Advise on Aero bits
 

Hi All,

So here's the scoop. I picked up a 2003 Z06 with the intention of turning it into my dedicated One Lap/track car. I have run One Lap several times but not in anything that was really built for the event.

I have also always wanted to build something that utilized aero as in a wing, splitter, vented hood, etc. What I'm looking for is advise on the path to proceed to achieving this goal from the racers on here who are using aero.

Remember that I'm not constricted by any rules or specs that I have to abide by so wing height, location and sizes are open.

I am also looking to gain insight on possible changes I need to think about when you introduce downforce into the equation such as higher spring rates, less pre-load on your springs, ride height changes, etc.


Currently the car suspension is setup as follows:
Pfadt S/A Coilovers
Spring rate unknown
Pfatty adj sway bars
Baer bumpstop kit
Pfadt alignment shim kit
-2.4 F, -1.7 R camber
Toe is basically zero all around

Thanks in advance for your advise.

Hi I will take a stab at your question. The first thing to do is try
and decide what sanction body you will run under. It could be
one, two, or three. Example SCCA,NCCC,NASA. etc.. Then read the
rules concerning the class you want to run under. Example SCCA
in certain class's can run a wing but it will have certain sq. ft for
the wing and cannot lay over the rear bumper. Lot's of rules....
Total stock class's mean your car is pretty stock down to the tires.
Ok let say your not stock. Down force is your friend, the more the
better. But you must look at function over forum. You see a lot of
pretty splitters for sale on the forum but in truth they really do
little for down force. You will need to find vendors that have done
R&D and can prove there worth on the track. Right now there are
very few diffusers on C5's. When you hear a vendor thinking about
making one everyone clamers for a pretty one--not.
Suspension --talk to guys that run on the track not the street.
It will be a combination of parts that will help you. Not one
specific part. Buy the best brakes you can afford. Trust the seat
of your pants, you will know what's right and wrong. The whole
thing is a experiment you will constantly be changing things..
to improve.
Well that is as vague as I can make it. No one on this forum has
the answer you want (including me)---you have the power and
the answer. Read more and good luck--rp

Lay the radiator forward, vent the hood with a Gurney flap, vent the fenders to either release air out the louvers in front of the doors or vent fenders into the engine bay and curl rear of front fenders in (do google searches of DTM and other aero race cars if my description is lacking), splitter, wing, flatten the bottom of the car and diffuse the rear which will require extra cooling for diff and tranny depending on how long you run, I'm not familiar with One Lap. From my limited understanding it is better to put 90 degree 'fins' like the new vette aero z06 package than canards on the front for the aero/drag coefficient benefit. What kind of corner speeds are we looking at? What tires will you be running?
I'd call LG, DRM, Katech, etc and get a package meant to work together. God knows it'll be better than my advice!

I'm interested to see the answer to this, but doesn't one lap require driving the car a couple thousand miles on the street too? It would seem that any functional splitter would get destroyed.

Check APR Performance.

Thanks for your responses so far. Let me pose this question for those that have had experience with rear wings. If you could use any wing and place it in any location, what and where would it be?

One Lap has no rules on these things so think about what you would do in building an unlimited class car. Also remember that you have to drive this thing from racetrack to racetrack over the course of 8 days and approximately 3500 miles.

The format of One Lap is 3 hot laps from a standing start with the total time scored in time trials. But there also are auto crosses, drag races, circle tracks, skidpads and even possibly a dirt track.

I'm guessing you can't remove the wing while driving between tracks?

I just worked with a splitter maker and they designed on that is easily replaced when I damage mine at the track. The goal of the development effort was:

1. Have the wing break off without damaging the front fascia and front fender mounts like most splitters do when you stuff if into something hard. It took three rounds of testing on track (that is code for me going off at speed and digging it in) to get it to breakaway properly, but it works.
2. Be quickly and easily replaced when it is ripped off or damaged in a race.
3. Be economical to replace and provide me the ability to keep spares on hand, which I now do.
4. Meet the measurement guidelines for the classes I race in.

