JMortensen

Just to clarify--the issue stated by all 3 machinists who questioned my flywheel was the outer rim. It is cut sharp on the backside, no radius, and that sharp cut goes straight through all 6 pressure plate mounting holes, which are threaded. This supposedly is a great way to get a stress riser. They all said that the threaded holes should not have been cut through. They were the only 3 machinists who had ever seen my flywheel, so it was 3 for 3, and it was seen years apart by machinists who did not know each other. The other big deal was that it took a LOT of balancing, despite the fact that it had balancing holes in it from Dave. I haven't seen the HKS unit up close in a number of years, but somebody posted a picture of one and it's backside was radiused, not cut in sharp corners. With that said, I've inspected if for cracks twice and no problems yet, and I've had it on for maybe 7 or 8 years with no troubles at all.

Nah, because if there is enough suction to pull it open, then it would suck oily crap into the intake, not let the boost into the crankcase. The only reason I think this happens is because I've seen what happens to a non-boosted engine with a plugged PCV. Leaks like a bastard. That's the blowby pressure pushing oil out of the seals. Seems like you'd have a lot more blowby on a turbo setup, which would mean the thing should leak like a seive if the PCV stays closed under boost. Or at least that's what I would expect to see. Cameron, Bernoulli also explains why stewardesses get sucked out of the plane when it loses cabin pressure. The differential speed of the 600 mile per hour air outside of the plane vs inside the plane creates suction.

Yeah basically the truck shifter is longer and the hole doesn't need to be redrilled is what I'm saying. I think the piece it attaches to in the transmission moves up and down a bit, which allows it to work.

Cary, I know your car that you're building is completely tube framed, all custom fabbed stuff. I know you are also planning on extremely stiff springs. That would counter the roll, and make the roll center not so critical I think. But in a "normal" Z chassis with "usual" spring rates, the roll center makes a bigger difference than it will on your car. We all know that you can't put 800 in/lb springs in a stock tub because the tub itself becomes the spring. With springs not playing as critical a role in countering roll, then RC becomes another way to deal with the issue. Trying to keep this rolling...

A bigger cam will let you run more compression, as will a better chamber design. F54 with flat tops and an N42 is about 10.5:1 and several people have complained about pinging. My L28/E31 with about 11:1 requires 95 octane. I'm sure Isk's HUGE cam helps him run pump gas, but IIRC he was having some pinging issues too. I think as a general rule Ed is right. 10.5:1 seems to be about the limit of pump gas, and is really pushing the limit in places like CA where 91 octane crap is the best we can get from the pump.

http://www.fototime.com/ftweb/bin/ft.dll/pictures?userid={7DC317B0-8EDB-4B2E-A837-F708D07C9769}&inv=9C67398D46D99D9&userid={7DC317B0-8EDB-4B2E-A837-F708D07C9769}&inv=9C67398D46D99D9

That's what I've heard before online, but I have never used the MSA short shifter personally. I was told about the truck shifter by a Nissan tech, and all my friends use it on late 4 speeds, early 5 speeds and late 5 speeds. None has ever redrilled the hole, the pivot to ball length is a lot longer, and the shift throw is REALLY short. Like you wouldn't want it any shorter short. I think you're right though when you say that redrilling the hole with a longer shifter doesn't hurt anything. Just redrilling the hole without changing the shifter was what I was taking issue with. And bottom line for me is that IME redrilling the hole isn't necessary with the shifters I've used.

Drilling the holes higher isn't the way to make a short shifter IMO. All you need is a longer section between the pivot and the ball on the bottom. I suppose if the bushing at the bottom was really deep into the transmission you could redrill the pivot 1/4" higher and it wouldn't fall out when you shifted, but I'd feel better with a more solid engagement on the bottom bushing and a longer section between pivot and ball. Truck shifters have a much longer shaft there, and fit right into both the early 5 speeds and the later ones. No drilling the transmission ears required. You do have to bend the stick and cut it down, but that's pretty easy to do. Any L series truck has the shifter needed.

Here is the key bit for me Cary: When I read this it says that if the RC is below ground "pro-roll" is created. Pro-roll being mechanical leverage that makes the car roll MORE. So the jacking forces are still there, but now they force the suspension to roll more than it would otherwise. That is the way I always understood it to work too. Once the outside of the LCA is pointing up, side load then compresses the suspension. If it is pointing down, yes, there is a jacking force, but it serves the function of lessening roll. At some point you could get too much of this, but like I said earlier I don't think it would be really feasible to do so with anything like stock components. I don't claim to understand all the terminology on that page, but that part seems pretty clear. I am SURE that Cary knows more about suspension design than I do, mine is more of an "imitate success" strategy. I do enjoy talking about it, and hope we can hash it out a bit more.

Much easier to swap the whole differential than to setup the 3.90 gears in the ZXT diff. Any good reason not to swap the whole enchilada? It will bolt right in.

I have JSK's front and rear setup, and Juan is impossible to get a hold of anymore. I don't know why, he used to be on hybridz all the time. He seems like a good guy in general, but if you can't contact him that's no good. Based on the returned emails that I've sent and the lack of a phone to contact him, I'd suggest you look at AZC or modern motorsports.

