JMortensen

Just to be devil's advocate here, a buddy of mine spent 5 hours on the dyno yesterday. He dialed in his a/f ratio, and the guy doing it was making fun of his single wire O2 sensor a/f gauge. Turns out the gauge was dead nuts accurate. Jon

If you've got the 8" threaded sleeve you pretty much can't miss. Are you going to run 240 inserts and section the struts? I believe that is recommended if you're going really low. I would think that you could run the sleeve flush with the top of the strut tube and be fine. Jon

This might help: http://www.gordon-glasgow.org/lsd4.asp This is the last page of the LSD setup discussion. Read the other pages if you're going to get into it yourself. Looks like 70 lbs might be a little light for a full on race car. Jon

Just an interesting side point. I have 250 lb springs in back and a clutch type LSD. So you'd think that I would have this problem, right? You can see in my video that the butt swings to the right on one launch, and to the left on the other in my video previously posted here: http://hybridz.jimzdat.com/zpics.htm Also may not be a problem for me because of G Machine bushings as stated earlier. Jon

I believe the MSA roll bar is an Autopower bar which bolts to the fenderwells. You'd be much better off getting one that welded to the strut towers and the roof and the fenderwells if you are looking to stiffen the chassis. Maybe weld a pipe between the strut towers too. Jon

I think I've narrowed the list and come up with the following stuff: 280Z stub axles, new wheel bgs modern-motorsport.com CV conversion poly bushings for rear control arms JSK front brakes try another stock gas tank (maybe weld a sump into it) buy the welder and work on the other suspension stuff: adjustable rear toe setup diff mount move TC pivot raise front control arm pivot new tie rods adjustable sway bars I think I can get this all into $2k. I'm going to stick with the crappy JWT rear brakes for now. EDIT--realized rear brakes are JCR, not JWT. That sound a little more reasonable? Please understand that I already knew that the original full list wasn't going to happen. I'm just trying to figure out what I CAN do. Jon

Thanks Pop. I should have said that I already had Toy front calipers on solid rotors and the JWT rear disc setup, and an adjustable prop valve and 280ZX master. Every time I go to the track I end up burning the brakes right off the car. I won't even consider the Toy setup anymore, just too much weight and I'd like to get something that's capable of handling more heat. Plus a racer I know just had a more drastic problem with them. He snapped the bolts that hold the rotor and spacer on... He was using metric grade 8.8 hardware though (SAE grade 5). Also, I wouldn't exactly be selling stock interior parts. Some are, but I also have some custom door panels, a good carpet kit, thinking might just go huge and sell my dash with Autometer gauges and Recaro seats too. Already sold my Autopower roll bar to Aux. Jon

