JMortensen

Thinking a bit more, even if you roll the car back and forth, that doesn't necessarily mean that the spiders are isolated. If you have a situation where the cross pin shaft is ovaling out the hole in the carrier (as seems to happen with drag raced cars with open diffs a lot), then you could have a clunk from this test and it could be the shaft rocking back and forth in the carrier. So I'll have to revert to my original statement. If you want to know which component is causing the clunk, you really need to test them individually.

How is is possible that one tire could have more lash than the other? You're not actually measuring "lash" at the tire, you're measuring all of the lash between the left tire and the right tire. To restate: when one tire is locked and you turn the opposite, you're turning the wheel, which turns the stub axle, which turns the companion flange, which turns the halfshaft, which turns the side gear, which turns the pinion gears, which turns the other side gear, which turns the other halfshaft, which turns the companion flange, which turns the stub axle, which turns the wheel. Whatever results you get on one side should be exactly the same as the other because you're moving exactly the same parts in both cases. And what you're testing (again) is the cumulative slop in ALL of the parts, and doesn't tell you if the slop is in the stub axle, the halfshaft U joints, the splines on the side gears, or the gears themselves. Maybe you have a badly adjusted drum brake or a stuck caliper if you have rear disk, but again, this test doesn't tell you anything useful, so I wouldn't even do it. You really need to test each part individually to find out where the slop is, and if it is in the spider gears, well, there is supposed to be slop in the spider gears. And if you have a limited slip like the OBX or Quaife, there might be a lot more slop in the gears and it's still totally normal. If you set the car down and roll it back and forth in gear by hand and hear a clunk, THEN you could say that you've found a clunk and isolated the normal slop in the spider gears (provided you roll the car straight back and forth). You might even be able to pin it down to one component with a stethoscope. But feeling for slop in the spider gears isn't proving anything useful about the condition of the diff because the spider gears are supposed to have slop in them.

I like this Charger: http://www.glennbunch.com/

Welcome back. The parts list is in the diff sticky thread, but if you already have an R200 you need to swap out the pinion flange, side shafts (assuming the splines are OK), and the rear cover if it has the finned one. If it doesn't have the finned rear cover then you just need the pinion flange and output flanges.

Could have been any number of bolts that got tightened with the installation of the new diff, from the driveshaft to the rear cover. Could be that the spider gears did have a problem. Could have been backlash. I can't tell you what it was. I can only tell you that your test didn't tell you what it was either. I'm not saying you didn't fix the problem, it certainly sounds like you did. I'm saying you didn't diagnose the problem with the test that you did and that this test shouldn't be used by other people because it is meaningless.

Honestly I would throw your results out the window because your testing procedure was so poor. If you want to ship me your diff I'll look at it and tell you if it has excessive wear, but seriously what you did had zero merit as a test for differential wear. Not trying to be a jerk, just trying to inform you and others not to do what you did, because it really isn't a good test of anything at all. It's like checking a sore throat with a colonoscopy and concluding that there is a problem because it smells like @&%$ in there. By messing with the output shafts you were literally looking at the wrong end.

This is bad procedure. If you want to check backlash, you shouldn't hold the output shafts and try to spin the input shaft. When you check backlash you should use a dial indicator on the ring gear, set as perpendicular to the tooth face as you can get, and then rock the ring back and forth. It is VERY easy to measure incorrectly by moving the pinion gear, so do it several times to make sure you have an accurate, repeatable measurement. When you grab the output shafts you are introducing the slop in the spider gears into your measurement. Spider gears are designed to have slop in them, so saying you found slop there is saying you found that everything is normal. I can't tell what you're measuring in the video, it looks like you've jacked up the rear end (or one side?) and are moving the wheels back and forth. Either way, this is feeling the slop in the spider gears, which is intended to be there. While it is possible that there may be excessively worn spider gears, I wouldn't try to measure it in this way, I would disassemble the diff and look at the gears and the crosspin to see if you have wear.

I'm getting close to buying a cam so I emailed Texas Speed. I'm not sure about the response I got, wanted opinions. Here's my email: And the response: Now I came back to this thread and looked at the dyno charts, and there does appear to be more torque and hp in the midrange with the stock cam than there is with the 228R or any of the others. I'm just looking at the charts thinking that I can live with have 25 less ft/lbs from 3500-4500 as the tradeoff for getting an extra 50 hp at the top end. Am I oversimplifying to think that the 5.3 is going to have a curve damn near identical to what's shown, just with lower numbers? I get that the bigger the area under the torque curve is the better, but I'm having a hard time convincing myself to go small probably because I did that with the L6 and then was so much happier when I went bigger later on.

Normally the forward mounting bars go up in front of the diff above the exhaust. It might be that you have it upside down. Not sure. If it fits there and you can make a bracket it looks like it might do OK. It's close to the ground but I've seen worse on street driven 510's.

