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JMortensen

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JMortensen last won the day on June 17

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About JMortensen

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    JonDatsun
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  1. JMortensen

    HybridZ PNW Auto-x Day

    Ooh, tuner challenge! That sounds like the ticket: open class racing. Would allow for better wing placement, paneled bottom, diffuser, etc...
  2. JMortensen

    HybridZ PNW Auto-x Day

    Add "both" to your poll. I am going to try for both and have no preference one way or the other. Only issue for me is I was over the sound limit last time, so I might have to spend my time screwing around with my supertrapps instead of socializing.
  3. I had a machinist set up a cam for me and he checked a couple different springs and landed on Schneider's as having the best seat pressure for my .490/280 cam. The springs and retainers are easy to come by.
  4. I checked it out and it's easy to see why the scrub is reduced. This actually looks like a pretty easy solution. I'm guessing there is a 12.2" Wilwood setup for an S13 that's readily available too. Still want to see what can be done with the dual ball joints, but thanks again, very helpful!
  5. That's a really interesting option, thanks. How would one go about figuring out which spindles to try? Assuming some Nissan stuff would have the same bolt pattern so might be able to bolt the existing suspension up to it, thinking would need new front brakes, or at least new caliper brackets. I know Nissan used the Set 2 and Set 6 bearings up through the 300ZX, so that part might be the same if I stayed Nissan.
  6. That's an interesting idea Dan, but I'd have several problems: 1. The cage is built to support the stock strut tower, and I'd be moving it over quite a ways. 2. Car would be way wider than it needs to be 3. Don't really want staggered tires. Always had issues getting the front end to hook up, and that's going to be exacerbated with narrower front tires 4. Tie rods will interfere with the wheels. Possible that a 16 x 10 or better, a 16 x 12 might work, but one of the reasons I went with the 15x14 is the easy availability of the FA tires 5. Doesn't really fix the scrub radius issue. Obviously would be less with a narrower rim, but might still be 4" if I couldn't do the 5.5" backspace. I like the dual ball joint thing because it could potentially be easy to implement, we'll see what the computers say. If the dual ball joint doesn't work and the car doesn't hook up with my new tires then I think I'll go one of two ways; either SLA or go to a 3" flare and run a 15 x 11 with the 275/35/15 Hoosier or 16 x 12 if I can find an appropriate slick to fit.
  7. I told Cary I would get some more measurements. The rack on mine is 5.5" in front of the LCA pivot. Tried to measure the height of the inner and outer pivots but car is on jackstands now and I didn't want to take it off just for that measurement. Stock steer knuckles and rack moved forward and up and tie rods are using .9125" bumpsteer shim. Bumpsteer is minimized. Hopefully that gives you enough to go on. If not it will have to wait until next week most likely.
  8. JMortensen

    HybridZ PNW Auto-x Day

    Looks like I should be ready for either/both days.
  9. The way the wheel moves is the part that kinda blows my mind. It moves back and forth a little bit, and you would think that would be really bad for steering feel or make the handling wonky, but new Mustangs are really good autoxers, so they must have something right. Same with the single ball joint BMWs. Many (all?) of the newer ones have the ball joint offset forward from the bottom of the strut. Again, this is going to mean that the wheel isn't going it pivot around that lower ball joint, so that should cause some weirdness in the feel, but they're very successful autoxers. I have power steering so I can't tell you how heavy it would be without. I know it was pretty hard to turn at low speeds with 10" slicks on it, so it's probably not good with 14s... There is a lot more to transplanting another strut system than it seems like. Angle of the struts and spindles, steer knuckle length, brakes, etc. If I were going to do that I'd rather figure out SLA. Probably same effort and if done correctly, better end result.
  10. General rules: Front engined cars usually have lower roll center in front and rear RC is slightly higher than front. For performance, low front roll center is best. If it's too high what it does is force the wheels to move outwards in order for the suspension to compress. This can really make it hard for the outside suspension to work under load. Conversely, an underground RC will want to compress the suspension more than it would otherwise with cornering forces. Higher roll centers can be used to allow softer spring rates. If you spring the car stiff enough, you can run low roll centers and not have excessive roll and reduce the jacking forces. As a kind of rule of thumb, 80% of the turn happens in the first 1/10th of the turn. This is why the minutia is important. If the car won't turn in the instant you turn the wheel, then you're not getting around the turn very well, regardless of what it will do once it changes direction and is in a steady state corner. Again, as a general rule, the end of the car with the lower RC will tend to grip better, so RC is a way to change handling balance. This is why you have a lower RC in front. Solid axle cars have a hard time with high rear RCs and they use different solutions to lower the rear RC to improve handling. Not really germane to this convo, but here is a link to a discussion of a Mumford link, which is a modified Watts link that can lower rear RC: http://www.locostusa.com/forums/viewtopic.php?t=77
  11. I've started my own thread on the dual ball joint setup, going to see how feasible it is because I have serious issues with scrub with 15x14 wheels.
  12. Inner control arm pivot height: 5.5" Ball Joint height: 6" Control arm length: 11.5" Clearance to xmember: 2 3/4"
  13. If that's all it takes it sounds pretty easy to do, but I feel like there have got to be some complications we're not factoring in. Looking at that Pontiac video looks like the end links will have to be reworked and made as long as possible. Cary has some software that figures it out too. He's asked me for a few dimensions, but he's gone until next week, so I haven't gotten around to measuring yet. Thread should pick up next week.
  14. That's similar to how the Autopower bars attach. They used to be SCCA legal. Not sure if they are anymore. I do think it's a LOT better for seat clearance, but it's very hard to connect door bars to. I haven't seen one of their bolt in cages in a really long time, but I seem to recall they had one door bar that clamped to the roll bar then bent down in front of the door and went forward to the A pillar. I don't think the door bar bent into the door area and I think it was only a single door bar.
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