JMortensen

Time to vote with your feet yet? CA restricts sales of race gas: http://www.arb.ca.gov/enf/advs/advs397.pdf

I see that your design has been compromised for headroom and legroom, so I get why the diag and the roof bars don't meet the A pillar bar, that's basically the same thing I did on my Z so that the seat can back into the plane of the hoop. What I don't get is what is going on behind the hoop. Seems like there is no rhyme or reason to it. The backstays should connect where the A pillar bars meet the hoop. That gusset that hits the A pillar bar junction instead attaches to the middle of the backstay where there is no load path. It looks again like your cage builder has missed the rear suspension pickups and put the cage back to the back of the car on the floor which does not get the maximum benefit from the cage and potentially reduces the rear crumple zone. This is the same guy who did your Z cage that had all those problems (too many bends in the main hoop, backstays went all the way back, etc), right? He welds nice (although he doesn't seem to like cleaning the tubes first) and bends tubing well, but he really doesn't seem to understand load paths. Here is a REALLY good SM cage: http://forums.corner-carvers.com/showpost.php?p=698867&postcount=144 FWIW, if I did my cage again it would come out different because of what I've learned about load paths, so I'm not claiming to be the foremost expert on the subject.

Pretty sure it's a 4 pinion open diff.

Here's a related link on another site: http://www.atlanticz.ca/forums/index.php?topic=651.0 That link says frontal area of 22 sq ft for a 240z. Sorry bearcat, I'm not going to look that one up for your car, but we'll play with some numbers here for fun. We'll use drag of .45. I think that is pretty close for a Z car. According to the formula, you need 540 bhp to do 200 mph. Keep in mind this tool is for estimating and isn't exact. 1300 bhp gets ~267 mph according to the equation. I can't remember Tony's exact speed, but I worked it out for 172mph and it comes up with 343 bhp, which sounds at least ball parkish. I think a stock 240Z ran out of legs at about 122 mph as reported in that other thread. According to the formula, that requires 122bhp. So it's sounding like a reasonably accurate tool to me, at least to get a general sense of what it takes to go xxx mph. Looks like I should be able to hit about 180mph in my car if I get the 400 hp I'm looking for (not that I expect to find a place where I can reach that velocity on a road course). My take on this? Bigger hammer works.

I'll throw a little more in too. Most purpose built race cars have horrible drag coefficients, because you can go faster around a circuit by making downforce than you can by reducing drag. I like the bigger hammer and more downforce way of doing things, but if you guys are going for land speed records I can't begrudge you that lower CD is going to be faster there. EDIT--Here is a formula from Competition Car Aerodynamics: BHP absorbed by drag = cd x Area (sq ft) x v^3 (mph) / 146600. I'll leave it to someone else to figure out the frontal area of a lowered Z car and figure out how fast you can go and how big a hammer you need.

That's an idea, but the oven is only 3 years old. I guess it doesn't hurt to try it out...

I have a Hotpoint stove that is running natural gas and it smells like gas in the house when I use it. Not real bad, but it's noticeable and my wife is particularly sensitive to it. I've called the gas company and was told there were no leaks, had my in-laws here for a while and my father-in-law asked if the flame in the oven was yellow. I told him it was, and he said we needed to adjust the air shutter underneath to get the flame blue, which would result in more complete combustion and no more smell. He left before we could get to it, but I just found and adjusted the shutter according to the manual, and moved it all the way in both directions and it seemed to make no difference whatsoever to the flame color. I checked the regulator and according to the manual, it does appear to be set for natural gas and not propane, and the range flames are blue, it's just the oven that is yellow. Can anyone shed any more light on this for me? Something else I can adjust? Repairman time?

I'm in front of a computer about 45 hrs a week for my business. When I'm not helping customers I'm usually on one of several forums, this being the main one.

The turbo pump does not have the comp springs, it just has the larger pump to deliver more volume. I ran the turbo pump that I bought new from AZC. I then added comp springs. With both comp springs it would peg my pressure gauge when cold, so I ended up just running one comp spring and one regular, sorry can't remember if the inner or outer was the comp spring but I don't think it really matters. If you're running an oil cooler you might need the springs, if not the turbo pump should do fine, I suspect. I wouldn't buy a used oil pump. They're not that expensive.

