JMortensen

PMOI is polar moment of inertia, which is essentially resistance to changing direction in a car. Moving weight in between the axles reduces PMOI, while hanging a 500 lb weight on the front or rear bumper would increase it. There is an argument that you don't want the lowest PMOI that you can possibly get, but that's probably a subject for another thread. The initial failures of U-joints with the diff in the forward position was due to the U-joints inability to articulate freely enough. Moving the diff back and in line with the companion flanges eliminated one source of angularity in the shafts, and then the halfshafts only dealt with the camber change.

I wonder if it would be possible to flip the R200 bar and maybe hook the front diff mount on the rear set of holes...

What John means by "helps driveline angles" is that there would be more room for the CV's and they wouldn't bottom and the cage on the drivers side wouldn't need to be flipped. This is contrasted to the moved back position where the CVs and halfshafts are near bottoming. John covers this issue in the "R200 Handling Issues" article in the bench racing area of his site: http://www.betamotorsports.com/benchracing/index.html

No, it's BS, but a good story. Mythbusters did one of their first shows on that story.

Added NWS to the title. I am just amazed at the number of guys willing to put bottle rockets in their ASS and light them off. And I wonder, do they not have internet connections? I mean I've seen probably 4 or 5 videos of guys doing this and getting burned, not to mention the few I knew in high school who did the same thing and got the same result. Morons...

Usually tall gears and road courses aren't compatible. Have you tried to figure out exactly what gear ratio you'll be needing? What is your redline rpm, what trans are you running, what tire size in the rear, and what do you figure your top speed will be? This might help you figure it all out (you can manually adjust all the ratios and stuff to suit your particular combo): http://www.geocities.com/z_design_studio/ Just as an example my old setup with 7000 rpm redline, 23.5" tall tires, 3.70 gears, and a Nissan 5 speed topped out at a theoretical 172 mph or so. It would never have gotten there unless dropped off of a cliff, but there was still plenty of room to adjust it higher by taller gears and tires if I wanted. I just plugged in 285/35/18, 7000 redline, 3.55 gears and the .773 O/D ratio and it comes up with a theoretical top speed of 196 mph...

Once you get CV's installed the location of the diff is much less critical than it is with the U-joints. I wonder if the solution to these issues along with a lower PMOI might be obtained by moving the diff forward. Take a look at a 911 and the transaxle outputs are 2-3 inches ahead of the companion flanges. No reason we shouldn't be doing the same thing. Alternatively there is the Terry Oxandale method of moving the diff up, although this raises the cg.

Dive/anti dive depends on the angle of the rod. If the rod is forward of the crossmember and angles down to the control arm, then the suspension will have "pro-dive". If it angles up to the control arm, then you'll have anti-dive. Likewise in the stock location angling down from the mount to the control arm gives anti-dive and angling up gives pro-dive. You can certainly relocate the rods, but the steering is going to be in the way. You could probably adapt a ZX steering setup in to fix that problem, but the question is: is it really worth all that hassle. You can change the mounting points and also just run stiffer springs to reduce dive as well, so changing all of the front suspension seems like a lot of work. One big advantage of a rear mounted rack is that adjusting in Ackermann is much easier. You might check my sticky thread on TC rod pivot relocation. If you did what you're talking about you'd basically be into everything I was into, plus a bit more with completely switching the steering rack to the other side. Lots of work.

The issues so far as I'm aware of them are: 1. Scrub radius increases with wider tires, so more kickback going over bumps through the steering wheel. 2. The farther you get from 0 offset the worse the leverage is on the wheel bearings. The larger the tire the worse for the wheel bearings too, but I would think your example of 10's with 2 inch backspacing would be pretty hard on the bearings. 3. I think there is a point at which you can have too much tire, but I think you'll have a really hard time getting to that point on a Z. I know tube80z ran 10's and 13's on his FP car that weighed under 2000 lbs.

One intermediate step might be to try some 510 drums. They're cast iron and although I always thought the aluminum drums were the hot ticket and all my 510 friends run Z drums, occasionally you'll see someone saying that the cast iron drums don't distort as much.

Sorry, I was thinking 240Z, and I looked online and found the same values you did. Thanks.

Anyone know these values off the top of their head?

The turbo/2+2 is where I get a little fuzzy. I think you would need the same collar as a 2+2, but I'm not sure if that is the same collar as the turbo, since the turbo came on a completely different transmission.

I think it's the pressure plate to be exact.

On the L series you don't need to open any of the hydraulic lines to change the clutch. Zparts.com has the page with all the collar lengths listed. You might have to find out what length you have and then get the appropriate pressure plate for it. zhome.com has a couple of pictures of the different transmissions and ways to tell them apart. Above and beyond that, if you want to tell what kind of tranny you have, you just have to lift up its skirt and take a look.

Doesn't Porterfield do shoes for the Z? Some R4 shoes might help, and that I think I would risk on the street.

Mine was bottom heavy, then I put the cage in and now it is top heavy. I can still spin it by myself, so it's close enough for me. I spun it a couple times when I first put it on the rotisserie with full suspension and wheels. That was too much weight and way too bottom heavy to be a good idea, but I have no hernias and I didn't tip the car over. You can always do a counterweight like Steve Parmley (zlalomz) did. Then it doesn't really matter where your center is.

Yes, that is normal maintenance for the track. It sounds to me like you were maybe starting to boil the fluid too. You might consider some venting to the front brakes. I've tried Porterfield R4 pads on the street and in my opinion it isn't a good idea. I had a not panic, but harder than usual stop with them once after a good long stretch of freeway and there wasn't much there. Turned into a panic stop by the end... Get closer to maintenance free? That's easy. Get some big ol 12 or 13 inch Wilwoods or PBRs or whatever suits your budget and slap them on. You won't have anywhere near the maintenance issues that you do now.

This thread is a year and a half old. Are you looking at the date before you post? I appreciate the fact that you're using the search function, but this is the second OLD post you've resurrected today...

Changed title to reflect what was in the thread.

Hmm... I wonder why the shop closed? I think you'll be needing a rebore. I've never seen .030 over pistons. Also the bore usually isn't done until the pistons are in hand. They have to be pretty close tolerance, so what I'd do is take the block to another machinist, see if they can get pistons or if you need a rebore. Once that is settled have them bore and hone to match the pistons you buy.

You realize you're reviving a post from 2002. To answer your question a Dana 36 Vette rear end has been done, I think it's very similar to the Dana 44 IRS rear end that came in the Viper, just a bit smaller It was used in the later Vettes before the transaxles came in. ScottieGNZ swapped the D36 and complete Vette rear suspension and was on the brink of high 9's when he parted it out and went to an GN powered FC instead. Now I think he has a 2JZ engine in the same FC... he's still around and obviously addicted to swaps.

Hmm... I have an 80 transmission and I never had that kind of issue until years of autox and time trial abuse started to take it's toll. I got the trans with something like 225K on it and put 40K of hard miles on it myself. Now my 1st and 2nd synchros are mostly gone and I think the mainshaft nut is backed off, and that's what I attribute my issues to (main issue is that it pops out of gear on decel, but it is hard to get into 2nd sometimes in autoxing situations). As far as oil goes, I'm sold on 50/50 mix of SWEPCO 201 and ATF. You can use the SWEPCO straight, but the ATF thins it out and makes it shift a bit faster than regular 80/90 gear oil.

I think he's saying that with a dished piston the quench is lost. So if you wanted dished pistons you really want the dish to match the combustion chamber. There are lots of V8 pistons done this way, but they have a more generic 1/2 dish.

Basically you just want the swaybar to start from a neutral position. If you put 240 lbs in the driver's seat like you said and then loosened up the end links you would see that there was about 1/2" gap between the driver's side end link and the bar when the passenger's side was just touching. So you add 1/2" of shims (washers to "lengthen" the post in between the actual bushings) and then the bushings rest on the control arm and the bar evenly. Now you just tighten them down evenly, and you've removed the preload. I could have said it better the first time, sorry.