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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.

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.

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.

There was someone here recently who was looking for the emissions decal, as he couldn't pass smog without it.

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.

Four bathroom scales would do it

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

Parts wanted forum

If you have the same issue on each side, could you just swap the calipers side-to-side and fix the issue?

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.

No, see, I knew what I was talking about the whole time! 😏 Thanks for the correction. My brain obviously still hasn't recovered from the holidays.

According to his build thread its a CD009.

Sparks from the rear end dragging I believe.

They're canards, essentially. They'll add downforce, but they're so small I'd imagine it'll be barely measurable.

Carbon Signal

I assume that's why this is a project thread.

Have you tested all the other sensors to make sure they're still reading correctly?

Xenonzcar.com has everything you need

I don't think that's his picture, just an example.

Sorry, I should have said two pins that go to +12V and 2 that are routed to ground, with switches or a component in each circuit. Those are their states when the relay is not triggered. I didn't communicate that very well, so that's my fault. Once the relay is triggered, then the output pin has 12V like you said. I'm glad you got it figured out.

Four pin relays have two grounds and two positive, not 3 positive and 1 ground. I could guess at what the wires are based only on that, but you really should be able to figure it out based on the wiring diagram. Trace LY as far as you can and see if it runs to ground somewhere.

If you don't have a step you will completely stop all flow through the radiator other than the circular areas where the fans are. You need some amount of space behind the radiator for there to be airflow.

What kind of pads are you running? If you're overheating your stock pads, you may be able to just go to a more aggressive pad and avoid the work of setting up ducts.

Often times ducting is needed for road racing. The higher airflow prevents heat soak and fade that you don't run into with short Auto-X runs.