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JMortensen

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Everything posted by JMortensen

  1. There is very little money to be made in making performance parts for a 50 yo Japanese sports car, both because the market is so small and because for many people the attraction to these cars is that they're cheap. Maybe that last part will change, but certainly when I bought mine price was the primary concern. Seems to me that Apex does more engineering than most, since he actually shows his FEA results, etc, and looking at some of the other kludged together shit that has been sold his looks relatively good. That said, there have been problems, like the failure to produce the tra
  2. The wrong one. Hawk Black. John Coffey recommended them 15 years ago and I bought based on the idea that they have a decently wide temp range. There are better options these days. Main issue I have is insane amounts of dust.
  3. I think you'll find that all those warnings you heard about not having any bottom end are way overblown. It will be fine, you're going to love it.
  4. I had a .490/280 cam and wanted to step up to something like you have but ended up LS swapping instead. I love almost everything about the way lightened flywheels work. Revs drop faster so it will shift faster as a result, much easier to heel/toe, engine braking is better, acceleration is better. 2 complaints you'll hear about them is that they make it hard to hold a consistent speed on the freeway, and the trans will probably sound like it has marbles in it at idle in neutral. I never had a problem with the freeway thing at all, and the marbles thing is irritating, but worth it. I've read tha
  5. The lightest you can get, I'd go steel if possible, and with the least mass around the edge of the wheel. You see some with holes around the perimeter. That is the way to go, as removing mass from the edge is more important than in the middle. When you go light you do have to be good about not putting too much heat into the flywheel, so if you have bad habits, you'll want to get rid of them before you ruin your new part. FWIW the AZC one was 12 lbs, I drove with a heavy pressure plate and cammed L28 with 44s in traffic, was easy to drive. I think the crankshaft itself is so long and heavy t
  6. Takes 5 lbs off, OK. Turns a 25 lb flywheel down to 5? I don't think so, but I certainly wouldn't run it if they did. If you really want lightweight, get a button clutch that has a smaller diameter multiplate clutch on an automatic flexplate. Here's the dual 7.25" clutch I've got on my LS. IIRC the flexplate and clutch and everything was right around 20lbs.
  7. I did something similar with 1/4" steel after 3 different machinists looked at my old AZC flywheel. All three picked it up, looked at it for about 5 seconds, then looked at me and said: "That's cool. Do you have a scattershield?" I think the stuff he was selling after the 90s was better designed. Mine had sharp corner cuts right through the pressure plate bolt holes and nothing was radiused.
  8. Mine's a trailered autox car so not many miles on it. It definitely has some stone chips in the flares, but the biggest damage so far has come from hitting a cone with the rear flare. Spider cracked the gel coat. Still haven't decided what to do about it, but I don't want to put a lot of work into making it pretty because it's a Rustoleum painted race car.
  9. I dig it. Reminds me of the 80's 930 Turbo with the black guards on the rear flares. Was considering doing something similar on mine.
  10. Having the cell in the pass side was done back in the day. It offsets driver weight and makes a lot of room for a big ass diffuser, which isn't legal but could be made to be easily removed. Search youtube for AJ Hartmann, he makes CF parts and shows how to install onto the car, IIRC shows how his gigantic splitter and diffuser are removed so he can get the car on the trailer.
  11. The JTR manual says up 3/4, out 1/4 inch. IME from stock on a 240, you need to raise the pivot about 7/16" to minimize bumpsteer, without moving it outwards at all. Making either end wider will increase grip at that end, so if you have an understeering Z (which is their natural tendency) then making the front wider would help. Almost nobody does it though. Some racers will run wheel spacers for that reason, that's about it.
  12. I realized the the shock will still be topped out, so I was wrong about cutting the tube releasing the spring.
  13. I'm betting those wheel speed sensors could be used for traction control. That would be really cool. Is that part of your plan?
  14. What is up with the SCCA shutting down the season? Is that just a covid thing? Just saw something hit my inbox yesterday about it being shut down. I'll probably be out of commission this year due to an upcoming surgery anyway. Can't tell if your pic is ABS or fire suppression. LOL
  15. The springs on a Z are soft and aren't compressed that much. I've taken plenty of them off by just aiming the strut away from me and zipping the nut off with an impact. The top hat will only fly a couple feet. It's not a big deal on a Z. On most newer cars, MUCH different story and very dangerous. IIRC though the 240 front spring rate is under 100 lbs rear is just over, and is compressed an inch or two. Not that much force. 280 has slightly stiffer springs and similar compression distance. If you removed the springs and then couldn't get the gland nut loose then I would think that using a saw
  16. Welcome back Tom! I agree about social media, useless for tech. Great for posting pics and getting likes.
  17. Just tell Tilton what you're doing. They'll give you advice. Take it. Worst case scenario you need to swap a master or both. They're not that expensive. Or make your own thread and state what you have for brakes and people can give their thoughts.
  18. On the flip side of the pedal ratio vs master diameter/effort thing, if you don't have a booster then the pedal won't travel as far. If I let you drive my car you'd never come back with a comment about the brakes, either travel or effort. Just feels normal. As to your first drive comments, when I drove mine for the first time it was just around the block and I found that I could just step on the gas and roast the tires for basically as long as I held the pedal down. It was intimidating, and immediately brought up that Mark Donohue quote. Anyway once I got it out on the track I realized tha
  19. Again, nothing rotates around the spindle pin, so this isn't necessary. In the case of the bushings, the polyurethane or rubber is doing this. In the case of a rod end setup, they do have teflon impregnated steel races and chrome balls. Here's a shot of an aurora rod end, I've put green where the teflon lining is.
  20. Not only is it not necessary, it's harmful. The suspension should move with as little resistance as possible, and the resistance that you do have is provided intentionally by the shock and spring. That's why I posted that video on how properly designed PU bushings are made. You can copy some of their tricks with energy suspension stuff and improve them quite a bit. Cary convinced me to do a lot of things on my car in the search for the least amount of friction possible. That's why I have the weird sway bar mounted on heims joints that I do among other things.
  21. That is incorrect. The bushing has an inner sleeve which slides over the spindle pin. When you tighten down the nut on the end of the pin, it locks the sleeve in place, and the rubber distorts to allow for the motion of the arm. This is why you should tighten all of your bolts and nuts with the weight of the car on the ground when using rubber. You want the bushing not to be deflected at ride height, so that it can move equally easily and equally far in either direction. If you were to tighten the nuts on the spindle pins with the car in the air, then the rubber would deflect quite a bit ju
  22. The bolt SHOULD NOT be pivoting. It should be stationary, with the bushings or bearings moving independently of the bolt. If the bolt is spinning in the housing, it's going to wear the bolt. If you're using poly bushings, refer to the video I posted earlier, which shows the sleeves being captured and the poly rotating around the sleeve. If you're using rod ends, the monoball is captured and the rod ends do the pivoting.
  23. https://www.boltdepot.com/fastener-information/Bolts/US-Recommended-Torque.aspx 5/8-18 is 180 ft/lbs
  24. ztrix.com IMSA fenders are wider than the YZ stuff if that sounds appealing to you. I have read that back in the day they ran 16x14 or 16x15s. I have rear flares that were taken off of the molds for Frisselle's car, and they fit my 15x14s like a glove. Always thought the BSRs looked a bit wider, might be where the 16x15s come in...
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