tube80z

I'm not quite following you here. I get that the suspended mass and non-suspended masses can have seperate CGs and this has an effect on suspension kinematics. But, when we measure a car for CG we lock the suspension in place and tilt it to find the angle it will balance at, which is more accurate than the method of raising one end and measuring the change in scaled weight. In this scenario anything lowered will reduce the CG of the system as a whole. The lateral weight transfer is additive of the suspended mass and non-suspended masses. Both are in the same direction. And at the end of the day we're looking for less of this to maximize grip. Cary

Cygnusx1 I think you did a good job describing what happens. Ortiz has an article about this I'll try and find. The reader had a similar question and he determined it didn't matter where the caliper was mounted. Cary

They are heavy but work well and are fairly easy to build. Cary

Will you have a cage and door bars? For some reason I thought you'd only have a roll bar in the car. If that's the case I think you can drop the bars that go from the shoulder bar kink back to the strut. I think those are to tie into door bars more than anything else. Cary

Another option would be to turn this V into a X by hooking into the struts. This should make everything stronger. And if you really want to make it work run a bar straight forward from this intersection to the front V from the strut towers. If you make a balsa model you'll see this causes a lot of improvement. Personally, I don't think the floor area needs the V and you'd be better off with a wide, low X as you have in your first pics. That is unless you decide to go with the single tube forward to the front of the car. And don't forget underneath the car as others have mentioned. If you can hook the rails to the rockers and close sections of the tranny tunnel with an X it will improve the stiffness. Cary

Hi Cameron, You should be able to weld all the way around the tube in the example above. I've done this myself a few times. I generally turn up the shield gas, assuming mig, and pull the gun cover back as far as I can. Then you need to let the stick out increase a ways but you should be able to go all around. If not then the next trick may be to use good ol' gas welding. I've never had luck with just wire wheeling and really prefer a flap wheel for the final cleaning. Did you clean the area with acetone of something similar? If not you may find this helps. I also preheat the weld area with a MAP gas torch. You can see this drive out water vapor and will help with make the weld a little easier. Cary

Try searching ebay. I've seen a few sellers selling lots of ten at really good prices. Cary

If that's the case then they will interfere with how the system should work. Safety stops should only be on one side if you have them. Cary

I have had good luck with the XM series QA-1 rod ends. Before that I used mostly aurora. They have similar monoballs. If you're camber plates put all the load on the bearing then you won't see them last too long. It's not loading the bearing in a way it was intended and short life is the result. While not really built for our cars the larger com-12 would probably last longer. Cary

What are the washers supposed to do? From your pics it's not clear what you're trying to do here. You need to clearance the inside of the bolt above and I would recommend adding the lip back in around the firewall mount as it adds stiffness. Cary

We've got a number of the used tires in Portland for a lot less than that, more like $200 a set at times. John Berget has these as well as a few other people if you don't want to make the drive to PIR. FWIW, I'm told Hoosier radials will have a similar price tag new. Cary

Agreed, I would see this as dangerous without locknuts. Moving the LCA forward has the most effect on ackerman. In some ways you have a small amount of tuning available by moving using these spacers. You can also move the crossmember back and forth a certain amount too. Ideally you want the LCA to be perpendicular to the ball joint in plan view to take the majority of the force. Otherwise you'll start putting more lateral load on the TC rods. Cary

If you decide to go the slicks route make sure you jump straight to radial slicks. Currently the hot setup is the GY FA radials, which we've found to work much better than the Hoosiers. I'm sure Hoosier will respond with a radial as there seems to be a lot of people talking about them after nationals this last year. And if you run where it is cold you will probably be faster with a good DOT radial (Kumho, Hoosier, or possibly Hankook). Their tread compounds generally work about ten degrees less than any of the slicks. cary

If you were you'd still be analyzing all your options and trying to consider if the changes would be safe. Then you'd probably have used a metal lathe to cut the struts, applied a specific bevel to the strut tubes, created an overly elaborate jig to hold things, had then welded using a process known have ever heard of, etc. Sometimes all you need are simple blacksmith skills Cary

Sometimes too soft will make it understeer. My rule of thumb, and I seem to be all thumbs , is that if you make two steps in the direction that should have a certain outcome (like less understeer) and you don't get your desired result then go the other way. I know this seems obvious but I've watched really smart people chase their tails as the keep going softer and softer and it works worse and worse. Cary

Two, one on top one on bottom. Jon gave you the part number above. The procedure to determine the friction reduction for this or any other mod is as follows. You press the car down slowly and let it rise back up and measure the ride height. Now we raise the car and let it lower back down and measure the ride height. The difference in ride height x 2 x spring rate at the wheel = the force required to move the chassis. The goal is to make this number smaller. I don't recall the actual reduction in pounds but there was a measureable, but small, laptime reduction on the enduro course -- damn you more secrets extracted Take a look at the hyperco perch video and you'll see why this works. Cary

