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JMortensen

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JMortensen last won the day on June 3

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About JMortensen

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  1. Ride the brake and gas up to the line. Re the blues, my friends were running 510s, but I recall they didn't do much until hot like the R4. Maybe I'm wrong, maybe they upgraded the compound since the 20th century.
  2. I went with Hawk Blacks based on Coffey's recommendation. He was saying they work on the big tracks and at autocrosses, although I think he ran at Willow Springs a lot which is not hard on brakes. So far I can confirm that they work at autox without heating up. Hoping they'll be OK on the track with some big ducts. Back in the late 90s I was running Porterfield R4 and friends were running Hawk Blues. Both had to get warm before they worked. Not safe on street.
  3. So you had brake temp issues? Boiled fluid or just cooked pads? Want to go out there this year, have more power and weight than you with 12.2 vented rotors and working on good 3" vents in the front.
  4. I like the Apex Engineered arms. Others like the T3 arms. This thread details the idea behind the Apex and compares to designs like the T3. Pay particular attention to the idea of shimming the strut fore/aft, something I think T3 advertises as a feature of their design (it's a bad idea):
  5. TERRIBLE design on those rears. A little refresher on flat plate control arms:
  6. As I mentioned on the previous page, a prop valve in the front is never a good idea. As brake pressure increases, the proportion of braking done by the circuit with the valve decreases. With a valve in the front, the harder you hit the brakes, the lower the percentage of front brakes you get. This is not good, because the harder you hit the brakes, the more weight transfers to the front wheels and off of the rears. So the wheels with less traction get an increasing proportion of the braking effort as you step on the brakes harder and harder. "Proportioning Modifications We could start this section by clearly stating that you should not modify your proportioning valve. But, what fun would that be? In all seriousness, making changes to the proportioning valve to effect brake bias should be left to those with the proper tools and measurement devices, but if you have tweaked your vehicle beyond recognition, this may be your only solution to restore a sense of proper bias to your braking system. We’ll start here with three of the most basic rules regarding proportioning valve installation and selection. 1. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed if the factory unit is still in place. Proportioning valves in series with one another can do nasty, unpredictable things! 2. If you have the deeply-rooted need to install your own adjustable proportioning valve, be advised that they should NEVER be installed in-line to the front brakes. The effect would be to make your vehicle rear-biased before you could say “terminal oversteer.” Front brake line pressure should always be left alone – only the rear pressures should be considered for proportioning. 3. In all cases, the basic brake system balance needs to be close to optimized to start with. This is the only way that a proportioning valve can be effectively utilized. You should never assume that simply adding a proportioning valve will address all rear-bias conditions, as even the best proportioning valves must be well-matched to the target vehicle." https://www.apcautotech.com/getmedia/d958a29e-4ebf-41fd-931f-bf7e4451801b/brake-proportioning-valves.pdf
  7. Not if the prop valve was set to a lower setting than the stock one it replaced.
  8. I'd make a cardboard template, trace it on one side then flip and trace on the other side. Cut with a dremel and cutoff wheel. I don't think they'll look right together with ZGs, plus you'll have the same issue with not having enough clearance for the tire with ZGs matching the body line the way everyone wants to mount them. You will probably have to find a set of matching fronts, or switch to ZGs all around and mount them wrong and slowly drive me crazy.
  9. Forgot to say the flare install on yours looks fine. If you don't like them I'd try reshaping before undoing all the work. Personally I'd be inclined to cut the "mud flap" part off of the back of the flare. Never was a fan of the MSA IMSA flares they used to sell because they had mud flaps on both ends of the car, and the front of the tire exposed, which is kinda backwards from what you'd want from an aero perspective.
  10. Depends on the suspension. If it has basically stock suspension you can install them lower, but when you start moving to shorter coilovers or sectioned strut housings, you start running out of room for the wheel to move up into the wheel well real fast. Camber plates make it a lot worse, especially on a 280 because the strut isolators are 3" tall vs 2" for 240Z. I cut my fenders and then put the suspension together with no spring and compressed and realized that my tire was hitting metal. Had to cut again much higher to prevent that from happening . In my case I cut the fenderwells so that they were flat from the top of the arch in the well to the outside of the quarter. Basically couldn't have cut any higher and made more room for the tire unless I had removed the whole wheel tub and rebuilt it. When the strut hits the bumpstop, there is about 1/2" space from the top of the tire to the fenderwell. I think the bumpstop is more than 1/2" long but I have super stiff springs so hopefully I won't have any issues. It's a pet peeve of mine to see ZG flares mounted way too low in the rear with really wide tires. Just obvious that nobody took the time to see if there was clearance for the tire, they just held the flare up to the body and marked and cut it there with no thought as to functionality. The other one that really bugs me is the tire and wheel being 1" from the inside curve of the flare, hellaflush style. You know that tire will hit the inside of the flare almost instantly, but still people do it all the time...
  11. I went and looked. Only the one, sorry.
  12. Just a quick question, Dan: I looked at doing my xmember kind of like yours and ignoring the stock bushing locations, and it seems to me (vague memory) that literally pulling the steel tube out of the aluminum pinion housing was a potential problem. Did you look into how those are attached, and are you sure that mounting the steel tube is strong enough? Would hate to see your rack disassemble itself on the track. Cool to see slotted LCA holes on someone else's car.
  13. My guess: part of the tranny jack.
  14. I didn't mean to say that your brake system was one way or the other, more just a general warning to anyone who might read this that you don't want a prop valve in the front circuit, that's all. If it helps 1.75 pistons in front and 1.38 pistons in rear is what Arizona Z Car used to sell (maybe still does???) with a hydraulic prop valve.
  15. I think your problem is that you're doing the equivalent of testing a cooling system thermostat by putting it in a pot of water on an electric blanket. Autometer brake pressure gauge goes to 2000 psi. I don't know what "normal" brake pressures are, but I suspect that you're WAAAAAAAY too low to test them in this manner. https://www.autometer.com/2-5-8-brake-press-0-2000-psi-no-tubing.html EDIT--If you put those gauges in front and rear and then turned the dial, then you could get useful info. FWIW I had a brake system where adjusting the prop valve made no difference at all, using 4x4 front calipers and early ZX rear disc. The problem was that the rears were so undersize that it didn't need to be reduced at all. If that's the case for anyone, the solution is bigger rear brakes or smaller fronts, NOT to put the prop valve in the front circuit. Hydraulic prop valves are not "proportioning" so you don't get a linear 70% or whatever amount of the pressure. They have a knee, after which the pressure falls off. What this means is that if you put one in the front brake circuit, the harder you step on the brakes the less front brake pressure you will get. Anyone who has looked at brake balancing knows that the harder you step on the brakes, the more weight transfers to the front, the less pressure you want in the rear. So it's a really bad idea to put a prop valve in the front brakes.
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