I've got a little money to spend, and I need help with what to spend it on. I've been mostly concerned with the rear end of the car, but there are a few little other things to do as well . Also, in this budget will have to be a welder. Thinking I'll try to find something used. Here's my complete list of things to do to my Z: 1. BRAKES. This HAS to get done this time around, #1 important thing to get done 2. Flares 3. rims and tires (was planning on steel circle track wheels, but correct width and offset for my 250/45/15 slicks) 4. diff mount (a la Jeromio) 5. JBJ link (or as Terry calls it, poor man's rear toe adjuster) 6. 4:11 diff 7. rear wheel bearings 8. CV conversion 9. fuel cell or fix tank. I've had a small leak from my tank that I've tried to fix about 8 times. Still can't get it fixed. Might be the seam in the tank leaking? 10. trans rebuild 11. Lexan windows 12. strip interior 13. would like to go up in spring rate with better struts (currently 200/250 w/Illuminas) 14. Make tie rods for front end and move pivots for control arms higher. 15. Frame rails 16. Fix rust. The car was painted about 6 years ago, and it has rust bubbling up. Not horrible, but it is there. 17. cut the ends off my sway bars and mod for adjustability and rod end links. 18. New TC rod mounts, possibly farther back, definitely higher up. 19. Relocate battery Stuff I already have: Complete 240 suspension out of a parts car Rebuild kit for the tranny w/main shaft nut 280ZXT nuts for stub axles My thoughts and confusion: 1st, the damn brakes HAVE to get done. I'd really like to go 5 lug for more wheel choices, but then I keep thinking that I don't need to since I have been totally happy running circle track wheels, and they're inexpensive. I'm thinking JSK fronts, Maxima front rotors in back with supra/cressida calipers in back, maybe just go to a Outlaw or Wilwood in back, depends on $$$ Would like aluminum 5 lug fronts, but I don't think that's in the budget, and I've got other things that have to get done. 2nd, the rust is really bugging me. There is a body shop a few miles away that has a Z tub epoxy primered waiting to go. I might be able to go down there and buy a whole new tub, which would make a lot of the other stuff easier, and I wouldn't have to fix any rust. I have about 5 minutes body experience helping a friend sand her Z about 10 years ago, so I'd be starting from scratch on that one. 3rd, I'm thinking maybe I should just find a rolling chassis that is already set up for racing (heard of a couple going CHEAP lately). Might save some money on brakes and suspension, and would probably save a hell of a lot of time with fixing rust and beefing up the frame. Might be able to find one already flared. 4th, once I start, I'll be able to sell a lot of my interior stuff that I take out and perhaps recoup some $$$, and maybe have a little more to throw at the car. My main priorities are brakes and fixing the gas tank or installing a cell. A lot of the stuff on the list I can do with a welder and a minimum amount of $$$ spent on materials. I used to just go to a friend's house to have something welded up, but now that I'm in WA and I have so much to do I feel like I need my own. I know there's no way to get all of this done on this budget. It would take 3 times the budget to get it ALL done, minimum. THIS CAR WILL BE 99% AUTOX/TRACK MACHINE 1% STREET. LOOKS ARE NOT IMPORTANT TO ME. IF IT GOES FAST I'M HAPPY. Anyone have any opinions, comments, suggestions, tips, tricks or other advice for me before I jump into this mess? Jon

If I understand your problem correctly then I suggest disconnecting the swaybar, which will allow you to drop the control arm down farther below the strut. Jon

I am 99% sure that I gave a 510 buddy an old stub axle out of a Z and he was able to use it in a 510. I think they are exactly the same. Jon

Ross had talked about machining ring gear spacers, but needed a group of people to commit to do so. I know that when I worked for Randy's Ring and Pinion we had some shouldered ring gear bolts made up for the new Jeep Rubicons, because they use smaller ring gear bolts than the previous Dana 44's, so shouldered bolts would also be an option (this was the exact same problem in a different vehicle). I think I'm just going to try and find a 200SXT diff myself. Jon

Interesting post, but I gotta say I've never noticed those problems. I know that I've bottomed my rear suspension, so maybe I've just been flexing the hell out of everything back there. I do remember getting together with a Z freak and a 510 freak and going thru about 10 halfshafts to find the shortest one to put on the driver's side. Aren't the 280 shafts supposedly narrower than the 240 shafts? Have I been fooling myself all this time? Or maybe because I've got camber adjusting bushings the pivots are moved out enough to prevent bind??? Regardless, you've put one more mod (CV conversion) on my list of things to do... maybe I won't get to autox this summer... Thanks, Jon

I agree with Rufus 100%. The check's in the mail Dan! Jon

OK, I either came up with something really brilliant or really really dumb, and I can't figure out which it is. Maybe you laserphiles can figure it out. The problem as I see it is projecting a laser to the front only will show you where the wheel is pointed, and will also show track change, but it will not show the change in the angle of the wheel (toe change) as the suspension moves. So your dot will move in an arc, but how this arc relates to change in toe is difficult to measure, unless you measure front and back, and can relate the changes front and back to the centerline of the wheel. So here's the idea: What if you used a mirror to bounce the laser back to the wheel area, and then watched the change in the distance between the laser and the reflected "target" point on the wheel? My thinking is that if the toe changed the reflected dot will get closer or farther from the laser itself. The laser could be "aimed" to the target could be adjusted by giving a little toe in or toe out so that the reflection hits where it would be convenient, and that point is then the target. Would take a little time to set up with the mirror; it would have to be perpendicular to the original beam, and the mirror would need to be flat for this to be accurate, but I think it could be done. I still think the dial indicators would be easier (just had to throw another little dig there), but at least with this idea you could measure not just where the dot goes, but also the angle at which the laser hits the mirror (toe angle). This should be pretty accurate because the toe angle will be magnified by the distance to the target and back, allowing for a really fine adjustment. Jon

