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JMortensen

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Everything posted by JMortensen

  1. Second on Dutchman. Best axle supplier I used when I was making stuff. It was done right, first time.
  2. You can't get around the limitation of a 1.250" stub axle no matter what CVs you use. IMO you're never going to keep the stub axles from breaking at that power level. Time for backhalf or an IRS solution that allows for larger diameter stub axles. I'd look to an 8.8 if you want IRS. Might as well upgrade that too while you're in there. The diffs are cheap and readily available, lockers and limited slips galore, wide range of gear ratios, there are very strong CV options for them, etc.
  3. You can specify the site in your google search this way: whatever you are searching for site:forums.hybridz.org
  4. Is Tokico still in business? I thought they were, but they aren't offering these for Z's anymore. Might see if they can fix it. I remember a lifetime warranty when I bought mine in the 90s
  5. Not sure why you'd want inboard brakes on a 9" rear end, but looks like this guy pretty much has the rest covered: I think that car is the best that I've seen. I love it. There are a couple things I would change, but not many. I do like what I did with my own with the 15x14 wheels and slicks, but I'm sure he would smoke me on an autox course and road course wouldn't even be close as he's got an extra couple hundred hp on my L33 truck engine which should put out ~350whp.
  6. To be fair, I have read of some people losing the control arm bushings on a hard launch. Seems to me Jeromio did that about 15 years ago and posted here, and there might have been another one. I'm not going to go looking for it now though. The point, for me, anyway, is that if the bolts are tight, the tube in the control arm already does this job. IIRC the way that happened to him is that the bolts came loose and the control arm slid out of the bushings under hard accel.
  7. Ok then. Obviously had that wrong. Seems like it's not necessary so long as you keep the big ass bolts on the control arms tight. Probably have to sand down the bushings so that you can actually bottom the bolts out. Hardly anyone does that though.
  8. If I'm looking at it right, this goes between the lower control arms in the back, connecting the bushings. There is a piece for that in the stock suspension. Looked at their site, and it appears that they use a different brace mounted higher, which would allow for the use of a finned cover with a bigger sump. I guess you could use this piece and their other brace together? Not sure that would really improve anything. I dunno. The more I'm looking at it the more I'm not sure what it is. Can't figure out why you would want the brace up higher and this one too, since they both do the same thing.
  9. One thing occurs to me. If they slotted the holes on both sides, you could adjust the toe with this. You'd need to pry the arms instead of using a turnbuckle like the Poor Man's Toe Adjuster that many of us have made, but that's not such a big deal if you're doing an alignment every couple years.
  10. There is already a link there that ties those points together. This one looks cooler, but I think that's the only benefit.
  11. I would suggest that you consider what you're going to want for camber and work from there. If you want more neg camber than plates will get you, then I'd make the LCAs at least as wide as the stock ones at full compression. With this setup you'd have 5/8" adjustability before you fell afoul of the 1.5x rule. I can't really tell you what plates and stock LCAs will get for max neg camber. I suppose it depends on your ride height. I don't think you can go farther than about 2.5 degrees (would be good to have someone else verify that), so if you are running newer radial slicks or Dot R tires you might need more camber to make them happy. Bias slicks don't need much camber by comparison. Also keep in mind that there is not a lot of thread engagement in the tie rods, so if you add a bunch of width there you'll need to deal with those too. That's easier now as there are aftermarket ones available.
  12. The scrub radius issue is a problem. I've got ridiculously wide 15x14 wheels on the front of mine. Had to use spacers to clear the bumpsteer spacers on the tie rod. Car has about 6" scrub, which is a lot. I did this after talking to Tony Woodward of the custom steering rack company and he told me that it really wasn't that big a deal and he had seen plenty of fast cars with 6" scrub or more. I think his experience was more to do with circle track though. You would want the camber plate as far in as you could manage to minimize scrub. The imaginary line from the top of the plate and the ball joint and through the tire contact patch is where the scrub radius is measured from. It's the distance from that intersection with the ground and the center of the tire. Tube80z was looking at a dual LCA system to work with the strut to alleviate the scrub issue on this thread: He kinda stalled out on that and I don't have software to figure it out, but that's an option if you have the software or know someone who can help you out with that. Otherwise, I think SLA is the best solution and you can solve other issues while you're in there, like adding more camber gain, fixing bumpsteer, using 5 lug hubs and bigger brakes, etc.
