[That1guy_tim]

Originally Posted by eimarshall

PM me if you really do want a pair. Fair warning though, I'm a rookie at this. Lets just say they look really good during a fly by on track....

Sir, have you seen my build thread.... Zero F's given about form.. Function>Form

[eimarshall]

Originally Posted by That1guy_tim

Sir, have you seen my build thread.... Zero F's given about form.. Function>Form

Haha!! Yes! Your fenders are dope! Deep on my idea list is the thought of copying that outlet curve with the vent outlet on the carbon fender. That's wayyyyyyy down my list though!

[eimarshall]

Evolving Aero: Here are my tentative plans for aero. I figure once I get all of this stuff together, I can do a test day and collect some quantitative data on what works and what doesn't have much affect by taking bits on and off for each session.

Rear wing: I ran this with an angle of attack at near 0 degrees in the center. APR says this makes ~240lbs of downforce and ~27lbs of drag in open air (not behind a car) at 100mph. That is a lift to drag ratio of almost 8.9:1. Changing the AOA to 5 degrees ups those numbers 290/36 for a ratio of 8.2:1. Less efficient but more downforce. 10 degree AOA nets 317/45 for a ratio of 7:1. https://aprperformance.com/racing-pr...ustable-wings/

Because this is a “twisted” wing, the ends are actually 15 degrees steeper than the middle. This means that when the center is set to 0, the ends are already approaching stall conditions. When a wing stalls, downforce no longer increases(much) with AOA, but drag does.

I will probably continue to run 0 AOA for now, but I may increase it to 5 degrees if I feel the need to apply more rear aero balance. That will depend on the ......

Splitter: I was happy with it, but I can only guess at what sort of downforce it made. Maybe 100lbs? If I’m lucky. I have a plethora of ideas to improve it. More contoured shape, lighter weight, tunnels, end plates, and more rigid mounting.

Contoured Shape: this comes from (again) watching too many AJ Hartman videos. He has some great details on how a wing shape is better at generating downforce. One way to cheat the wing shape is to simply add a very long bevel to the front edge and then increase the splitter angle to between 2-4 degrees with the front being lower. This would be simpler but wouldn’t quite be the same since the leading edge is not a straight line. This leads me to…

Lighter Weight: This can be achieved by making the whole splitter body out of carbon fiber with a foam core. The foam core can be carved and shaped to create a wing profile before being wrapped in carbon and infused with resin. I had started making plans for this but then AJ Hartman released his splitter for the Camaro. I was ready to hand over my first born but….

Tunnels: It didn’t have tunnels! Splitter tunnels can double the downforce of a splitter by creating a void the air will try to fill. Filling that void causes a low pressure region. (At least that’s the simple explanation) There are a ton of articles about the benefits of splitter tunnels. The big problem though? The Camaro has the Aux radiators right where you would want to stick a tunnel. This really limits the size of the tunnel. I actually talked with AJ about it and he wanted to keep the kit simple for now. He thought it would take a good bit more work to make tunnels to fit, and he thought the wing shape was more important for the time being, as he doesn’t have any actual wind tunnel data for the Camaro.

End Plates: I am continuing on my journey of creating my own carbon fiber splitter. But because AJ was such a nice guy, I decided to buy a set of his splitter end plates. In another video, he talks about how they can add an additional ~50 lbs of downforce by sealing the high pressure zone at the edge of the splitter and generates cleaner vortices. They are a fairly complex shape and I figured it was not worth the effort of me creating them when he has such a nice (and thoroughly tested) set available. https://ajhartmanaero.com/low-drag-s...r-side-plates/

Back to the (future) tunnels. I also bought a 3D printer with the idea of making some bits and pieces for the Camaro(and a bunch of silly toys for my kids). I watched a couple more videos and write ups and decided I could probably design a tunnel shape to fit under the aux radiators and 3D print a mold to lay carbon in. Well, I realized that I would need to print the plug to make a mold. and that it would be larger than my printer's capacity...... I’ll create another post dedicated just to this.

Revised mounts: The last thing for the splitter, is mounting it more rigidly. I bought a set of the rear brackets from AJ to replace my elevator bolts(probably still going to run elevator bolts just ones that thread into his mounts), but I also reinforced the trans cooler mounts by running a piece of flat aluminum from the rear trans cooler bolt to the innermost tab on the aux cooler duct mounts. This really reduced the lateral play in the whole trans cooler mount. I will likely also have to revise the lateral mounts, but that will have to be figured out after the tunnels are installed.

Canards: I had to trim these to fit around my vent covers and thought why not use the cheap plastic ones as templates to make some out of carbon fiber. I also figure I can make a couple versions. The ZLE ones have such a steep angle that I have no doubt that they are contributing to the drag on the car. I am going to try to make some smaller half size canards to see if I can still get a little downforce without as much drag penalty.

