calZ

100%. A lot of people think diffusers are only to help create downforce, but the reason they're on basically every road car now is for drag. When you're driving along, assuming no wind, you're going through perfectly still air. Any air that is not perfectly still once you've passed has had work done to it. Diffusers allow higher speed, lower pressure air below the car slow down and regain pressure, getting closer to ambient conditions. In a perfect(impossible) world, it would leave the back end of your car with ambient pressure and zero velocity. That would equate to no drag. Blunt rear ends just dump all that air into the freestream without recovering any energy from it. This is all basically trying to make the whole car a wing. Capture some air, force it to accelerate under the car, then allow it to slow down and exit the back of the car without separating. Look at F1 sidepods, for example. Using the whole car as a lifting body is how you're going to maximize downforce, but it's so hard to do if you don't have a bunch of time and money for R&D. Yep, suspension and driveline is a huge pain in the ass for aerodynamics. FWD cars are easier because you don't have the diff and axles hanging down in the back. The sooner you start your diffuser, the larger you can make it and the more you can get out of it. Being longer also means you can use a less aggressive angle and still get the height out of it you want. The angle is tough and dependent on your speeds. Too sharp and the air is just going to separate, rendering the diffuser useless, but too shallow and you aren't maximizing its effectiveness. Better than a flat plate is to have a smooth transition with a gradually increasing angle. It's really not that much harder to fabricate either.

I don't know if I've shared this before on the forum, but my day job is an aerodynamic analyst/designer. I work on planes more than cars, but if there is anything in the book that seems like it doesn't make sense or isn't covered, I could probably help decipher it. Some comments: 1. Absolute value of Cd is useful when comparing different vehicles, but I agree with deltas being the most useful when designing or modifying something. As long as your modeling/testing is equivalent, changes in Cd are accurate and reliable, and that's all that matters. You know how your car performs at whatever its current Cd is, so whether it's going to improve or not is what you need to know, not the true value of Cd. We're kind of now getting to the point where we'll fly UAVs for smaller programs based solely off CFD, but anything big or that carries people gets multiple wind tunnel tests during development. 2. Steady(well-behaved) flows are pretty easily modeled very accurately in CFD, but unsteady, messy flow is tough. You get into needing dynamic simulations which are very expensive computationally. It's trivial to run yaw simulations, so I'm not sure I agree that yaw is something that will surprise you if you're doing things on a computer or in a tunnel rather than just track testing. 5. Rear wings will always increase drag. I actually worked on a case where an SAE car gained a bunch of downforce with a front wing at zero drag penalty due to the upwash from the wing keeping a ton of air from hitting the front tires, but that's a niche situation. Air dams, flat floors, and diffusers are essentially "free" performance. You can lose both drag and lift if done properly. 6. I don't know if I agree with calling airdams a crutch, but an airdam without a flat floor is leaving a lot on the table. The less air you let under the car, the easier it is to manage and the easier it will be to make your diffuser effective. That's true with or without a flat floor. If you put a flat floor on but leave your front end the same, you're still going to generate a bunch of lift on the bottom of your front bumper for anything shaped like a Z. Modern cars are pretty good at not having much upward-facing area, but old cars with the diving board bumpers really need airdams. 7. Yep, adding aero to just one end of a balanced car is an easy recipe for an unbalanced car. Adding just a mild wing to a car prone to oversteer or a small splitter to one prone to understeer would be pretty safe, but you always have to be aware of the whole system.

They mention it in the article, but if you want to watch the entire build process, it's on the Street Bandito YouTube channel. A few years back he made a K-swapped carbon time attack Z. Tim also sells carbon Z body panels through his company, Industry Garage

No, he used to do it in runs since there are minimum orders. When jhm made the post about needing donations, I mentioned that merch runs since a good amount of money was always generated that way. We could easily do another one, but cockerstar hasn't been online in 2 years, so we'd need a volunteer to draw up a logo and organize the ordering and purchasing.

Any chance we could do another run of merch? I know that was really successful last time and I think provided a couple years' worth of costs.

Bot

There are a few people these days running the exhaust under the oil pan to the turbo on the right side. It's not unheard of

Is it not extremely out of balance with being as thick as it is with a bunch of holes on only one side?

@tube80z

https://kineticmotorworks.net/ https://invincibleextremes.com/shop/ols/products/datsun-240z-260z-280z-s30-ford-super-88-swap-kit

I still have no idea why you'd want to do this, but good on you for working at it.

Yes

If it isn't, it definitely could be.

A 9" with a 205 is too far imo, but a small amount of stretch has been proven to increase grip. Bulging sidewalls make the tire mushy.

I don't think I've ever seen a billet, CNC-machined backplate before. That's show car stuff

https://forums.hybridz.org/topic/36272-viper-v10-engine-in-a-z/page/2/#comment-755645

Haltech is a pretty good option with almost Motec features without the Motec price.

What are they?

Yes, you said this already. You said if you adjust the stop, the pedal will come up further. That would change your measurement, would it not?

How do you know the rod is too short if the pedal is resting on the stop?

The ad says it's $1000 for prep and paint, so I think a consistent color is more of his concern rather than the fine details.

ProTunerz makes one, but it's just a simple plenum. Looks nicer than the stock intake, though.

It does not need it and you can block it off. Someone on hybridz rigged up a way so he could switch between fresh air and recirculating, but it's not necessary. You could always just crack one of the side vents open if you want fresh air.

If the mounts don't fix it, you could always just put a small dent in it with a hammer where it rubs. I know it would be painful to do, but there have been plenty of tests showing that dents (especially just one) aren't going to noticeably affect things

Are you after just the bottom flange or like a full sewing pattern for the boot?