The Evolution of EMarshall's CamAERO
 

Over the last 6 years My Camaro experience has migrated from being the DD with an occasional Auto-X, to a dedicated track car. Along the way I took notes from many sources on how to make myself and my vehicle better and faster. And in the last 2 years I have taken a greater interest in improving the aerodynamics of the Camaro as opposed to simply adding MORE POWER!!(although that will likely happen eventually) I hope this thread is as informative and interesting as many of the others on this forum. Huge props to @khcoaching and @glamcem, two other current or former PNW Camaro6 members for inspiring me on my journey.

Story time: I got my Camaro in late 2017 after an uninsured mustang driver got a death wave and shot out in front of my BRZ. I ordered my Camaro with only the specs I wanted. 1SS 1LE with PDR and black bow ties in HBM. It arrived just in time for my wedding!

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I daily drove the Camaro for 2.5 years and won my class at the local AutoX with the car in essentially stock form. At the end of 2019, I tried my first track day (the Ridge Motorsports Park and was hooked. The next summer I watched a Porsche dump its coolant at 140, a 5th gen Camaro lose a belt and a gasket, and a Lambo catch fire. Given that I was wanting to commit to more track days and eventually travel to other tracks, I decided to buy a truck and trailer and the Camaro became the weekend/track toy.

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Up to 2021, my only modifications had been the GM performance alignment, ZL1 rockers, and a couple sets of wheel and tires for various duties. I had the original SC3 tire on the stock rims, a set of square 19x10 Apex Arc8s with all seasons, and a set of 19x10/11 Forgestar CF10s with 305 RE71Rs for AutoX. That summer khcoaching showed up on the Camaro6 forum and I managed to pick his brain at an event the week before the SCCA Time Trials National Tour stopped by my home track. His pointers helped me reset my PB 4 times during the competition and I won my class by a 3 run combined differential of 1.2 seconds!

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The next winter I decided to perform some mild modifications. I did the MRC strut grind thanks to Glamcem's how to thread and added the BMR rear toe arms and cradle lockout kit. These helped me get my alignment to -2.7 front and 2.0 rear with 0 toe. I had polished off the SC3 tires at the competition and felt the RE71Rs were a bit of a one lap wonder, so I got my hands on a set of 305 Hankook RS4s on 19x11 of Forgestar C5Vs. I lost a little time with these (about 1.5-2 seconds on a 1:50 lap) but they continue to wear like iron, so I use them for warm up/learning laps.

Throughout 2022, I continued to read khcoaching's posts and pestered him as much as I could at events when I ran across him. I learned much from his data driven approach to finding time, and slowly worked my way up to what I felt was the maximum pace the RS4s could handle at the Ridge. Alas, in finding that pace, I had my first big off. I grabbed 2nd instead of 4th in the middle of turn 9 at the Ridge (high G uphill right hander at ~100mph).

https://www.youtube.com/watch?v=bQ8tN3x3Cx0

Thankfully the only thing that broke was the rear traction. I went sideways into a gravel trap and stopped 4 ft. from the wall. 2 tires de-beaded, a cracked rocker panel and some extra grip marks in the seat were thankfully the only results. I fixed everything back up and ran a few more events before finishing the season with an OnGrid Time Attack event. I was significantly outgunned in my class, but had a blast chasing some VERY fast cars!!

Fabrication attempts. aka. making it up as I go.
In the Fall of 2022 I let the mod bug get a hold of me. I made plans to add some safety features to the car(OMP HTE-R seats, CMS roll bar, 6 point harnesses.) but also decided to copy much of khcoaching's and other Camaro6 member's findings by adding DSSVs, sway bars(Hotchkis+BMR), and a full set of rear arms(BMR). A black Friday deal netted me a set of forged Apex VS 5RS in a square 19x11 setup and a screaming walmart deal nabbed me a set of 305 SC3R tires that everyone raved out. I came across a set of AC carbon front fenders and a knock off ZLE wing, so on they went as well. Lastly I decided I wanted to add a front splitter to keep some semblance of aero balance. I ordered an APR unit but as soon as it arrived, I knew it wasn't up to my standards. Let's just say it had more flex than Arnold Schwarzenegger in his prime....

After reading every article I could find on how to fabricate a splitter(AJ Hartman, Professional Awesome, and lots of forums), I decided to craft my own out of plywood, angle iron, and a little ingenuity mixed with elbow grease. I decided to go with a 4inch lip all the way around and a beveled leading edge(AJ Hartman talks about this quite a bit in his videos). Because of clearance issues loading the car onto my trailer(ground clearance and width) I decided to make it easily removable as well.

