JMortensen

I put the lasers on the diff and driveshaft today. An immediate problem was that I couldn't get the diff centered because the pinion nut sticks out farther than the flange, but I kinda figured I wanted the relationship of the flat part to the flat part, so having it perfectly centered isn't that important. So I positioned both lasers so they were sitting flush on their respective pieces and ran a piece of paper back and forth. I know with the angle finder that there is a 2 degree angle difference between the two, so that was going to make the gap grow vertically, but I wasn't able to detect any horizontal movement at all, so I marked the position of the motor mounts on the frame. I'm going to cut a bit out of the tunnel for trans clearance and then I should be able to get the trans jacked up and fix the angle problem, then I can just double check to make sure that I'm square left to right, and I'm hoping it will be good to go.

Here's a cheap 9" alternative: http://www.dutchmanaxles.com/products/housings-and-rear-ends/irs-housing-axle-package-cv-style.html

Sounds like it's a Dana 60 gearset. Looks cool, if it is D60 there are LOTS of LSDs, lockers, spools, etc available, as well as a buttload of gear ratios. Not sure about the $4K though. A good ring and pinion and helical LSD runs about $1000- $1100. There's a yoke, some side stubs and bearings in addition to the housing. I wonder how much this one costs: http://www.dynatrac.com/products/pro60irs/pro60irs.html

Looks like I may have found it (them) on ebay: http://www.ebay.com/itm/98-02-LS1-Camaro-Trans-Am-T56-4L60E-Dust-Cover-Shield-Driver/360706600303?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D19461%26meid%3D3470231973860324170%26pid%3D100005%26prg%3D8798%26rk%3D1%26rkt%3D5%26sd%3D370748693682%26 http://www.ebay.com/itm/98-02-LS1-Camaro-Trans-Am-T56-4L60E-Dust-Cover-Shield-Psgr/370748693682?rt=nc&_trksid=p2047675.m1851&_trkparms=aid%3D222002%26algo%3DSIC.FIT%26ao%3D1%26asc%3D19461%26meid%3D3470236327325398752%26pid%3D100005%26prg%3D8798%26rk%3D1%26rkt%3D5%26sd%3D360706600303%26 There is a little hole along the bottom of the bellhousing. No cover there?

I bought my motor and trans separately and don't have the dust cover for the bell housing. Anyone have one?

I wouldn't put bearings in an R180 unless it was a rare gear ratio or something like that. If not, just go buy a used one. R180s are a dime a dozen and putting all the money and effort into replacing bearings in a diff that was run low on oil and might have R&P damange doesn't make a lot of sense to me. I would save the money for something that will actually provide a benefit.

How accurate does this need to be? I'm spinning my laser and drawing about a 1/2" circle on a 10' ceiling and I can't seem to dial it in much more than that. Good enough? Also, for someone math challenged, I figured I'd take my digital angle finder and check the angles on the trans and diff yoke, then use the distance between the laser points on a piece of paper at the trans and at the diff to square it up side to side. Sound reasonable?

You don't need to run the factory module. Pretty much any module will do. I had a friend with a 280Z distributor who ran a Chrysler module out of a van with a 318. You will need to figure out how to wire a different one, but they're pretty simple and it shouldn't be hard to find a generic schematic online. IME, your symptom is a classic module fail. Runs fine, dies instantly. Cools off, runs fine again.

The Miata studs might be the same as the RX7 and Camaro studs. ARP stock number is here if you look. 12mm x 1.5, they fit right into the hubs, no hassles whatsoever. I can't imagine the last .25" being a deal breaker. If they are it's probably time to start looking at different wheels.

Thanks guys. I think I'm going to do what I need to do to get the trans up in the tunnel as this will allow me to get the car lower to the ground when it's all said and done.

Correct me if I'm wrong, but I think the ability to adjust one angle is all you need, whether it's the pinion or the trans doesn't matter. I have the RT diff mount, so I'm covered there. Anyone else want to pop their head under their 240 LS/T56 setup and tell me if the trans hangs down below the frame rails? I know this isn't usually an issue, but since I'm doing side pipes I'm actually concerned about clearances here. Going to be a LOW autox car...

