Corey's NB Journal

[Magpie]

I have similar splitter rods on mine, however they are only additional support not providing the main support. The mounting bolts used are quite small and it does not take much force to 'pull' them out. Make sure you use large fender washes on the base to spread the force out. However if the splitter is not producing any real downforce then it is not an issue where they are used.

My setup. I can put my full weight on the splitter with this setup.


All up there are 4 x Heim Rods (2 in the picture, 2 inside the wheel arches) as well as the 2 x smaller rods (not installed at the moment) as well as the mounting bracket in the middle. You can see the two VERY SMALL holes at the top of the splitter that are used for the smaller rods.

[Corey]

Any chance of an NA set in the works?
I'd be your first customer!

Sent from my GT-I9505 using Tapatalk

Yes definitely plans for an NA version, I'll get back to work

[Corey]

Are the splitter rods for show or function?

On my Integra, I've mounted them behind the bumper - holds the splitter and is not visible unless you look in the "mouth". There's also the added benefit of not getting in the way when I remove the bumper which is quick-release.

Good point, I'm a big fan of the splitter rods showing so might keep them out in front and i can take the splitter/bumper off as a whole if i put some simple strong bars holding it to the chassis then I can remove it easily.

I have similar splitter rods on mine, however they are only additional support not providing the main support. The mounting bolts used are quite small and it does not take much force to 'pull' them out. Make sure you use large fender washes on the base to spread the force out. However if the splitter is not producing any real downforce then it is not an issue where they are used.

My setup. I can put my full weight on the splitter with this setup.


All up there are 4 x Heim Rods (2 in the picture, 2 inside the wheel arches) as well as the 2 x smaller rods (not installed at the moment) as well as the mounting bracket in the middle. You can see the two VERY SMALL holes at the top of the splitter that are used for the smaller rods.

Yeah I had a look at your splitter set up at WTAC and was pretty impressed, it can take a beating too. I'm thinking of mocking something up in ply wood first and foremost as I don't have much faith in this TDR splitter being functional. I think if the ply wood goes well I can make something up out of Alumalite sheet. I'm planning to run some aluminium bar down from the chassis and bend it or attach it to a bar of aluminium that runs across the length of the splitter (similar to your main supports) to get better weight dispersion over the whole splitter and make it sturdy and then just having 2 front rods as well. Does your splitter also act as a flat floor at the front Magpie, and benefits in extending it so far?

[Magpie]

It can only extend back as far as the rules allow However the idea is that the flat part is to accelerate the air under the car, however to gain the most benefit you also need to have an air dam above the splitter. Hence making the 'mouth' as small as possible helps with downforce as a greater high pressure area can be created.

Another added benefit of my splitter is giving air from the engine bay an escape route. At the moment I have too much air passing around the radiator to get much effect, however soon I will be making a duct that should also allow the front mouth size to be reduced.

I still have to upload the photos of the damage to the splitter when I hit a bit of track debris at WTAC. No choice, under the car or run over it with a tyre, could not go left due to car turning in
I was very surprised at how little damage there was considering the impact. The CAS sensor failed on the next lap

[Corey]

It can only extend back as far as the rules allow However the idea is that the flat part is to accelerate the air under the car, however to gain the most benefit you also need to have an air dam above the splitter. Hence making the 'mouth' as small as possible helps with downforce as a greater high pressure area can be created.

Another added benefit of my splitter is giving air from the engine bay an escape route. At the moment I have too much air passing around the radiator to get much effect, however soon I will be making a duct that should also allow the front mouth size to be reduced.

I still have to upload the photos of the damage to the splitter when I hit a bit of track debris at WTAC. No choice, under the car or run over it with a tyre, could not go left due to car turning in
I was very surprised at how little damage there was considering the impact. The CAS sensor failed on the next lap

Ah right, for WTAC aero rules i assume? I will be leaving the mouth as big as possible, maybe even making a duct to flow more air into my radiator as my intercooler takes up most of the room in front when it gets installed. I'm going to do some experimenting when the weather clears up and notify you all how I go. Do you think sealing up the gap between the bottom of the bumper and splitter makes a big difference? Will look at doing that with some strips of foam too.

I remember you telling me about the damage but the splitter too it like a champ and didn't look like it really affected anything.


