JMortensen

Lightened 432R with dual exhaust (adding weight back?) complete with S20 and crap Nismo roll bar: https://www.facebook.com/photo/?fbid=10159065665906559&set=pcb.1922406734626606

If you're bolting in a strut brace and have a welder, would it be possible to weld up a better brace, either off of the strut tower or off of your braces to the firewall? I think the idea of a master cyl brace is a good one, just not convinced that the bracket they're selling would do much.

Yeah, I'd learn to live with it, especially if you're going to lighten up the flywheel (which is very worthwhile).

Yep. Can add that the noise is a lot more prevalent in cars with light flywheels. Here's a thread from Miata.net where they talk about the rattle associated with light flywheels, with one person describing it as I usually do, sounding like marbles rolling around inside the transmission. I think the consensus is that it's gear lash, and the gears in the trans are rocking back and forth between power strokes, so the lighter the flywheel and the slower the idle speed and the lopier the cam, the more likely you are to hear it. https://forum.miata.net/vb/showthread.php?t=732227&highlight=flywheel+rattle

Can be improved upon by tweaking the angle of the louvers. Bigger slots and more vertical leading louvers looks uglier, works better. Here is a video from AJ Hartman who makes CF wings and diffusers and splitters, and he tests in the wind tunnel with the Race Louvers all the time. He doesn't give away all the info, but he does give you the basic gist of what they found. Found one specifically on louvers:

Watch some Holdener videos. He states the lift and duration. They're not "all the same" but any big cam manufacturer should be able to sell you a cam that makes power on an LS1 and if you stick with similar lift and duration, you'll get similar results. It's not hard to get a big bump.

Can't help you on that one. I think it might be in "How to Modify" but I sold that book 10 years ago.

26" is big for a Z. If you pull the tire back you're reducing caster. Might work, but will increase understeer.

I've used one before. It's impossible to cut a straight line without clamping a straight edge to it. If you were cutting out a bunch of weird shaped panels it would be a great choice. Produces tiny crescent moon shaped chunks that are sharp AF. Don't use without pants that are long enough to cover the tops of your shoes. For my $.02, I prefer the sheet metal shears (like scissors) for straight lines: https://www.harborfreight.com/pistol-grip-air-shears-98580.html When I have to cut curves I use a bandsaw or a jigsaw. They won't cut a curve as nice as the nibbler, but they're a lot easier to control and it's easy enough to sand the rough edges with a belt sander.

I doubt that a flap right in front of the cowl would turn the positive pressure area into a negative one, maybe as you said, change the pressure enough to get the air to flow. You could think if the windshield as being a flap that is 20x as tall and I think the windshield would overpower the flap. It is something that could be easily tested though; just tape a piece of angle to the hood in front of the cowl vents. Probably easier than making a block off plate to close up the firewall.

I've got 14" wide slicks, V8 swap and I'm at 2352 lbs. Could turbo the 5.3 and be at 2425 lbs or so and have 1000 hp if I wanted. I don't want, but it's well within the realm of possibility. The 3's are doing pretty well at the local autox. I appreciate what they are and the advantages that electric cars have. I just want that battery weight to come down.

I think this is the wrong move, but it would be pretty easy to test if you put yarn tufts on the cowl vents. If they blow into the cowl, you're forcing air under the hood. You mention relieving the low pressure under the hood, but you want low pressure under the hood. You'll already have low pressure on top of the hood as the air flows past, and if you can get it, you want lowER pressure under the hood. The pressure differential will act on the surface of the hood, making downforce. If you equalize the pressure, you'll eliminate the downforce. The opposite is when you see a hood blowing up like a balloon, like the Janspeed car. You can imagine if that's .1 psi on the bottom surface of the hood, which is something like 3x5 feet as a rough estimate, that's 2160 square inches or 216 lbs pushing up on the bottom side of the hood. You can see what looks like here. Leading edge and sides of the hood are bowed up pretty severely. Looks like a thin FG hood, but makes the point pretty clearly: Not sure I follow you here, but just to give an example here is a link to some pre-fab rad ducts: https://www.jegs.com/p/Five-Star-Race-Car-Bodies/Five-Star-Radiator-Ducts/2834016/10002/-1 Years ago I linked to an article from Circle Track magazine where they showed the difference between a ramped duct with a smaller inlet like in the link above vs a duct as big as the hole in the grill without a ramp, and there was a significant advantage to the smaller opening with the angled duct. I want to say it was worth 100 lbs downforce or something crazy like that. The article is gone now, unfortunately. A NASCAR isn't exactly the same as a Z because circle track cars have no fenderwells and they can exhaust a lot of air out of the sides, but I would still do the duct that way since it's better in theory and I don't think it will be significantly harder to make. YMMV.