  13. Looks like I saw a year old post there. Oh well. Probably missed caperix but might help someone else down the line...
  14. This is incorrect. Many of us have held this erroneous opinion at one point, including myself. BlueovalZ explained it to me maybe 15 years ago: the control arm doesn't need to be level to start losing camber, it needs to be perpendicular to the strut before it starts losing camber. This is basically impossible, unless you're running really tall tires and trying to scrape the frame on the ground. 24" wheels or something ridiculous would be required to get there. There is a really good thread (IMO best thread on this site) started by Tom Holt and with lots of info from Dan McGrath, aka 74_5.0L_Z, where he takes on all the suspension kinematics. The Z has a very flat camber curve. It just doesn't have enough gain to offset the roll with soft springs. Here is the post where he diagrams the camber curve:
  15. Agree with Leon. I have to wonder if there is a measurable difference in a 6-3-1 vs 6-2-1 design. I would think if you grouped the primaries so that you got an exhaust pulse every 120 degrees on the 6-2-1 you'd get roughly the same effect as the 6-3-1. The main thing is the primary lengths, and according to Vizard, even that is secondary to not having as many bends in the tubing on a V8. You see some people go to great lengths to get equal length primaries, and I think especially when they use a lot of really tight bends to make the rear cylinder primary as long as the front, they're probably losing overall.
  16. I believe there are differences in the pedal assemblies, although I can't tell you what they are. The pedal box is the same between stick and auto, just use different pedals, so if you could find a 280 brake and clutch pedal you should be good to go.
  17. I did. Haven't yet sprayed oil in there, but that's the plan. I am going to use Corrosion X when I eventually do it.
  18. I think you're right about creating a space for corrosion, but if you look, the whole chassis is built by layering sheet metal and spot welding it together. My 70 is pretty rust free... except for all of those areas. I just cut the pass seat mount out. Rust between the seat mount and the floor. No rust anywhere else on the floor, as I fixed it years ago. That's the story for the whole car. My take is that trying to get the rails perfectly sealed is a fool's errand. For frame rails and hollow cavities, I think the best thing to do is shoot oil inside of them after welding. This is what Krown rust prevention in Canada does: https://www.krown.com/en/ I suppose you could spray oil everywhere there are overlapping sheet metal panels too, but there are a lot of them inside the cabin, and you'd have to dig out the seam sealer to get access. It would be messy.
  19. I think it's a matter of running the right compound that still functions at high temps. Back in the day katman had a thread where he was talking about running 2 3" ducts to the front brakes to keep them cool. I looked for it and couldn't find it. Joe Demers was making a heat sink that fit between the piston and brake pad, might be a tight fit on a 14" wheel. Found it: http://www.coolshims.com/coolshims-technology.php. John Coffey talked about adjusting drums in between sessions. Heard from several people that ditching the AL rear drums and running the cast iron ones off of a 510 is an upgrade because they can take more heat. If brake recirculators are allowed that would be a biggee, as this would protect against boiling fluid: http://www.colemanracing.com/Brake-Recirculator-P3775.aspx
  20. Coilovers are a better solution, but no problems with cutting. I ran my first Z on cut springs for quite a while. My friend who cut mine also ran 240 springs and perches on 280ZX struts in his street 510s. He cut all of the springs, and again, never had any issues. There are a lot of rednecks that cut them with a torch, or just heat the spring up until it sags to the proper height. This takes the temper out of the spring, and can cause the spring to fail. If you cut them with a cutoff wheel the heat is very localized and doesn't cause a problem IME.
