EXTERNAL AERODYNAMICS

4) DUCT TAPE!!

Or, LeMans buckets might be shallower if using modern rectangular LEDs.​
Then, you could swap the fiberglass covers with lexan and transparent blue mylar.​
Would look "semi" stock." Maybe less weight too. The stock light buckets are pretty heavy - mechanism, etc.​

2) I guess that touch of oversteer is from a throttle "Blip"- or drop?" "...when I ask for it."
I enjoyed "pointing the nose" of the little racer that way. It was a real hoot.

Cheers - Jim
 
The electric solenoid headlight conversion is pretty well documented diy project. Or, remove the headlights completely and install fill pieces. Those things are very heavy.

I know you want to keep the stock look, so the vacuum tank might be easiest.
 
69427 said:
Yesterday's track day went well. Nothing broke or got scratched up. A few conclusions I came to during the day:
1) I need to brake later. I'm still trying to get accustomed to how much quicker the car decelerates with the decreased weight.
2) The car is very neutral through the corners, with a touch of oversteer when I ask for it.
3) I'd like more front grip. I can't find many more ways to pull weight off the car, so I may have to look for other methods (stickier tires, steering geometry changes, etc). I'll be starting another thread regarding Ackerman geometries pluses and minuses. I can move the steering rack position pretty easily, but I don't have a sure way to decide which position is best for my situation.
4) And finally aerodynamics. I'm getting down the straights quicker than before, the car feels steady, and the brakes and engine are apparently cooling sufficiently in the process. A problem I ran into repeatedly was the headlights popping up at about 120. I don't have the vacuum system re-hooked up after I pulled out the vacuum tank, so I had to manually close the lights after each session. I don't know if the problem is purely aero pressure getting under the headlights (or maybe entering the headlight opening gap behind the front bumper), or if it's a combination of that and no vacuum in the actuators to help keep the headlights down. I welcome input or suggestions about this issue, as my plans at the moment are to reconnect the vacuum lines and perhaps install a small plastic vacuum canister to compensate for small vacuum leaks in the system.
Click to expand...
i'm running the mx5 (miata) electric motors on mine. Never have to worry about them popping up by themselves again, and gets rid of the vacuum hoses (only vac line left on my car is PCV). I did measure the weight at the time, from memory I think it was pretty much a wash between the motors/wiring and the vacuum actuators and hoses. I did end up making some double shear brackets for the motors, I eventually cracked the single shear brackets (sourced from the Corvette Forum). But my car does get a lot of use and hard use at that.
 
I was hesitating posting this one. I was going to keep it "my little secret" but there is an opportunity rising here.

UOP Shadow was a unique CAN-AM team that brought a lot of innovation (in External Aero) to the track.

Here is an example that could be a potential solution to increasing front grip, eliminating the weight of headlight buckets, and vacuum tank..
It would involve a reasonably-fast acting (solenoid) ACTUATOR set up, a modified headlight assembly, and sort out some switchology.
1756297723902.png

This video was shot at Goodwood in England last year. LINK:

At the 5 minute mark you'll note the deployment of the front and rear spoilers. No brakes lights in the video, so unclear if tied to a brake switch or manually operated.
A "Plug-and-Play" headlight bucket could offer track toy and still double as a DD. Just need some switch-thinking. Definitely require some testing and a cooperative series.
I'd think track-days would be pretty open. Could be fun.

