Presented by Nine Lives Racing
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jh36
jh36 Reader
11/27/20 3:48 a.m.
jh36 said:

In reply to NOT A TA :

The area under the bumper (which I believe was the oil cooler opening on the TA cars)  is where I was originally planning to duct in. The area IS large enough to accommodate the needs of the air box and the brake ducts. I have read a couple of tidbits that made me wonder if just above the splitter might be higher pressure and advantageous. I'm still not sure if the geometry would work on the z-axis, so to speak. 
Regarding the bumper, I am going to try and mount steel 67/68 reproduction bumpers over the fiberglass. Since "stuff happens" in wheel to wheel racing, I do want a hair of protection. There was a day that I ran all fiberglass in my Porsche but I would like the peace of mind of a little protection. And it would only be a little!

 

NOT A TA
NOT A TA SuperDork
12/1/20 11:04 p.m.

In reply to jh36 :

That will look cool with a chrome bumper & real grill.

I know what you're talking about with the fiberglass. I had a '74 Camaro with just fiberglass out front and was always nervous about a frontal impact.

Hoping Steve will see this thread pop up in latest topics and read the first page in the morning.

jh36
jh36 Reader
12/2/20 6:08 a.m.

In reply to NOT A TA :

Exactly!  I am surprised some well meaning bump drafter never folded me up. I went back to big bumpers and enjoyed racing more. 
I just read an older article of Steve's on approaching the "complete package" of aero. I have plenty to do before I need to tackle aero, so I'm going to wait and get solid input before I start anything beyond the skirts I've already committed to. Splitter, under tray, venting, diffuser, wing. I'd like to have a full scope before leaping...or as much scope as possible. 

He writes truth as I understand it from other disciplines I have lived in. I want to understand the entire package before I start building aero in sections. 

sleepyhead the buffalo
sleepyhead the buffalo Mod Squad
12/10/20 8:21 a.m.
jh36 said:

So, off-the-bat, one concern I have is how low those hang... being metal.  Are you looking to have them 'skim the ground', 'seal to the ground', or other?  Some of the curbs at VIR are high enough to get hung up / ground off.  It's usually advisable to have a sacrificial material that's splayed out' a bit so it can flex out/up if the car heaves down, or runs a curb.  Garden edging is probably an ok first cut material.

Can I get some more 'wide angle' shots of the body and/or the car without it on?

jh36
jh36 Reader
12/10/20 8:54 a.m.

In reply to sleepyhead the buffalo :

Thanks for the input!

The bottom of the skirt is flush with the bottom of the main frame rail so it is probably not as low as it appears in this picture.  I am not at the point of having the ride height set, but I get your concern....I've launched off of those curbs a couple of times.

I think, because they are no lower than the frame, I should be fairly safe (but not absolutely safe).  I don't see many rubs and scrapes under the car from the past, so hopefully that's a good sign.  

The reason I originally made these is because the body sits a little higher than a stock 67 due to the design of the main hoop and halo of the cage.  In order to lower the body to original height, I would need to chop the main safety structure, which is possible, but i did not want to do.  These allowed me to cover the frame rail and hopefully serve some aero purpose.  

I can extend these with a flexible material as you suggest once the car is fully assembled and ride height/corners are set.  Maybe that becomes part of the overall package.

sleepyhead the buffalo
sleepyhead the buffalo Mod Squad
12/10/20 11:49 a.m.

Alright, I'm going to start a picture cross-posting thing...


 

one thing to keep in mind, is we're going to deal with parallax screwing up some of the visuals


 

jh36
jh36 Reader
12/11/20 6:07 a.m.

In the category of stuff I need to order, there is the trunk lip/spoiler. I ordered this body without one, thinking the wing would be best alone. Thoughts on running both, or if there would ever be a reason to run a lip and no wing?  It's easy enough with what I have, but if there is a compelling reason to add a lip, I should order one soon. 

stafford1500
stafford1500 GRM+ Memberand Dork
12/11/20 7:36 a.m.

The spoiler is the easy button for getting downforce without as much tuning effort. They are more draggy than a wing assembly at the same downforce level though.

Ultimately a wing assembly can get you more downforce and better control of that downforce, but it will require extra planning/fabricating/tuning to get the most out of it.

That chassis style means you are going to tie into the rear clip to hang a wing and the body will likely float around the mounts that pass through it.

On the subject of wing spoiler combinations, you can make them work, but the spoiler will not look typical. It will need to be laid back quite a bit so that the wake does not cause problems for the wing bottom surface. As mentioned in a few other threads, think of the acr body as the main element in a wing assembly, and all the other stuff that gets bolted on as the 2nd/3rd/etc flap elements. You want to get the flow around the car to do the majority of the work, since it is the closest thing to the ground (most potential downforce). The other items (spoilers/wings/diveplanes/skirts) just get used to fine tune and in some cases effectively make the car larger (long over hangs front/rear/sides like the splitter and wing assemblies).