I used roostmonkey's mount and had interference issues with the tunnel on my 5/70. There is a flanged area of sheetmetal that must not be there on the later cars. His mount was drilled to fit the early and late cars, so bolting it on wasn't a problem. I trimmed the mount where it hit the flanged metal to solve that problem. The only issue I think you might have to resolve is whether there is enough room to redrill the mount hole 35mm forward. I think that might be getting close to the edge of the mount. I'd be inclined to flip it around so that the vertical brace is closer to the bolt hole, if it does indeed have enough length to redrill the hole.

Here is the other one I was thinking of: http://forums.hybridz.org/showthread.php?t=132252

It took a little digging, I had to search for username mayolives and all threads in the drivetrain area, but here's the one thread I was talking about where he thinks his CV is bottoming. There was another one that went into more depth and had several other people complaining that they were bottoming too, but I can't find it anymore: http://forums.hybridz.org/showthread.php?t=116040

Just imagine a couple inch long, inch wide strap of metal like you'd buy at the hardware store. These straps are welded to the front and back of the diff mount and hang below the cross member. At the bottom they have a hole drilled in them, and there is a bolt connecting the front to rear. The bolt is below the crossmember, so when the diff pulls up the bolt hits the crossmember. Put a piece of hose over the bolt if you want less vibration.

It's not the sway bar that the halfshaft bottoms on. It's that the halfshaft compresses until it can't compress anymore, and the suspension isn't all the way compressed. So the halfshaft then acts like a bumpstop in the suspension. Once you hit it, the force of the suspension trying to compress actually goes through the halfshaft to the differential itself. Search for username "mayolives" and "CV bottoming". He had this issue even with the CV's, and I think he was pretty sure that it wiped out his limited slip. His car runs VERY low. IIRC, others posted about similar issues on that same thread.

I actually missed the CLSD thing. I wouldn't give up on it yet, and haven't seen any 4 pinion CLSD with damage other than shearing the drive clutch inside teeth off. Seen and heard of 2 pinion CLSD damage, but I think that's because they don't load against the carrier as evenly.

What I've seen a lot, especially with drag racers or guys who like to do burnouts is that the cross pin shaft wallows out the hole in the carrier. I think this allows misalignment of the gears, which might be interpreted as slop in the gears. Spider gears are normally pretty sloppy feeling IME. That's a general feeling, I don't have a spec to quantify exactly what I mean by that. .012-.015 is a lot of backlash. I thought spec was .004-.008, but I don't have access to the FSM right now to check that. If your diff is messed up, a used one should be a cheaper and easier fix than rebuilding the one you have, but I kinda doubt it is the cause of the clunk unless it's really screwed. Diff clunk is extremely common. Usually related to one of the following; front mount, mustache bar bushing, U-joints, control arm bushings, loose splines in the stub axles. The first thing to check is the front diff mount, Ron Tyler's mount (made by roostmonkey and Z'sondabrain seems to fix the clunk for a lot of people.

Grab a shim and the yellow pages and find your local gear shop. See if they have something close. You can order shims from Nissan but they're just there to take up space so anything close will work. I think MikeC once posted that a 12 bolt Chevy shim works. There should be something at the gear shop that is close enough, and they can probably sell you a shim set or a bunch of different thicknesses so that you can adjust until you get it right.

With stock suspension? That's a good trick.

Panasports are heavy. Wats are expensive. Both look nice. I believe you can fit a 15x8 without coilovers, not sure on that but you should be able to find out with a little searching. I like a 15x8 with 225/50/15. 15x7 is right for a 205, some people put a 225 on the 7 but it fits the 8 better. 4 x 114.3 is equal to 4 x 4.5 which is correct for a Z.

I agree.

We've had some previous discussions about cutting the radiator support out. The general consensus was that if you beef up the part from the strut towers back (or on a Z from the sway bar mounts back) then the core support isn't necessary and so something like you see here might not be a bad idea. If you just cut it out of a stock vehicle you'd have major problems, because that box holds the ends of the upper and lower framerails. Nice looking car!

I think that the most common breakage is the stub axle that holds the wheel. Can't remember hearing of people breaking the stub at the diff...

My guess is they cut the clevis pieces too short and it didn't fit the jig. Rather than fix the jig or the clevis plates, they made up for it in the weld.

How much lighter is this than a stock chassis? A couple hundred pounds maybe? Having lifted a 240 bare chassis with a couple friends, they aren't that heavy. I'd be more excited about having a source for FG body parts like roof and quarter panels than getting a whole FG chassis. If I were going to go 10/10ths I'd do a tube chassis and lay the FG body over it...

Derek Bell and the 917: