tube80z

Sounds like you have it nailed Jon. For welding the pipe I would clamp it to a section of you TC tubing if you have any left. That should be good enough. Cary

I have direct experience with my car and hotter on the inside is what is generally required. How much hotter depends on the tire characteristics and toe can have an effect as well. What you're really looking is to have the tire optimized when cornering, which leads to the higher inner temps when measured at the end of a run. In the Motec seminar Claude shared IR tire temp data that showed surface temps during a lap and you could see this. What we measure is well off what the tire sees. He even showed us examples where we would have done the completely wrong thing based on pyrometer data we'd measure in the pits. It also became pretty damn clear that if you're doing any serious racing or chassis development you must have this level of data or you will be working in the dark. Cary

Allergies here too. I know this all too well. Some things to think about. Ideally you want the rack to be at the same level as the LCA inner pickup point. If not you'll get some bumpsteer from that. Did it raise a lot more than your pickup points? If you had studs that were in the crossmember you could use spacers under the rack mounts to move it up and down. Along with your slots this would allow for some variability in the front RC. But it may be a little hard to get the rack any lower that you currently have it. You can use a couple of plumb bobs to align the rack and crossmember. I have yet to see a Z that is straight as far as crossmember alignment is concerned. I think it has to do with how old the cars are these days. My bent race car had the crossmember cocked to try and straighten it out. You also need to weld a tab to the mount near the rack pinion. The aluminum appears to be pressed to the tube and I had one that came apart after a lot of use. You can bolt through the tab to the lower ear of the aluminum mount. Or that was the solution I used. You could probably drill a hole and use a set screw into the metal rack housing but that would be more work and the rack would need to come apart. I think you'll have to clearance more of the rack for the tie rod. I had to remove some of the flange on my old car. Be careful you don't have oil pump clearance when moving the rack. I had the motor set back and this was a major issue on my car. Cary

In general I've found diamond are made much better than some of the other cheap ministock wheels. MRT is one that doesn't have a decent center hole and you'd probably need to use lug mounted balancing. Cary

Why don't you run in super production, If I were you, I'd look more at the ITE or open IT class as this would be a better match I'd think. You're really jumping into the deep end of the pool. As far as suspension goes take a look at the threads at the top of this section and look for advice from Katman and Johnc. This is assuming you want to keep running struts. Super prodction doesn't put limits on the type of suspension that I'm aware of. So you can do things like double a-arm conversions, etc. Cary

In order to use more caster without power steering you need to move the spindle forward on the strut. Increased steering effort is caused by the lever from the actual turn center to the tire's contact patch. You can do a little of this with custom RC/bumpsteer spacers and moving the lower balljoint. Cary

Don't forget even though the rate is low there is significant preload on the stock springs. Cary

I wonder if putting an X in the core support would work. I've seen that on a few rally cars. I also wonder if a car setup this way is doing this because the front and rear roll angles are vastly different, causing the chassis to take more of the load. Cary

Cool dude. So we'll we see it out this year? Cary

For a street mod car I'm not sure you can do much with the rack. I guess you could eliminate the bushings and move the rack and possibly pour in some new ones but I'm not sure how much, if anything that would gain. I had thought SM allowed liberal creativity on the outside, as in tubular control arms, custom fabricated strut housings, etc. I would think you could take some advantage with the steering arms and if you used a two piece strut you should be able to set the pin lead on the strut. This would let you experiment with much larger caster angles. I don't know if this will work with low profile street radials or not. Cary

Coleman lists them in their catalog. I believe they are set for the some of the basic chasis that might be bought. So some custom fab would beed to be done for a datsun version. Cary

The mount you have above is basically what I've done to my nissan rack. I welded a mount to the rack tube and use that to attach. Very similar in the end. I only chose this route because I had the rack and I'm cheap. For your ackerman adjustment why not build it maxed and then put spacers under it as needed. You'll have to watch the clearance to the oil pan but this should work fine. If you try and lower the car a lot you may have interference issues if you raise the crossmember/inner pickups too much. I still like the idea of doing something like this and have spacers that would allow one to move the crossmember to adjust the roll center. You'd need adjustment like Jon has on for the TC rods but it seems like it would work. For racks you might also take a look at a number of the sand rail companies. They have some low cost options that might work as well. Cary

The basics are that you want it adjusted so that the bar is straight across when load is applied. When they are not loaded you may see the bar skewed at an angle. Ideally the monoball should be very close to the center for optimum use and safety in the event of a failure of one of the circuits. A properly built system will not let the monoball shift as the car experiences side loads. This is a good think to check as you'd have different brake balance corner to corner if this happens. Cary

For drag I think a simple coast down test would be sufficient. SAE has some info about these tests. Your idea for measuing lift and the distribution should work fine. It's commonly used to create aeromaps for cars. You will need to keep accurate records of the atmospheric conditions, properly setup the car, and make specific changes for this to work. You will need a datalogger but you don't necessarily need linear pots. I've had some success using plain old rotary pots and some linkage from RC cars. Good penny-giles pots will set you back about $250 a piece. If you have access to a motec system it will surely work. But you can do this with just about any data system and some low cost sensors if you use a little ingenuity. Cary

As it was explained to me ackerman is a function of the tire construction. In the case of the FA tires you are using they like ackerman. The swift uses 100% ackerman and I know a few teams have added more when they run on teh slower street courses. So I'd put on as much as you can get. I intended to build a new set of steering arms but never made it that far. I bent the stockers out a little and moved the rack closer to the crossmember. I don't have any detailed notes anymore but I seem to recall getting near 70% ackerman with this setup. I thought it worked better. I don't think you'll be able to get a lot more than than this simply because of the packaging. The only way I think you could get it to work would be to convert to rear steer. I've made a few tie rod using swedged steel tubing (for 5/8) on the outer end for the rod end. On the inside I cut a slot in the swedged piece using my mill and then cut off the threaded section of the stock tie rod and welded this in. I saw this done at a hotrod shop I hang out at. The only trick was to preheat all the parts and then let cool in sand. Cary

Your guess would be as good as mine. I think the issue is that with no balance bar you'd need to have the same travel of both brak rods for this setup to have a chance of working. I seriously doubt that will ever happen. Best bet, as mentioned above, put a balance bar between the masters. Cary

I think if you run a longer bolt and a spacer in the middle you'll make it a lot stiffer when you have the rod end on the outside or inside. Cary

I used turnbuckles and cables from the hardware store. The only reason I did this was thinking about it while I was working out on my blowflex, which has a lot of cables and associated hardware. The turnbuckles allowed me to accurately set droop/preload on the springs. I think both Jegs and Summit sell a kit for drag cars that would work. I attached the top to the strut tower wtih a metal strap that had holes and bolt that was welded to it. This was then had the turnbuckle attached to it. The bottome had another bolt that had a clevis end welded to it and then cable down to a bracket on the TC rod. Other options would be a mechanical stop against the bottom of the swaybar. I thought about this for some time and chose the cables because I wasn't sure any of this would work when I first did it. Now that I know it works I could see investing more time in a better solution. Cary

Can you turn one of the rod ends 90 degrees. Maybe the top one on the end of a slider adjustment? I personally think you have way too much droop. Look at late model bimmers and porsches. They have a lot less. Cary

What happens if you put the channel on top of the TC mount? Does that gain you anything? And for droop, how much do you have? If you're springs come unseated you can limit to that with no real change in how the car works. Cary

For what it's worth the swift manual I have recommends 28 PSI when running these tires on an oval using max downforce (3450 lbs) on a ten inch rim. Cary

I think a lot of it depends on tire construction. The FA tires I use on my car seem to work best for me at 18 PSI HOT. I generally start in the 16.5 to 17 range with them cold. I've never had a tire come off the bead but a few of the hoosiers had issues with not holding air. Well after that fact I heard they may have had a construction problem. A lot of this depends on how much your car weighs, etc. If you want to get real tricky you can play a couple of games with your tires. You can paint them with latex and put them on paper to look at how the contact patch changes with pressure, camber, etc. This is best done by using a modified press. Or if you need to see an actual pressure distribution you can use Fuji prescale pressure sensitive paper. Cary

IR guns aren't very useful for tires. The surface temps drop too quickly and they have a tendency to even out before you see the real trends. They are very useful in taking track temp measurements. You really need a good probe pyrometer. Just remember for autox you'll never see the core temps that road racers speak about. If a hoosier R25A slick will show you core temps in the 100 to 125 range when it is working good. When you get over that you'll find they are getting greasy. When taking tire temps remember to take 5 tire readings. What I mean by this is start with one tire (always the same one and usually a front), work your way around the car, and then take the temp of the tire you started with. This will let you see how much temps are dropping as you go. You can use this to guage if a tire that you took the temp of later is actually hotter. In general, once I have established that I don't have an outside edge hotter than the middle or inner I will usually only look at the middle and inner for what needs to change. Remember toe-out heats the inside and toe-in heats the outside. This can mask how the tire is used. For autox pressure rise is a better indicator of how the tires are being used, IMHO. Work to get the front and rears to come up the same amount. You'll also have a target hot pressure that you'll find that works best. You'll need to adjust the starting temp based on ambient temp. Always use the driest air you can in tires. Any water that is condensed and turns to vapor will cause an abnormal amount of pressure rise. Adjust pressure in 20% increments to figure out what works best. That will quickly let you see what you need to do. Cary