Can you have a peak under your car and see if the trans hangs down below the frame rails? I'd appreciate it.

So other people with 240Zs also have the trans hanging down below the frame rails? Just hadn't heard that as an issue. I think the mounts I have are a bit high on the motor in front (this was done to protect the oil pan, so I think that I could make more clearance in the tunnel and lift it up for ground clearance, which would make my aero plans easier. Was thinking about the lean issue and I think it doesn't make much difference. Your motor leans all over the place when you drive on the road via hills, road crown and camber, etc.

Ah. Good to know. Thanks guys.

Looks like I'm at about 1.7 degrees, but I'll need to drop it down to have a bit of clearance between the tunnel and the trans, so hopefully I'll be in good shape. I know this one has an upgraded shifter in it already. Can't remember what kind. Is it all that likely that I'd need to replace the shifter?

I've got some motor mounts and put them on the motor and put it in the car. When I was test fitting the motor alone, I figured it would be level and I could see that there was going to be a real issue with the bell housing bolts and the firewall, so I took a hammer to the firewall for clearance and then I bolted the trans up and dropped the whole thing in. Looks like with the trans jammed up against the top of the tunnel I still have a bit of a lean back to the motor. The question really is, does it matter??? Anyone know? Thinking driveshaft angles more than anything here... Also anyone have an opinion on this shifter placement? This is a 70 so the hole is in a different spot. Looks serviceable, just wondering if this is typical.

If the frame is bent where the suspension attaches, the alignment will be screwy and it might be unsafe to drive. If it looks OK underneath but the floor is and rail is dented in the middle, that's not a big deal.

You can run a diffuser at the back of the splitter too. Cary showed me a video of the COT a while back and they were talking about significant increases with a diffuser in the back that led nowhere.

Yes on the BFH. Just look at where the suspension bolts on underneath and check for bent frame rails in those areas.

Check the suspension pickups, and if they're OK, beat the floor back with a BFH. Finding replacement struts or arms if you need them shouldn't be hard. I have some RUSTY 280 arms you could have if you want to pay for shipping, or come pick them up.

Looks pretty serious. I have to wonder if there is a point at which front diffuser is too long.

With regards to the S flaps and the verticals on the splitter, seems like you can't really do both in the same spot. It would be possible to put the fences in a ways, maybe a foot or so from the edge to "capture" the air on the splitter, and then use the S flap to evacuate air from the engine compartment. I think it makes a lot more sense to use the S flap if you have a path for air to get out of the engine compartment as well. If you have a full fenderwell, you can only pull from under the frame rail. If that area is removed there is a better path for air to get out from under the car. FWIW I agree with Cary that the calcs on the Bimmer should have some value. I don't think it's "shoot blindly in the dark or pay for a wind tunnel session" and in fact, I question the usefulness of the wind tunnel sometimes. You can get a good idea of the overall effect, but if you have limited time in the tunnel you might make more than one change at a time and then you lose the capacity to figure out which change had what effect. This manometer testing gives the chance to test and test and test at comparatively low cost. I think cfd would be another really good way to go. Seems to make more sense to get things fairly well optimized with the cheap repeatable methods, then go in and fine tune the thing with the tunnel.

You'll just be testing the breakaway, not the correct operation of the unit. You can do some funky stuff hanging weights off of the tires to check the operation and figure out what the TBR is.

So the diff is out of the car? I tested my clutch LSD breakaway with 280Z side stubs. Just stuck one in a vise with the splines up. Set the LSD on that one. Stuck the other one on top. Took a piece of metal 3' long and drilled a couple holes in it, and bolted it to the stub, then put a torque wrench on the metal to measure the resistance. Basically copied Gordon Glasgow's idea, but using the short stub axles from a 280Z instead of the long axles from a roadster's solid rear axle. If you don't want to actually measure the resistance, just make yourself a lever and pull and skip the torque wrench. http://www.gordon-glasgow.org/lsd4.asp

You should be able to spin them in different directions with a lever, but your springs are now jamming all the gears together and that should make it difficult to spin.