JMortensen

Yeah his Datsun project is basically putting his Enviate hill climb chassis under a very modded Z kinda sorta shape. It will be badass, and there won't be very much Datsun left.

Sounds like a badass swap to me. My understanding is 325 whp is pretty easy to do NA. If you start thinking that isn't enough power, turbo it and make ridiculous power. BeastieHatch has a J swapped Civic and it's putting down 600 to the front wheels (now has electric motors on the rears too). https://www.turnology.com/features/beastie-hatchback-the-v6-turbo-powered-civic-to-end-all-civics/

I think the strongest argument for it is the way circle track racers will adjust their crossweights to make the car turn left better, because they don't give a shit about turning right; what improves one hurts the other, so getting them balanced or close should make the car handle turns in opposite directions more equally. Also see this on rovals, where they'll set road race cars up to handle on the oval portion because it's higher speed than the infield and results in better lap times overall. https://grassrootsmotorsports.com/articles/understanding-corner-weights/ Would be interested to hear how far off yours were and how big a difference it made after fixing it.

Stock LCA is 14.5" IIRC. Pretty sure on that. On mine I made the control arms 15" long, left the axles stock, and I have my camber plate tops flipped around to reduce neg camber in back. I had pretty stupid amounts of neg camber with the ride height that I have.

Re: ride quality. I took my dad for a ride in my Z with 200/250 springs, camber plates, heims jointed fronts and TC rods, and Illuminas on 1 back when he was about 75 or so. His comment: "Seats are comfy!" With respect to camber change, what you're looking for is to keep the tread flat under load. With independent suspension, body roll = camber loss, so with soft springs you might be rolling over more than your static camber can compensate for, and then you roll onto the sidewall of the tire. You need more camber or less roll to keep that contact patch flat. If you have the camber right you should be a little hotter on the inside. Adding caster helps as that will give you more neg camber when the wheel is turned, but you'll have to trim your airdam/fender if you haven't already. You seem like you are already past this stage, but for other people who might stumble in here, you can use a dab of shoe polish running over the edge of the tire onto the sidewall in 3 or 4 spots to see how far you're rolling over onto the sidewall. Inflating the tire more keeps it from flopping over as much but also hurts grip if you do it too much. Better to adjust the camber so that you can run the optimal pressure for your particular tire. You're wrong about the camber going negative when the control arm goes past level. It's when the control arm goes perpendicular to the strut tube that you would actually start to lose camber. This was pointed out to me many years ago by blueovalz, who built a really awesome Z here, then sold it and moved on and no longer posts. You can confirm this with Dan McGrath's post here, in what is IMO the best thread on the whole forum:

There are problems with all of these solutions: Bolt in camber plates won't move enough to get you the neg camber you need for autocrossing (I think you'll find 2 degrees isn't sufficient unless you're running all season tires and not real serious about it). Stickier tires will create more roll which requires more neg camber. Camber bushings with delrin/aluminum don't allow the control arm angle to change, which it HAS to do as the suspension compresses. TC moves in an arc, so the control arm should have some front to back movement available. Some of that might get taken up in TC bushing flex, some in crossmember flex, but it's not ideal. Camber adjustment with these also adjusts bumpsteer. Moving the xmember pivot requires removing the washers that are welded to the xmember, which is tough to do without screwing up the thin xmember metal. Moving them out will gain you some camber, but you can't go too far before you run out of threads on the tie rods. I slotted my xmember and found that moving the pivot up about 7/16" minimized bumpsteer. The old JTR recommendation was up 3/4, out 1/4, which is too high on the bumpsteer for my car, and still not enough neg camber. Longer control arms will have the same problem with the tie rod threads. My suggestion would be a better camber plate like Ground Control or TTT. This will allow enough movement to actually get the camber you want without worrying about the tie rods. The tie rods used to be more of an issue, because one of them is LH thread 14x1.5, which is tough to find taps and dies for when making your own, but now there are several vendors selling aftermarket tie rods. If you get new tie rods with a turnbuckle, that basically doubles the amount you can adjust before you start getting too close to the end, and that frees you up a bit. If you go with replacement tie rods, then my second choice after the good camber plates would be custom LCAs with the heims joint inner, and you can decide to make them longer or move the pivot. Moving the pivot would have the added benefit of being able to adjust the bumpsteer. EDIT TO ADD: if you're worried about the 14mm shaft on the top of the Tokicos in combination with monoball camber plates, Ground control makes bushings to fit them in a 5/8" monoball. I'm sure TTT does the same.

I think you're missing out here, regardless of whether you do it diagonally or setting fronts even. Mine was really far out. I'd be shocked if fixing this didn't help.

There are SO MANY other things that could affect it, that I think your results (and mine) aren't really meaningful for other people. The thing about the Miatas is that they have a tendency to lock up the LF tire under braking. Not sure that I've heard anyone say that about their Z. FWIW I learned a new trick the other day: when corner weighting, set the front weights equal, rather than setting the diagonals even. This is supposed to load the front tires more evenly under braking. Between setting the fronts equal and making the lines equal length, you MIGHT be able to tell the difference. Probably not... To me these are things that you do when you're building because it's theoretically better. The actual difference it makes is probably pretty minute.

I didn't think the position of the T made a difference either, but since I was plumbing it anyway I went ahead and did it as evenly as I could.

I read something on Miata forums about the length of the hard lines being different, and this contributing to their tendency to lock up the LF tire, so I tried to put the Ts in the lines right in the middle. But yeah, T the front lines and go to the front master, and T the rears and go to the rear master.

