tube80z

Dan has some good information about caster above. I don't think that is the problem here but it could be adding to it. I say that because we've had two cars running the FA rears all round that were setup very close to Jon's car and neither of them lifted tires when going into tight turns under braking or in transition. After thinking about this for a while the car is rolling on a diagonal on the inside front to the opposite rear. So we're already extending the inside rear tire. If we're on the brakes then the rear will be very close to fully extended before we start cornering. Now add roll mostly from the front end dipping on one side and steering induced ride height change and it's looking closer to what is described. So how to fix. I'm thinking we need to go stiffer. As the rear tires are not up to the same temp as the fronts I'd go with more rear spring and if there's a lot of rake reduce that at the same time. If that doesn't fix it then more front bar or stiffer front springs. This will help reduce front roll, dive, and rear lift. Cary

Nice run. What time you were hoping to get? Sorry to hear that PP is looking less likely to happen. It would be great to see it come together. Cary

It may be logger dependent too. I'm not completely sure what I was using corrected for roll, which would give higher numbers. Hopefully more data this next year to see how Hoosier and Avons compare. I created a math channel that looked at 1/4 seconds of cornering for continuous (autox) and then picked out the highest number for peak. On an EP car on GYs I would see similar numbers on a race technology DL1. But that was the best I ever saw and it could drop a lot depending on track conditions. For lateral acceleration (or longitudinal) are you thinking of comparison of cars or just as a gauge for your own car? Bob Knox recommends a 0.3 second moving average filter for acceleration data. Cary

You can also bolt angle iron to the ST bar and run the rod end from it. Heavy85 has a nice piece he built here, http://i1150.photobucket.com/albums/o618/ls240z/Mobile%20Uploads/image_zps6017f710.jpg Cary

On slicks you should see 1.6 continuous and spikes near 1.8. Tires keep getting better and better.

You need to reinforce the nut you used. A threaded bushing could have been used, which would have more weld area. And a rod end would give you much more room to raise the inner control arm if you need to. The large bearing you have looks like it would contact the top of the crossmember. Just a few things to think about. Cary

MSD box has a tach out option. I think it's a 5 volt square wave.

My guess is the bushing that's used to guide the shock rod at the top. Those can wear and you get that rattling. If you go with the larger Bilstein size you can use a different piston (COBB) that has more tuning options. (Digressive, linear, etc.). Option 3 use the strut rod and a linear bearing as the bushing but done have any piston or oil in it. It will be a control arm so to speak. Them mount a coil over shock inside of the strut. This used to be done years ago in IMSA before you could get good struts. Then you can use much cheaper shocks compared to struts. Option 4 like Jon mentions is convert to a 2 piece strut and use 240SX struts. They have built some really nice pieces. Option 5 go to a-arms and no more struts. Obviously rules may play into this. I'm doing option 5 myself after reviewing the other alternatives. More fab but cheaper running costs when done. Cary

Actually if you make two cuts to the centerline at angles it makes a cope. Lay a coped tube on a flat surface and you'll see. There are tables of what angles to use. The paper method is pretty cool too. Cary

Just underwear. That's all that's needed.

If you play with Kevlar you'll need carbide scissors. They will probably cut up the blanket. I really don't think you have anything to worry about. But your idea of bonding kevlar to the tunnel or the bellhousing should work. You can get a bellhousing that's rated to contain the flywheel clutch for your setup. It's very heavy. Cary

The QA-1s are called a slot bearing. They are a 2 piece design and not designed for the amount of vibration you'll see on the rear suspension. We used these first as they are low cost and they lasted one event and the liners pounded out. Then AM Auroras in 5/8 and they pounded out and then 3/4 X/Ms (not sure but their top lines) and they worked fine. I've done CMs on a street car and those seem to be working fine but it hasn't done a ton of mileage. It's your money but I don't think you need to spend $200 a rod end to get some that work. Hope this helps. Cary

I had one on an L6 mounted similar and never had a problem. They are really good pumps and the controller worked very well to warm the engine as well as cool. I'm thinking about adding one to my LS too. Cary

Tube adapters can be had in any size for most thicknesses in the 0.065 to 0.120 range. I'd agree with John that 0.095 would be good here. Very successfully used on a 2600 pound car with 474 WHP and huge slicks at hillclimbs, track days, and many autocrosses. To use the tie rod end you have to build a mount that is thick enough to have the taper needed. Then the rod end is inserted into this. Take a look at BMW lower control arms inner joint to get an idea. In the case of the Z it would be a bracket bolted to the strut housing. Myself, I would opt for using rod ends. Aurora, NHBB, FAG as John mentions all make quality products. The Auroras that died were the top of their line and their engineering department was sent the rod end. All I got back as that the surface area of the ball must have have been two small for the load, which is ludicrous if you look at what's listed as acceptable loads in their catalogs. All I know is the larger size worked fine for a long time. It may seem like these are a waste of time to build but changing from polly bushings to rod ends and the extra floating link helped the car put power down better. And not just in rough areas. All I figure is that a lot of friction was reduced. It also made changing the strut out very easy. One thought on the arms I forgot to mention is that using left right in 5/8 or 3/4 threads changes the toe very quickly. It might be better to use the same handedness and 3/4 on one end and 5/8 on the other. This would allow for smaller increments of change per turn. Hope this helps, Cary

Flex plate is just for starter. The shiny metal bit on the flexplate is the new friction surface. They are sandwiched together with the clutch bolted to that.