Did you figure out how/where to order that thing LJ? Jon

OK, I'm sorry. I have been there too, so I guess I should be more understanding. Some times you gotta make do with what you have on hand. I can definitely understand that. One thing though. If you attach the lasers to the hubs when you raise the control arm that will change the angle of the hub, and your line is going to go farther across the floor than the hub actually moves out. I don't think that will negate your measurements, but it might make your parallel lines farther apart and harder to measure. Jon

I can't argue with your reasoning. That would work. No doubt. BUT-- you'll still be measuring on the floor with a ruler. I don't see how that could possibly be as accurate or as quick as using dial indicators, I've never seen a ruler that measures in .0001's. Seems like you and Owen REALLY want to use a laser for this. IMHO it just isn't necessary and makes the job twice as hard. I'm not trying to come off snotty or anything, but this is reminiscent of when I suggest that people can use an air hammer to take out stub axles. People just don't want to do it for some reason. I think I've told 50 people that method, and not a SINGLE person has actually done it that I am aware of. They want to make a special slide hammer instead. It's just not necessary, and they would have completed the job in the time it took just to go get the parts to make their slide hammer adapter thingy. Turns a 10 minute job into a hours long project. Again, not trying to get bitchy with anyone, but I think you're going to make the job a lot harder than it needs to be. I think you'll be pleased with the results regardless of how it gets done. If you're pushing the car really hard, this will make a noticeable difference. Good luck with your projects guys... Sorry if that was a little preachy or self-indulgent. Jon

The lasers are still going to move in and out while the suspension travels up and down, so you'd still need a way to measure the toe change independently of the track change. Level really shouldn't matter as long as it is safe enough to jack the car up in the first place. So slot the holes, figure out where the bumpsteer is fixed, drive straight to a muffler shop and have them weld the washers in place. Now its permanent and you don't have to worry about the bolts. Jon

Since the control arm and the hub move independently, any change here might not be a toe change. You'd still need a front and rear marker to tell the difference in the movement of the front vs the rear of the hub. So now you would need 4 laser pointers and a reference point. That's why if you buy a bump steer gauge it comes with a flat plate that can be bolted to the hub. I've also heard of people strapping a metal plate to the wheel itself. The plate gives you a lot more room to jack the control arm up and down without the dial indicators falling off the surface. Yes to your other statement. The difference in the movement between the front and rear dial indicators indicates the toe change. I don't know how much I moved the pivot point. Enough to fix the problem. I get kinda frustrated reading about people arguing about 3/4 or 15/16 or whatever. What should be done is it should be moved until the problem is solved. Anything else is (bad) guesswork. If anyone is going to go through the trouble to fix it, it may as well be fixed right. You're right about the potential for the car to yaw I suppose, although my rear wheels were on the ground at the time. I should have taken the time to make a plate to attach to the hub so that I could raise the control arm, but I can tell you the difference was night and day on the track. I did the test in a spot where my jack would not roll, and I had repeatable results. I didn't just check it once when I got to where I thought it was fixed, I made absolutely sure before I locked the bolts down, then checked it again to make sure nothing had moved. Jon

The ZX is a totally different chassis. I don't think they are very close in length at all. It's been a while since I tore apart my last ZX parts car, but I would swear that they were a LOT longer. Sorry to give you a non-answer answer to your question, but I think you're barking up the wrong tree if you're trying to switch from one driveshaft to the other. Jon