Tire blockers: With a 3D printer, I also thought I could model a tire blocker for the front since the 305s have a little poke to them. At the bottom of the bumper(just above the 1LE lip, you can see about 2-3 inches of tire face. I thought this would be a great way to learn a little about CAD modeling and explore the benefits of rapid prototyping with a 3D printer! I could also make some for the rear tire as they poke a little as well. More to come on those as well.

Upper grill block off and radiator ducting: I saw Lewisracing's thread on his NASA ST2/ST3 build and liked the upper grill block off and rad ducting idea. It should be simple enough to make a piece of carbon to fit across the upper grill. I haven't decided how I want to do the ducting but I have a couple ideas. I pulled the upper radiator block-off plate that also provides mounting for the bumper. I might try to remake that out of carbon fiber. That will save a few pounds. Or I could delete it and create a different shroud/duct plus bumper brackets that mount to the crash bar. I am also thinking about leaving part of the upper grill open and making an inlet for air to feed to the intake. I also just saw another local 6th gen guy on FB make an OTR intake using a C6 corsa system. We'll see where I go with this..

That about sums up my ideas for improving the aero parts. Lots of stuff to do and figure out. Thankfully(kinda) the season here in the PNW doesn't really start until May. So I've got time to figure things out.

[That1guy_tim]

Excited to see the 3d printing journey!

I want to print a rear diffuser. It would obviously need to be printed in sections and glued together.

[eimarshall]

I think printing the part directly would have some trade offs. you would likely have to use some carbon fiber filaments and even then the final piece may not be that strong structurally without significant reinforcement. but printing a shape as a mold or as a template for a mold would be feasible.

Streeto Bandito made the entire body of their 240Z by printing it in pieces, and then combining them to make the custom shapes. They then made a mold off those shapes and used the mold to make the carbon fiber parts. I'm copying that process for the splitter tunnels right now.....

https://youtu.be/iLhU8J8F7aM?si=85T_PTa0M8_qC5x0

[KirillWA]

Awesome read. Thanks for sharing, Eddie! See you on track this spring.

[eimarshall]

Originally Posted by KirillWA

Awesome read. Thanks for sharing, Eddie! See you on track this spring.

Thanks Kirill! See you out there!

[That1guy_tim]

Originally Posted by eimarshall

I think printing the part directly would have some trade offs. you would likely have to use some carbon fiber filaments and even then the final piece may not be that strong structurally without significant reinforcement. but printing a shape as a mold or as a template for a mold would be feasible.

Streeto Bandito made the entire body of their 240Z by printing it in pieces, and then combining them to make the custom shapes. They then made a mold off those shapes and used the mold to make the carbon fiber parts. I'm copying that process for the splitter tunnels right now.....

https://youtu.be/iLhU8J8F7aM?si=85T_PTa0M8_qC5x0

Love the industry garage 280 builds. That's what gave me the idea for the diffuser.

[eimarshall]

3D modeling and printing:
The tire blockers I designed are a little different than the air dam types typically seen. My design is triangular and mounts to the bumper and fender just ahead of the wheel, and smoothly directs the airflow from along the bumper out away from the side of the car. The bumper/fender has a slight "flat" area around the wheel well. Perfect for mounting a deflector. Only it's not "flat". It is very curved.......

To model the tire blockers, I taped off the area around the mounting location and drew on the approximate area that would be covered by the deflectors. I then took a pair of orthogonal images of the area. One from the front and another from the side.





I then created a new project in OnShape(free online cad software) and imported those images as reference images in the front and right planes. What made the modeling particularly difficult(at least to this novice modeler) was the fact that the bumper is curved in all three directions. There is*the curve of the bumper front to back, top to bottom and along the arch of the wheel well. I sketched up the curves I had drawn on the bumper in the right plane to get the lateral profile. I then sketched 2 curves in the front plane. One for the rear profile(rear edge of bumper to the outer edge of the tire) and one for the front profile(front most line drawn on bumper to outer edge of tire).



Using these three curves I created a couple of extruded structures and combined/subtracted/intersected them until I had 3 specific 3-dimensional curves. One that traced the rear edge of the bumper along the wheel well opening, a second that traced the front edge of the "flat" area ahead of the wheel well opening and a third that followed the same curve of the wheel well but stood out from the side of the car enough to block most of the leading edge of the tire.



I then sketched a triangular shape that connected the bottom of each curve and another connecting the tops. I then lofted the two triangles together using the 3 curves as guides. This initial part was just from the bumper/fender seam down to the top of the 1LE lip. I repeated this whole process for a smaller piece that went upwards from the bumper/fender seam and ended at a point a few inches up the fender. The result of the two parts was this wickedly curved shape.



