JMortensen

I am running them with a slotted xmember.

John gave specific guidelines for ride heights, etc, that he got from ITS racers and his own experience. I don't really think that's the best idea; I would prefer that the guidelines should be more general. Correct spring rates should be figured out by what is necessary to manage body roll, heat up the tires, prevent the car from bottoming, etc. Stickier tires will necessitate more spring. This fact alone would be an obvious limitation of a specific spring rate suggestion. Even if you don't change the tire size, a Yokohama A008 in 225/50/15 from 1993 will be nowhere near as sticky as an A7 from 2016, but people are running all different sizes these days. Race ride height should be as low as possible before suspension geometry becomes an issue while also being sufficient to prevent the car from bottoming frequently. The more you're willing to modify the car, the more extreme you can go with all of this stuff, eg if you want to run the car really low, you can do that by modifying the suspension pickup points to correct for roll center heights, bumpsteer, etc, and then you can run much stiffer springs to keep off of the bumpstops, etc. If you're just going to bolt parts on, using John's guidelines will get you in the ballpark and you can tune to your preference from there. For my part, there are a lot of guys here who know better than me. I just had a lot of time to post, and when I was building my car I modified just about everything and had long conversations about what should be changed and why. I had some new, original ideas, but a lot was just taken from other people.

I don't have a recommendation for 2+2 rates, but I would think the 250/275 would be fine for a weekend warrior. If you run camber plates, you'll lose about 1.5" on the front height and 2.5" from the rear without doing anything else. Since most people want the car level or raked a bit, you might end up too short in the rear. I've only sectioned 240 struts, so I'm guessing on the 280 stuff, but I've seen numerous threads over the years from people who went too short in the back on the 280 struts. I'd keep searching or find someone who has 280 experience before you cut. I would think you'd want to cut the front and leave the rear. If you didn't have enough height in the rear you might have to add more in to the strut tube instead of removing it. Keep your pieces that you take out of the front struts, maybe you could weld them into the rear if necessary.

Interesting. I was actually considering this and had thought of attaching to the strut. Glad I didn't do it now.

You can use the MR2 shocks, no problem. If you are still using rubber isolators, you can save yourself the hassle of sectioning the rear struts by grabbing some 240 isolators and running them in the rear. That will drop the car 1" without doing anything else, then you just make the spacer to fit the strut insert. When I did this about a decade ago, I found that a 1.5" x .095 tube fits the BZ3099 just right. You can buy that on www.onlinemetals.com by the foot. http://www.onlinemetals.com/merchant.cfm?pid=7562&step=4&showunits=inches&id=283&top_cat=197

VLSDs have 30 spline inners with longer shafts and spline sections. Pic: http://s38.photobucket.com/user/soapsuds43/media/J30VLSD007-1.jpg.html

LSD > welded for autocross, road racing, sporty driving, etc. The tighter you shim an LSD the more push you get, but you can get the traction with a lot less push out of the LSD vs a welded diff.

You can shim the LSD tight. That's probably what he's doing. Either that or running it without any additive. They chatter really badly without additive. This thread has more on shimming. http://forums.hybridz.org/topic/27605-r200-lsds-and-breakaway-shimming-done/

As NewZed says, swapping the stem seals will get you clearance for .530 lift cam. The practical considerations after seals, springs, and retainers that will allow for .530 lift really boil down to more engine wear. How much wear and what kind of mileage you could expect I can't answer, but maybe someone else can.

Hey 280ZX guys, just found something really really cool on another site. This is an Aussie Bluebird race car from the 80s. They cut off part of the semi-trailing arm and then make a bracket that bolted to the back of the diff cover and used it to make a couple of control arms, basically turning the semi-trailing arm into an upper and lower arm with a trailing link. http://www.performancegarage.com.au/blog/group-c-bluebird-turbo-vid

OK, how do you know that from experience?

