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Everything posted by JMortensen
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FWIW, the shifter bushings on the 2 ZX NA transmissions with this issue were fine. Both of us had replaced with factory bushings.
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Something similar happened to my car on the track, and has happened to my friends car twice on the street. Ours got REALLY locked into 5th and another gear at the same time. On hers, the trans had to be pulled and the shift pin moved by hand. Our solution was to shim up the detent springs. It happened so rarely, I can't tell you for sure whether that worked.
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Serious Twin Element Rear Wing
JMortensen replied to 260DET's topic in Windtunnel Test Results and Analysis
Images not working. EDIT--yes they are, it's just so faint I didn't see it. Clicked around and hit them though. -
Camber change after 1.5" drop?
JMortensen replied to mtnickel's topic in Brakes, Wheels, Suspension and Chassis
If you drive like a grandma, your rear tires will wear the insides first. If you drive hard, the front tires will wear the outsides first. Either way, if you rotate them a lot you should do OK. -
Just looking for input on tires for my GMC 1500 which will, with any luck, be towing my Z all over western WA pretty soon here.
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Camber change after 1.5" drop?
JMortensen replied to mtnickel's topic in Brakes, Wheels, Suspension and Chassis
If you have the capability to do all of that, then you might consider making a set of front control arms. It's not that hard to do, a bunch of people have made arms and posted about it here (240hoke and bjhines come to mind, there have been many others). I had a machinist make mine in the attached pic, they're about as simple as you could ask for. Just a stock arm that was cut, a tube welded into the cut end, and the threaded tube end welded into that. I would make it so that with the rod end all the way adjusted down, they are stock length. If you made your own front arms and bought rear camber bushings, I'd guess you'd be into it less than $200. $75 for the rear camber bushings, and a little bit of tubing, some threaded tube ends and some rod ends and jam nuts for the front. EDIT--Looks like I saw the price on the front camber bushings. Rears are more expensive. Still should be able to get out of it for $300ish. -
13" wheels on a 240Z?
JMortensen replied to surplus-addict's topic in Brakes, Wheels, Suspension and Chassis
You'll have to grind on the calipers to fit 13's IIRC. I put some on my Z years ago, and that is my vague recollection. -
Camber change after 1.5" drop?
JMortensen replied to mtnickel's topic in Brakes, Wheels, Suspension and Chassis
Lowering a bit on your typical Z gets you too much neg camber in back and still not enough in front. Simple solution is an adjustable front control arm for the front and camber bushings for the rear. Be careful not to try and get too much neg camber in front as you quickly run out of tie rod adjustment. -
Coilovers without sectioning strut tubes.
JMortensen replied to richie2619's topic in Brakes, Wheels, Suspension and Chassis
I ran unsectioned struts and camber plates for years. Couple things to note: 1. Camber plates are shorter than rubber hats, so you'll lower the car without losing bump travel just by installing them. 2. The larger diameter tire you want to run, the lower you'll want the car to be to make it "look right". 3. You don't LOSE travel when you lower a Z without sectioning the struts. You move where the ride height is within the travel. Instead of having 3" of droop and 3" of compression, you might have 1" compression and 5" droop. That's where my car was. 4. When you get really low weird things start happening, particularly to bump steer. I had some hellacious bump steer in my car when running it really low. If you want to keep your car at its current height, but you're going to take out the ST springs and add camber plates, you'll GAIN bump travel, which will be better and you can also run a stiffer spring to keep it off the bumpstops. Suggestion: don't get polyurethane bumpstops. Get softer ones from Koni or similar. Bumpstops are a big deal. -
I was going to mention the wire diameter. I got the thick stuff (I think it was around .040) and regretted it for my rotor bolts. It's amazing what a pain in the ass it is to twist that stuff up, even with pliers.
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Just check to see that the ring gear mating surface is true. If you have ring gear runout, then your backlash will be impossible to adjust properly.
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Serious Twin Element Rear Wing
JMortensen replied to 260DET's topic in Windtunnel Test Results and Analysis
I have a side view of the profiles for some wings McBeath designed for someone else too... -
Gary Savage is making them. There are threads on the subject. Search "R200 clutches" and you should find him, and some threads explaining why you want to replace the stock spacers with actual clutches.
