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calZ

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About calZ

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    California

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  1. As long as you don't mind seeing where you're driving and not having a hood, I don't see why not. Do it and post progress here.
  2. He said he has to use the original brakes.
  3. calZ

    1978 280z 3.1L Turbo LDS Parting Out

    This thread is over two years old and he hasn't been online in almost a year. Don't have too much hope.
  4. Don't worry about it. Even people who deal with aero design on a regular basis get things wrong. I really like Gray's Garage. Those two videos are good. I used to race a Mk1 MR2, so the short series of clips he posted for them was very useful.
  5. Thank you as well. Talking aero on Zs is more fun for me than discussing it on my day-to-day work. You're mistaken on this. The yarn lays nicely on the surface inside attached flow because the smooth airflow is pulling it backwards. When flow is separated, it swirls, pulling the yarn every which way. Here's a lift curve for a couple NACA airfoils and a flat plate. In a fluid, pressure varies inversely with velocity. The faster a fluid flows along a surface, the lower the pressure is on that surface. Once separation occurs, the average pressure difference between the upper and lower surfaces shrinks or disappears, which causes the loss of lift. Agreed. Attached flow minimizes drag and allows any other aerodynamic device to work better. Kind of the same response as above, but a wing's lift doesn't correlate directly to its drag. Look up the term "drag bucket" to see how you can minimize drag on a wing by choosing an airfoil that fits your flight profile.
  6. To your point about the front of our roofs resembling the leading edge of a wing, I'd have to agree with a caveat. VGs aren't on aircraft wings to help out at cruising AoAs. They're there to stave off stall and maintain lift and control power at extreme angles of attack. A car never really sees anything other than a static angle, so having them in the flattest area doesn't make sense. You could put them ON the windshield in an effort to help the turning onto the roof. That would be an interesting study. Putting them on the roof near the front, though, is going to be less effective than further downstream where the closeout angle is more severe. On to the link you posted. There's a lot of things going on there that make me question the quality of the CFD work. The comparison images are almost worthless since the writers didn't use consistent color scales, and detail is lost since they used banded coloring. I could go on, but it's not entirely relevant. Just be wary of blindly trusting that study. That said, their results aren't necessarily wrong. They very well could be reducing lift the amount that they quote. That doesn't have anything to do with what VGs are intended to do and would be more of an unintended result. Their sole job is to re-energize the boundary layer by tripping it and creating vortices, thereby keeping flow attached. In the case of the Evo, their purpose is to reduce drag and get more air on the wing. If you speed up the flow over the rear of top side of an S30 the pressure is going to drop and lift will go up. That's just physics. It's why 911s had to go to whale tails to keep the rear ends down.
  7. The VGs are near the leading edge on a wing because that's where the most curvature is and where the boundary layers needs more energy to stay attached at high angles of attack. I don't know exactly what the flow looks like coming over the rear of the windshield, but I'd guess it's relatively well-behaved over the roof. The lift increase with the VGs tells me that they increased the speed of the flow over the hatch. That's always the problem with fastback cars. The more you reduce the drag and keep flow from separating, the more the rear end wants to take off.
  8. The reason older cars don't do it is because of heat. A return system maintains a lower fuel temperature at the injectors. The heat that gets sent back to the fuel tank, though, and causes more fuel evaporation. To adhere to modern admissions standards, OEMs have chosen to deal with the extra heat in the injected fuel rather than the extra evaporation. Your setup looks good to me.
  9. calZ

    Reproducing factory decals - What's needed?

    There was someone here recently who was looking for the emissions decal, as he couldn't pass smog without it.
  10. The rear hatch is relatively steep, but you don't have a chance in hell of getting the flow to reattach with a Pantera hatch. Yes, an abrupt surface can be used to decrease the overall area of unattached flow, but that's done by reducing the closeout angle and then abruptly changing slope. You aren't doing that when you add a Pantera hatch. You're taking the same slope that isn't ideal and then making it worse. It makes perfect sense to me and isn't counter-intuitive at all.
  11. calZ

    Z Car weights

    Four bathroom scales would do it
  12. There might be cheaper options, but this would 100% work and is still reasonably priced. http://www.dakotadigital.com/index.cfm/page/ptype=product/product_id=127/category_id=694/mode=prod/prd127.htm
  13. If you have the same issue on each side, could you just swap the calipers side-to-side and fix the issue?
  14. There's a ChampCar team that runs the Silver Mine unit in their car, and it has held up under race conditions so far. The EZ-steer kits are made to go onto ATVs with gross weight ratings of up to 3000lbs, and most Zs don't weight more than that.
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