I think Dan is on the right track here. Other people are trying to get the cars lower, you're making the floor lower instead. That's not to say you can't make a taller car fast. There is that 4WD V8 Z in Australia that runs really high ride heights and is very quick, but 800 hp and 4WD can overcome a little bit of weight transfer. In general though, the lower the car the less weight transfer and roll you get, so in theory traction should be better. If you look at what Cary (tube80z) is trying to do with his build, he's gone dry sump and small bellhousing/button clutch so that the drivetrain can be lowered, and then I think he was talking about raising the floor as well to get the whole thing lower yet.

It used to have a lifetime warranty, regardless of whether you were racing or not, which is pretty impressive. Never heard of a broken one.

My understanding is that you can pick up about 10 hp by tuning MS on a Miata. Did you do it for power, and did it work? Sold my Miata, but still curious to know...

The ones I've heard sounded like a marble rolling around in the bellhousing. Again, these were due to light flywheels. My friend had her transmission rebuilt twice trying to stop this noise. Didn't help. If you're using a standard weight flywheel, then you could rebuild the transmission and see if that helps. Probably try some heavier gear oil first, as that's a heck of a lot less hassle.

If you really want to piece it together you can buy threaded sleeves, top hats, the whole deal from colemanracing.com or similar.

No clue.

That is the old chromoly AZC suspension. Nice Nissan Comp oil pan too. Those are pricey. The link behind the diff has been modified to fit the finned cover, and it doesn't look like it was done very well. Could be that it has an LSD, could be someone just put the cover on. Several people have made them and sold them here. I think Savage42 had a run of them at one point. Might look into it if it's a concern for you.

I reclined my hoop until it was just about touching the dome light bar across the roof. I put a small screwdriver in between the roof and the hoop on the sides to make sure it was lined up and welded it in so there is about a finger's worth of space in there on mine, and I still needed the diag moved over so that the seat slid back into the plane of the hoop, and I'm 6' tall. If you don't have that dome light bar part of the roof in there, then you might be able to lean it back a little bit farther. Without going out and looking at mine, I think the issue there is the further back you get the lower the bar needs to be, so you may make space for the seat but wind up with a main hoop that is not tall enough to save your head in the event of a rollover. The other issue I can think of off the top of my head is interference between the hoop and the wheel wells. I assume you don't have the wheel wells anymore, but the concern is that the wheels might hit the hoop. I guess it depends on the diameter of your tires. If the X in the main hoop is for stiffening, I would suggest an alternative: just run the diag to meet the rules, then do a lower X between the rear strut towers and the bottom of the main hoop. This connects the strut towers to the strongest part of the cage. It was a real PITA on my car but should be pretty easy to weld in on yours since you can put the floor in later.

That diagonal might not leave you enough room to squeeze the back of the seat in line with the main hoop. When you're designing a cage having the diag hit the top of the hoop and not be in line with the rear stays is not ideal, but it's one of the compromises that is commonly made on the Z because of the position of the seat relative to the door opening. I'd suggest getting the seat installed and checking before you weld it all up. Easy enough to fix with it just tacked in...

Justin Olson had a full YZ kit he was selling. Not sure if it's still available. He's in Portland. Here's his FB page: https://www.facebook.com/justin.oleson.1?fref=ts

I didn't recognize the name, but when texis30O mentioned the black car, I think I know who he's talking about. Sorry to hear about his passing. Take some shots of the underside and we can ID the suspension for you. FWIW I was just reading something about the TWM airbox and the pop rivets working loose through vibration and going into the motor. Seems like a little dab of epoxy and a little piece of FG mat would solve that problem.

http://www.koniracing.com/bumpstops.cfm

This happens all the time with light flywheels.

6 years late, but here's a cheap solution for a 2" X pipe: http://www.coneeng.com/pdf/3-1%20&%20%202-1%20%20Collector%20PDF.pdf Just get a couple of their 2-1 collectors and weld together, boom! X pipe. Looks like $55 for regular, $75 for stainless, or thereabouts.