tube80z

What about using packers? Cary

Yep, and he's a bastard! Cary

I think Vic's car was fast because he was the first guy to start playing with some stiffer rates and getting them to work. Locally we have a number of Zs that have copied this (including the red one in your earlier pic, which belongs to Dave Kipperman) and they have all responded very well. Before we started doing this we all got beat by Miatas, vettes, RX-7s, etc. You'll also notice Vic doesn't have any bumpsteer spacers and appears to be using an EVIL underground front RC, which I have found to work very well for me in autox. What isn't mentioned is when you hook the sway bar to the strut it acts like it is larger because of the reduced motion ratio. I think you'll find a 7/8 about equivalent to a 1 inch bar in the normal locations. Cary

This should work fine. I agree you really want the lever on the sway bar to be at a 90 to the linkage that goes to the lower control arm. In your previous example the bar looked to have a falling rate. In the past I've made a few adjustable bars like this by grinding a falt along one side of the bar and then placing the 1/4 plate on this and welding along the edges and a few plug welds too. You can put build all the anlges you need into the plate. I hope that makes sense, or you'll force me to make some poor drawings too Cary

You'll also be adding dive if you drop the front location down. Cary

I was hiding in Mexico for the last week. Managed to get good and sick so I can't say it was a lot of fun. A couple of things I noticed on your pic with the heims hanging down. You have them screwed out quite a ways. On the TA cars they had them threaded in all the way and held with red loctite. I also noticed the ears have a bit of clearance for the heim, this can be taken down to almost touching and you could gain a little more clearance by thinning the section under the heim. You can also rotate the clamp, it doesn't have to be in a direct line, mine weren't. But you need to make sure things are clamped really tight. I think you'll find that if you rotate it up and move the heims in you'll have enough clearance. Cary

8s would be a lot easier. But all this is in the stock location so I don't see the issue with interference. My tube was 6 inches long. You can't go too long and as you'll run into the curve on the bar itself. I think I only moved it about 2.5 to 3 inches total. Mostly I left it alone but I could brag it was adjustable and that was worth at least a half second For the spacer use one that presses in and then you can run one bolt size smaller and you don't have bits if spacer falling out, which I agree is a PITA. And for a bolt consider a pip pin. You can pull it with no tools if you want to disconnect the bar. I know a national level Miata driver that does this when it rains. Hope this helps, Cary

For some reason when I wrote this I was thinking about the front swaybar and not thinking rear. I agree it's a lot easier to use the stock locations on the back. I ran a front bar like this wtih no problems. I milled a slot in the pipe and it had two bolts for a pinch clamp, which looked similar to a toe-rod adjuster you see on many trucks. The end was capped and a u-bracket welded to it to hold the heim. When tightened it seemed as stiff as the bar, never loosened, and allowed me to have a longer or shorter bar for very little $$$$ outlay. Make the lower mount double shear and weld it on if you can. That will be stiffer than a bolt-on mount. And as you have mentioned out some spacers on the rod ends to allow for a little more room. Cary

Looking good Jon. About the only thing I would have done differently is use tubing where you used the flat pieces with bolts. Either should work fine. I've used the long mount on the control arms to keep the heims lined up. It worked and I didn't have any problems with it so I think it is a good solution. Have you looked at possibley hooking directly to the strut housing? Another low cost option is to use a mount similar to what you did for hooking the heims to make the sway bar adjustable. Simply cut off the forged or welded ends and make a split clamp you can loosen to slide back and forth for adjustment. As you mentioned water pipe works well for this. Keep posting pics and keeping the rest of us motivated Cary

For a beginning autoxer the best thing to do is to walk the course with someone experienced and in a similar car/class if possible. Most of the time you'll be welcomed and the person will share information. Watch and ask questions about what line they would drive and ask why. Generally in a slow area you need to minimize the distance driven even if that means you do some weird unintuitive things as it waill almost always be faster. When you start driving you want to work on car placement first. Getting very close the the cones and being consistent for your runs. It's much better to come into the corners going too slow and then getting on the power early. Most beginners have a tendency to try and carry in too much speed and overslow the car at the apex and blow the exit. Another thing I see all the time is someone holding steering lock for too long, which slows the car down and often upsets it for the next transition. Generally, when I walk the course I'm looking at the spacing of objects (turns, gates, etc.) to see if they increase, decrease, or stay the same. I also pay a lot of attention to the pavement, just dragging your foot every now and then can tell you if there's more or less traction in a certain area (parking lots are notorious for getting polished areas). Does the pavement stay level, rise up, or fall away? Very important. That's usually what I'm looking for. Most clubs will have someone with a lot of experience or maybe a national level competitor. They will usually be willing to ride with you and give you pointers. Take every advantage of this you can. And if they are willing ride with them. And remember, this is supposed to be fun. If it's not you're trying to hard Hope that helps, Cary

