Home Made Splitters/undertrays

[Neil]

HT have a few home made splitters in the build section

More info mate who is/what is "HT"???. I need help. 2 Build sections Motorsport and Projects, Overhauls and Build-ups.

Cheers

Neil.

[zebra]

Neil

Get under the Radical and take some photos

[Russman]

Would it make the car unbalanced at all having a front splitter with a factory rear wing?

Always easier to get rear end aero 'grip' than front aero 'grip'. Wings are easy by comparison to splitters.

[Neil]

Neil

Get under the Radical and take some photos

No need Zeb,,, I can tell you whats going on under the Radical and all other Sports/Prototypes.

The Radical has a flat floor which extends all the way back to the rear of the cabin and then it has a massive diffuser much like a DTM car.

The other type is a tunnel system which is basically a diffuser that starts at around the front axles and goes all the way back to the rear of the car. Not practical for sedans as the tunnels go either side of the driver so it's only good for centre seated sports cars.

I've been looking at making a splitter out of this stuff

http://www.alusign.com.au/

has anybody ever used it?

[Trex]

More info mate who is/what is "HT"???. I need help. 2 Build sections Motorsport and Projects, Overhauls and Build-ups.

Cheers

Neil.

Hard tuned

http://hardtuned.net/forums/index.php?showforum=389

But there is a f**kload of pictures/how-to's in google if you type 'home made splitters' some from people who actually race (why i mentioned HT)

You guys would know a lot more than myself. But i always thought splitters would only be good on fast tracks with high speed turns and having a low enough car, so it doesn't lift the front up?

And going on from your post Neil, would a splitter that went back further than the front bumper be better? or I'm guessing it would be a case of trial and error, and what type of bumper and other mods are used?

Edited August 2, 2014 by Stagea97

[ssxRicho]

I made mine out of marine ply (15mm), like Russ's its flat and goes back to the steering rack.

My understanding (not a professional) is the splitter works best when there is the greatest pressure difference under the car. So you need to block off as much of the front of the car as you can so air doesn't go under the car from through the front bar.

I also added a NACA duct on either side under the splitter for oil and intake cooling.

It will only work if it's solidly mounted to the car, if you can't stand on it (80-100kg) it's not going to me doing much.

[Neil]

What we all really need is a fully covered undercar,,,nice and flat leading into a big rear diffuser. That really can't be done,,,the exhaust being our major stumbling block. I just stuck my head under my GTS-T and the front splitter has to stop just before the dump pipe. You could make cutaways around it but what a pain in the arse that would be. It's also very impractical,,,you would lose all your jacking points and servicing/repairs/cleaning kitty litter out after an off at race meeting would be a bloody pain.

So lets forget about the front for a sec and see what else we can do,,,my thinking is one of our major problems is air getting stuffed around by everything under there and then it comes to a screaming halt at the rear bar. Now maybe we should look at making something that lets the air travel out the back more smoothly,,,yes a diffuser would be great but in the interim just smoothing out the air flow back there might help.

Cheers from the aero genius,,,NOT

Neil.

[34GeeTeeTee]

What we all really need is a fully covered undercar,,,nice and flat leading into a big rear diffuser. That really can't be done,,,the exhaust being our major stumbling block. I just stuck my head under my GTS-T and the front splitter has to stop just before the dump pipe. You could make cutaways around it but what a pain in the arse that would be. It's also very impractical,,,you would lose all your jacking points and servicing/repairs/cleaning kitty litter out after an off at race meeting would be a bloody pain.

So lets forget about the front for a sec and see what else we can do,,,my thinking is one of our major problems is air getting stuffed around by everything under there and then it comes to a screaming halt at the rear bar. Now maybe we should look at making something that lets the air travel out the back more smoothly,,,yes a diffuser would be great but in the interim just smoothing out the air flow back there might help.

Cheers from the aero genius,,,NOT

Neil.

Marine ply + Gate = Fire

[Russman]

What we all really need is a fully covered undercar,,,nice and flat leading into a big rear diffuser. That really can't be done,,,the exhaust being our major stumbling block. I just stuck my head under my GTS-T and the front splitter has to stop just before the dump pipe. You could make cutaways around it but what a pain in the arse that would be. It's also very impractical,,,you would lose all your jacking points and servicing/repairs/cleaning kitty litter out after an off at race meeting would be a bloody pain.

So lets forget about the front for a sec and see what else we can do,,,my thinking is one of our major problems is air getting stuffed around by everything under there and then it comes to a screaming halt at the rear bar. Now maybe we should look at making something that lets the air travel out the back more smoothly,,,yes a diffuser would be great but in the interim just smoothing out the air flow back there might help.