I personally wouldn't use the tubing thicker than (0.95). My reasons are that I'd prefer the arm to bend rather than the frame to get bent. Same argument for CroMo tube. The 5/8 rod ends that wore out were Auroras. The liner was pounded out of the fixed end of the lower control arm. Stepping up to 3/4 ball/race cured that. For a street car it would be interesting to try and use ball joint style ends. One of the local hot rodders uses Ford tie-rod ends for all his axle linkages. He said they were cheaper than rod ends and last about 5X longer. Only downside if you need to change the mounts. Rod ends are much nicer in that regard and you don't lose any alignment when taking it apart. Hope that helps, Cary

If you do decide to rebuild I would look very hard to modern cars and how they have reinforced the tire well near the driver's feet. If your welding in tubing it wouldn't take a whole lot more to strengthen that area. It is one of those things you never want to find and when you have an attachment to a car it doesn't help. If you can overcome that and objectively look at what you have and different options you'll be money ahead in the long run. Good luck, Cary

T3 plate or CrMo plate or stock TC rod modified. You should be able to get small samples if not there are online metal dealers. To fix the offset shear issue you can do double shear with a solid rod end. That was the planned next step if the single stick didn't cut it. But we never had a problem on a car that can break at 1.4gs so figured we were good.

Ceramic can use lighter weight oil versus grease for lubrication. There is some info around wide 5 conversions for circle track racing. For the money they are probably not a good trade off unless you can't use a larger bearing and are losing a steel bearing during a race due to load or heat issues. I doubt that would be many of us. REM finishing and good grease along with the spacers would be a large improvement. When I checked on ceramic prices one bearing was the cost of doing all 4 corners.

I have used those for a few years and I liked certain aspects but they are not a good street shock. They are digressive shocks and probably too harsh for street use unless you really want a canyon carver weekend toy. They work best on a race car with very light unsprung weight. They require yearly rebuilds as the seals seem to die and lose oil. The cost of the rebuild last time (a few years back) was $175 a corner. I had them rebuilt in the winter and they leaked most of the oil out before they were used in that summer all while sitting on a shelf. When I called GC they said they'd need another rebuild at the same cost. I don't think GC makes them anymore but will service what is out there. I wouldn't recommend them even if you can find a set. I can post pics of my insert and measurements it that would help. They are very short compared to most inserts you'll find. Cary

I've done a few sets like that and used Subaru inner rack ends. They are metric but look very similar. I've seen some Triumph or MG products that were similar but probably standard threads. Keith, the clivice is a standard part you can order from speedway or summit. For the plate I'd recommend a higher grade steel than mild. My local steel supplier has a plate they call formaloy 4040 or something very similar that is a lot stronger than mild steel but will still bend rather than brake. For any 0.25 inch brackets I like to use it. One option for these is to make the hockey stick out of an old TC rod. You will need to grind for clearance to make it work with a 5/8 clevis. Your next step up is 3/4 and a thicker hockey stick and it may not bend. But that means something else might. Cary

Another option is you can have bearings REM finished and cryo treated. Some places will do it for Timken bearings but many times you need to take them apart. I never knew you could do that until a friend took some apart, cleaned them, changed to a lower drag seal, and put in better grease. Ceramic would be the best option but are very expensive. Cary

For the springs I'd run the rear either the same or perhaps 50 pounds lower in rate than the front. The higher rate will help keeping the chassis from moving so much and if the suspension is compressing from downforce it will about half of what you're seeing now. I'd agree on as much caster as you can do, which will also increase the wheelbase and help with stability. In looking at the picture of your car from the side it looks like you need to lower the rear. That would reduce the angle of the windshield and might get you a few more tenths. Any reason no rear spoiler? That should help reduce drag and make the car more stable at the speeds you're running. A friend has an EP car and it routinely hits 158 on the straight at PIR and when braking the car is moving a lot from the in car footage. He said when he ran the GT-2 Z it was much better in this regard. One difference was the rear spoiler. Hope this helps, Cary

You also need a lot more spring (450 to 550). A friend ran a splitter a little larger than that and grounded it from 4 inches doing 160 on the straight at Thunderhill. This would allow you to lower to keep more air from going under. Cary

Another thing to look at is the liner when you start getting weird results. If you bend the torch a lot it wears quicker. Drive rolls lasted much longer than liners when I had my hobart handler. When you're welding it should make a sizzle noise almost like bacon cooking. If you don't have that you're moving too fast, wire speed too high, or not voltage is wrong. That was my key indicator when using the handler was to adjust the voltage to get that noise and it worked much better.