jmortensen

I don't think there is a law against fuel cells, certainly a lot of drag racers use them on cars that get driven on the street. Personally I would avoid a cell at all costs unless it was necessary with the body you're racing with. My cell is 20 something lbs heavier than the stock tank, so just installing the cell will make my car slower. If you don't have a firewall between you can the cell, then you run the risk of spraying fuel into the passenger compartment if you get rear ended or have a rollover. Not to mention the stink in the car when you dribble a little gas filling it up. If you do the remote filler to the stock location, that makes the cell a lot more liveable day to day, but it becomes much harder to separate the cell from the passenger compartment. Then there is the cost of the cell and plumbing it. The only upside to a cell is that you can run larger fuel lines. Aside from that, there is no other benefit except the crash worthiness of the cell itself. Having been in a 72 Z that was rear ended at 50+ mph and seen that the tiny amount of fuel that leaked went outside the car, I just don't think it's a smart way to spend money. I'm sure others will disagree, but that's my $.02.

When you talk about molesting early Z's the first thing that comes to my mind is the smog equipment, the barcalounger springs, long steer knuckles, and the 4 speed 3.36 combo. Why did we get so screwed?

Brake booster is leaking, so when you step on the brakes you're getting a vacuum leak letting more air into the engine which speeds it up a couple hundred rpm. Because you have a leak, there isn't as much pressure differential on either side of the diaphragm, so you don't have as much power assist. If it's really bad you won't have any at all.

There are a BUNCH of reasons, but just a few would be rod/stroke ratio, fuel management improvements, ignition timing improvements, cooling system improvements, combustion chamber shape. You can reach 200whp on 9:1, and as I've said there a number of times, it's much better to be able to optimize the timing for power than it is to run too much compression and have to back the timing off so that you can run without pinging. Also your cam is too small and you should ditch the DGVs IMO.

Go to hybridz.org, search, and read for a couple days. Then if you have a specific question, ask it there.

You will find more info on this at hybridz.org I think. My personal take on it is that the Toy calipers are too strong for ZX rear disc brakes, and you end up with a system that is too front biased. I ran the ZX rear disc with the stock front calipers and found that I could get the bias just right with an adjustable prop valve. With Toy fronts and ZX rears I took the prop valve out and still had way too much front braking. This might not be too big an issue on a street car and certainly the rear disc is better looking and much easier to work on, but if you're trying to get the best possible braking, a bigger rear brake setup or smaller front is a good idea. Most people upgrade to the 280ZX master at the same time, I don't think it is absolutely required, but a stock master with Toy calipers has a lot of pedal throw. There are vented rear brake options, but really vented fronts solves the braking issues on a Z that is driven really hard. If you look there are options from Arizona Z Car and others that have vented fronts and rears.

Whatever you decide on, I too hope you'll stick around. GLWS.

BBC Documentary "Grand Prix - The Killer Years" http://www.youtube.com/watch?v=grlkYMTi7hg

L28 with 44 mikunis MSA 6-1 with 2.5" mandrels from JC Whitney Dynomax Super Turbo http://www.classiczcars.com/photopost/data/500/dynomax.wmv As much as I wanted to ditch the 6 for an 8, I still think the 6 sounded pretty awesome.

I like shocks as an answer, but there are some other options too. You could get that airdam lower to the ground very cheaply and easily by adding a little skirt on the front and might pick up just a little bit of time, a splitter would be another option too. I'd say droop limiters but your car doesn't seem to have as much body roll as the other Zs in the class (judging by pics of last years Nationals) which makes me think you might already have them. I bought a 75% faster than stock power steering rack for my autoxer, I think something like that would probably help you too.

It's smoother, doesn't chatter, and can run regular oil without LSD additive. It doesn't affect turn in as much and can use less hp than a stiffly shimmed clutch unit. Downsides are that they don't grip as well and often require a softer rear suspension setup and sometimes deletion of the rear sway bar to prevent the inside tire from spinning.

