In reply to Patientzero :
Thats inspiring. Nice work
In reply to Patientzero :
Thats inspiring. Nice work
In reply to Patientzero :
Yeah, dude. That splitter is boss.
Just priced out some 1/2" birch...and I got an event on the 21st...hmm
yep, 1/2" birch works wonders. All you really want to do is prevent water from soaking the bare plywood. Do at least use deck stain. (literally, any paint will also work) or, if your mad and you jump a lot of curbs just cut a second one and carry on.
For those adding layers, birch is already multi-layer adding another would just make it heavier. you know, overkill.
Anybody ever use 3/8 pvc board for this?
In reply to wvumtnbkr :
we played with it. wound up being heavy and it really didn't like sunlight. Grew more than expected.
Johnny_at_NineLives said:In reply to wvumtnbkr :
we played with it. wound up being heavy and it really didn't like sunlight. Grew more than expected.
Thank you! I already have some, so I might try it.
I will keep an eye on it to make sure it doesn't tear anything up when it grows!
I didn't realize this thread was still alive :)
I ended up with this as my splitter:
Which looks like this installed:
Can you explain how that mounts?
Is it able to "pivot"?
Thanks!
How far off the ground should a splitter be to be effective? Car in question is a 2nd gen rx7 with fairly light springs (500 front, 300 rear).
Thanks!
morello159 said:Carbon said:Keith Tanner said:I use aluminum :) I also add a "NOT A STEP" sticker because it is not designed for that sort of point load. It's lasted for years. I did spectacularly mow some weeds with it a few years back, the sharp leading edge of the aluminum cuts them nicely and will actually launch them over the roof.
What thickness al did you use if you dont mind me asking?
Also interested in what aluminum was used, as I have access to a water jet and also need a front splitter...
So I never answered this. The answer is "I don't remember". It's not terribly thick aluminum but I don't know what grade. Highly unlikely it was 6061. I'll see if I can measure the gauge next time I'm in the shop. I have a bunch of pics of the build, I'l see if I can dig them up too.
wvumtnbkr said:Can you explain how that mounts?
Is it able to "pivot"?
Thanks!
Assuming this is directed to me, I was suprised to see that they're quick connect.. I didn't realize it when I bought 'em!
They don't pivot, when locked in, but they do to be removed. See my thread on my install to see 9 lives racing videos about it that shows it off.
In reply to wvumtnbkr :
Doesnt have to be on the ground...air flowing under it is what really makes them work (so ive read)
I was considering a water based bedliner.
Am I ridiculous?
It should last forever if you just stay in the lead all the time.
Or WAY behind the pack?
I built one for our EG civic racer,added tunnels or the 1st time.
BMW E46 Splitter and Air Dam, Part 1
I thought I’d share the detachable wood splitter I made for my E46 built for NASA Time Trial racing. This post was originally on another forum and has a lot more detail than is probably necessary for this crowd. None-the-less, here goes…
My concept uses three points to attach the splitter assembly to the chassis- The leading edge of the OEM aluminum undertray and the two frame spar/bumper mounts. The rear mount is a simple piece of ½”x.120 U-channel that was cut to length and had three holes drilled to line up with the OEM plastic undertray screw holes. I counterbored the bolt heads so no hardware protrudes. This gives me a deep slot for the splitter’s rear edge to slide into and align laterally on the bolt heads.
For the splitter template I used a large sheet of cardboard I saved from the carbon hood packaging. I slipped it into the U-channel and supported the front with jack stands.
I then used a 4” machinists square to transfer the vertical outline of the bumper on to the cardboard. NASA TT5 rules require a splitter that protrudes no farther than 4” from the vertical projection of the OEM bumper. I cut the template oversize so I could make the final marks and cut once the splitter was mounted and the air dam was in place. I then transferred the template to a sheet of ½” birch plywood and cut it out.
The front frame mounts are made from 1.25”x.125” aluminum structural tubing. I attached them to the outer bumper damper bolts on each frame spar. This spot is perfect because it is a straight down drop to the floor pan without getting in the way of the brake ducts, air filter, or headlights. To get my adjustment I slotted the holes ½” either side of level so I can make final splitter angle adjustments once the car is on the ground at race weight.
The front splitter mounts are made from a combination of aluminum square tubing and angles. The center piece is a 1.5”x.125” tube that slips over the 1.25” frame mount tubes. The inner and outer tubes are connected by a quick release pin that I’ll show later. I attached the center tube to the two sections of angle with an 8mm bolt. This arrangement allows some angle and position adjustment just in case it’s needed later. Final weight of each mount came out to just .65lb.