Your laser pointer idea has merit but would be a big hassle in the end, I think. You'd have to have one on the front and back, and have a reference point to check against. The track width changes A LOT when you start changing the angle of the control arm, so your pointer would make a wide arc regardless of how you changed the control arm angle. So you would need a way to compare the arc vs the centerline of the tire, unless I'm missing something. Using dial indicators is easy, because you can zero them and as you compress the suspension you can see how the front and rear indicators move in relation to each other. So you jack the suspension up an inch, and watch the dial indicators. If the front goes around once and the rear goes around twice (just an example) then you've still got quite a bit of bumpsteer. Move the pivot until the dial indicators move very close to the same amount over a few inch range where the car will spend most of it's time (meaning measure the bumpsteer at the ride height you'll be driving at, not at full droop or full bump). You can buy 2 magnetic base dial indicators from Harbor Freight for like $40, then just stick them to a big piece of metal and start measuring. Jon

That'd be one hot floor... Jon

When I changed my bumpsteer I used two dial indicators, one on the front of the rotor, and one on the rear. I pulled the front springs, and put jackstands under the ends of the control arms. I jacked the car up and down very slowly while measuring the change on the dial indicators at the rotors. Prior to this I had tried strapping a long stick to the hub and using a plumb bob to measure on my garage floor, that just didn't work for me. I don't think the idea of jacking the body would work for most people either, because bushings will deflect and throw off your readings, but since I have rod ends on the control arms and TC rods, I think it worked pretty well for me. The "standard" way of checking is to bolt a flat plate to the hub and jack the control arm up and down while measuring with dial indicators. To get adjustability I drilled a new control arm hole directly above the original hole and connected the two making a slot, and removed the spot welded washers. I would do my test, then loosen the control arm bolt, tap the control arm up a bit, then test again, until I got it right. It took me a couple of hours to adjust both sides, and it was my first time and I stopped for a coffee break. Modding the crossmember was also easy. The only "hard part" if you could call it that was putting the crossmember in. I use washers on both sides of the control arm, but I never welded them back onto the crossmember. I have not had them move over 4 or 5 years of racing like this, and I check the torque every so often and they have stayed tight. Owen, if you extend your control arms 3/4" and don't change the length of the tie rods, you're going to have some pretty serious toe in! The tie rod length has to change with the control arm length. There is a decent amount of adjustment in the tie rods, but if you go too long on the control arms you'll be forced to make new tie rods. Jon

The reason people shoot for "nearly level" is because that is what is possible without moving the pivots, and using bump steer spacers. This has turned into the target for many people, but it is not what is ideal for best handling. John Coffey described the ideal situation in another post: The highly prepared 510's at the autox I used to go to every month in CA had the inner control arm pivots moved WAAAY up (like 3"), and I think they ran bump steer spacers in addition. They fixed the bumpsteer with spacers at the tie rods like Owen described. The more the control arm points down, the more neg camber is gained when the body rolls or the suspension compresses. Wheelman and Owen have it right on bumpsteer. The spacers are better at correcting the camber curve than fixing the bumpsteer. EDIT for Pop--the spacer deal that Owen is describing uses shims between the steer knuckle and the tie rod to move the outer end of the tie rod down until it is parallel with the control arm. Jon

I said don't bother because of the way he plans to use the car. The problem with using a rod end and bump steer spacer kit is the tie rods. You'll have to make them. The inner tie rods are metric thread IIRC, and any rod end you get is probably going to be SAE. I was planning on doing this myself, using 1" hex aluminum stock and drilling and tapping the inside end to match the rack and the outside end to match the SAE rod end. You'll also need to bore out the holes in the steer knuckles, and you would STILL benefit from raising the inner pivot and raising the roll center. My plan is to get the inner pivot as high as possible, and do all of the above, still haven't figured out if I want to continue running bump steer spacers or not. Might be overkill, but if I'm going to go for it, might as well go for it, right? This is a LOT of work compared to just raising the pivot, so you have to weigh the ROI of doing all of this. If it is an occasional autoxer, probably not worth it. Bumpsteer spacers or raising the pivots or both might be better if you're not building a racecar. Jon