I started with half inch plywood because it was cheap, relatively sturdy, and could be easily shaped/modified using tools I had on hand. After cutting a rough shape I started looking at possible mounting solutions. I removed the front bumper and front undertray, and trimmed back the wheel well liners to the front edge of the wheel opening. I knew I would have to run a couple splitter rods through the lower grill, and I figured I could create a couple of brackets that hung from the metal support under the headlights. The "detachable" part was quickly solved after watching another AJ Hartman video where he mounted his flat floor using door latches. I took the undertray mounting tabs that hang off the trans cooler brackets, and bent them so that they pointed vertically. I then drilled a second hole and mounted the door latches so that the open side faced forward. There was a little lateral play in those trans cooler brackets but vertically they were solid.

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(Most of these photos were taken much later, so you may spy other changes...)
For the rear of the splitter, I installed nutserts in the front most tabs of the aluminum brace(holes from the front undertray), hung elevator bolts down about 2 inches and secured them with jam nuts. I slotted the rear of the splitter so that it could slide onto the elevator bolts and be held up by the flange.
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I started trying to figure out a way to make the side supports easily detachable( yet still solid enough to support each side), I thought the same elevator bolt/slot trick might work but that meant installing the splitter would require aligning 4 slots, ~70" apart, at 2 different fore/aft distances. Not very easy. After a couple of other attempts, and a few beers, I realized another set of splitter rods would actually work perfectly. There were already large enough holes in the headlight/aux rad support frame for an M8 bolt, and I could put the bottom clevis and bracket just inside the bumper and in front of the wheel well so it would be easy to access(remove one wheel well liner retaining screw). I decided to support Professional Awesome's great write ups and videos on splitter and aero design by buying a set of 4 splitter rods from them.
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The wire you see is the pull to release one of the latches. I usually put the rod through the loop to prevent it from flapping around.

The half inch plywood was fairly sturdy, but I figured I would rather over engineer it than have it rip off on the first run. So I installed angle iron in a pattern that extended forward from the rear slots, past the door latch mounting points, to a point about 2-3 inches behind the front bumper. Then I ran a single piece across the front, connecting the two fore-aft lengths and added a diagonal on either side that ran to the outer support mounting points. I also decided to reinforce the underside of rear slots and lateral mounting points with a 1/8" steel plate cut to size and drilled to accept the bolts from the angle iron supports. I decided not to cut a vent for the trans cooler since there is about 3 inches of clearance below the cooler and enough of a gap on the trailing edge of the splitter for air to escape.
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Again, these photos were not taken during assembly(rather during deconstruction for V2.....). I also added some splitter biscuits to protect the leading edge from scraping on the ground.

I added a piece of L shaped plastic from Amazon to create an air dam and seal the splitter to the 1LE lip. A final trim and bevel of the front edge, followed by a little sanding and a liberal coating of black spray paint, and viola!
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The final splitter and hardware ended up weighing about 25lbs. It mounts by sliding the rear of the splitter up at an angle onto the rear elevator bolts, then lifting the front so that it is approximately level, before sliding the whole splitter back another couple inches to get the latches to lock onto the middle support bolts. Then I attach the bottom of the splitter rods ends via their pins and re-install the bottom wheel well liner screws. I can stand on the center of the splitter, but the sides still flex quite a bit and would most likely break if you tried to stand on the outer corners. Total ground clearance with it on the car is about 4 inches (under no load). for a couple hundred bucks and some fun time in the garage, I'm pretty proud of it.
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EMC^2: EMarshall's Carbon Creations!
If you have a keen eye, you will also notice my lateral air curtain vents are blocked off with a carbon fiber panel. This was the second part of my fabrication journey.

In my time watching AJ Hartman videos, I took note of many of the different little aero tweaks he tested in many of his wind tunnel testing videos and I thought, "Hmmmm. Maybe I could try to make some carbon fiber parts. He makes it look so easy!" Obviously he has years of experience and you don't see all the prep-work and time and effort that goes into making all his molds and such, but I figured I'd try my hand at some simple stuff to start.