I was explaining helicals yesterday on another site and came up with what I think is my most concise and clear explanation to date, so I cleaned it up a bit and figured I'd repost it elsewhere. Helical diffs work like this: two large side gears in the carrier are connected to the axles, and a bunch of worm gears drive off of each side gear and ride on each other in the center. The worm gears connect the two side gears together, so that when one side gear turns at a different speed than the other, all of the worm gears must also turn. When there is no load (no torque) and the unit is not preloaded (some are preloaded from the factory, some aren't), you can jack up the rear end and spin one side with one finger and the other side spins very easily in the opposite direction. There is probably even less resistance than a normal open diff and spider gears. When you put power to it though, the torque drives the side gears outwards into the case, and all the worm gears get driven inwards to the bottom of their machined pockets in the carrier. The force of these gears jammed up in all of their respective slots is what creates the resistance to differentiation. All of the gears also try to walk off of the gear they're riding on, so there is axial and radial friction between every gear and the case. If you try to spin one wheel at a different speed, it must turn all of the gears in the differential while they're loaded. The amount of force produced here can be quantified by how much torque it can hold. This is what is called the Torque Bias Ratio. Really aggressive TBR's are 5:1, most common are ~3:1. This means that a 5:1 TBR can keep putting power to the wheel with less traction until it has 1/5 or 1/3 the traction of the other wheel and the torque applied does not exceed the traction of the inside tire. If you have less traction available or apply too much power so that you get wheel spin, then the gears inside lose some of their friction against the case. As the speed differential between the wheel speed and the car speed increases on the wheel that is unloaded, internal friction in the limited slip decreases and that tire spins more and more freely. If one wheel comes off the ground and there is no preload, all of the torque goes straight to the lifted tire. As soon as traction is restored, the diff resumes the task of limiting slip. This definition that I've given is not typical, and I know it. Usually you see something like "the differential takes the torque at the wheel with less traction and transfers it to the wheel with traction" or "sends traction from the wheel that slips to the wheel that grips". You might see some math applied: "If the inside tire can put down 100 lb/ft of torque, the LSD will send 300 lb/ft to the outside tire." This is really not what is happening at all. It's more accurate to say that the helical LSD can lock the axles together to a certain degree by applying friction equally to both axles to prevent it, and once you go beyond the limits of the friction created by the diff or the traction available at the lesser tire and try to put torque down, you get wheel spin. There is no gear reduction mechanism in the diff, no mechanism to take power from one side and add it to the other. The limited slip acts uniformly on both sides. By way of contrast, traction control systems actually change the speed of one tire vs the other by applying the inside brake really do SEND the power from one side to the other by limiting drive to the spinning tire and applying more torque and power to the side with drive. Helical limited slips do not do this (no limited slip that I know of does). We may truthfully say that the inside tire is putting 100 lbs of torque to the ground and the outside is putting 300 in a helical example, but the gears inside the diff are still applying the same amount of frictional force to both axles to resist differentiation. Limited slips allow wheel speeds to differentiate for corners and still maintain the ability to resist spinning one tire out of control, but they are not "sending power from the wheel that slips to the wheel that grips". LSDs are like sway bars in that respect. They attach to both axles of the car, so whatever effect they have is shared on both sides. The result of their equal effort can be quantified in terms of how much more power can go to the outside tire before the inside starts slipping, but the effect is not obtained by virtue of the diff transferring power to the outside tire, it occurs because the diff resists slipping and the fact that there is more traction at the outside tire. If you have a clutch LSD shimmed really tight, it might have a TBR of 1000:1 or maybe it would even be locked up solid and be infinite like a spool. But that doesn't mean that a diff with an infinite TBR puts infinitely more power to the axle with traction. It means that it drives the axles EXACTLY EQUALLY and if one side has traction it does infinitely more work than the side that has none.

Congrats to you John, for helping him get there. I haven't seen any results and wasn't able to find any online. What was the gap, and was JT second?

I've bought from them and been to the shop with mixed results. No problems with the things that I purchased, but they screwed up a friend's mail order purchase several times and gave another friend bad camshaft advice.

4.38 gears came in older (R32?) Skyline, OS Giken makes a few sets that are $1500 I think. John Coffey could probably hook you up with an OSG gearset if you wanted to go that route. Quick change is an entirely different differential. They're definitely cool, but they are long and I don't know if there is room in a Z. You'd definitely have issues with the rear brace across the rear control arm bushings. If you really want to change the diff and you don't need to change ratios from track to track, I'd go with a Ford 8.8 IRS. Gear ratios from 2.71 to 6.14, helical LSDs are about $500, stronger and lighter than the R200. Only bad part is you'll need to figure out axles and mounting. I can sell you gears, install kits with bearings, LSDs, and even bare housings through www.m2differentials.com. Probably easiest to go get one out of an Explorer (31 spline axles vs car 28 spline and has an aluminum housing) and then buy the parts from someone like me.

Moving the wheels back reduces caster. This would make it easier to physically turn the steering wheel but would make the car handle worse. Stock is about 2.5 or 3 degrees caster if I recall. Lots of racers run 5 or more degrees, and it makes a big difference. On my car with 23.5" tall tires the tires hit the fenders with the wheels turned at about 5 degrees of caster. I bent the fenders for clearance.

Can't answer your question directly, but if you can't figure it out you could just get some towers from another head and mark them before you pull them off.

Might run it across the border for a Krown rust treatment. http://www.krown.com/#default

I can't stand Dan Neil and Matt Farah, and Salley has no reason for being on the show at all. Adam is great and I've been a casual fan since Love Lines, but the show doesn't flow and it tends to be either confusing, boring, or annoying. TGUSA is still way behind TGUK, but the last two episodes were miles ahead of TCS. I took TCS out of my DVR after Brock was on and they had him racing slot cars. WTF was that?!!

I bought a part from Jerry and he tweaked it a little to fit my needs. I got it quickly and paid less than I thought it was worth. Would buy from him again.

The real thing to be concerned with is that they know to cut the peened area off before taking the nuts off. If they don't they'll wipe the threads off of the stub axle from the peened area to the end.

Really any gear oil works, but I ran SWEPCO 201 mixed with ATF 50/50 for faster shifting.

You can look at what the solid one did in the wind tunnel, and it still had more lift in the front than the rear, so I would say that the solid in front unless you have a spoiler thing is a myth.

If you have coilovers, then 5 should work. Like I said though, I'd see if you can find someone who has run 16x10s with ZGs. Shouldn't be too hard at hybridz.

I'd do the 16x10s with the 255. I would think that would fit nicely on ZGs with a 4.5 backspace, but might be nice to talk to someone who has actually run that combo. You could fit the 16x8s on the car without flares. You've got them, so use them.