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Everything posted by JMortensen
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KW is supposed to be top notch. Dude's background music is super annoying.
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Seems like it should do the same thing. IIRC the adjustable slave has about 1" of threaded section. Couldn't tell you how much of that is unusably short, I seem to remember running around the middle of the adjustment. Could probably get a longer bolt and cut and make a new pin if necessary. EDIT-at some point the angle on the fork is going to be bad and that might cause wear...
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One way limits slip on accel (common for FWD). 1.5 way limits some on decel, more on accel. 2 way does both accel and decel equally. FWIW, a limited slip doesn't "lock" but a locker does. That means even if you lift one tire off the ground, the tire on the ground will still get power. A limited slip limits, unload a tire and it will spin. High end 1.5 ways are adjustable by changing the ramp angles on the cross pin shaft. If you do sim racing you can see adjustments for percentage lock under accel and decel, that's adjusting the slip for each. Here is a screen from Assetto Corsa. This fully adjustable limited slip is set up basically like a 2 way. Should probably back off that decel a bit, but it's fairly stable under braking. 2 ways are nice for drifters because they tend to make the car loose on corner entry. If I jacked up the power and coast settings the car would act more like a welded rear end. If I lowered them all the way it would be like having no LSD at all. Helicals can be set up to do any of the 3 options, 1, 1.5, or 2 way.
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IMSA GTU vintage racer build
JMortensen replied to clarkspeed's topic in S30 Series - 240z, 260z, 280z
Roof mounted pedals was a bold choice. -
I think you'll have a hard time finding flares built to the precision you'd need to take advantage of that tiny gap from the rivnut being reduced. I only have experience with the zccjdm flares and the MAS flares from back in the day, but neither of those was a super tight fit. Another option is to silicone them on. Saw a video of a guy in Japan doing a RWB 911 and he just used a bead of black silicone to fix the seam, looked good to me, but I don't mind the welting either and just have the flares screwed on with nothing at all to fix the gaps on my own car, so YMMV.
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I think you're probably more likely to warp the sheet metal welding than installing rivnuts, and rivnuts can be easily removed if they get messed up or cross threaded. Rivnuts are easier and work great. I'm sure the welded nuts will work, but I just don't see the benefit.
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240z SCCA vintage race car, restoration
JMortensen replied to AydinZ71's topic in S30 Series - 240z, 260z, 280z
You can also slot or redrill the inner pivot on the crossmember, move the LCA pivot up and this changes bumpsteer and RC. -
I didn't summon you, troll. Go away.
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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
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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.
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'78 280z 5 speed transmission rebuilt - still rattles
JMortensen replied to alex44's topic in S30 Series - 240z, 260z, 280z
Yeah, I'd learn to live with it, especially if you're going to lighten up the flywheel (which is very worthwhile). -
'78 280z 5 speed transmission rebuilt - still rattles
JMortensen replied to alex44's topic in S30 Series - 240z, 260z, 280z
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:
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LS1 street cam recommendations
JMortensen replied to nick-james's topic in Gen III & IV Chevy V8Z Tech Board
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.
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Front tires rubbing on fender
JMortensen replied to fusion's topic in Brakes, Wheels, Suspension and Chassis
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.
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Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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. -
how do you feel your engine swap changes the character of your Z?
JMortensen replied to thedarkie's topic in Non Tech Board
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. -
Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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. -
Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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? -
Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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. -
Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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. -
Rear spoilers, opinions and comments welcome
JMortensen replied to fusion's topic in Body Kits & Paint
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.