clarkspeed

When you are running relatively stiff springs, controlling body roll with ARB's is not so important. You really only need the bars to balance Front and Rear moments (understeer/oversteer). So if you removed the rear bar, it shouldn't take to much stiffness in the front bar to balance out. I reduce front bar stiffness until I get some good oversteer and then put one adjustment back in. In Mark Donahue's Unfair Advantage he talks about setting up his cars by changing spring rates with no ARB. He only adds the ARB so he can fine adjust at the track. And if you notice most pro level cars run pretty light bars. On track it is very important to rotate the car and get on full power as soon as possible. If you are having problems like you describe, reducing rear spring rate should help plant the rear. But there are other factors involved like tire size and stiffness so it's hard to say what spring rate will work. But I know plenty of other fast Z's that run a large delta between front and rear rate. You just have to try and see what works for you.

If you are double adjustable try softer compression. Then try softer rear springs. 325 or even 300. Very small front ARB. Thats what it took to get mine to hook up. I run a Quaife and when you lift a tire you instantly loose 1 - 2 seconds. I still have to be careful over curbing. Nice Aero.

I used a more simple and elegant design that I blatantly lifted from this website. I slightly modified Tube80's design using a stock control arm from page 4 of this old rear control arm design post. Used a 3/4x5/8 rod end for the forward one. I recently sourced some oil impregnated bronze bearings for the inner pivots instead of polyurethane which falls apart if you get oil on it . Works well and my rear RC is where I wanted it anyway. Being able to adjust rear toe transformed my car, it went from a darty unstable handful at 120+mph to rock steady at 140 on the banks of Daytona with one hand out of the window waving to the crowd. http://forums.hybridz.org/topic/62776-yet-another-rear-control-arm-design/page-4?hl=%20rear%20%20control

The Bilstein P30’s work ok with the stock valving. I ran a couple races with them before I had them revalved. I really liked the “feel” of them which is purely related to their low speed performance in transitions. I initially had them revalved 100/300 which was too stiff and killed the transitional feel of the car. I then worked with a Bilstein engineer to revalve again based on my measured data. Turns out my current valving is not too far off the stock numbers. My car weighs 2450# wet with me in it. I think if you were around 2100-2300# the stock valving would be really close. My comments are for road racing of course.

Funny thing is once you paint it all, no one really notices they are gone. It will look like it was meant to be that way.

I know the guy that bought the first one and has raced it extensively with no problems that I know of. Larry is also on this forum maybe he will chime in.

I removed them on a race car with full cage. 12lb sounds about right. Makes a lot of room for other stuff like electronics.

Keep us updated Mike. That car is sick! Would love to watch it run.

Depending on what cam you have you may be chasing the fuel values. Under WOT you may find a spike at 2500-4000 rpm where the engine wants a lot more fuel under load. To counteract this with SDS I had to create a rich condition before the spike and then pull it back out after the spike.

Interesting article and a compelling argument for motor in wheel. I would believe no degradation in ride quality but performance is another story. I doubt you will see a F1 or LeMans prototype putting their motors there. 2 lbs of unsprung weight may not be noticed by most, but 2 lbs off unsprung rotating mass is heaven.

I'm not familiar with the MM rear brakes. Sounds like weight was considered. I agree that the ARZ kit is a great deal. You cant duplicate for less. But I do think you can have too much heat sink. Its just more unnecessary weight. A move from 12.19 x 1.25 rotor to a 11.75 x .810 saves 2 lb.

Wow, 13" rear rotor, really? I've taken rotor temps at the track and could not imagine ever needing anything close to that, especially on the rear. I think you may be missing my point, nothing wrong with upgrading brakes IF YOU NEED TO. But if you are going to spend $700-800 on an axle, why is giant better than just a little bigger? All those big brake kits sold could be even lighter if sized more reasonable. Every pound counts out on the corners.

Nothing wrong with insurance. You could put in a 500lb Nascar cage too. Those giant rotors are just not worth the unsprung weight gain for me.

Keep in mind, tires make your car stop, not the brakes. I havent posted that in awhile. Kits with 12" rotors and Wilwood calipers are pure overkill, and having designed a set for myself using smaller and lighter components, I can say it is not cheap going the Wilwood route, regardless of size. I haven't purchased from them, but the Silvermine stuff looks attractive to me for anything under 150mph.

I never knew that phenomena existed or ever thought about it. You would that SAE and automakers would have plenty of data on the subject. As far as cooling, I run a Ford double pass radiator with the oil cooler mounted in front of it. After I sealed off the front, my water temps went to 150 at Daytona on a 95 degree day. I installed another 190 thermostat with 1 hole drilled instead of 2, blocked 1/2 the grill, and got the temps rock steady at 190. I have been taping off the grill to block as much air as possible from going into the box and still keeping the 190, barely. However my oil temps have remained steady this entire time at around 240-250. They seem independent of water temp.

I was running stock efi and cam in an 82 ZX with a ported out 75 manifold. Everyone who drove it was amazed at the power it had. I would keep the compression low and run cheap gas for daily driving.

That's a good set up. I built one to drive 140 miles a day with a P79. Just fresh engine, blended the ports into the valves, port matched the manifold, weber big throat, headers, 2-1/2 exhaust with cheap 3" Catalytic converter. Ran like hell on 87 octane. 23mpg.

Why do the LCA's have to be adjustable? More track? The TTT stuff is HD but that means more weight. That's a tough failure. Good luck.

I sprayed mine with a gun and industrial paint. Didn't prime first and still get a lot of chips in it. But you don't need expensive paint since UV protection is not an issue. Painting a cage is the hardest thing I have ever painted. Impossible to keep the gun distance even, get 360 degree tube coverage, while paint is blowing back in your face. You will not want to do multiple coats. Plan on taking some time to do it. Powder coating is the way to go for pro results.

I shopped the eastwood also. Ended up buying the Thermal Arc 181. Couldn't be happier. And I can TIG if I want.

Grinding back the LCA is common for running the AZC big brakes. I've never seen anyone with boots burning either. When the car is level there should be enough air gap. I don't run TTT control arms, but I doubt mounting from bottom is a problem.

All is good if you don't over cam it and keep the power and torque down at low rpms.

Measure it on the car. Straight edge and cheap digital angle gauge from Harbor freight or phone app level. I've driven some fast cars without any adjustment.

Holy teeth chatter Batman! There can't be many shocks on the market that can handle that. I may have to do some experiments with my tube frame car in the future to explore this. It should be fairly rigid, light, and gobs of grip on 12" slicks.

I rotated a ball joint about 50 times. The center sits about 0.5" above the control arm flat. It makes a difference if you are measuring RC. I measured everything out last year and put into SusProg3d. Not sure if my referance points would match what you are looking for. What are you going to use for motion analysis?