Cheers from the aero genius,,,NOT

Neil.

Yeah that's why not many people do it. Very fiddly making something so custom and vulnerable. Eliminating as much turbulence as possible is the answer...

[zebra]

At the beginning of this thread a guy pmd me some photos of his flat floor on a skyline.

I will let him post them if he chooses. But was a neat setup with cutouts for the exhaust

[Sir Lord Van Von Vader'ham]

I made mine out of marine ply (15mm), like Russ's its flat and goes back to the steering rack.

My understanding (not a professional) is the splitter works best when there is the greatest pressure difference under the car. So you need to block off as much of the front of the car as you can so air doesn't go under the car from through the front bar.

I also added a NACA duct on either side under the splitter for oil and intake cooling.

It will only work if it's solidly mounted to the car, if you can't stand on it (80-100kg) it's not going to me doing much.

as above.

I have used both alupanel and normal ply. the alupanel is about $120-150 a sheet, ply $50 a sheet. Ply takes a lot more abuse where as the alupanel is kind of like a knife if you go off track (which i do a lot ) and can dig into the ground and rip off. interestingly thats when i learned how much it was helping, in all but 2 or 3 corners a wakie after it came off my car started understeering a heap more, like a normal 31...

my splitter comes out about 80mm from the bar lip and goes back to the crossmember. it also helped a lot with cooling.

ive learnt alot from the aero section in here > http://www.timeattackforums.com/forums/

you still down the road andrew? your more than welcome to come have a popeep

[zebra]

Yeah I still in town

Shoot through your number and I'll give you a call.

[Dale FZ1]

My undertray also goes past the crossmember, as per James. It was conceived to assist solve cooling issues, and to date seems to have hit the mark.

The front end grip improvement is an added bonus, can only think that a decent splitter takes it up a notch or 3 depending on detail.

Composite board prices seem pretty steep down South, more like $80 in Qld.

[Pezhead]

Thought I might chime in on the discussion here. I've done a lot of fibreglass and carbon DIY so have some thoughts to add.

On the subject of strength, we need to remember that the down force created by the splitter is spread across the entire exposed area. So to say you need to be able to stand on it is a case of over-engineering. Total down force is spread across area to get Force Per Area e.g. PSI or kg/cm^2.

The lip I built for my car is only 3-4 layers of fibreglass and one layer of carbon. This was enough to structurally withstand a traffic cone hit at around 40kph. It only cracked and fractured it a bit. Easily repairable.

So I don't think you need to stand on something to test it. The PSI area of the shoe contact area well exceeds any down force you can get from air movement.

What you do need to consider is your mounting point structural integrity (e.g. material & strength).

Short explanation:

When choosing material choose for lightness and strength. If the material isn't strong enough at a pin-point load, reinforce it with other materials such as washers or metal plates layered into the construction.

Long Explanation/theoretical maths (All approximate guesses, so please don't take the maths and measurements too seriously):

Say you are bolting it to the car across 10 mounting screws. For the sake of ease, let's just assume that load is evenly distributed across those points (it won't be and must be considered). Let's also assume that the 10mm bolts are used so there is no real possibility of fastener failure either.

So say 200 kg of down force is spread across 10 points. Each point taking a 20kg load.

Now, a fastener with a 1 cm washer might have an area of 0.8 square centimeters. But you also have to remove the area of the hole for the screw from the material (m5 hole @ 0.25 sq/cm area). This leaves you with about 0.55 sq/cm of area in the material. So you are expecting the splitter material to withstand 36kg/cm² without pulling through the material.

If you increase the washer size to 2 cm the area increased 3.14 sq/cm (ala PI*R²). Now the area without the M5 size hole is 2.9 sq/cm and thus load over that area decreases to 6.9 kg/cm². So doubling the size of the washer, re-distributed the workload area over 5 times in this instance.

Load spread across the entire splitter will be the 200kg over the area of the splitter. If the splitter extends 10cm in front and 1.5m wide then the total surface area is about 1500 sq/cm. So the pressure load per sq/cm would be about 0.13kg/cm².

[r33_racer]

Here is a few pictures of the front bar off the race car. Its not a home made splitter(carbon fibre bar made by a local bloke), but it might help with how to mount the bar and splitter and make it quick release. 4 mounting spigots with some simple latches on the top two to hold it in. The bottom two just slide into the receiver tubes (welded to the bottom of the radius rod mounts) and bottom out.

Hopefully that might help with someone having a go at making/fitting something up.