One thing he noted on a video was that cars with an air curtain feature can actually have increased drag when running a wider tire due to the air curtain actually directing air into the leading face of the tire instead of around the edge of it. by the looks of it, stuffing a 305 up front on our cars likely runs into this problem.(note: I don't think the ZL1 has the air curtains at all, maybe this is why). I had the bumper off already for the splitter mounting, so I thought I could save a little weight and possibly reduce some drag by removing the front lateral vents(and DRLs) and the hidden ducting on the bumper. A front bumper block off panel and a small piece to block off the vent in the wheel well wouldn't be too hard to create...right?

I ordered a carbon fiber kit and layed up my first test piece. A simple flat panel on a sheet of glass I had handy. A wet layup of 3 layers of 3K carbon fiber fabric. I then trimmed the sheet using a Dremel and cutting wheel to fit the air curtain vent hole in the wheel well. Piece of cake! (sorry no picture)

The front panel would be a little harder. After experimenting with thermoplastic and other materials, I decided to go old school and try make a curved panel using a hammer and dolly. It took some patience and a couple of attempts before I had 2 panels made out of 22 gauge steel metal. I bought a mold making kit and stank up my garage(and house) with the gel coat and fiberglass resins, but the result was a couple of decent molds that I could use to make the block off panels.

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I had read about folks using simple storage vacuum bags to make a wet lay vacuum bagged part. A quick amazon delivery later and I had some vacuum bags and a little hand pump. I layed everything up again with 3 layers of 3K and topped it with a layer of peel ply and bleeder cloth. I popped everything into a vacuum bag and sucked the air out with the little hand pump. I quickly realize the single vacuum bag was not holding vacuum well. not surprising. but I though maybe I poked a hole in it or something. So I tossed the whole thing in a second bag and sucked the air out of that one. It held better but would still loose vacuum after 10 minutes. I checked in on it every few minutes and re-applied vacuum. I did that for about an hour and a half while working on some of the splitter stuff, before finally just letting it go. the benefits from a wet layup vacuum bag aren't that great, and it was my first attempt, so I wasn't expecting perfection.

When I pulled the first panel, it was better than I expected. I rinsed and repeated on the other mould, but somehow got a air bubble in the middle of the panel. I chucked it and tried again. The third one came out nearly as good as the first and I felt it was good to go! I trimmed up the panels and did a little sand and polish on them before drilling holes and bolting them onto the bumper with some black M6 button head bolts. The edges weren't perfect, but the fit was good enough. I figure without the weight of the DRLs and plastic bit, I saved 5-10lbs(the DRLs are surprisingly heavy!)

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Mind you this photo was after a full season on racing grime and impacts.

Action shot!
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Nice, that was a fun read. Toying with the idea of aero for next year but I think i would sell my car and do it on a C6.

I have toyed with the idea of swapping to different chassis(almost bought a 4th gen Viper ACR 3 months ago....) But have never quite bit the bullet.

Very nice, well done! I like it, at least you can enjoy the toy for what it is.

As for the ZL1, they have the auxiliary coolers on both sides where your "air curtain" pieces go. The backside of the coolers have a vent for air flow as well.

The ZL1 has the larger opening that goes directly to the cooler. The SS has the same cooler but the air feed comes from the bottom corner of the central opening.
Green is air curtain. Red is aux cooler. Yellow is brake duct
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The outlet for the air curtain is right behind the side marker light. I don't think the ZL1 has it but I don't really know. I'll snap a pic tonight of the outlet location on the SS 1LE as well as my little block off plate.(which AJ Hartman now sells for $60..)

Edit: you can see the cutout in the wheel well liner in the 3rd pic of my second post.

The blue ovals are the ducting for the auxiliary cooling - you can see the back side on the wheel well liner to the right.

The brake cooling is in the red ovals. And obviously you can see the main radiator in the middle.

Right on. Makes sense. No air curtain for the ZL1 to worry about. You can even see that the wheel well liner in your photo doesn't have the cutout for the air curtain exit.

Dude, Love your write up! Love your splitter design. And DRL covers. You should sell those. So i don't have to make a pair. lol

Also love to see the professional awesome parts on the car. Those guys are rad!

What a great thread! It was pretty cool to see all the steps to where you're at now.

Ken

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....

Testing, testing....1,2,3....With the new mods I knew I would have some learning to do to keep up with the car. I watched khcoaching's track videos to help me set cues on track for target speeds, braking points and adjusted lines. The first track day of the year for me was towards the end of May (I was also recovering from shoulder surgery though most of the spring). With the alignment set to -3.5 front and -2.7 rear with a little toe in both the front and back (at khcoachings recommendation), the car was amazingly stable. I was amazed right away at how planted the car felt at speed. I warmed up during the first session and then in the early afternoon dropped a full second over my PB. I was running the RE71Rs to just use them up and did just that. They got thoroughly cooked by the end of the day.

