[eimarshall]

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!



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.



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!



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).



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!!

[eimarshall]

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.


(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.


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.

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.


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!


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.

[eimarshall]

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.



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!)


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

Action shot!

[Christian1LE]

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.

[eimarshall]

Originally Posted by Christian1LE

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.

[DevilsReject97]

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.

[eimarshall]

Originally Posted by DevilsReject97

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


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.

[DevilsReject97]

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.

[eimarshall]

Originally Posted by DevilsReject97

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.

[That1guy_tim]

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!

[khcoaching]

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

Ken

[eimarshall]

Originally Posted by That1guy_tim

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!

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....

[eimarshall]

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!!!)





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......

[eimarshall]

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!