Yes, I was probably the original source. And that info came from Richard Pare who was one of the designers. Richard has a business with Steve Lathrop called ICP. They build a number of special parts for formula cars. Richard and Steve used to go around the country teaching a club racer race engineering class. I learned a lot more from those guys than I did from Claude Roulle's seminar (not to say that it's not good). And the best part was it was only $250 to attend. Sadly they quit doing it because they couldn't get enough attendees. Richard shared that these were super secret and used by WilliamsF1 a some years back. Williams was one of the last remaining cars that ran coil springs. And these almost won at Monaco. And for what it is worth, Richard said these won't help strut cars at all because we already have so much side load on the shafts. He said to do the standard racer trick of using bearings under the spring to reduce friction and that's about the best you could hope for. I guess I should also mention you don't need these if you don't have a coilover arrangement, meaning the spring is separate from the shock. Just another thing to think about Cary

Reiger makes such pieces. There are very common on rallycross cars and used to be used on a number of rally cars. I don't know if ohlins, penske, or any of the other high end brands do this. Maybe JohnC can tell us. I think he ran Penske tripples on his car. At one point some of the high end touring cars were using hex shaft in an effort to have increased stiffness. I don't think anyone does this anymore because of the sealing issues. Cary

I think that would be a fine way to go. I guess I don't understand how you do this unless you start restricting movement with the LCA, like roller bearings instead of sphericals. And when you do that you run into issues with compliance as parts bend. This is sorta like the sway bar mod you did. You could use rollers but when the bar and frame rail bends they bind. So until I see a better way to do this I'll stick with what I know works. So if anyone can show me a better way then I'll be happy to scrap the current parts and build those. This car will never be done and this is why. Cary

Just to set the record straight. The tube80 has yet to run under its own power. Hopefully this coming year. But the old design of parts have been statically tested. And we ran this configuration on a modified stock-type arm (toe-control link) on our old yellow Z for three years with no issues. I don't have the means to meaure side load on the struts. And to be honest I'm not all that worried either. What we have here isn't really much different than the front end of a FWD vehicle. I'm sure those have side loads too but it doesn't seem to be too big of an issue. Cary

That's already been done in a Jame's Bond film If you hit the curbs wrong on Medford you can get a little air. And their have been times when that extra little tenth seemed like a good idea. Bent parts after the fact seemed to indicated it may not have been. Cary

Bending the J-bar isn't going to happen often. I did it once and changed things a bit by adding a piece of metal to the bottom. Regardless, the J-bar isn't as good as using a double shear bracket and solid rod end. I think what bends this part is heavy braking and then hitting a FIA style curb or getting the car into the air and coming down under brakes. At least that was my experience. If you look at a number of formula cars from the early 70s and even some trans-am cars from the 80s and 90s they have figured all this out. I was trying to go the easy route and discovered that it isn't always as easy as it looks. The rear arms pictured about from the first version of the back of my car were tested and worked just fine. I didn't see any issues of bending the clevice or the attachment point. But since I'd already seen a problem with the similar joint in the front all this is changing to solid ends in double shear on the inside especially since I was going to double the HP/TQ. And since I did read the Carrol Smith books I owe him that much. And I will probably change the aluminum toe adjuster to a swedged steel part because it makes me nervous too. Although I've used the tubing for TC rods and tie-rods for a long time. I usually build new ones every other year. I had three reasons for wanting to do the rear arms this way. The first, which will sound silly to most, is to be able to quickly change rear toe. And before Johnc rips me a new one for that being stupid I would like to point out that it is an autox thing. By changing toe I can get more heat into the tires when it is cold. The second reason was to increase the installation stiffness and a side benefit I'm hoping for is reduced stiction. And lastly was to have an easy way to change squat/lift and RC positions. On the second version of the car this all attaches to adjustable mounts. All of this is easy enough to test if you have a porta-power and a pull ram. You do what is called a parasitic compliance test. To do this test you push and pull across the axle and note deflections versus force. The second is you push and pull longitudinally (front to rear) again noting defelction changes per load. These kind of tests will tell you a lot and give you an idea of what will most likely be the first thing to fail. This simulates how the forces are actually fed into the pieces. Not a mathematical proof but a nice old fashioned low tech way of measuring this before you do something stupid in front of your friends. It's much better to find something out in the garage where your emabarassment can be contained Cary

There are other bars, you just need to look real close. I'm curious why it appears to have a lot of production car still left in it. Cary

I'm not following all this but I don't think you'll get much stiffness from the rocker stiffenning on top and bottom. Maybe stick to the bottom and build an X across the floor. The center would need to come out but then you could connect the four corners. In lieu of a cage that might be the next best thing you could do. The only other option I would see is to make the car more of a back bone design by enlarging the tunnel and integrating the front and rear suspension loads into this. Before you start any of this you may want to build some basic models and see what works best. Even crude balso designs can help you figure a lot out. Class rules, if you're worried about that, will probably get in the way of a lot of this. Cary

I raised them about a half inch. I don't really know why they look so low in the photos. Cary