JMortensen

Well poop. I just went out to the garage and plugged the steering wheel on, and sure enough the wheel is just exactly in the same plane where the FIA bar would go. I guess I'll just have to try not to do a barrel roll...

Look at a given class for a particular type of racing, the class regulations for the max wheel and tire size and the size tire that was run by the champion in that series, and then show me the car that won a championship by running narrower tires than are allowed. There are VERY few examples where a tire less than the max allowed size will be faster, but they are out there. A couple of examples come to mind: 1. Land speed racing or circuits where the top speed is very high and there aren't many turns; places where aerodynamic efficiency trumps traction. 2. Power and/or weight limited cars like your FSAE example. If they were allowed unlimited power or set a minimum weight it's a pretty safe bet that they would run bigger tires. But they're maximizing to a particular rule set and they have optimized designs for weight and limited power, both of which dictate against large wheels. 3. Using bigger wheels at one end to balance a car that is not able to be balanced within the ruleset or by adjusting suspension settings. I used to autox with a guy who ran 8's on the front of his EP Ford Fiesta and 6's in the rear and this was faster because it balanced the handling. Likewise you might see a 911 running bigger tires in the back. I know Coffey has mentioned 350Z cars in stock classes running their slightly wider rears in the front. 4. As you mentioned, ice racing. Skinny tires with studs means more pressure per stud, so they're really trying to get the best balance of weight per stud to maximize traction. 5. Some classes of mud racing where you want a tall tractor tire that gets to the ground under the mud rather than trying to drive over it. I'm sure there are more, but for the vast majority of racing classes, more tire is better. If you're going to play monkey-see monkey-do with tire sizing though, I think the best place to start is the car that is most directly related to your own. For most of us that means looking at someone like John Thomas who runs a 16x10 which is the largest allowable tire and wheel combo in FP. He could choose a 16x7 or a 16x8, but he doesn't. Or Greg Ira, who runs a cantilevered slick on his EP car. If skinnier was better, one assumes he would run a regular sidewall. Those are the two most successful Z racers at present, but it's important to keep in mind that they are very limited in power compared to a lot of the cars on this site. Even at the power levels they run, they have opted for the max wheel and tire size. For those of us who are road racing and autoxing in a world of far from perfect suspension designs and not so limited horsepower, I think the best way to play is to get the widest tire you can fit to the car. We're shooting for the Glenn Bunch model, not the FSAE model. If you haven't seen it, Glenn has a 2500 lb Challenger running 15x14's on front and 15x17's on the back. http://www.youtube.c...ennbunch/videos

Clunks in a Datsun are almost never a result of loose backlash. Search "diff clunk" here and at www.classiczcars.com and you'll find lots of info on that. The whine is probably a bearing noise. Take it to a shop or better yet, find a new diff. Buying one that doesn't have problems will probably be cheaper than having that one fixed.

The FIA bar really does do something, which is why the FIA requires it. It is essentially a big gusset for the bend that I've outlined in red. Your idea is pretty close to another way that I've seen it done. I've drawn that one out for you below in green. Assuming the rocker is strong, then I think this option is stronger than the typical FIA, but it cuts down the size of the hole that you have to get through to get into the car considerably and seems to work better on newer cars with really large doors.

Saw this video on another forum. FF to the 8 minute mark if you don't want to watch the drifting. I didn't watch all the way through, so if there is a Rick Roll at the 5 min mark I apologize. Point is, the car rolls, A pillar bar folds to a disturbing degree, and driver's head is halfway out the window! The need for the window net is pretty obvious, but the FIA bar is something that I don't think I've ever seen on a Z cage. This is something that just about everyone uses now, from NASCAR to prototype racing. I've seen Spec Miata cages built with them too, so I don't think they're illegal for lower SCCA classes. It is a straight bar which goes from the bottom of the A pillar bar to the to the halo or the junction between the A pillar bar and the halo or the A pillar bar and a gusset to the halo. Sometimes they'll go vertically down from the A pillar bar junction down through the door bars and to the rocker. The point of the thing is to give the top corner some support. The main hoop has support from the backstays, but without the FIA bar there really isn't anything bracing that top corner in most cages. Here is what it would look like on my car. I gave the quarter shot so you could see that it is actually attaching where the gusset hits. If I didn't have the gusset it would go to the junction between the A pillar bar and the halo, and then the bottom of the A pillar bar. I was hemming and hawing about actually adding this to my cage since the dash bracket on the other side is right there, but I think I'm going to just get it done. It won't be hard and I think it's worth the effort.

Side pipes also get the exhaust out in front of the rear wheels and increase ground clearance.

Download the rulebook and figure out what class you're going to be in and then you won't have to wade through all the ifs ands and buts.

If you're going to use my short shafts, you can also use early Pathfinder front CV's as they have the same ends but with (too) short shafts.

Click on your user name in the top right corner, then turn off email notifications. No point in deleting the account.

For the next guy: hose clamps are a lot easier than C-clamps when trying to align the strut tube in the angle iron. I used a chop saw for mine as well. I put a piece of 2" tape around the top of the strut and cut to it, and put another one 1.5" or whatever it was down from there and cut to it. No problems with the thickness of the blade if you do it that way. If you just draw a line and try to hit it, yeah, there's a decent amount of slop there and you might make a mistake. The tubing cutter makes a better cut, but as I recall there is a lot more elbow grease involved. Been probably 20 years since I've used a big tube cutter though...

