tube80z

Yeah, photobucket seems to have screwed almost all the car threads and other forums I view. It's understandable but it would have been nice if there was an easy way to migrate but then they couldn't hold people's pictures hostage.

I know we all like to fly the Z flag but if you do have to start over a newer platform could be a better move. Not only suspension is better but you get a stiffer chassis often and much better aero. Sure you can get there with a Z but you're going to need to do a lot of work rebuilding much of the car. So my vote from a racing results standpoint would be to look at some other platforms. Cary

Holy fill your pants you're not kidding. Time for a flat floor conversion? Or do you think everything else is too tweaked? Just happy you're not hurt.

Bummer for sure. Glad all the work you put into safety was worth it but too bad it had to get used. From the video it almost looked like the road had a drop going into the corner and compression braking was enough to lose the rear end. And on a hill there's rarely any room for run off. Cary

Their online material (http://www.powertraintech.com/Files/PDFs/Clutch%20Facts.pdf) states 400 TQ per disk. So you may want to verify. That sounds like it might be an okay way to go. My limited experience is that you raise the revs and do a couple quick dips to get the car rolling and then fully engage (pit driving). I think as long as you use the button and the stock flexplate it will be a little better. Mine is a button and ring gear that's mounted to the clutch cover. This is using a low ground clearance bellhousing and reverse starter. If you're planning to ebay a cheap cover I'd go with a Tilton as they had hardened pads for the disks to touch. I have a quartermaster cover and they are just hard anodized from the look of it. As to how loud they are it's fairly obnoxious when in neutral. It sounds like something is broken or about to fall off. Many of the street dual disk systems employ some kind of strapping between the disks to keep them from rattling back and forth. Cary

I get the motion ratio changed but if you're using a stock arm and everything connects in the same place up top then you're not changing the geometry. And it's the geometry that determines the camber curve. It works the same way up front. Cary

You mention using this on the street. The clutch you mention is similar to a rally clutch where a 3 disc race setup is stacked up the same using two thicker cerametallic discs, which allows for more slip. This setup isn't as grabby but still is fairly violent on take up. And when in neutral they are loud with the discs banging about. If you plan on having good launches you're going to need more weight than the traditional button allows. This is streetable but doesn't have the best manners and you need to make sure you don't slip it too much. A number of friends are running these in CP autox cars and an LS2 powered XP RX-7. In the RX-7 it doesn't seem too hard to take off and not kill it but you need to raise the revs and be fairly quick on engagement. Jon Mortensen uses one in his XP car too if you want more of data points. I don't think you can go any smaller than 7.25 and still drive on the street. The smaller options don't have enough heat capacity. Although I know you didn't ask that. Hope that helps, Cary

I think you'll find the many things have been figured out over the years so some content areas don't see much new content. That can all change based on new donors cars being available or someone willing to push the ball a little further up hill. Cary

I helped with a jerico to an L-series setup. We used the front from an automatic if I recall correctly. Then a big chunk of aluminum that bolted to both. It was turned to have a center hole that fit into the automatic bellhousing. I've seen variations on this theme over the years. Here's some pics of what it looked like, https://csgarage.com/blogs/csgarage/17986933-adams-s14-jerico. There's also the quicktime bellhousing, http://www.jegs.com/p/Quick-Time-Bellhousing/Quick-Time-Nissan-Engine-Adapter-Bellhousing/2834608/10002/-1 I've heard they will do custom versions if you give them a call. Cary

Paul Henshaw is on both facebook and viczcar. You could try asking him. Cary

My only advice is to see what level of support you can get. A really good up front price doesn't mean a lot if they need to be shipped vast distances for rebuild or if there are no dealers close by with parts. A long time ago I bought the ground control double adjustable inserts. Loved them at first but after sitting over a winter they lost all their oil (store on the shelf) and GC wanted $100 a pop to service them. This time they don't seem to work as well (no dyno charts ever supplied) and they lost oil again the next year. Now they want $250 a piece to service and that was some time ago. I gave them to a friend and he said they now want more than I paid for them to be serviced. While it may cost more I'd want to work with a dealer that supplied dynos and rebuilds that weren't too costly as those add up over time. And a company that has a good inventory of parts that might even have race track support. That probably means different companies in different parts of the world. For a Z car that's used in a race environment you want to ideally use an inverted strut. This puts a stiffer part under bending load than the smaller shock shaft. And for the higher quality parts you should be looking at linear bearings or roller bearing top hats. These will reduce stiction when the suspension is bound under corner or braking load. Even things like the type of seal used on the shaft can make a difference. The one true standard across all these is that anything that ticks all those boxes is usually expensive. My personal feeling is that a S30 Z car isn't stiff enough to need anything more than a double adjustable shock. Hope this helps, Cary

The problem with your drawing is that you didn't include the hub and where the wheel face will go. Ideally you want to go all the way down to the ground and see where this falls in relation to the tire's center on the ground. One problem that often arises is the front track grows when you try and make all this work. For a street car a ball joint is probably going to be lower maintenance. The joint you're looking to use is huge overkill for what's needed. One thing to remember is that you might want things like ball joints to bend or break if you hit a curb or other large object. If you don't have a "fuse" to blow then all that force will go find the next week link. You don't want that to be the frame rails. Hope that helps, Cary

For the 40 carbs it was straight through with no venturis. It was a no cost test and more of a curiosity for me. You have one of Vizard's graphs a few pages back in your post. So my guess is that you either did see it or some other pub that referenced it. In case you're curious here it is. choke(mm)=(CV x rpm / 2600)^0.5 CV us cylinder volume in CCs and RPM is the point of max power.

