JMortensen

How about an Autometer tach with a built in rev limiter? Going to the 6AL isn't going to give you any other benefit, and an Auto Meter tach will replace the craptastic factory tach.

It's a slip over piece on the shaft. Some later open diffs have 4 pinion carriers, where the carrier bolts together and I wouldn't be surprised if one of those had a cross pin that you could see through the middle of. A 2 pinion cross pin is going to be a solid shaft like that one, although most don't have that slip on piece.I gather you're turning the pinion and the side gears are turning the same direction. That's always the case. The test is to turn one side and watch the other side. If the other side turns in the same direction, then it might be an LSD or it might be an open that's been welded or has some junk in the spiders. Some helicals will spin opposite directions just like an open. So the test isn't 100%, but that is pretty clearly an open diff.

Were the heads of the bolts hitting the diff on accel or decel? If accel, then your gears are backwards. The side gears should move out under accel pushing the CV's away from the housing. I really think someone needs to make some solid spacers for these things. Seems like you guys are having a ***** of a time with the washers (compressing washers on decel is what allows the stub to move inwards). That stub needs to be clipped in. If it's not it could slide out a bit and strip the splines off. Saw a pic of that from an EVO just recently. Don't attempt to figure out slop in the diff issues by turning the wheels. Not an accurate test of anything. There is slop between the side gear and all of the helicals that has to be there, and even if everything is perfect there will be a good amount of lash in there.

There are handling issues to be dealt with, increased understeer and oversteer among them, those can be dealt with. There isn't too much controversy over whether welded is faster than an open diff. It is. The real problem with a welded diff on the street is that it isn't very safe. Then again, "spirited" driving in canyons isn't safe either, take it from someone who has literally been over the edge. Locking the rear wheels together is a reasonable enough thing to do when it is dry, but when you have hi performance tires on your car and it's raining and you get off the freeway onto a decreasing radius offramp, or when you crest that hill at the edge and realize that there is a wet sharp turn just on the other side, that's when it gets sketchy. I've known people that commuted daily with spooled trucks to work in the rain/snow/ice of Seattle, so it can be done, but it's a lot more dangerous IMO than having an open diff in those situations. I wouldn't use a welded or spooled diff on the street. I'd save up for the LSD.

That's an open diff.

No clue. I have had mine apart, but I don't think the side gears would have the circlips in different positions. Externally the side gears are the same dimensions, and I wouldn't think they would cut the grooves in different spots if there wasn't a good reason. I would think that the difference is built into the carrier. Anyway, if anyone else doing the install wants to report back, maybe we can clear it up. All that's needed is to pop the inners into the diff and check.

PM'd with Rossman about this a bit just to get it straight, but on my 300ZXT LSD the long side is the driver and the short is the passenger. Ross says he checked and it actually works the other way in his diff.

Just a comment on the stock engine placement. 240 with L28/5 speed, R200 and Autopower roll bar was 49.5F / 50.5R. I didn't even move the battery. These cars are really close out of the box. I love that little V8 idea, but think that it's better suited to a smaller car like a 7 clone or an Atom or Radical or something like that.

The copper washer is not necessary. http://forums.hybridz.org/index.php/topic/37885-noise-after-replacing-stub-axle/page__p__303892__hl__%2Bcopper+%2Bwasher+%2Bzcarnut__fromsearch__1#entry303892

Tried Khan Academy? The guy does just about every subject you can imagine.

The cars weren't racing each other in the video. I seem to recall the description said the WRX was faster. The Z looked pretty well done, and had a diffuser and rear wing and interesting fender vents and a splitter. Sounded like it was a normally aspirated L6. They did a walk around of the car sitting in the paddock, and then there were some on track shots.

Couldn't be something as simple as putting the long shaft in the right side, could it? The shaft that plugs into the diff is only about 3/8" different, so if you do this the one side looks pretty good, but the other won't clip in.

Wow. Begs the question if that is a one off or if there was a production run of those at some point.