You're searching forums for your own name so that you can chime in with your thread jacking pedant posts? LOL I suppose I should have known. Like a hair trigger Beetlejuice. Please, can we spend less time talking about how you're misusing words and more time talking about spoilers and aero and how they work, and less about who made them or making excuses for them?

He's asking a question about a spoiler. We are having a conversation about which spoiler works best and why. You are derailing it with bullshit about why we shouldn't criticize a given part because it was produced 50 years ago. Must be using that British English, or your language pedantry isn't as strong as your Datsun pedantry. From Merriam-Webster: critique: an act of criticizing criticism 1a: the act of criticizing usually unfavorably I don't need to rein in anything. You should rein in your tendency to interject with offended posts that have nothing to do with critiques of these shoddy parts.

I think we finally got to the heart of it, Alan. Only took 20 years. The HybridZ forum is dedicated to putting modern engines and aero on the S30. We have every right to criticize what was done 50 years ago and there is no mandate for anyone to consider why it was done that way originally. The purpose of the site is to modernize the cars, using all of the knowledge and developments that have taken place since then, not to consider the limitations of engineers back then or restrict ourselves to them, let alone canonize those badly designed roll bars or flares or undertrays on race cars. Don't force your hagiographic pedantry on me, and for my part I won't bolt a carbon fiber swan neck wing onto your 432 when you aren't looking.

It's a no brainer that the tray would help reduce drag, although we know through 50 years of experience that making it flat, incorporating a splitter in front and having it lower at the front than the back will make it better than the original design. Some of the stuff they did back in the day was pretty shady. Look at their homologated roll bar. Terrible. And now we'll get Alan Thomas in here being an ass because I criticized the factory roll bar. BTW, you better hope those aren't his pics. He's super generous about it when people use his pics to spread the general knowledge online.

Probably not useful to dredge up the past, but my take on it at the time was that they probably asked Bob if a flat paneled floor would make downforce, Bob looked at a stock ride height Z with stock front end and said paneling the bottom wouldn't do anything for downforce. That's probably true. You'd need it a lot lower and with some rake to do much for downforce. Mike's take away was "undercar aero doesn't work on Z's" and this info came from on high. BOB said it. I mean, it was BOB, FFS. I don't know what Mike asked him about the radiator duct, but he specifically called me out and tried to make an example of me on that one. We already didn't get along, and hey, I rub a lot of people the wrong way and I don't make excuses for it, but that one really got on my nerves because he obviously hadn't thought to test a rad duct and then tried to make me look like an idiot for asking about it. You can go back and read all the drama if you want, but I think the basic point was this: They put together a wind tunnel test, which I donated to and am eternally grateful for. Mike said he read some books but in the end they didn't test anything outside of some simple bolt ons. I pissed Mike off really badly because he went all out on this and as soon as he posted the results I started asking about all the stuff I thought he should have done and didn't. The second time he asked for donations I said things like "Make a flat plywood floor that you can clamp or screw to the bottom to test" and Matt came back telling me how ridiculous it was to use plywood and how they were making all of their parts out of carbon fiber. Before testing to see if they worked. Then they got pissed and started throwing insults.

They did not test any paneled floor ideas at all and said Bob at the wind tunnel told them it wouldn't work. Mike Kelley who organized the first test said that the radiator ducting was a bad idea because Bob said so. I mentioned testing flat bottoms they were talking about doing a follow up wind tunnel test and pissed off the guys involved to the point where I think I single handedly killed the project. Double Then they went and put both ideas on their own cars. Mike and Matt did NOT accept suggestions very well, let alone criticisms. Quickly resorted to insults and took their ball and went home. I can tell you that I emailed Simon McBeath, the author of Competition Car Aerodynamics and he suggested paneling as much of the bottom side as possible. The things you need to look out for are getting air to the trans and diff for cooling (NACA ducts work to get some air in there), exhaust heat, and when I do mine I will go aluminum in the middle so that the paneling itself isn't flammable.

http://i46.photobucket.com/albums/f127/bjhines/V8 240Z project/IMAG0417.jpg

Look at the way bjhines did his air dam support. He covered the whole space between the rad support and the air dam, preventing air from going under the rad support. That's a much better way than what you're showing here. Doesn't prevent the air from going up and over the top, but 1/2 the job done is better than none.

Both. Stock height is kind of ridiculously high for track/high speed stuff. The front of the car is wide open and just shovels air in under the hood where it gets trapped and ends up going under the car, creating lots of drag. If your rules allow, making a duct from the front to the radiator so that all the air that goes in the front has to go through the radiator will reduce the amount of air going in, as without a duct it goes down in front of the rad and up over the top, and through all the holes in the rad support. Also louvering the hood to get rid of that air under the hood without forcing it under the car is a good idea.

Not sure if this link direct to the album will work. https://www.facebook.com/media/set/?set=a.1581733071873043&type=3

DM me your email address I'll send you the full size ones, or you can find them in my albums on FB: https://www.facebook.com/Jon.E.Mortensen/