I ran a couple more track days in June, but they were busy events, so I ran the RS4sand saved the new SC3R tires for a good day. That day came about a month and half later at the start of July. A fantastic day with Turn2 at the Ridge gave me a chance to really push and boy howdy!! I had never run 100TW before but holy smokes! All my braking points and corner speeds seemed like nothing. I reviewed my data throughout the day and set a couple of new targets.*I really pushed braking points, upped mid corner speeds, and was able to just mat the throttle on most corner exits!!
https://youtu.be/SVQu41ovEhU?si=Xy6IrsLWbVzp__os*A

A couple weeks later I picked up a spare APR GTC-300 wing khcoaching came across and tossed it on the car. To balance it out, I bolted on some knock off ZLE canards and went back out. I lost ~4mph on the front straight, but man was it stable at speed. I felt I could almost go through turn one with just a brush of the brakes (probably not though…). I lost a half second on the straight from the drag of the wing and the canards, but immediately made that time back in the 1-5 complex.

A nice cool fall day gave me a prime chance to reset my PR (again) and I didn’t let myself down. I carved off another ~0.8 seconds and finished the season with a 1:46:37, happy as a clam! (although I forgot to turn on the PDR!!!)

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That brings us to this fall where I starting tearing things apart again.....I had some more ideas for carbon fiber bits, plus I bought a 3D printer...... :D

Bits and pieces
I learned a lot last year. About fabrication, carbon fiber, aero, suspension, race seats, myself… and knew I wanted to learn more. So here is a breakdown of where the car sits, and ideas I have that could hopefully improve it.

I would love feedback from anyone with experience in any of these areas of interest.

Power: Yeah, I know I said I wasn’t doing that yet. But I’m not really diving deep. I picked up a ported LT2 intake and a 95mm TB. I might just do the LT2 for now to avoid a tune. We’ll see. Its low on my list of priorities.

Wheels/Tires: I loved the SC3Rs and will keep running them for now. I know they have more to give. I still have the RS4s for warmup/easy days. The third set of wheels are staggered (19x10/11) with OEM offsets. I am considering ditching them as I felt the 305s were a little pinched on the 10” front rim. Maybe experiment with a stickier staggered set? Not sure yet.

Brakes: I didn’t mention these above, but I am running a set of Girodisc front rotors and OEM discs in the rear. I was running ST43 pads until mid summer. Then I switched the front to DTC-60. The rears are wearing at half the rate of the front. I have yet to experience ice mode and I’m keen on avoiding it. I thought about going to ZLE brakes, but I’ve only just gotten into the 100TW tire realm. I might try some other pad compounds this year. (3.12s? XR1s?)

I am also running the SS brake ducts. I was thinking about making these out of carbon fiber, but I don’t think the resin I have could handle the temperatures anywhere near the brakes.

Suspension: I like the DSSVs and am running them at nearly the lowest setting. I might try to get the car “corner balanced” (even though only the front is adjustable) but I was pretty happy with it last year.

Alignment: Per khcoachings thread, I ran -3.5 front with 1/16” toe out and -2.8 rear with 1/32” toe in. The car is very stable, and the tire wear is looking really good. It is probably too much camber for the RS4s as I get some low-speed understeer with them in this setup. I will likely stick with this for now.

Interior: God, I hated installing those race seats. I think I had them in and out of the car 20 times. The driver seat sits on a planted base, Recaro sliders, and OMP uprights. It’s a little higher than I would like, but relatively low on my list of priorities. Maybe switch to a BK base? I really don’t want to go through that headache again.

The passenger seat is on a BK base and BK uprights (I think). This puts the seat way too far forward. I am trying to figure out how to mount the uprights further back on the base without covering up the base mounting holes. I may just throw some sliders in there and call it a day. Idk


Any recommendations? Thanks!

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!

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.

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.

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

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

Thanks Kirill! See you out there!

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

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.

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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).

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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.

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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.

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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.

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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!!

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Killing it dude! looks great!

Those 3d printed pieces came out amazing!

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.

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

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.

Might need another order from you man. These look great!

CAD(Cardboard Aided Design) modeling the new splitter!

I wanted to make some slight adjustments to my splitter design, so with the use of some large pieces of cardboard I tweaked the shape slightly. The basic shape is essentially a 5 inch extension of the SS 1LE lip. I made the whole thing about 2 inches narrower(1 inch each side), and contoured the corners to match the curve of the endplates I picked up from AJ Hartman.
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On these pictures with no bumper, you can see where I am planning my mounting points. I also have AJ Hartman's rear Camaro mounting brackets. For now I am planning on keeping it removeable, but that may change once everything comes together. We'll see.

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If you look closely, you can also spot some red lines where I am planning eventually mount the splitter tunnels. That may not happen for a while though. I am kind of rushing to get the big stuff all buttoned up before baby #3 arrives at the end of April....

I did quickly throw on an LT2 intake I had sitting on a shelf since last summer. #Thatwaseasy

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Full Carbon Splitter-Part 1: Assembly!

My first splitter was ½” premium plywood and angle iron for structural reinforcement. It was removable and could be taken on or off in about 3 minutes. I felt pretty happy with the way it came out, but I knew I could do better.

I picked up a couple of ½” sheets of 4lb/sqft PVC foam and cut them to match the template from my previous post. I then set about contouring them to provide a slight wing profile to the whole splitter. The foam is rigid enough that I could just hit it with my orbital sander and carefully taper the body of the foam core to the rear. I got the trailing edge down to around ¼” and felt going thinner might start to tear apart the foam.

I also perforated the core with a 1/8” hole every ~3 inches. The would allow resin to bleed from one side to the other and allows the bridging to help strengthen the whole panel.

I then profiled the leading edge for a nice, rounded taper. A vertical leading edge can cause turbulence and airflow separation. The rounded taper promotes attached airflow and will help the air accelerate under the splitter, using Bernoulli’s principle to create a lower pressure region on the underside of the splitter. Splitters don’t really work by generating high pressure on the top of the splitter. I mean maybe a little, but largely the faster airflow under the splitter provides a suction or downwards force.

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For the layers, I decided to go with 2 layers of 6K 2x2 twill for the top of the splitter, so that it would be have a nice finish without needing too much resin to fill the fabric. On the bottom, I chose 2 layers of 12K 2x2 for strength and rigidity.

Since I settled on a wet layup and the whole part would take some time to perform the layup, I bought a resin with a pretty slow hardener(2+hour). The downside was that this resin really needs heat to cure and harden. So I built a low temp oven out of plywood and insulation sheets. Its capable of ~150 degrees using a smoker heating element in a sheet metal box and a couple of 4 inch duct fans. I actually built a smaller version first when I was experimenting with CF stuff last year, but the big splitter needed a bigger oven.

I used a sheet of melamine plywood as my surface and cut the peel ply, bleeder cloth and vacuum bag to size. I then waxed and coated the melamine in a release agent so the resin wouldn’t stick.

The bottom layer of the layup would end up being the top side of the splitter, so I started by coating the melamine board in a thin layer of epoxy. This would have given me a perfect finish on the top of the splitter had I not accidentally offset the first layer of CF by about 4 inches….. I had to peel it back up and that created some little air pockets. I then used a squeegee to saturate the first layer before adding the second. Rinse and repeat. For the core, I put a skim coat on each side of the foam. Each layer of CF was cut about 4 inches larger than the core, so I could wrap the fabric from the top (bottom during layup) down over the edge. I then draped the first layer of 12K on top and saturated it with resin using the same squeegee method. Next, I made sure it was tucked in nice and tight to each edge of the core.

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I didn’t get any shots during the actual layup as I had my hands covered in resin and I realized I only had a single pair of rubber gloves after I got the first layer down.
After the last layer of 12K, I added the nylon peel ply and then the bleeder cloth to absorb excess resin. I then taped the vac bag down to the board and pulled vacuum. I quickly sealed a couple of obvious air leaks but my vacuum gauge only read ~-25psi, so I probably had a couple that I couldn’t hear or find. I made sure all the edges were still nice and tight around the core and dropped the whole board into the oven. I let it sit at ambient temp for a couple hours to make sure the resin didn’t start to cure before the excess got squeezed out by the vacuum pressure. Then I turned on the oven and fans and closed the whole thing up to sit overnight. After 24 hours at 150 degree F, I turned off the oven and left for a week long vacation.

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The dots of resin saturation are where the perforations in the core allowed resin to bleed from the bottom of the layup through to the bleeder cloth. Which means the top was pretty saturated and the perforations were an excellent idea.

Full Carbon Splitter-Part 2: Assembled!

