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A Gurney flap creates suction on its rear side. The flow doesn't have to be perfect, and you aren't getting laminar flow anywhere on a car. Look at basically any racecar with a radiator ducted to the hood. There's a Gurney flap to increase the suction in its wake. Flow isn't binary. It isn't clean or dirty, and pressure isn't just high or low. There's varying degrees to all of it. The smoke in the Ecoboost picture you posted is still flowing through that area, even if it's a little messy. The more you vent out the top and rear of the wheel well, the cleaner the flow will be alongside it because there won't be as much spill. He's done a pretty good job of that on the car in the video, so the flow by his wheels is likely even better than the aforementioned Ecoboost picture.

I try to avoid making absolute statements without having run the CFD, but I'm pretty doubtful that you'd get even close to the same benefit from the vortices that you'd get from a Gurney flap. The vortex lowers the pressure in the area, but not like the flap would. The flap essentially creates a vacuum behind the flap that the vent air has to come out and fill.

I'm confused what you mean by the dive planes would do better. The Gurney flap is to lower the pressure behind it and help get air out of the wheel wells, not create downforce by themselves

Everything from the usual suspects I find doesn't fit under the 272mm, but there may be something out there other than the T3 kit. If you decide to go with the Maxima calipers and Z31 rotors, I believe I have a setup and live in LA. Would be happy to sell them to you.

Great write up and car. That's a hell of a shell you got for $3k.

The NACA inlets don't really need to be in an area of particularly high pressure to work. They just require the flow to be attached to the surface. The total pressure coming into the inlet should easily overcome any elevated static pressure on the rear of the car.

A bot posting about a bot. That's a new one for me

What type of suspension bushings do you have?

https://forums.hybridz.org/profile/58825-sophiaprin/ Nonsense post in a long-dead topic

The 280ZX also came with manual or power rack-and-pinion steering. You should be able to pick one of those up easily enough. Post a wanted ad in one of the popular Datsun parts groups on Facebook. Be careful about scammers though.

Here's another one. It's very subtle and might actually be a real person, but they post about 5 meaningless but not obviously spam comments in a row, and then will sneak in a link or reference to 4wheelparts or similar.

@tube80z

Just spam bots searching for specific terms to spam and try to drive traffic to a website. We really need another mod or two to be added from the active users to delete the posts and ban the accounts.

Could always just order some shorter springs rather than having to cut and weld the perches. Costs money vs time, but as time goes on I'm more and more willing to spend the former in an effort to save the latter.

What material?

The horror stories I've heard about warping make me uneasy about blasting. What type of media do they use?

I'm in LA as well and have been thinking for quite a while about taking my car to Metalworks in Eugene. If I get it dipped I'd really like to get it e-coated, though. There used to be a place in Seattle that did it, but they closed down during the pandemic.

The clocking is necessary to maintain a constant rate, but in reality I don't know if you'd notice a huge difference on a steering shaft. I always love sharing this video. The final 2 demonstrations show why the clocking is important.

Ah ok. Nice work. You should be good then.

Did you go poly on the tension rod as well? That has been shown to cause cracking for some people

The flange is the one drawn by Ron, and then I think it's just a pretty standard plenum design. Looks the same as every blingy plenum for other engines. Nothing groundbreaking, but nice to have something on the market for those who want it I guess.

So I ran through your parts list, googling for the exact part when I could and estimating when I had to. Prices in USD Turbo 1800 BC 350 Inj 400 Plugs 25 Intake 1500 FMIC 1200 Pump 100 FPR 150 ECU 1600 Clutch 500 TOTAL 7620 Convert that to AUD and it's $11,283 at current exchange rates. With those parts I would expect an even larger bill, to be honest. $2k-4k for install as well as tuning is a bargain in my opinion.

I'm not near my car right now and don't remember the footwell area well enough to 100% confirm that's the correct spot, but I believe you're correct. The oblong holes in the engine bay are fed by ducts like these: https://www.thezstore.com/product/5706/reproduction-fresh-air-duct-kit-70-73-240z They take air from the round holes on the core support and feed those ducts. Then there would be a round knob at the bottom of the dash to control a flapper on the blocked off round holes in the interior. That mechanism looks like this: https://www.autopartone.com/products/72-73-datsun-240z-oem-climate-control-fresh-air-vent-switch-right I had been planning on doing the same thing, and I think others have run wires that way in the past.

The guy whose harmonic balancer fell off is on this forum. He's been posting about it over in the turbo section.

Ah man that sucks. Just when you almost had it all buttoned up. Hopefully it's something minor and you have it back on the road quickly.