What makes you think there isn't rust under the seam sealer? My car had tons of rust in the seams (even the ones with factory seam sealer. That's why I'm going to oil the frame rails when I'm done...

I think ashintar has this one nailed. It's not about setting ride height so much as it is about getting the front end high enough to be able to drive in and out of and over speedbumps without scraping.

You'll need to do some double checking on the strut size. I think 56mm is wrong. Coleman Racing (www.colemanracing.com) sells part number 450-700 which is 2.08" and 7" long, and they sell 420-700 which is 2.04". They also have 450-500 and 420-500 which is a 5" sleeve. I don't have a 280Z, so I don't pay as much attention, but I thought that the smaller one fit the 240 strut and the larger fits the 280 strut. I might be wrong though. Search and you should find that info easily.

If memory serves, the step that you're looking at is the one for a rubber o-ring (which I never bothered running). I think you need to bore out the whole length of the sleeve to the strut diameter plus a little for clearance. I thin bjhines did this on his project. The question is: if the sleeves cost ~$60, can you have the machine work done for less than that?

I don't know about the spring height. There really isn't a reason to use a 12" spring on a 280 because the stroke of the strut is the same. Maybe they're trying to set the sleeve on top of the stock spring perch or something, but my GC setup from the mid 90's (for a 240) came with a weld on perch. 150/200 is a big step up from stock, but yeah, it's pretty light. Don't go too overboard with spring rates unless you have the shocks and chassis to handle a lot stiffer. That setup would ride pretty comfortably with Tokicos, and that's probably what GC was shooting for. FWIW, I just remembered that the 240 front hubs have a different offset for the rotor and the rears have different wheel cylinders, so unless you're changing brakes too you probably want to avoid changing the struts.

The 240 tubes are different diameter and the rears are 1" shorter. If you're sectioning the struts, this won't matter. If not, the rear will be 1" lower than the front to start with and on a 240 you generally run the front lower to get a little rake to the car, so you might run out of adjustment before you get it where you want it. I can't imagine that it's easier to get the 240 struts (thinking spindle pin here) than it would be to just get the right sleeves, but if you have access to the 240 struts and are sectioning, yes that works. The other option is to get the correct ID sleeves from someplace like Coleman Racing. I bought new sleeves from Coleman about a year ago, I think I paid $15 per sleeve and they were longer than the GC ones. I believe the actual adjuster (the spring perch that screws onto the sleeve) is the same for both struts.

R4 is a race pad, meaning that it does next to nothing until it gets up to temp. I put R4 pads on my car the day before a track day to try and bed them in and damn near rear ended someone at a stop light. They just don't do a damn thing until they're hot. Blues are going to be the same way. Blacks, from what I understand take a little bit of heat but not as bad. I haven't used them personally though. If you're trying to get more rear brakes (which I would imagine would be your problem with that setup) I'd look at something fairly aggressive in the rear, and not aggressive in the front. Like maybe an organic pad or non-race semi-metallic in the front and an R4S in the rear or something like that. Balance is the goal. Of course they'll react differently when they get hot, which to me is the best argument for a system which can be balanced with the same pads and an adjustable prop valve.

Here's another unlikely drifter:

After talking with the guy who helped me on shock revalving, I decided I'm going to try not to use a rear ARB. In theory there should be more traction available without one. If I find that I need one then I'll make a bracket and weld it to the bottom of the arm so as to maximize the length of the end link. With my modded stock arms I think I had ~5" long end links and room for the CVs. It could be done as simply as just welding a 1" x 1/8" piece of strap with some holes drilled in it in the span of the arm. More likely I'd end up with two pieces to mount the rod end in double shear, or a square tube with one wall cut off.

Really don't know. This is the tricky bit, balancing the lightness with stiffness.

I'm shooting for 2250 lbs, but I have a stripped interior and Coffey's FG hood and hatch and gutted doors, no headlights, pared down wiring, etc.

OP is in CA. Maybe with ethanol blends it would work OK, but before ethanol on CA 91 octane super, this was not a good idea.

There have been other threads on rear LCA's that compare the various options. Search and you'll find them. IMO tholt's thread is the best one out there, and the idea that Dan and I simultaneously came up with in that thread to have an A arm with a toe link and the A arm part attach to the rear of the strut housing is the best I've seen from a theoretical reduction of stiction and freedom of motion perspective. I do believe I'm still the only one to actually make a set, and I haven't run them. One more thing for the OP, since you have the camber plates already, have you looked at flipping the top hats around so that the strut is biased to the outside of the adjuster bolts? I know this works on the GC style plates, not sure about AZC or TTT. ERW chromoly...

Yes. Brain fart. The point here was not that the rod end failed, because they didn't. The point was that the arm itself failed and that is an indicator that there vertical loads imparted onto the control arm. Now you could say that MM's design looks much more stout and is better built than AZC's, and I can't really disagree with that. It's still 3" or so of threads in bending, which is the part that I have trouble with. ERW cromoly tubing? They make such a thing?

STB puts bending loads into the rod ends. Apparently a big front bar was enough to snap Pete's front control arms, and 7/8" rear bars aren't that uncommon on Zs. Brings to mind the failures that Dave Kipperman had on his chromoly AZC arms. Different arms, I know, but they still broke at the arm where the nut was welded on. IIRC, he fixed one side and then the other side broke. Shouldn't have happened were there no load there.