Heres some shots of the stock SE manifold that I ported with a rotary tool and some small grinding wheels. The stock manifold has a 2-3mm lip on the inside lip which I smoothed out.

How it used to look.



How it looks now.





I'm going to work on it a bit more and also perform some rust treatment to the inside using an electrolysis tank.

Heres my sad mx5 out in the rain because I don't have a garage for her..



I really need to get some slim plates.

[Magpie]

Yes the splitter is built to suit the rules of the class it runs in.

At least it has grip, imagine driving it in those conditions

[rascal]

I have similar splitter rods on mine, however they are only additional support not providing the main support.

My setup. I can put my full weight on the splitter with this setup.

I started off with splitter rods the same as Magpie's centre ones,

however ended up bending both of them over time as they provide no give.
Have changed to stainless cable supports, which works much better as provides some upwards flex, with the same downward strength.
I can also stand and bounce on my splitter..

[hks_kansei]

re: the electrolysis.

It works great, but bear in mind that once you're removed the rust via that method it will be a LOT faster to gather surface rust afterwards (the water bath removes any oils that remain, as well as any scale etc that may be helping keep the rust away)

also remember that you'll likely need to place a thin wire anode down each runner, since the electrolysis needs line of sight to work best.



I've also heard stuff about it encouraging hydrogen embrittlement to metals, but frankly know nothing about. (might be worth reading into since manifolds are already prone to cracks due to the massive heat cycling they deal with)

[Dan]

I started off with splitter rods the same as Magpie's centre ones,

however ended up bending both of them over time as they provide no give.
Have changed to stainless cable supports, which works much better as provides some upwards flex, with the same downward strength.
I can also stand and bounce on my splitter..

Yeh, practicality is a big thing to consider with splitters. Something to think about also is how important getting the nose down low is to generating downforce, reducing lift and reducing drag.

For a street dríven car I think a cheap polyurethane lip with a short 50mm splitter section already on it may allow you to go lower than you could with a conventional splitter which could then enable you to possibly generate similar downforce numbers to a splitter while also, reducing drag and keep the car more practical.

Hopefully I am ok to post these here, these are a couple of diagrams I took a photo of out of Competition Car Aerodynamics which compares different front aero changes made:
This is the effect of an airdam taking the front of the car from 200mm to 100mm at 180km/h. One thing you can see that aerodynamic drag reduces at a higher rate the lower the car gets while the downforce starts to plateau so something to keep in mind is that downforce returns start diminishing the lower the car gets:


This visually shows the change in downforce & drag:


Here is a diagram of the aero changes of various splitter lengths at 100mm ride height using the same model as the previous diagram. As you can see the splitter doesn’t really change the drag but improves downforce. Again the returns diminish so a short splitter section (50mm) on an off the shelf polyurethane lip may give you large a portion of the gain you get from a splitter without the disadvantage of impracticality (the increase in downforce from a 50-100mm lip is close to the change of the air dam from 100mm to 125mm):


This is a real world example after this of a GT2 specification Porsche 911 (997) tested in a a wind tunnel. The results correlate well and show a non-significant change in drag and as the splitter gets larger the gains in downforce also start diminishing (remember that this car is VERY close to the ground):

[Magpie]

That is a great book!

However when you get too close to the ground you actually LOOSE downforce hence the diminishing returns. In certain circumstances it can have catastrophic results.

How do you plan to check your downforce and or evaluate your design?

In the beginning I used a coast down tests to measure the drag coefficient of the car then did changes and re did the tests. They are accurate!

This gives a very basic method http://www.instructables.com/id/Measure-the-drag-coefficient-of-your-car/. Another site is http://www.iwilltry.org/b/how-to-measure-the-drag-coefficient-of-your-car/. For me I can use data logging for more accurate data.

One of the sites I use to help in the calculations http://ecomodder.com/forum/tool-aero-rolling-resistance.php

Some of my old test data, doing 3rd gear pulls with the wing at 0, 5 and 10 deg

Starting from 45.7kmh (2,900 rpm) after 9.09 sec
00 Deg 108.2 kmh (6,730 rpm)
05 Deg 107.9 kmh (6,600 rpm) - 108.2 kmh was acheived at 9.26 secs
10 Deg 104.8 kmh (6,490 rpm) - 108.2 kmh was acheived at 9.83 secs
Therefore it could be argued that the wing at 10 deg is about 1 sec slower going from 45 to 110.