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Chassis Setup (corner weights)
JMortensen replied to 74_5.0L_Z's topic in Brakes, Wheels, Suspension and Chassis
Christ that would be like a 1000 lb spring on my car. -
Chassis Setup (corner weights)
JMortensen replied to 74_5.0L_Z's topic in Brakes, Wheels, Suspension and Chassis
Just a word against adjusting track width with rod ends. There is a rule of thumb that says 1.5x the thread diameter in the tube, so that leaves you with something like 5/16" adjustment IIRC. You can push it farther than that, but we have had threads in the past where control arms failed in this area (AZC chromoly arms). Also, droop limiters in the back should help that inside tire wear. -
Serious Twin Element Rear Wing
JMortensen replied to 260DET's topic in Windtunnel Test Results and Analysis
I've looked at it and considered various options. The Ciro Design wing is popular here for autoxing and it uses two of the old APR aluminum extrusion elements. The second flap is the same size as the wing, which is not what McBeath recommends at all, yet it is pretty popular and obviously it does work. I've seen one of these on an Evo where the AL wing had cracked around the mount after a few years use, just a warning. You don't want your wing to exit without warning. The problem is that it is hard to find a chord deep enough for use with a second flap. Most of them are 10" and McBeath suggest that the flap should be 30% of the overall chord length (wing + flap), so that would be about a 4" chord on the flap. It's hard to find a good wing that small. APR did have an aluminum two element with a 7.5 inch main and I think it was a 3.5" flap (I think this is the one used in the wind tunnel testing), so that flap would be close to the right size flap for a 10" wing, but as I recall it only came in one relatively narrow width. The other problem in my particular case is that I can have 8 square feet of wing, so optimized I think I had it figured with a 14" chord on the main, and it's hard to find wings that big. FWIW, I don't believe APR makes that AL dual element wing anymore. One option is to make your own aluminum wing. There was a guy on the pegasus porsche site who built his own AL wing. There is another thread on that forum where he made another, bigger wing too: http://forums.pelicanparts.com/porsche-911-technical-forum/294153-poor-mans-aero-wingin.html I was thinking that I would buy a standard wing from Kognition or G-Stream or one of the other quality budget makers, and then make my own flap. Already have all the aluminum to do the flap, in fact. The idea would be to put the flap on for autox, and then take it off for track days, just by changing the end plates. I have a bit of hesitation with the idea of running a HUGE dual element at track speeds because I don't think I'll have the front downforce to match. In autoxing, the forces are low enough that you can't really get too much from any one area. There are quite a few sites out there that talk about making your own CF or FG wing too, with vacuum bagging and the whole deal. Usually involves a hot knife and foam core. Look around and you'll find some. I'm still apprehensive about composites so I didn't look into this that deeply. McBeath wrote a book on composites, FYI. If you use an off the shelf main plane and then make a flap, the main wing isn't going to be optimized for the flap, but I don't think that makes it a losing proposition, at least it's not in the case of the Ciro wing, which is far from optimized and still works. The nice thing about rear wings is that you can always go bigger. I wonder if it wouldn't be easier to just get a larger single element wing than to go through the hassle of the dual in your case. Are you exceeding the capability of your existing wing and can't find a larger single to replace it with? -
Wet driving tire advice
JMortensen replied to ancientz's topic in Brakes, Wheels, Suspension and Chassis
Yes, they slip in the wet (and the dry). -
Wet driving tire advice
JMortensen replied to ancientz's topic in Brakes, Wheels, Suspension and Chassis
I have 195/50/15 R1R's on my Miata and when it rains I go from about 2/3rds down the time sheet up to about top 1/3rd. They kick ass in the rain. -
I've got a thread here on shimming the breakaway torque on a similar R200 LSD. It's not hard to do, but I wouldn't do it just because your car makes less power than an STi. Coffey is right, there are MANY variables to consider, and for most people it's not going to make a huge difference, and shimming will only make it more likely to chatter which some people really don't like. My $.02, run it and if you still get inside wheel spin, then worry about changing it.
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Why 1.75"? When I was deciding the SCCA had a reg for 1.75 x .120 for roll bars (not a cage, just a bar) on cars my weight. They were also making noises about changing the spec for a full cage at the time. I ended up guessing the wrong way, as they REDUCED the spec at the time from 1.5 x .120 to 1.5 x .095. My 1.75 x .120 6 point cage and driver's door bars are significantly heavier than they needed to be. If I were doing a cage right now I'd go 1.5 x .095. I know you drag race, so if NHRA wants something bigger that's a good reason, but other than that lighter is better. Also if you get into chassis stiffening members and you end up with a 12 point or something like the rest of us crazy idiots, do the stiffening tubes in something lighter weight. Mine are 1.625 x .065.
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Has anyone tried this type of air deflector?
JMortensen replied to djwarner's topic in Windtunnel Test Results and Analysis
Agree with Richard. FWIW, when you see these deflectors on Blazers and wagons, I think the idea there is to keep the rear window from getting dirty, rather than to lessen the separation of flow on the hatch. As far as solutions to the flow separation, you could look at WRX vs EVO. The WRX had a roof mounted deflector along the top that did the same basic thing. If I recall, the EVO's VGs were the better solution, but those were sedans with a pretty steep rear window angle. Since the angle of the hatch isn't that severe, I don't think you would want these things on the side directing side air across the window. Seems like the side deflectors would be high drag.