jmortensen

A 3.90 LSD wasn't offered from Nissan that I'm aware of, but you can put one together yourself. You would just need the later version of the R180 LSD. I think you could buy it out of that group buy right now. I seem to recall that they only have one or two R180 LSDs left, so if you wanted it you should grab it now. I am not entirely sure of this part, so don't hold me to it. I know the difference between the early R180 and the later version is the size of the hole in the ring gear. One has a larger hole and the other has a smaller hole. I ***think*** that the later version has a larger hole. So if you tried to use the early LSD with the later gear set the ring gear would actually be loose on the carrier. It needs to fit tight, so you need to get the correct carrier to go with the correct ring and pinion. I know that zcarnut, Steve Golik, has described in detail the differences on Hybrid Z before. I guess I should look up that old thread and then add that information into my What diff should I choose post... The other complication that I can think of is that the later diff takes clip in axles and the earlier ones take bolt in axles. I think that problem has been solved for the open diffs, but not sure about the LSD. I don't think it would stop me though if I were running an R180...

R180 is lighter, you wouldn't need all the bits to swap it out. The 4 pinion R180 LSD should hold down 300 hp or so, so you'd have a ton of room to grow power wise. The R180 changed around 1976. You'll find good gear ratios in the later years from the front end of the 720 4x4 trucks. 3.90's and 4.11's and I think 4.56's too. This later R180 will require a different LSD than your 73 would use. In the early years it's only 3.36 and 3.54s that are common, and neither of those go particularly well with your NA L28 and 5 speed combo. You'll have a theoretical top speed of 200 mph, but an engine that can't push the car faster than 145 or 150 mph. So if you want to change the gear ratio, I'd look at the later LSD and the truck diff for the R180. R200 is heavier and bigger than you really need, but you'd never have to worry about it. It is really too wide for the early Z suspension and you end up bottoming the halfshafts. CV conversion fixes that problem. Details at www.betamotorsports.com click on bench racing then R200 handling issues for details. You could easily find 3.90's, and 4.11 R200s are fairly easy to come by too. You would need all the additional parts to install it, and then possibly the CV conversion. Your choice, but with the current engine you have I'd go with the R180.

The viscous is the less racey of the two, it's passive and doesn't do anything until one wheel starts to spin. At that point the fluid in the carrier provides resistance to one wheel spinning faster than the other. The clutch style is actually torque sensitive and the harder you step on it the more it locks the two side gears together. I haven't ever heard my clutch LSD operating, other than when the fluid gets cooked the clutches can make a whirring noise when cornering slowly. I have read about clicking from other Z owners, but it hasn't happened to me. I much prefer the clutch style, especially when consider all the BS you have to go through to use the VLSD.

Why a VLSD? It has a different spline count inside the diff than the normal R200 open or CLSD diffs, so you'll have a lot of trouble adapting it in. Check out this thread, as it explains the process in the Shortnose R200/R230 section: http://forums.hybridz.org/showthread.php?t=114798 If you're just looking for a limited slip, there is a group buy going on over at hybridz.org. R200 clutch LSD for $450 I think it was. It's a good deal. http://forums.hybridz.org/showthread.php?p=690759#post690759

This is correct. Yes. Rule of thumb is you want 10 psi oil pressure for every 1000 rpm. When I installed both comp springs, it was way too much pressure. 1 comp spring and one stock spring is about right with no external cooler IME

You can buy a "real" turbo pump from the dealer. I have never heard that there is a difference between the standard and auto either, so you'll have to figure that out for yourself. The turbo pumps have larger gears, and that's what distinguishes them from the stock one. They have a higher flow output because they had to push oil out to the cooler and back. Add Nissan comp springs and now you have the comp pump with higher pressure and volume. I've never heard of issues from running both oiling systems. The solder joints are the weak point in the spray bar, but if you're concerned, resolder the joints. The spray bar should be the more effective method for oiling the cam, and lots of 510 racers add the spraybar to the stock internal oiling (although they run a separate oil line from the block). If it were me I'd run one comp pump spring and one standard pump spring on the turbo pump.

Cut the shells. Take a hacksaw to them. Cut towards the meaty part of the control arm so that if you go a little more than through the shell you don't weaken the arm. Once you cut through the shell it looses it's tension and you can pry it out with a screwdriver.