Jolane, I tend to disagree with the usual idea on this one. I think the RC should be as high as possible (cause it isn't going to be that high anyway) and the control arms should be as long as possible. That's the way I've seen it done on the fastest 510's I've seen. Pivot was moved up 3" or so, and the control arms were lengthened 4 inches or more. These were some wickedly fast autoxers that had this setup, and it seems to me that that all of the really really fast 510's had the pivots moved like this. I don't think that you can move the pivot up much more than about 2" on the Z, and you really can't move it in too far IIRC just because of the layout of the front crossmember. But the best thing to do would be to get the control arms as long as possible and the pivots as high as possible. The "How to Hotrod Your Datsun" book had a bit in there about getting the control arms level or pointing a bit down, and I think that is repeated over and over and over. I think it was originally intended to say "Don't lower your car so low that the control arms point up, cause then it will handle REALLY bad" and has been turned into "If you have the control arms level that is the best handling setup". Then you'd need to adjust out the bumpsteer, which is a whole other issue (search on that one).

I wonder if the Bernoulli Principle would suck the valve open under boost. Works when you route the PCV to the exhaust. There is pressure in the exhaust but it will still pull vacuum in the crankcase.

The 280 stubs will bolt up to 240 halfshafts no problem. If you do the CV conversion with 280 JY stubs and 300ZXT JY CV's it shouldn't be that bad. I spent ~250 on 280 stubs and the CV's, need to put another $210 to Ross for the adapters, and that's it. So under $500. Add in your $420 for Ross's 240SX setup, and you're still under a grand. In reading all the stories, it appears to me that stub axles break when they get a shock loading, like when drag racing or in road racing if you lift a tire, and it speeds up, then when it comes back down and gets traction suddenly. I have never broken one, but I think kind of like you it's something I just don't want to have to worry about. At least after the rear disc conversion the wheel won't fall off if it does break...

You'd have to jump --really high-- for the suspension to droop all the way so that the springs came off the upper perches. You can zip tie the spring to the upper perch through the holes that are are drilled from GC. On the bottom if you miss the perch when you set the car down on the ground for example it will fix itself on the next bump. Kind of scary the first time you hear it, cause it sounds like a loud "boing" in the suspension. Droop limiters are not necessary IMO except maybe for rallying. I've never seen any Z with droop limiters of any sort in any type of racing. Even if you're pulling tires off the ground under hard cornering you still won't be all the way drooped on the lifted tire if you have a sway bar.

Drilling still seems like a good idea to me, since you can use a larger diameter rotor and get more braking torque, then lighten the rotating weight by drilling. Porsche and Ferrari still use it, that has to say something. Cracking between the holes happens, but the rotors don't need to be replaced until the cracks get from one hole to the next. On the Porsche 911 race car I used to work on we never replaced the rotors in the couple years I worked on it, and the rotors were starting to crack when I got that job. That car was doing 165 to 170 from what I recall in the straights, so it used the brakes a lot. The main issue for me with brakes is not having to screw with them so often. As has been said so many times here, stock brakes work on ITS cars that post very fast road race times, but they require ducting and adjusting and frequent rotor and pad replacement. Not wanting all that hassle, I went with bigger brakes just to avoid having to bleed them between sessions and replace rotors every other weekend. When it comes to brakes, too big will slow you down but too small won't.

Here's my take on this, and I've done absolutely NO testing. A roll cage that attaches to the suspension pickups or strut tower bars keep the chassis from flexing where the TOP of the suspension mounts. So the top of the struts aren't leaning out on corners, etc. Subframe connectors will work to keep the BOTTOM suspension mounts from twisting. So you brace the top of the strut and brace the subframe where the control arms bolt on and the frame rails in the front and now you've added more strength than either would alone. Again, no testing, but seems reasonable.

Acetone is an aromatic I think, along with Tolulene, Xylene, and other solvents. Lots of vapors. As someone pointed out in another thread, you might get better gas mileage just because the stuff at the pump is oxygenated alcohol crap nowadays. I don't think that a few ounces would make a huge difference, but I haven't tried it, so who knows...

240SX's came with long nose too. I don't know when the changeover to the short nose happened, but it's probably right around 89. 90 is the changeover to the short nose in the 300ZX IIRC. So if the 240SX this guy has is a long nose R200, then he already has the 280ZX diff for all practical purposes.

When I ordered an ACT pp, and noticed that the stock number was exactly the same for a 280Z as for a 240SX. So the PP is the same. I don't know about the flywheel, but clutch and pp are identical.

I was at an autox once where one of our regulars pulled into the parking lot with a cop on his tail, lights flashing. Apparently he couldn't wait 1/2 hour more... sucks but funny. Also saw a GSXR750 do a wheelie right towards a cop. Cop flipped his lights on, dude set the front wheel down and pulled over for his ticket.

Why try to engineer it like that when you have a coilover? Even if you can get a pretty close guess on the weight of that you've added to the car, you still won't know the corner weights until you set it on scales anyhow, since every turn of the coilover is going to throw the weight off and cornerweights are going to vary from car to car. If you want one and a half inches lower at the rocker, just guess where the spring perch needs to be, set it on the ground and roll it back and forth a bit, and if you're wrong jack the front end up and turn the spring perch up a few turns until you hit the height you want on the nose.

Section the tube so that it fits the strut. IIRC that measurement is 1 5/8". Then use your coilovers to adjust the height of the front end. Is that what you were asking?

That's exactly what I do, my high compression NA needs about 95 octane to keep from pinging. 50/50 with 91 works out just right.