Upon return, I cracked open the oven and pulled the board out. I pulled the vacuum bag off and peeled the bleeder cloth and peel ply off the splitter. The release agent also made for a painless separation of the splitter from the melamine board. I dragged the rough splitter outside and washed off the remaining release agent. It was looking pretty good!

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I trimmed the edges close to flush with a Dremel and then sanded them smooth. The results were fantastic!

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The only defects were tiny imperfections on the surface from peeling up the first layer, and a couple of mysterious silver stripes around the edges. Eventually I realized those were from the silver sharpie I used to delineate the approximate shape of the core during cutting and layup. Whoops.

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I was still considering making the mounting system sort of a quick release, but finally decided against it for the sake of rigidity and simplicity. I bolted up AJ Hartman's rear splitter mounting brackets and made a quick cardboard template to drill holes in the splitter. His technique of keeping the brackets loose until attaching the splitter was quite handy! I mocked up the lateral and front splitter rod mounts and drilled holes for them. I mounted the Professional Awesome splitter rods to the splitter and reused their titanium splitter pucks for the front most mounts.

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Full Carbon Splitter-Part 3: All the CaRbOn

I after tracing the 1LE lip, I added an air dam using plastic corner guards from Amazon and wrapped it in leftover 3M carbon vinyl. Lastly, I added the end plates/tire blockers and a couple more splitter pucks from AJ to protect the nose and forward most lateral points.

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A quick weigh in shows the splitter and all associated hardware clocking in at a svelte 12.8lbs!

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One last mounting and she's good to go!!

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Overall, I'm extremely satisfied with the splitter, it's decreased weight, contoured shape and increased rigidity are vast improvements over the plywood one I ran last year. Of course it probably cost 4x as much in materials alone, but I think it will be worth it.

Of course I had to really test it….

https://youtu.be/SnYfajusQNQ

hot damn good work man i wish i had skills like this haha

Great job man!

Thanks guys! I can't wait to get it out on track! Unfortunately that likely won't happen until late May, seeing as baby #3 is due next week....

Very nice!

That came out amazing! Great work!

Incredible thread! Love the build.

Hood Vent
 

Because I am located in the cooler climate of the pacific north west, I haven't experienced any real cooling issues. Obviously these cars have a ton of cooling capacity but it has always irked me that the hood vents are so covered up and restricted. The factory hood vent for the 16-18 SS might appear 15" long and 4" wide but the vent insert cuts that down to only a couple inches in both directions.

Aerodynamically, the vents are fairly flush but all that air that goes through the radiator needs somewhere to go. Mostly, I imagine, it dumps down underneath the car past the headers. Great for header cooling but not so good for generating downforce. Plus causing the air to mostly stay in the engine bay(or at least have to fight past all the things in the engine bay) will increase the air pressure on the aft side of the radiator, restricting flow. Restricted flow through the radiator generally means less cooling and more drag. Both things I feel I could improve.

Initially, I had removed the vent inserts last year during a hot PNW track day(air temp around 95) as a precautionary measure. Over the winter I thought about adding a set of Racelouver's hood vents or something but never bit the bullet on a set since cooling has never been an issue for me.

Aero however is something I am playing with. I figured if I could make a little ramp or kick up in front of the existing vents, they could generate a small area of low pressure that could draw air out of the engine bay, decreasing the air pressure behind the radiator and thus decreasing the drag on the front of the car. Racelouvers has a ton of data on their website show this if anyone needs to sate their inner nerdiness.

So rather than just buy something, I decided to design and 3D print a little ramp that could clip onto the front of the vent. There happens to be a nice little hole at the front corner of the vent, and the curvature of the hood isn't soo much that I need to compensate for it.

I snapped a pic with a reference measurement and threw together a quick CAD design in Onshape. I designed the piece to be about an inch tall, with a nice smooth ramp and some cool looking reinforcing strakes on the front and on the underside to help direct airflow. The edges are just slots with a gap of 0.04", approximately the thickness of the hood. I added a nice chamfer along the leading edges and sent the design over to my 3D printer. I also utilized the little bolt hole in the corner as a locating pin.

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The first test piece matched up pretty well, but I tweaked the dimensions and reprinted 2-3 times before everything fit perfectly.

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I thought the blue actually matched nicely, but because this piece would be seeing some pretty high air temps, I printed the final version in PET-CF. This material is supposed to be heat resistant up to 205 degree Celsius or about 400 degree Fahrenheit!

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I like the look but might still do something to hide the blue edge of the hood that got revealed when I removed the OEM insert. The ramps look cool though!! Hopefully they are functional too.