JMortensen

That's a little different from what I thought I was looking at before. No clue as to whether it's going to affect anything. It would make me nervous though...

I don't know the technically correct names, so I use stub SHAFTS in the diff and stub AXLES at the wheels.

That's an interesting thought. Might just do the X first, then look at both options. Good ideas here too. Gussets are definitely part of the plan, have no fear. I'm going to run open track days and play around in FP until someone bitches that I've removed the rusty drip rails or I get my V8 swap done, whichever is first. Then I'll probably be in a class that I have absolutely no chance of winning. I just want to make this one as fast as I can possibly make it. If I decide to really try to compete in autox on a higher level or start actually roadracing instead of just timetrialing, I'll get another car.

Not a problem. The driveshaft is fine. I believe the stubs that go into the sides of the diff (the part that the halfshaft bolts to) are different between the 180 and 200. So you need the stubs from the 200 The halfshafts should be OK. Strut bearings??? Now you're talking about rear wheel bearings, but those shouldn't have anything to do with the diff swap. You should have the stronger stub axles, due to the fact that this is a 280. The wheel bearings are kind of a PITA, so search and find some threads about grinding away the peened nut on the inside of the stub axle before you dive in.

I've done that many times with an iron block NA L6... Suppose it depends on what type of racing you're talking about though. It would be a lot harder to do in a drag race than autoxing or time trialing.

That list is written to include EVERYTHING a person could possibly need. If someone were to buy an R200 out of a Z31, they would need everything on the list. If they bought the diff out of a 280Z, it already has most of that stuff on it. 1.Yes, you need the mustache bar. 2.The yoke is the part of the differential that the driveshaft connects to. So if you bought a 77 R200, it would have the correct yoke on it already. For those who are installing the 300ZX diffs, they need to find a yoke from an earlier R200 and put it on their diff. 3. The rear cover from the 77 will work. 4. The stub shafts I think need to come from the R200, I think the R180 has smaller stubs with less splines. I haven't verified that personally, but I'm pretty sure. Diff mount needs to be flipped around and the crossmember and rear transverse link will work fine.

I think it's just a bad bit of casting, don't think it will hurt anything if removed now. If left in it could break off and that wouldn't be a good thing.

The purpose of the tubes from the hoop to the strut towers is to provide another load path for the door bars in case of a side impact. I guess I'm not following the second part. Can you draw it for me? EDIT--Just clicked, don't need the picture. The curved plate part had me confused because I was thinking you meant on top of the tunnel. Yeah, I suppose I could do that. I'd have to cut more holes in the rear deck, and they might be going straight through that thicker plate there. I'll have to work it all out and see where everything ends up. Thanks for the idea.

No, you convinced me to do a full cage. The original plan was to do a bar, but now I'm going for broke.

I've been pretty well set on doing Cary's X design for a long time. He and I have discussed it at some length via email, and he's done some modelling of various different designs and found that it really made a big difference in the stiffness of his models. With the spring rates and tires I intend on running I think it's going to be worthwhile. I figure for ~10' of tubing at about 1.1 lb per foot for this thin walled tubing, it's going to be worth it. I didn't really feel like I was doing the right thing on this control arm stuff, which is why I wanted to get more opinions from everyone. But I do feel my latest idea comes with an absolute minimum of weight added and should keep the control arm mounts from tearing out. I'm looking at doing a pretty thorough cage, and at this point my goal is not to leave any stone unturned. I'd rather overdo it now that the thing is on a rotisserie than underdo it and have to tear it all apart again.

Think I have it. The tunnel is already reinforced in this area, so I think this will work. Weld the plates in on the floor to strengthen the mounting to the chassis as originally intended. Run a small 1x1x.063 square tube gusset from the floor to the side of the tunnel. Do the X as I had previously intended. Also added in the shoulder bar in blue just to clarify the plan there.