Here's what I can add. I haven't dynoed any of this but I used to own a flowbench and did a lot of work flowing things (heads, carbs, mufflers). Some of those things were Weber carbs. When you get to a 40 running a 36mm choke you are maxed for the most part when it comes to flow. Sure you can put in larger chokes but you're only changing how it responds when you're not maxed out. Assuming the engine wants all that air then to make more power you need to move up carb sizes. Here's what I saw on my bench. Weber 40 with 4.5 aux venturi compared to Weber 45 with 4.5 aux venturi. Below is carb and then secondary choke diameter. What seems to control flow is a lot of the shape changes seen by the air when it goes through the carb. 40 -- 32 out flowed 45 -- 32 40 -- 33 out flowed 45 -- 33 40 -- 35 tied 45 -- 35 40 -- 36 lost to 45 -- 36 40 -- 40 lost to 45 -- 36 What you saw for power changes doesn't surprise me. Our old engine that was smaller than your combo worked much better when running the 38mm chokes with the 45 carbs. It gave up a little down low but could pull all the way to 7500 where the limiter was set. When running the 40s with the 36mm chokes it started to give up a little over 6300. Have you ever seen David Vizard's formulas? If I did the math right it claims your sweet spot to be a 37.25mm choke at 7K. So I'd say you're right in the ballpark with what you've got now. Hope this helps, Cary

If you want advice you're going to need to provide more detail on what it's doing. It could be all of the above. How does it upset the chassis? Pull to one side of the other? Does the back want to swap positions with the front? Does the front end wash out? More along those lines would help.

For a racing car you don't want any compliance. Those often lead to weird limit behaviors. If you're looking for advice there's some good info in the online tech section here, http://www.ronsutton-racetechnology.com/pages.item.29/Tuning-Support.html

For a budget chump car check to see if they haven't closed the bump stop rules. If they haven't then you want to look at running either bump springs or some of the softer circle track bump rubbers. Then use packers to close the gap and you now have a much stiffer "spring" and all the benefits. If the penalty is too much for a real 2.5 inch spring then you could cut the coils a lot and raise the spring seat above the tires. You'd probably still use the bump stop of some kind for fine tuning. There are a lot of low buck ideas you can use in the grey areas to get better handling. The bump stop stuff is already being done by a number of teams.

Coleman used to sell a similar item but I can't find it on their site at the moment. You might have to search for birdcage clevis to find them.

I think the big difference is really stability and control. In a street car you want to have a limit behavior that is benign. This gives the driver confidence in their ability to take the car to the edge and still be able to bring it back in one piece most of the time. But often those tricks end up slowing down the ability of the car to provide good feedback when transitioning quickly for a more experienced driver. I once heard an explanation that you have a triangle (or radar diagram) where you have grip, stability, and control. If you want a really stable car then you generally have to give up grip or control and vice versa.

I know this is a few weeks old but I just "discovered" this thread. The advantage to raising the floor is you end up lowering the CG of the car. That's something to think about before you get too far along.

The long links are appealing. I've seen a lot of cars running the bar across like a strut bar and then you have the long link. You could even hang the bar from the strut bar via rod ends to make a nice low friction mount. I've seen a couple of touring cars use rockers on the ARB linkage so you can get long links and mount the ARB down low. You can also fit droop and or pitch limiters this way. As you turn with the strut mounted version you'll see offset that will sideload the strut. Somewhere I read a quote from a touring car driver that mentioned he had fought understeer on their car all year and then it was solved. When he asked the race engineer what the change was he said it was the ARB mounting location changing from the strut to the control arm (same wheel rate was seen). Ideally it would be nice to have some hard data to back this up but I don't. I just wanted to throw this out there as an FYI. I personally was all set to do this myself until running across this. When I took my first class with Rouelle I sat next to a guy who built some really trick cars. He shared in class how changing the rocker geometry so that the pushrod/rocker/shock were in plane from the old setup where the pushrod was out of plane with the rocker made a large difference in front grip and driver feel.

Looks awesome!

Look at used nascar swaybar on ebay or go to Roush's outlet store and you can find anything you want. A friend used one on the front of his 260 EP car. He used the spherical mounts you can get for them and used the straight arms and then bent them to be close to the stock pickup location on the lower control arm.

You really don't want to connect to the struts. I know a lot of production cars do this now but for a racing car you're better off connecting to the control arm. The reason being you increase the side load on your struts and that increases the friction that needs to be overcome before everything can move and the shock can do its thing.

Sorry to hear Tony. I know the feeling of being violated all too well. For me that was the part that was a little hard to get over. Sending bad karma their way. Cary