Connecting the two sides is another aluminum angle that spans the center of the splitter. This part provides a lot of strength and stiffness across the middle section. I had to notch the mounts and the stiffener so everything would continue to sit flat when bolted down.
A small notch was needed in the bottom rear edge of the bumper cover to clear the mounts. You can’t see this cut unless you’re under the car. I also had to notch the fender liner pieces too.
Here you can see how the splitter mounts are attached and put together using a quick release pin.
Every single time I see this thread title I think "Why would you need a machine that splits plywood into individual plies?"
Nice work, Rick. Looks well designed.
BMW E46 Splitter and Air Dam, Part 2
I want to be able to install and remove the splitter without taking the bumper off. This way I can load the car into my trailer easier with the splitter off and then take a couple minutes at the track to pop it back on. Plus I don’t have to give up any street driving ground clearance like I would with a permanently mounted splitter. With this in mind, a while ago I removed the front fog lights and filled the openings where the lights were with a thin sheet of plastic. The fog light bezels are made to remove from the outside very easily, and they happen to be big enough for me to fit my arm into when removed. This is how I install and remove the pins that hold the splitter in place.
With the splitter mounted and level I then traced the outline of the bumper directly to the wood surface using the same 4” square.
My splitter came out to 3.25” off the ground, which should be a good height for balancing performance potential and prevent bottoming out too much.
To fill the gap between the splitter and the bumper I am making and airdam out of .070” HDPE sheet. The airdam is mounted to the splitter surface with a length of .75” x .062” aluminum angle. I cut numerous slits into the angle so it could be shaped to follow the contour of the bumper outline. It is attached with #8 wide head wood screws. The part is made as two pieces so I formed and joined them in the middle with a rivet.
With the airdam mount in place I marked the splitter at 4” projection and trimmed the splitter to final shape.
The airdam material is soft and easy to cut but also very durable and lightweight. I carefully measured, cut, and riveted the HDPE sheet to the aluminum angle forming a perfect gap filling piece that stays permanently attached to the splitter.
With the fabrication finished I took everything apart and scrubbed the aluminum pieces with a red Scotch Brite pad and painted the splitter wood with truck bed liner to seal and protect it. You can also see the finished rear mounts and braces in these pictures. I am using two pieces of 3/16” aluminum that protrude from the back of the splitter. These slot into the U-channel bolted to the undertray providing a sturdy metal to metal junction. Braces were also added to connect the front mount angle brackets to the rear mounts. These braces added a lot of strength for their half pound weight penalty. Final weight of the splitter assembly is 15.5lb. If I change to ¼” Alumalite I should be able to drop another 3-4lb.
Before I reassembled the parts I traced the splitter outline onto the rest of my 4x8 sheet so I can cut and prepare a spare to keep in the trailer.
The underside of the splitter is perfectly flat other than a 1/16” lip and button head fasteners at the back edge. I used ¼” ribbed elevator bolts to attach the wood to the aluminum mounts. These have a very wide head that sucks up into the soft wood when you tighten the nuts down.
One last thing to show is the leading edge of the splitter. It is important to put a nice radius on this edge to reduce aero pitch sensitivity and help prevent catching on things in the paddock and on the track. Plus it just looks more finished.
Lastly, here are pictures of the finished product on the car. Looking mean! I am hoping for a 1-1.5 second improvement at High Plains Raceway due to the aero improvements.
In reply to Rick O'Shea :
From what I've been able to find out, about suitable materials for aerodynamic devices, is that alumilite is much like cardboard. It bends ,crushes, and folds and in doing so it isn't suited for the job. Also, you can't radius the edge well. So,in short, work with wood. Add ducts, fences, ramps, plates, dive planes, and vents until you've exhausted it's potential. Then replicate that splitter in aluminum or carbon fibre.
In reply to Patientzero :
Nice work on the splitter. Is there a cap on the edges, in the last photo it looks like a side cap?
In reply to ThemWitches :
It's rubber edge trim like this.
In reply to malibuguy :
Notice in the video he doesn't consider a possible increase in pressure on the top side of the splitter nor does he mention the benefit of much lower pressure on the bottom of the splitter or lever length to the front wheels. Also doesn't take into consideration changes to airflow over/under the vehicle due to adding the splitter. He just uses pressures he measured on a stock Insight and uses math to make up what he believes. No mention of changes in drag, which I'd think he'd be yapping about since he's all about "road" cars not race cars. Seems like the point of his video is "Buy my book" but offers no credibility other than "I write book and do videos".
You'll need to log in to post.