Arne, that is your inaccurate stock gauge talking. Hot oil pressure on an L is usually somewhere around 15-20 at idle. My question in regards to this whole setup is why would you possibly want to unplug the cam? Are you worried about too much pressure, or is it that the spraybar seemed to work better with the cam unplugged? Regardless of the reason why you're trying it both ways, when the engine is actually running you want the pressure, so you'll want to have the cam plug in. Right now you're testing FLOW, not pressure. When the engine is running, you need pressure as much as flow, especially for the bottom end.

That's the best way I've seen this put into words. I still can't believe it when I see FI "purists" talk about "upgrading" from carbs to that craptastic early Z injection.

Totally normal for most lowering springs. I bet if you search you'll find a bunch of other similar threads. Stiffer springs have to be shorter than the original, otherwise it would ride higher than stock.

I'm not arguing with you in theory, but there are plenty of channels that aren't there to "take over the world". In fact most channels now are somewhat specialized. The History Channel isn't trying to sell music videos, Spike TV doesn't do children's shows, etc. If there are enough of us out there that want to watch racing, it would be profitable to show it. If there aren't enough of us interested in watching it, then it wouldn't be profitable. The original Speedvision was started by a racing afficionado, who got backing from investors. I see no reason why it couldn't be done again if ther market is there.

Tom, you going to post some videos on your website? We'd love to see 'em. Oh, and congratulations!!!

There was an article about the guy who started the Speed channel in Road and Track or Car and Driver within the last couple months. They were talking about Speedvision and it's decline into Speed, and all that. The guy was well aware of the internet petition and it was mentioned in the article. But the channel was bought by outside investors and there was just too much $$$ in the NASCAR for them to turn it away. You can't blame them from a business perspective. To me it seems like the perfect opportunity to start "The Road Racer Channel" and not show the NASCAR crap. Evidently not as much $$$ to be made, but sometimes its not about being the richest F'er on the block.

If that picture is current, it doesn't look like he's taking the weight penalty and running the 12" wheels... interesting.

Downforce.

Ball joint separator isn't necessary. Just unbolt the ball joint from the control arm.

This is one of those situations where the lazy man works the hardest IMO. It will be much harder to do this job with the control arm attached to the car, even in the front where you only have the one bushing.

Here is a picture from the AZC website showing the new upright pieces that Zack referred to:

No, the blue bar really is the rear sway bar, the gray is the ST bar. The way the bar mounts is that the straight part in the middle attaches to the frame rails that connect the wheel well to the front suspension bushings. Mounting the bracket to the frame rail requires drilling one hole in front and one in back of the rail, then using long bolts which come down from the floor past the rail and capture the D ring part that holds the swaybar bushing. The bent arms then go up over the leading edge of the control arm and the end link part is pretty self explanatory. I think the blue bar might be upside down though... the gray one is right side up.

I took a pic of the two together when I got the ST bar:

FWIW I took my MSA rear bar off of my 5/70 and I was amazed at the amount of bind it had. It was binding on the frame in the front, and then I had to play with the end link length as well which was really funky. I'm glad I got rid of it. The ST bar apparently needs to be spaced back about 1/2" or it binds as well, but that's really easy to do, and once in the right zone it's a much nicer design IMO. The later MSA bar for the 280s might be a bit better because they have the brackets that drop down off of the frame rail, unlike the 240s. My car used to pull REAR wheels off the ground in slaloms with that bar on. That's pretty weird for a Z...

That's a very good solution to the problem. Should be fine that way for a very long time.

The 72 has the preferable ashtray configuration (even if you don't smoke it makes a nice cupholder). It also has the correct shifter location to install at 5 speed. As Enigma says it has the curved transverse link behind the diff, making R200 swaps easier. My understanding is that the sheet metal in the 72 was galvanized. That's OLD memory talking there, so it may be wrong, but seems like I read something like that on IZCC years back. The 72 gained some weight vs the earlier cars. Still haven't figured out where they put it, but it seems to be the case. I like the 72 for a driver. I'll keep my 70 for a stripped down balls to the wall race car due to its lighter weight.

You should use the original brackets. You might also consider reinforcing the frame in front, since over a period of a few years the sway bar will start to tear up the frame rails. Lots of info on this at hybridz.org, haven't looked here but I'm sure its been discussed. www.baddogparts.com sells a weld on angle bracket that significantly strengthens this area.

Get em Will! Get em!!!