Not trying to rain on your parade, but there are several issues with an aluminum block L series (or a DOHC head--the other mythical L series mod that is always just about to be figured out): 1. Cost 2. Illegal in just about every racing class except the "open" classes 3. If you're going to be make the car illegal for a given class and run "open", you can make a hell of a lot more power with a whole different engine, and the cost is MUCH lower, eg V8 swap. I'd be curious to know what you think this aluminum block will cost, what it will weigh, and how much benefit could really be obtained by using it. Then compare that to say a LS2 swap with a brand new engine and transmission. Compare weight, power, cost, etc. It'd be interesting to see where that would end up...

From http://forums.hybridz.org/showthread.php?p=708798#post708798

Russell, the yarn test has been done. The air goes INTO the engine compartment. The base of the windshield is a high pressure area. The base of a spoiler that you put on the hatch is a similarly high pressure area. There are a bunch of other aerodynamic threads on this site where these topics have been covered pretty thoroughly. OTM's yarn test with the chase vehicle has been tried as well. Let's not let this one get too argumentative or redundant. What is interesting about this thread is the drag information. If you want to talk about downforce or upforce or vented hoods or spoilers or any of that, try one of the other threads.

Thanks for those Justin. There will definitely be a shoulder bar across at the kink. I have been waiting to get a tubing bender for that one. I need the bender because the brace behind the driver's seat needs to bend back to allow the seat to slide all the way back. I just had a tubing bender delivered, but they sent the wrong one. The second picture with the straight bar all the way across the bottom is a good idea, and I had that option when I put the control arms together, but opted against it just because I didn't want to have to try and remove the original frame rails and then have to build another front diff mount. It might have been the "best" answer, but I just didn't want to have to hassle with it. The bar from the top of the hoop to the back corner is something that I've seen in older racecars and on some Japanese cars, but it's purpose is the same as the diagonal bar in the main hoop, mainly to keep the hoop from folding in the event of a rollover. So that one is a bit redundant. The ^ from the shoulder bar down to the control arm mounts is a possibility.

Yes, you need a new yoke from a 280Z or 280ZX with an R200. It is a simple part to change if you have an impact gun. Take the old one off, put some red loctite on the nut and put the new one on. The torque spec is ~150 ft/lbs, so I usually just put my gun on 5 and lay into it. The R200 does not use a crush sleeve so overtightening the nut is practically impossible.

It totally depends on the rest of the engine. Triples work best with a much larger than stock cam, and that works best with high compression. I figure I gained about 40 whp by putting them on in place of SU's. I think Dan Baldwin had similar results verified by the dyno. Just slapping big carbs on with a stock cam isn't going to get as big an increase, and you also have to figure that they need to be tuned to be optimized. Tuning them isn't really that hard on Mikunis, harder with Webers, but you'll find a lot of people chase their tail trying to get them running right. Tuning is somewhat expensive because of the cost of the jets as well, so factor that into the cost of upgrading.

I don't suppose there is a reason why that BRE idea couldn't be done this way...

You can also do an external surge tank. Several people have gone that route. Tim240z had a pretty good post on his a couple years back if you search you'll find it. Basically works just like you said, doesn't need to be big, and just uses a carb type fuel pump to fill the surge tank with a fill and return nozzle at the top and the fuel feed to the engine at the bottom. Oops, I see now that you had already considered an external tank... Why do you think it's going to take up a lot of space??? 12 oz of fuel in the surge tank should be MORE than enough. The surge tank on carburetors is the float bowl, so it really doesn't have to be a large container at all.

Well I suppose just in terms of mounting everything in a stronger way just welding the plate to the floor and plug welding to the bottom would make the control arm mounts less likely to tear out. Maybe I should just do that and then concentrate on the X...

Let's have fun laughing at the idiot and not get political, alright?

You can see from this picture where the strong part of the frame rail ends: I suppose I could run a small piece of tube or a gusset from the SFC to the bearing holder area here. I don't think I'd physically have enough room to weld it in all the way around.