Since you mentioned bumpstops, what kind of bumpstops are you going to run? They're actually a very important part of the suspension, and most people with Zs run hard, crude, polyurethane from Energy Suspension, which suck donkey balls. I would suggest if you don't already have them you look at some of the longer, more compressible ones like Koni or FatCat Motorsports sells. They act more like a spring than a piece whose only responsibility is to keep suspension parts from slamming together.

I wouldn't think it would be a problem if you have a needle bearing in the top hat already, but since it obviously is, bearings on the springs should help.

It's pretty common for the spring to wear on the coilover sleeves. The problem is worse when you use longer springs. The longer the spring, the more it deflects. Bearings under one or both ends of the springs are a good idea as they help the spring to compress with less friction and will allow the strut to rotate more freely. https://www.ebay.com/itm/Strange-S1409-Spring-Seat-Bearing-Kit-2-pack-Torrington/123588766568?hash=item1cc676eb68:g:SvYAAOSwNm5ZsbJl

dupe

That doesn't look abnormal. This thread goes over a bunch of causes:

The G Machine TC setup is better than running poly in front IMO. Still should run rubber on the back so that it moves freely. They do wear, and may need replacing every few years. I used to take them apart and inspect and grease them up every so often. This video on polyurethane bushings in a Miata is really really really good. If you understand how the bushing is supposed to work than you can reduce some of the problems you'll encounter with the poly bushings that you'll buy for a Z, main one being the poly is too wide and the center sleeve is too short on pretty much everything as it comes out of the box. You can fix with a belt sander. Also I'd suggest drilling and tapping the control arms and sway bar saddles for zerk fittings. You will have to drill a hole in the bushing as well, but this will allow the bushings to be greased during services and will cut down on friction a lot. Don't bother with the inside bushings on the rear control arms. The bushing saddles aren't tight enough and the grease won't get in between the bushing and the sleeve. Outers on rear lcas works, as does inners on front, and the saddles on the sway bars.

FWIW, I had a brand new brake system with new calipers, hard lines, soft lines, and dual masters that wouldn't bleed. Tried by myself, with help, with a mity vac and couldn't get a good pedal. What finally worked for me was using a 60cc food syringe and putting the fluid in through the bleeders at the calipers. I think there was a bubble that just wouldn't come out of the masters no matter what I did, but pushing the fluid backwards dislodged it.

Yes, the hoop can be welded to the surrounding sheet. I have some shear panels welded between the sides of the car just behind the door and the vertical part of the hoop, and a couple 4" wide tabs where I welded the map bar to the top of the hoop. I totally agree that this is the way to take care of the C (actually B since Z has no B pillar) pillar paint cracking. 20 years or so ago I had a friend who ripped the A pillar off of his 240 autoxing it. He fixed the A pillar and welded in a 4 point bar and added one 6" wide shear plate just on the top and that got rid of all the interior panel creaking when he would go into driveways.

I can definitely relate to Michael. Mine took 12 years to drive, although I took a couple years off. My suggestion is if you really want a done up chassis that's caged and ready to race, buy someone else's race car and start from there. If it's a street car I'd focus on things that are easy to accomplish and don't get too hung up on perfection. Things like strut tower bars make a big difference on a 240. Look at Apex Engineering's K member front crossmember setups, bolt in and connects the front X member to the TC rod buckets. Another simple area to brace is from the end of the rocker panel to the upper frame rail. You can pull the front fenders, weld those tubes in, cut the little piece that separates the fender from the wheel well, and bolt the fender back on.

The boxes are the same, it's the pedals that are different. If you got an automatic brake pedal should install right into your existing pedal box.

In my limited experience when mechanical pumps fail they spray oil all over the engine compartment. Electric pump doesn't put heat in the fuel like mech pump does, if that matters. Had issues with vapor lock on the L6 way back when. I fixed by eliminating the stock mech pump and fuel rail. Not sure if SBC has that problem very often.

I feel like I can handle tuning a carb if I have some track time and my wideband. I got my triple 44s to run pretty well. I was guessing on the carb and guessed wrong, but I am way more confident in my ability to troubleshoot a carb than troubleshoot EFI.

I am... electronically challenged. I can cut and weld stuff together, but I can't wire a lamp.

L33 5.3L Aluminum block 799 heads .581 220/224 112+2 with Demon 650. Dyno results: 337 whp, 334 tq. Looks like he grabbed the wrong run and so it shows 330. Take my word for it. Needless to say all the moves I did on the carb in preparation were WRONG. Catastrophically wrong, like it would barely make it through a pull wrong, check out the massive dip in the torque curve! I put bigger jets in it, then brought still bigger jets, we needed to go smaller on everything. Leaned it out, leaned it out some more, more leaning, more lean, then finally it put out the 337 number. It sounded like it had a miss at the start, and as we got further along it was running rougher and rougher. Suspect bad plugs or wires. Didn't have time to change them out, as he didn't have plugs and wires there. They thought this was the cause of the rough graph. A BMW came in and did a pull and theirs was smooth. While we were making jetting changes we started talking about running it 1:1 where primaries and secondaries open together. I had tried setting it up like that and it just fell on its face, but we made it work. I'm happy about that because I won't get into the secondaries as I'm midway through a corner. It's not dialed in but it's safe to race and I'm happy with the numbers, of course I have to wonder where it would be running on all cylinders...

I don't think you'll get it done for $10K. For that amount you could replace the 305 with a crate SBC that makes a lot more power and upgrade the trans and diff. Probably run out of money before you get to suspension and brakes.