  21. Terry sold his Z and bought a Manta, which he did up to an even higher level than the Z. It's just awesome! http://www.fototime.com/ftweb/bin/ft.dll/pictures?userid={7DC317B0-8EDB-4B2E-A837-F708D07C9769}&AlbumId={B0B466A9-4204-4F78-BC4C-DEBD9966B5B9}&GroupId={E9BD2EDD-A388-43BD-B264-DFF5CB43B8E2}&nt=a I still see Pete posting from time to time. Katman was moving away to focus on engineering on more modern racecars, E36s at the time. I assume if he's still in it he's probably working on newer stuff than that. Mike Kelly sold his Z after several failed attempts to put an engine in it. No idea on Denny. I miss Coffey. We emailed or FB'd with each other on a weekly basis. As to miata.net, they allow for the newbie questions over and over. I haven't seen the antipathy that you describe towards those posts. Seems like there isn't a "protect the searchability" drive like we have here. I know when I got my 99 I searched and found so many threads on my particular issue that I posted again and immediately got an answer with no admonition to search. Turns out coils were dead, killed precat, killed cat. PO had replaced coils and left it like that and I had to go through the exhaust to fix.
  22. FB is great for sharing pictures. For sharing tech info, it sucks. I often respond to FB posts with links to posts here a lot just to save the hassle of typing it out or having to copy/paste. Not an attempt to boost numbers here, but if it works out that way so much the better. When I was an admin here we talked about what the purpose of the forum was, and the general idea was that it should be like a library or an wiki page where people could go to find the info they were looking for. Adding a million posts about the same issue makes searching harder, so that was strongly discouraged. I still think this is the right policy, and I'm sorry to see that it isn't as strictly enforced, and also happy to have had my hand in pruning the information tree in that way. There is a mix of "HybridZ is great" and "HybridZ screwed themselves by being too strict" on FB but seems to me most of the other forums have declining membership as well, and this one seems to have a fairly consistent level of tech postings that is higher than most of the others that I'm on (miata.net beats this forum out, but I think it's pretty safe to say there are a lot more Miata owners than Z owners at this point). I think the response to the funding issue a year or so ago showed what is really going on. Casual Z owners don't care enough to engage in a serious forum, they just want to post pics and have people like them. People who are more serious about modifying or racing are going to stick around, because this is (still) a repository of very good info.
  23. That's the second time I've been wrong in a very similar way in about a week's time: the other was trying to relate a traction vs slip angle curve to a tire that was broken loose. Ah well, thanks for the correction. What did you think about the videos I posted?
  24. Thought this through a little more. I think a better way to explain would be to say that a stalled wing doesn't create lift, but instead creates drag because of the big wake that is created by the flow separation. You wouldn't say that there is more pressure on the rear of the car inside the wake than on top of the car, and likewise there is more pressure on the top of a wing when it flow is attached than there is when it is stalled.
  25. First, let me say that I'm enjoying digging into this, so thank you. Second, I'll point out that I'm not an engineer and have no training whatsoever, but I have read a few books on aero. Third, I think you're missing something here. When you look at a plane wing that is not stalled, it makes aerodynamically EFFICIENT lift. A stalled wing still makes lift, but there is more drag than lift and that's what causes the plane to fall out of the sky. Just look at the yarn on the plane wing. When it isn't stalled, the yarn is pressed down on the wing surface. When it stalls, the yarn is no longer pressed down, and it flails all over the place. This is proof that there is more downforce with the flow attached to the surface than when it stalls. The yarn is literally pressed down on the wing surface. Back to cars: the thing that we're trying to prevent is the rear of the car from acting like a stalled wing, and the reason why we're trying to prevent it is to reduce the size of the wake behind the car and its drag. Also, if we have a spoiler or wing that would be in the region of separated flow, we can make it work. The purpose of the whale tail is to change the angle of the flow off of the back of the car. If the flow over the top of the car points down, you will get lift. If it points up, you will get downforce. You can intuit this if you watch F1 in the rain and see the rooster tails shooting up 20 feet behind the cars, but it's not something that I ever read in a book. There is a guy on youtube that runs Gray's Garage and he does water flow testing with model cars, and he talks about this at some length, in addition to showing the rolling separation vortices behind various models. Pretty interesting. Here's one that compares your whale tail 911 vs other fastbacks with CFD: Here's another where he does the water tunnel testing with an MR2, which is particularly relevant as it has a Pantera style rear deck:
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