.



https://www.miataturbo.net/attachmen...ine=1461381117

https://www.miataturbo.net/attachmen...ine=1461381117

https://www.miataturbo.net/attachmen...ine=1461381117

https://www.miataturbo.net/attachmen...ine=1461381117

Took me a second to realize the garage door hinges weren't part of the spoiler, LOL.

That air dam looks nice, what'd you make it out of?
LOL same here

Couldn't find some localy or from sponsors, so got it from there :

Colored Plastic Rolls, 10 Ft.

Allstar 24" sheet plastic, which is wide enough for a Miata air dam. Comes in a roll. .070 is not quite stiff enough for air dams, use the .100. Google search, it's everywhere.

http://ecx.images-amazon.com/images/...L._SL1500_.jpg


https://www.miataturbo.net/attachmen...ine=1461593128