I think in terms of this dicussion the terms are used interchangedly but that's not necessarily correct. As Ortiz points out more yaw intertia will make the car understeer on entrance and oversteer on exit because of the resistance to changing direction. While this may seem like it is more stable you do have the issue of once it it's starts to go it is that much harder to get back. So it's not always better. In the case of an autox car it is more important to be able to change direction more quickly than generate ultimate cornering numbers. In the case of the mid-engine 510 that's really more about a poor chassis making it undriveable than anything else. 510s have poor camber control in the back, a lot of squat, and when you couple this with wide sticky tires and power you get the antics the Jon describes of Dennis' car. What I don't think gets mentioned is that this car still has more yaw intertia than something like a formula ford, which are very good autox cars. If you happen to be fortunate enough to take the motec seminar by Claude Roulle he'll share a lot of info about ballast placement and yaw intertia and how much of a tuning tool it is. I have to run ballast on my autox car. One trick I use with it is changing the ballast. When it is cold and I need to get more heat into the tires I will put teh weight at the outer ends of the car, increasing the yaw inertia. This creates a measureable increase in tire temps. Cary

Actually, I think that's what I'm using. They were cheap and so far have been fine for sway bars. Cary

Jon, you can find economy lined bearings. But for the control arms you want the high strength ones. The other option is to do this using something like Ford tie-rod ends. But then you don't have as easy a time changing angles unless you make the mount a bolt on. For sway bar end links I'm using the cheapie QA-1 lined ends from racer wholesale. I'll be damned if I can find them on their site but they were around $7 a piece for end link sizes. Mine are three years old and have no noticeable play. Cary

I'd use the lined ends for mounting the bar. This will see a lot of stress and lined ends have lower friction. I'd also opt for them on the sway bar end links but I don't know if you'd see a measureable difference or not. Lined ends will last longer. For the control arms you definitely wanted lined ends. I'd look at Aurora or the QA-1 ends that have built in wipers. I tried using some of the non-linered ends on my car and found that they wore very quickly (less than a season of autox abuse). Cary

My 240z that I raced at hillclimbs was 2050 with a 200 pound driver sitting in it. That was a full unibody wtih cage and an L6. I ran lexan windows, fiberglass doors, nose, and extremely light wheels and tires. Things you may not think about that weigh a lot. 1. Wheels and tires (steel belted radials are heavy) 2. 280Z suspension is heavier than 240 stuff 3. seats 4. Fluids -- use a small radiator and gas tank 5. Rotating weight matters. For a drag car you don't need big fancy brakes. It's up to how much you want to do but I've seen 280s that are 2100 pounds ready to go but they are real race cars. Cary

The bar will still twist just fine. It just has more for aft movement than before. This is a much lower friction mounting method than the typical poly/pillow block mounting. It lets the bar bend in the middle, which poly/pillow mounts fight. This pic is from the rocket sports trans-am car. This is also mentioned as a good upgrade in Rowley's race car engineering book. Once you've got all the basics covered it's tricks like this that separate first from fifth place. Cary

The were in the Z car magazine a few years back if I recall correctly. I'd run them if I had the clearance. Cary

If you're running hollow 4130 bars you can probably weld tabs and re-heat treat. I tried this on a solid bar and had it crack a few times, which lead to a simple bolt-on bracket. I wasn't really sure what alloy the solid bar was. Maybe a different filler would have worked, maybe not. I'm sure JohnC has a lot of good advice on what can and can't be welded as far as sway bars go. Cary

Not really. For the front your idea sounds good. I'd weld in a doubler plate (could be a large washer to the tube). If you wanted to make it stronger you could wrap the frame rail so the vertical edge was caught. In the back I'd just drill a hole in the upright and bolt a male heim on both sides. You can weld a washer as a doubler spread the load out. My local bolt store sells uncoated steel washers that are good for this. Cary

Thanks for the info Keith. I'm not sure if it's easier or harder to do this for autox versus a road racer. Up to now I mostly used subjective feedback, a stopwatch, and tire temps. After going to Claude's seminar I invested in enough datalogging to be able to measure this on the car. I have yet to put this in actual practice beyond experiments in the shop. And from playing with this you can use ordinary linear rotary pots and linkage and seem to get data that's good too (low buck version). Where I'm really headed is being able to get real-time tire temps via IR sensors, which should help answer some of these questions. On the GC advance designs. Do you think the issues you've seen are unique to road racing? Why I ask is that I find them to work very well for me in a SoloII environment but they weren't valved right when I first go them. They feel much better than the tokicos and Koni (DAs) I've used before. Cary

Thanks for the info Keith. I'm not sure if it's easier or harder to do this for autox versus a road racer. Up to now I mostly used subjective feedback, a stopwatch, and tire temps. After going to Claude's seminar I invested in enough datalogging to be able to measure this on the car. I have yet to put this in actual practice beyond experiments in the shop. And from playing with this you can use ordinary linear rotary pots and linkage and seem to get data that's good too (low buck version). Where I'm really headed is being able to get real-time tire temps via IR sensors, which should help answer some of these questions. On the GC advance designs. Do you think the issues you've seen are unique to road racing? Why I ask is that I find them to work very well for me in a SoloII environment but they weren't valved right when I first go them. They feel much better than the tokicos and Koni (DAs) I've used before. Cary

I believe the how to modify books said they were triumph parts. I had a 510 that used sentra inner rack ends in a similar manner. The joint is beefer than most of the rod ends people use. Cary

Keith, when you are developing shocks how are you doing it? Do you use linear pots and damper velocity histograms or some other method. Cary

Keith, when you are developing shocks how are you doing it? Do you use linear pots and damper velocity histograms or some other method. Cary