If you are looking for something you can put on and take-off the car for something like One Lap this design is probably your best alternative.

Do you have any pics of this splitter? Who is manufacturing?

A lot of the competitors tow a small trailer behind them.

Like these guys

http://i258.photobucket.com/albums/h...psfb58b936.jpg

http://i258.photobucket.com/albums/h...ps5983bf42.jpg

Most don't remove the wing but some do remove the splitter or a portion of it at least.

Does laying the radiator forward do anything for the aero?

I am thinking about the vented hood but which way to go? Just vent a stock hood with louvered panels or buy one of those C5R replica hoods or what? Is there a hood that the racers are using that is truly functional and not just a show piece for a waxers car?

I will take some pictures later today. I did get permission from Michael Jercan to post his phone number here. He can be reached at michael@crzyeng.com and 213 200-5820.

Here are pictures of the splitter parts. I consists primarily of the splitter and the main supports. Not shown are the turnbuckles for supporting the front and managing the splitter height as I can't go below 3.5" in SCCA racing. The bolts for all the splitter hardware are nylon. They do a good job of holding the splitter, but upon any sort of severe impact they shear, thus saving the bodywork and frame from damage.

https://scontent-a.xx.fbcdn.net/hpho...92902523_o.jpg


https://scontent-a.xx.fbcdn.net/hpho...59213638_o.jpg


https://fbcdn-sphotos-f-a.akamaihd.n...95483887_o.jpg

Yes, laying the radiator forward works if you vent the hood, especially if you box in the radiator because you are negating the parachute effort on the underside of the hood. As far as venting the hood, it depends on how much your time vs money is worth. I won't drop 2500 bucks on a hood, some people will.
Do a search for 'recession aero' on this forum.

In your case without any sanctioning body --I would place the wing
I guess with your vette a couple of inch's below your roofline. you want....
to catch live air instead of the dead air or vaccum ( if placed to low)
You want to have all the downforce you can produce. Other folks
have talked about a front splitter which you should have to balance
the car. And don't for get the diffuser. Another piece of the puzzle.
All parts of the downforce combo. I have seen mountings for the
wing extend beyond the rear bumper...your call. Staight vs swan
wing stands..................
There's more.. ride height, the use of cunards, springs, wheel size, there is a lot..................................... ....
to going fast...rp

wing that extend beyond the rear bumper--your call.

It is my experience even with a at the roof line height a relatively flat wing at about 4 degrees angle of attack produces ample downforce, more than I can compensate with a 2" splitter and ample hood venting in the front. I am still trying to tune out some of the understeer on the car with 315 tires up front and 335 in the rear.

I would guess that without significant redesign and testing on front aero it will be real easy to upset the balance of the car with too much rear wing and diffusers and such.

Just slapping stuff on and going to One Lap, if not test and planned might just hurt your lap times vs. an all mechanical grip car. My first attempts at adding aero to the car produced negative results, not better. The car is a whole package and adding stuff does not automatically make you faster.

I would offer a slightly different alternative, given that you do not have to comply with "rules".

The original F1 wings loaded the tire contact patch directly by means of the wing support struts being connected directly to the top of the wheel hub support. These struts sometimes failed, leading to banning this method. However, engineering solutions now make this method a viable, and preferred mounting method. Because the load is transferred directly to the tire contact patch, a relatively softer spring can be used, allowing some chassis movement over bumps etc. I would suggest that you investigate an engineered solution to your aero, which utilizes this type of hub loaded aero as it would give significant advantages on a street driven car on real world road surfaces.

Kerry Hitt. Making aero for the C5 for ever. Advanced Composite Products. That's a good place to start.

Now that is an interesting idea. Thanks

Who makes this splitter. I am track prepping a C5, and this looks great...