Cary (tube80z) changed my mind on this one some years back. I was planning on running pretty high roll centers so that I could run less stiff springs and relatively stiff bars with 10" slicks with the idea that relatively softer springs make the suspension more compliant. I changed plans and dropped my front roll center to near 0 and left the rear slightly higher, and decided on much stiffer springs with smaller sway bars. I'm going to try and get it to work with no rear bar at all. The reason is that stiff springs limit travel, but they don't add stiction within that range of travel. If you run a high roll center you get less body roll because the suspension arms are geometrically fighting the roll. They cannot fight the roll AND respond to bumps very well at the same time, so you lose some compliance by going to a higher roll center even if the effective roll angle of the chassis is the same. Your roll center adjuster in the rear is pretty nice looking. We had a guy here with screen name blueovalz. He cut the bottom part of the strut off and welded on his own to do the same thing. His reason was a little different though. He had pretty large 17" wheels and to get them where he wanted in relation to the wheel wells (he built the flares himself) he had the rear LCA's pointing up at a pretty good angle from the diff to the wheels. Looked like he was running a pretty significantly underground rear RC. I want to say that he lowered the outer pivot 2". It was a good mod for him. He sold his car to another guy on here and has moved onto a Manta build which is pretty damn awesome. The guy is a very good fabricator and was super helpful. Here is his fototime site which still has all of his Z pics: http://www.fototime.com/ftweb/bin/ft.dll/pictures?userid={7DC317B0-8EDB-4B2E-A837-F708D07C9769}&uid={7DC317B0-8EDB-4B2E-A837-F708D07C9769}&guid={1B2E8518-DFD2-42EF-8487-7EB3BDCF2F68}&custdom=1 I'm sure Cary will chime in if he sees this too. He's talked about adjusting ride height in very small increments to change RC and overall balance. My car (or maybe it was me) wasn't sensitive enough to the changes I was making, so I'm hoping that with a lot of chassis stiffening that it will respond better and I can utilize some of his ideas.

Cam and pawl is old tech race car stuff (like formula car). I don't think you'll see that kind of setup for any diff the we would be likely to use. Detroit Locker would be close, and those are available for the H233 which makes me wonder if that would work on an R230. I did have a friend who had an OLD Detroit for an R190. This was pre-soft-locker. He had it in his 510 and it scared the crap out of me the first time he went around a corner.

Mileage? Cost?

How about a used GTR or some other fast (used?) car that isn't as expensive (WRX, EVO, Vette etc) or, if this is a track thing, a used race car that is faster than a GTR? You can buy a used Stohr D Sports Racer, a used trailer and a used truck to pull it with for less than the cost of a new GTR, and it will be WAAAY faster around a track. I appreciate that the GTR is a truly bad ass car, but I really don't like the idea of being car-poor.

Seriously badass.

If you're drag racing a trailer queen, a spool is better than a limited slip. Much stronger, and you really don't want any differentiation anyway. Not the safest thing on the street though.

Engine braking is totally normal.

That's pretty similar to what I used for a while. Only problem is that you can overheat them quickly in a track situation. I got less than 5 laps before I boiled the brake fluid on one particular occasion when it was 110+ degrees, and the brake pad linings started chunking off. On several others I boiled the fluid after a couple sessions. The pad above had the friction material either disintegrate or just lose its bond with the backing plate on both pads after 3 sessions. I had ducting, but it wasn't very good and it was 2" hose. If you're going to be on the track with brakes like that, just mimic what the ITS guys do as far as venting the fronts.

Your options at that price point are to luck out and find a cheap used Z31T (probably junkyard at that price) or the OBX, which needs to be inspected before running to make sure it's assembled correctly.

FYI, that pad with the hole in it is a stock caliper R4S pad. Fine for street and autox, not OK for track use with sticky tires. If you're going to do a lot of track days with 20-30 minute sessions, use the R4 pads or Hawk Blues. Not sure how drifting affects brakes, so YMMV.

If you have a pyrometer you could take temps off of the brakes after driving and see if one is hot. Might be able to jack the car up and turn the wheels by hand and see if you can feel which one is stuck.

The main issue is getting the bias set correctly. You can put huge brakes on the front, and if the rear isn't doing anything you'll still have worse 60-0 braking performance than a properly setup and maintained stock brake system. A lot of the systems that use Toyota fronts and 280ZX or comparable rears are so front biased that I suspect they don't actually improve braking distances. On my car I removed the prop valve entirely and still couldn't get enough rear brake. I found the car stopped a lot better with stock front calipers and rotors and the ZX rear disc. That said, there is more to braking than distances, and larger and/or vented brakes will provide more heat capacity, so that even if the brakes don't function as well in a braking distance test, the poorly biased brakes might still function at the end of a 20 minute track session where the stockers might have overheated. I've overheated my old stock front or 4x4 front and 280ZX rear brakes many many times, boiled the fluid a lot and even punched a hole through the back of the brake pad with the piston. Wilwoods are still not completely problem free, but they should cut down that kind of hassle.