Cheers - Jim
 
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69427 said:
Yesterday's track day went well. Nothing broke or got scratched up. A few conclusions I came to during the day:
1) I need to brake later. I'm still trying to get accustomed to how much quicker the car decelerates with the decreased weight.
2) The car is very neutral through the corners, with a touch of oversteer when I ask for it.
3) I'd like more front grip. I can't find many more ways to pull weight off the car, so I may have to look for other methods (stickier tires, steering geometry changes, etc). I'll be starting another thread regarding Ackerman geometries pluses and minuses. I can move the steering rack position pretty easily, but I don't have a sure way to decide which position is best for my situation.
4) And finally aerodynamics. I'm getting down the straights quicker than before, the car feels steady, and the brakes and engine are apparently cooling sufficiently in the process. A problem I ran into repeatedly was the headlights popping up at about 120. I don't have the vacuum system re-hooked up after I pulled out the vacuum tank, so I had to manually close the lights after each session. I don't know if the problem is purely aero pressure getting under the headlights (or maybe entering the headlight opening gap behind the front bumper), or if it's a combination of that and no vacuum in the actuators to help keep the headlights down. I welcome input or suggestions about this issue, as my plans at the moment are to reconnect the vacuum lines and perhaps install a small plastic vacuum canister to compensate for small vacuum leaks in the system
Click to expand...

I have seen the pneumatic logic diagrams for the headlights before. It reminds me of an old player piano (only the piano is more understandable). Could you cap the headlight vacuum actuator to lock them in place?
 
Now that we are on the subject, here is an experiment I intend to conduct. I have already built diffuser tunnels between the frame and rocker panels/side skirts. Air is fed to them via the front fender splash panel behind the tire and barge boards along the frame. I built CF plugs for my headlights, which have a fair size cross-sectional area. I made the plugs removable so I could just let air flow into the fender well above the tire. Now I need to build a simple CF upper/rear inner panel inside the fender well just forward of the firewall to smoothly guide air down toward the side pod diffuser entrance. It will be interesting to see if there are any benefits with regard to reduced frontal cross-sectional area or any improvements in downforce as more air is directed into the side pod diffusers...or, it is a total disaster and creates lift instead of downforce.

56 Corvette Tunnel 5.jpg
 
BBShark said:
I have seen the pneumatic logic diagrams for the headlights before. It reminds me of an old player piano (only the piano is more understandable). Could you cap the headlight vacuum actuator to lock them in place?
Click to expand...
At a minimum I need to do that. (y) Right now there's vented (atmospheric) pressure on both sides of the actuator diaphragms, so there's nothing additional trying to help the springs keep the headlights down. I believe I have a non-GM check valve in my hose collection that I can plumb into the carb plenum vacuum and headlight actuators to refresh the vacuum quantity every braking event. IIRC C4s have a small plastic sphere vacuum tank that I could repurpose to compensate for vacuum leakage during the non-braking periods. I'm also going to look to see if it's possible to make a simple linkage to lock the headlights down for track days.

Non-aero amusing story from last weekend's track day. I had a guy stop by where I was parked between sessions (He was driving a Nissan 370Z). He told me that when he first saw my car on the track he thought "Oh hell, another guy with an old Corvette who's going to be driving parade-speed laps and holding everybody up." (To be honest, the first two laps in my first session were of modest speeds while I tried to warm up the engine, brakes, and tires.) He then said "but then when you passed me on the next lap I quickly figured out I was wrong about that". :LOL:
It's kind of a familiar experience for me. I almost always have the oldest car at any track day, and early in the day it often feels like people think I'm hurting the property values there by my appearance with this antique. But frequently after a couple sessions a couple guys will stop by asking questions why my antique seems to be holding its own out there. I always answer direct questions about what I've done to the car (to be honest, I'm always flattered when someone is curious about my car), but if the guy doesn't ask any questions I generally just let him think it's stock and I'm just brute force horsepowering my way around the track.😉
 
mfain said:
Now that we are on the subject, here is an experiment I intend to conduct. I have already built diffuser tunnels between the frame and rocker panels/side skirts. Air is fed to them via the front fender splash panel behind the tire and barge boards along the frame. I built CF plugs for my headlights, which have a fair size cross-sectional area. I made the plugs removable so I could just let air flow into the fender well above the tire. Now I need to build a simple CF upper/rear inner panel inside the fender well just forward of the firewall to smoothly guide air down toward the side pod diffuser entrance. It will be interesting to see if there are any benefits with regard to reduced frontal cross-sectional area or any improvements in downforce as more air is directed into the side pod diffusers...or, it is a total disaster and creates lift instead of downforce.

View attachment 57593
Click to expand...

I'm definitely interested in your results. (y)
 
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