If the chip is not too big you can grind it smooth and run it.

You could juggle them in between taking them out and flipping it over, but it's not strictly necessary.

Exactly right! The "right" way to do this is to put the control arm on a rod end so that the angle of the LCA doesn't create a bending moment on the arm or the crossmember. Probably the worst thing to do is use the camber adjust bushings in front, because they don't allow for ANY angularity of the arm, even that which it would normally have as the suspension goes through its motion (caster sweep). When I put adjustable T/C rods on my Z I had poly front bushings and after adjusting the caster to where I wanted it I realized the LCA bushing was bound up pretty tight, so the next mod was to put rod ends on the control arms. I suggest you do the same. FWIW, the rears that we have here are aluminum and delrin and are not self lubricating. I used to lube mine once a year and finally removed them to put something better on, not because they had worn out.

I had progressively built up my motor from ~180 whp to ~240 whp and at the very end there I finally hit the point at which I needed throttle modulation, I could no longer stomp on the gas at the apex. It was fast, and it pushed you back in the seat, but above and beyond that it's all somewhat subjective. I felt like it wasn't fast enough, which was why I decided to do a V8 swap. I had plenty of terrified passengers though, and even my wife who would get squirrely on onramps in the lower hp iterations was pretty much afraid to drive it with the triples...

Do a search. Should find pics of my car and bjhines' car, and I think johnc has posted pics of one of his betamotorsports.com customer's cars.

You mean the whole diff, not just the LSD, right? Because it would be pretty miraculous if the LSD fit in the R180 or R200 case. I do recall a guy who put a Supra diff in a Z and as I recall he had used the Supra CV shafts as well. There was a write up with pictures here probably 6 or 6 years ago.

Let me be more specific: I think if you really want that feeling of being pushed back in the seat with a low power to weight ratio, the solution is sloppy, softly sprung suspension and a big cushy seat.

Your Titan does 0-60 in about 7.5 seconds. I get the same impression of power in my GMC Sierra which has 315 hp and does 0-60 in 8.5 seconds. I think if you really want that feeling of being pushed back in the seat, the solution is sloppy, softly sprung suspension and a big cushy seat. I drove a 911 Turbo that was modded and had 550 hp. The feeling was different. It didn't lay back like my truck does and give me the impression of a large mass accelerating, but I could feel my head pushing into the headrest on the seat under WOT. If you had an accelerometer you could really measure the acceleration and prove my point, but I think it's a pretty safe guess that your car is faster than your truck and that the feeling comes from something other than the g forces during acceleration. If your car isn't faster than your truck then I suggest a long look at the stickies in the L6 forum. I think you can get most of the hp of a Rebello build in your garage if you take the time and study the threads and books like How to Modify, and then do your best imitation of that, provided you have some skill and mechanical aptitude.

Not worried about the pressure from the weatherstrip against that aluminum piece?

Just in general seems like people really want to bend tubes where they don't need to be bent. A lot of the bends in these rear supports and door bars are just not necessary. A straight tube is stiffer than a bent one. Keep it straight whenever possible (except for door bars which should protrude into the door cavity for max protection). Where multiple tubes have to hit in the same area it's best to connect them. So to have that X and then connect the backstays to the top of the hoop doesn't make a lot of sense. Much better to either move the X so it hits the backstays, or since you already have problems with the backstays, move them to hit the top of the X if that X is legal. Not sure on that one... Connecting multiple tubes to a "node" makes the cage stronger and more rigid and allows loads to path directly from one bar to another instead of having to travel down the connection between two separate tubes that aren't connected at a node.

I think the message to get from this thread is use a steel caliper bracket instead of aluminum. What are you using now?

What I did was to assemble the suspension without the spring, and set the strut so that it lined up dead centered in my camber plates. If you don't have camber plates, I'd try to line the 3 studs of the top hat with the strut tower, or bolt the strut top in and aim the strut shaft towards the hole in the top hat. Then I said "Screw this!" and made a new control arm where the strut doesn't need to stay perpendicular: http://forums.hybrid...n/page__st__120 I think idea behind the arms in that thread are far superior to anything for sale commercially.

I had a subscription and stopped after one year. If you're into understanding the theory behind formula car engineering RCE is great, unfortunately it doesn't often translate well to what most of us are actually doing. McBeath also wrote a book called Competition Car Aerodynamics and most of the stuff in the articles is reprinted there, along with a bunch more. It's worth the read.

Doc, it hurts when I do this.

Not only should you shim it, but you should shim it so that the strut lines up correctly with the strut tower up on top. The further from perpendicular you get, the more side load you put in the strut as the suspension compresses.

I did one inch and skipped an inch until I was told to do the above about 1/2 way through.