The printer I bought is a Bambu Lab X1 Carbon that I got with the AMS system on a decent black Friday deal. I could have gone cheaper, but I felt all the automation and safety features of the X1 would be worth it. I was worried that if I bought a cheaper system, not only would I have to spend time manually tweaking/adjusting/fixing things but that the wasted time would turn me off from the whole hobby and I would get frustrated and not use the printer at all. Plus the capabilities of the X1 include the ability to print carbon fiber impregnated filament. PLA-CF, Pet-CF and even PAHT-CF and PA6-CF for higher temp applications.

I dumped the STL files into my 3D printer's slicer and cut the lower portion into 2 pieces since it was too tall for my printer. I figured I'd probably have to adjust a couple things so I printed it in some cheap PLA to start. The initial fit was close but I must have mis-scaled it somewhere, as it was about a half inch short. Also I didn't think about it initially but the side abutting the "flat" area around the wheel well needed to be curved front to back(I had modeled that side of the triangle as flat.). I tweaked the model to make that edge slightly concave and scaled it up a few percent and hit re-print.





https://youtu.be/GqOfO7-v0GA

I also thought maybe I could fold a piece of CF around the wedge to make the final part out of CF, but the complex shape and very sharp leading edge would make that difficult. I might still try this, but for now I decided to add mounting posts to the part. I removed the side marker in the front bumper and measured the distance and dimension of its mounting holes. I then added two posts to line up with those dimensions and a third post near the bottom. Two more posts on the upper fender piece and print again to ensure post locations fit the existing holes. This took 2-3 iterations to get the locations just right.

I started going down a rabbit hole trying to add threads to the posts in the model and modeling nuts to screw onto them, but then had an idea. I grabbed my cheapo tap and die set and found an M7 thread fit snugly around the post. I printed out some solid infill "nuts" with a smooth bore and with a quick twist of a tap, M7 nuts for my M7 threaded posts!

Drill a quick hole in the bumper and fender for the other mounting posts, final print in PETG-CF, and wham-bam wadda-ya-know!! A nice looking tire deflector!!

[That1guy_tim]

Killing it dude! looks great!

[SSEssence]

Those 3d printed pieces came out amazing!

[eimarshall]

Thanks Guys! I'm thinking I might wrap them in a CF vinyl to help blend them in. The replacement 1LE lip is gloss black, the other 1LE bits are satin black and the CF fenders are another "black". The Tire blocker adds a 4th or 5th shade of black.... probably too many...

I'll probably rattle can the 1LE lip satin black and see how it looks too. or wrap it... idk.

[eimarshall]

"Quick" update. I wrapped the tire blockers in CF vinyl and love how they look. They match the fenders significantly better.


I also ran some test lay ups of CF on foam core samples in preparation for the splitter and was surprised by my results. My test block was a 4"x8"x1" block of 4lb/sqft closed cell foam with a 1/2'' radius on the top edges. I put 2 layers of 3K 2x2 twill weave CF fabric on both the top and bottom of the block. The block was placed on sheet of glass to get a mirror finish on one side.

The goal was to try out different lay up and vacuum bag processes and see 1. How easy it was, 2. How successful it was, 3. The weight of the final product, 4. What extra considerations I needed to take into account.

Trial 1. I tested using resin infusion and quickly realized the glass side was not getting sufficient resin flow. The resin essentially race-tracked around the edge of the part where the edge of the foam/CF met the glass. the infusion mesh ensured the top got resin but the bottom did not. I tried to fiddle with it while it was infusing and accidentally broke vacuum next to the feed line. failure all around.

Trial 2. Resin infusion again. this time with perforations through the foam every 1.5" and infusion mesh only over ~half of the block. This infused much more successfully. I thought an air pocket was still getting trapped but it filled in better than I thought. I 3D printed a port for both inlet and outlet and those proved much more robust than just gum tape on the lines. I had the feed line above the part and that led to gravity pulling too much resin into the corner. Final results were cosmetically sound but the mesh definitely left a pattern. Final weight was about 100 grams after trimming. A little heavier than I was expecting but a good result. I was still worried on how well the bottom of a large panel would infuse.

Trial 3. Wet lay up and then vacuum bag. The layup is a bit more frantic and messy since you are on the clock as soon as you mix the resin. but once its wrapped the bagging and such is a little easier. cosmetically this was an improvement over the infusion since there was no mesh to cause an imprint and the final weight was about 60grams. I was very surprised how much lighter it was.

Both block 2 and 3 felt equally solid but I was curious why the infusion was so much heavier. I had perforations on both but maybe the infusion filled those holes in more completely? I grabbed a hack saw a chopped both test pieces open. the infusion block was significantly more saturated with resin despite the closed cell nature of the foam. and the perforations were full.

I was expecting the infusion piece to be lighter, and maybe if I got the process more efficient, it would be. but for simplicity and reliability I think I'm going to go with a wet lay up for my final splitter build.

Materials ordered and templates cut. Hopefully I can post the results in a couple weeks!!

[That1guy_tim]

Photo getting point by from Porsche... *chefs kiss*

My seat was too high with the sliders in it as well... I took them out and bolted right to the planted base.