I only spotted your thread yesterday, so still catching up to what you have in mind, but the cabin cooling air discussion is where I jumped in. I would not bleed air from the base of the windshield for cabin cooling on this car. I would lean toward a thin slot type duct at the B-post on each side. Make sure you have a means of getting the air out or you will just wind up with a stagnant bubble of hot air in the cabin.

jh36
jh36 Reader
12/11/20 9:23 a.m.

In reply to stafford1500 :

Thank you Steve.  Since the main hoop is the b pillar, that would be pretty easy...I imagine you are describing a piece of ducting about as tall as the window opening and maybe an inch wide?  That could attach right to the main hoop and pipe air in thorugh flex hose.

To get the air out, I was wondering if a few holes in the lexan rear window would be a good idea?  

jh36
jh36 Reader
12/11/20 9:26 a.m.

In reply to stafford1500 :

Regarding the wing/spoiler....your thoughts are steering me away from the lip and toward the wing.  Early on, I was assuming, and i think you are confirming, that ultimately the best result would be with the wing.  I need to get with Nine Lives asap and get a design going!

stafford1500
stafford1500 GRM+ Memberand Dork
12/11/20 9:58 a.m.

The B-post ducts you described are what I am talking about. They can be tuned with tape for cooling flow depending on the track conditions (hot/cold/raining). Make sure you have some ducting pointed at the driver or plumbed to the helmet for the most comfort. Yes, exiting the air form the cabin at the middle of the deck in the rear glass will help keep the air flowing toward the wing nicely and minimize some of the air rolling in around the C-posts.

jh36
jh36 Reader
12/17/20 5:22 p.m.
jh36 said:

In reply to stafford1500 :

Regarding the wing/spoiler....your thoughts are steering me away from the lip and toward the wing.  Early on, I was assuming, and i think you are confirming, that ultimately the best result would be with the wing.  I need to get with Nine Lives asap and get a design going!

Accomplished.  I just connected with Johnny and the wing is on order.

jh36
jh36 Reader
1/29/21 7:37 p.m.

Within a week or two, the wing should arrive. I am hanging doors and figuring out how to attach the front end. But my mind keeps wandering to the back of the car. 
The stock car body had no sheet metal under, or on the sides of the tube frame in the rear. 

I assume I should fabricate a bottom and sides to stop awful air things from happening. I am not at the car but this picture is exactly how the stock car was right after the body came off. 
If I put sheet metal on the outside of the tube frame, and then vented the wheel well, would that be sufficient or at least a start?

I know I am opening up a can of worms without a lot of details, but hopefully that made sense. 

NOT A TA
NOT A TA SuperDork
2/9/21 11:44 a.m.

Since you've got a flat floor can you extend that back and into a diffuser? The frame angle of the lower rails looks about right for a diffuser but you'd need to measure and figure out how quick it would expand and how far forward you'd want a diffuser to go to get the center of pressure where you'd want it. Using sheet metal back there and boxing things in might lead to other considerations because it would be different than the stock car way and affect things like rear end cooler, brake cooling, etc but I'd think a diffuser and side panels would be an advantage if they're within the rules you need to follow.

jh36
jh36 HalfDork
7/2/21 5:38 a.m.

Now that the car is rolling, I will start playing with this level of thinking again. I bought the Professional Awesome quick disconnect splitter kit and welded a mounting bracket on the car, but ran out of time to mount it on our test weekend. 
That is the next aero step.

the rear and diffuser will be next. Everything on the rear is effectively tucked up under within the frame rails so it should be feasible. 
There is a diff cooler, so I will need to provide so ducting for it but I can see a couple of ways to pull that off. 

jh36
jh36 HalfDork
7/6/21 5:27 a.m.

I mounted the splitter this weekend. It is essentially horizontal but is adjustable. 
The Professional Awesome mount kit and quick disconnect system is great. I used Alumalite. 
The leading edge is 3" out from the air dam and it is 2.75" high. 
I need to attach filler pieces between splitter and dam still. 

jh36
jh36 HalfDork
7/6/21 5:28 a.m.

jh36
jh36 HalfDork
7/21/21 1:54 a.m.

Here we are today...

jh36
jh36 HalfDork
7/21/21 1:59 a.m.

VIR testing is coming up and I am tying up loose ends. 
On my list is cutting 2" holes in the rear window to relieve cabin pressure/create air flow. 
I would like the peace of mind that comes from hearing from some experts before I fire up the hole saw. 

Will this achieve my goal?

Will this create any appreciable issues with air flow in the rear?

 

Johnny_at_NineLives
Johnny_at_NineLives GRM+ Memberand New Reader
7/21/21 11:09 a.m.

In reply to jh36 :

are you adding airflow for driver cooling?

 

jh36
jh36 HalfDork
7/21/21 6:12 p.m.

In reply to Johnny_at_NineLives :

For cabin comfort and fighting a parachute effect. 

jh36
jh36 HalfDork
7/21/21 6:12 p.m.
Johnny_at_NineLives said:

In reply to jh36 :

are you adding airflow for driver cooling?

 

And if I haven't said it enough, I love the wing. 

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