Plan is to redo all the coast down tests when I can find a suitable road in my area. I can try out a combination of the splitters I have as well as the AOA in the wing and changing ride heights. However will also need to have the ride height sensors logged to make the analysis easier. No plan to get them into the Haltech just yet...

[Corey]

re: the electrolysis.

It works great, but bear in mind that once you're removed the rust via that method it will be a LOT faster to gather surface rust afterwards (the water bath removes any oils that remain, as well as any scale etc that may be helping keep the rust away)

also remember that you'll likely need to place a thin wire anode down each runner, since the electrolysis needs line of sight to work best.



I've also heard stuff about it encouraging hydrogen embrittlement to metals, but frankly know nothing about. (might be worth reading into since manifolds are already prone to cracks due to the massive heat cycling they deal with)

Interesting, so you would advise against it? Is there any way to re protect it from rusting?

I started off with splitter rods the same as Magpie's centre ones,

however ended up bending both of them over time as they provide no give.
Have changed to stainless cable supports, which works much better as provides some upwards flex, with the same downward strength.
I can also stand and bounce on my splitter..

You've got a good point, and if you ever scrape the front hard, the splitter would bend a bit and give the cables slack rather than possible damaging the rods.

Do you have a closer shot of your splitter cables I can look at?

Yeh, practicality is a big thing to consider with splitters. Something to think about also is how important getting the nose down low is to generating downforce, reducing lift and reducing drag.

For a street dríven car I think a cheap polyurethane lip with a short 50mm splitter section already on it may allow you to go lower than you could with a conventional splitter which could then enable you to possibly generate similar downforce numbers to a splitter while also, reducing drag and keep the car more practical.

Hopefully I am ok to post these here, these are a couple of diagrams I took a photo of out of Competition Car Aerodynamics which compares different front aero changes made:
This is the effect of an airdam taking the front of the car from 200mm to 100mm at 180km/h. One thing you can see that aerodynamic drag reduces at a higher rate the lower the car gets while the downforce starts to plateau so something to keep in mind is that downforce returns start diminishing the lower the car gets:


This visually shows the change in downforce & drag:


Here is a diagram of the aero changes of various splitter lengths at 100mm ride height using the same model as the previous diagram. As you can see the splitter doesn’t really change the drag but improves downforce. Again the returns diminish so a short splitter section (50mm) on an off the shelf polyurethane lip may give you large a portion of the gain you get from a splitter without the disadvantage of impracticality (the increase in downforce from a 50-100mm lip is close to the change of the air dam from 100mm to 125mm):


This is a real world example after this of a GT2 specification Porsche 911 (997) tested in a a wind tunnel. The results correlate well and show a non-significant change in drag and as the splitter gets larger the gains in downforce also start diminishing (remember that this car is VERY close to the ground):

Wow, info overload. I'll analyse that and take that into consideration when building mine. I dont believe my splitter (or should I say lip) would hold any weight at all and in turn really not help with any downforce.

[rascal]

You've got a good point, and if you ever scrape the front hard, the splitter would bend a bit and give the cables slack rather than possible damaging the rods.

Do you have a closer shot of your splitter cables I can look at?

This is probably the best shot I have. Don't take that many photos, as too busy driving it instead...
It's just 30cm or so of cable looped at each end and held with a screw clamp. Cable is 200kg breaking strain so wont be exceeding that anytime soon...
I've had a mate and myself (total 150kg) stand on it at the same time and it didn't break so happy it will withstand whatever downforce it produces with ease.

[Magpie]

For cushioning I use high density foam, it also acts as part of the air dam. However my splitter is not in any way attached to the bumper, rather it is pulled up by the rods. In the extended version the front smaller rods are drilled through the aluminium edging so that spread the load and the risk of pull out is reduced.

[rascal]

For cushioning I use high density foam, it also acts as part of the air dam. However my splitter is not in any way attached to the bumper, rather it is pulled up by the rods.

Mine is also not attached to the bumper



however I just covered the gap with a $6 PVC strip courtesy of Bunnings Motorsport Division. (OZ equivalent of US Home Depot Racing Dept)

[Magpie]

rascal I used a rubber strip to cover the same gap on my first splitter