mom'sZ Posted November 11, 2005 Share Posted November 11, 2005 OK, I'm going to throw this out there and see what you think folks. Please help me if I'm wrong about any of this. I'm thinking that for my car, which I'm trying to prep for SCCA ITS (78 280 Z manuf. date 6/77), there may be a slight advantage to using a R180 differentail instead of the R200 because of it's lighter weight. Also, (I could be wrong) but aren't the half shafts and u-joints slightly smaller (lighter) which would be less reciprocating weight and some amount less unsprung weight. (since at least some of the half shaft and the outer u-joint should be considered unsprung) Because the diff weights less, the weight can be placed somewhere else with greater advantage. (like on the pass. side floorboard - ha) Did the 78 5-speed car come with a R180? What determined which diff came in this model, was the R200 an optional item? I've searched the rules and found nothing wrong with this rules wise. Also, the R180 never came with a factory LSD did it? So if I went that way I'd have to go with an aftermarket limited slip right? That's ok, I was considering the Quaffe. One last question. I'm quite mechanical, but have never set up a differential. Could one conceivable buy 1 Quaffe and swap ring and pinions for different tracks or to have the capability to quickly change final drive ratio, would one have to have mutiple housings with multiple guts? Just trying to figure where this fits into the budget. Hey and while I'm at it, since the gears are exactly the same in the 4-speed is there any advatange it might have for tracks where the extra gear of a 5-speed provides no advantage? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 11, 2005 Share Posted November 11, 2005 Halfshafts are all the same from the 510 right up through the 280ZX. Same length same size same everything. The R200 came in all manual 280Z's, so I don't know if the R180 would be legal, rulebook should tell you. You can buy a Nissan clutch LSD for ~$500 for the R180 or the R200 sold under the name Power Brute from http://www.differentials.com, or you can buy a Quaife for ~$1500. Personally I don't think the Quaife is worth the extra $1000, but I know lots of people disagree with me on that one. Lots of ITS guys just weld em up too. Swapping a LSD or Quaife is pretty easy and usually doesn't require changing the backlash or anything of that nature. Changing ratios in a diff is a PITA. Much easier to have multiple diffs in the ratios you want. You can get 4.11s and 4.38s R180s out of mid 80's 4x4 Nissan 720 trucks. If you could run a real low gear ratio than the 5 speed might be worth it, but I think you'd have to run the 280Z 5 speed and not the ZX 5 speed with the closer gears IIRC, which is kind of a bummer. Quote Link to comment Share on other sites More sharing options...
260DET Posted November 11, 2005 Share Posted November 11, 2005 If you want to get serious consider a gear type (Quaife/Torsen) diff. I have one in a R180 and love it, so nice accelerating out of corners. Adds another dimension to setup, more potential to exploit, if you really want to get right into it. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted November 11, 2005 Author Share Posted November 11, 2005 yeah, I was aware some guys weld them. I don't think I want to go that route. I know the ZX 5-speed is illegal, so that's out. If the R200 came with all manuals, then the R180 may be out as well. Ive read and reread the rules, hard to tell. Anybody know for sure? Quote Link to comment Share on other sites More sharing options...
Mikelly Posted November 11, 2005 Share Posted November 11, 2005 I'm pretty sure Jmortensen is correct on the R200 in all manuals... I think I read that in one of the books I had on Zs that disappeared... Maybe Alan Thomas, Eric N., John C. or one of the other "knowledge/ history" buffs could 100% confirm this. Mike Quote Link to comment Share on other sites More sharing options...
johnc Posted November 11, 2005 Share Posted November 11, 2005 If I was building an ITS 280Z I would try both diffs. You have a minimum weight of 2,730 with driver and the closer you can get to that weight, the better. Most likely you'll be underweight so the extra 35lbs from the R200 won't be a big disadvantage because of where it is in the car. Plus, its easy to find a 3.90 geared R200. The disadvantage is the that the cost of the R200 LSD units are a bit more then for the R180. Also, be careful and check for halfshaft bottoming on the driver's side of the car when running the R200: http://www.betamotorsports.com/benchracing/R200handling.html Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted November 11, 2005 Author Share Posted November 11, 2005 Very interesting read John, about the halfshafts. I would have to assume (rule book on computer at home) that modifying the half shaft to alleviate the problem would be illegal in IT. Anyhow, from your reply, it sounds as if you think it would be legal to use the R180? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 11, 2005 Share Posted November 11, 2005 I thought we had figured out that the 280Z chassis was wider, so the halfshaft issue was a non-issue on the 280. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 11, 2005 Share Posted November 11, 2005 I hadn't figured out the width issue. I was "told" by someone that the 280Z chassis was wider but I have never measured one. Thinking back, I should have measured Ken Jones' 280Z while I was out in Florida. EDIT: I don't know for sure if an R180 swap into a 280Z that originally had a R200 is legal or not. Most likely it isn't, but I don't think your fellow regional ITS competitors will care. Quote Link to comment Share on other sites More sharing options...
PeterZ Posted November 11, 2005 Share Posted November 11, 2005 I think that at 2700 pounds the differential weight won't matter since the 240 minimum wt is 300 pounds less and should be faster than any 280. If you're running a 280 for fun then "run what you brung" and fun it will be. Quote Link to comment Share on other sites More sharing options...
2ManyZs Posted November 12, 2005 Share Posted November 12, 2005 I raced a 75 280Z in ITS for 5 years. I never encountered any issues with the halfshafts running an R200 running the car with the GC coil overs and at minimum ITS height. The R180 would fall into a "grey" area of the update/backdate rule. It doesn't specify that any of the 280's were ever equipped with the 180 from the factory, so therefore on the spec line for the 280 only the R200 is listed, since automatic cars are not allowed in IT, they wouldn't have included the later 280's that came with the R180 diff. In my mind, you will be better off running the R200, due to the extra weight the car has to carry anyways. I ran mine with a 4:11 that was welded, and never had any trouble. The Z/ZX 5 speed question is probably one that no one will ever protest. My car weighed right around 2700 with a 2 inch Autopower weld in cage if I recall correctly. This was also long before full gutting of the interior was allowed in IT, so making minimum weight now should be fairly easy if you build a well designed cage of the minumum diameter tubing. As far as protests are concerned anymore, if you race in a region where there are some dominant E36's such as the DC region has, you should have to worry about anyone protesting you on the diff or tranny as you'll have a tough enough time trying to run in the top half of the pack today. When I raced the 280, I could stay with the top running 240's and RX7's in the turns, but couldn't keep up on the straights due to the extra weight and the handicap of the stock FI. Of course, if your region has an SPO/SPU class, you could always build the car the way you want with larger brakes and yank the FI in favor of the stock SU's, cut a lot of weight off the car (those bumpers are anchors) and just go have fun. Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted November 12, 2005 Author Share Posted November 12, 2005 Thanks 2ManyZs for sharing your experiences with me. I am trying to prep the car as a legal ITS car. But my driving abilities will keep this effort from being anything more then a 'for fun' outing. Quote Link to comment Share on other sites More sharing options...
katman Posted November 21, 2005 Share Posted November 21, 2005 R180's came in the 280Z's with automatic transmissions only so me thinks you are stuck with the R200. However, as other astute Hybridz'ers have pointed out, you'll proly need the extra weight anyway and I can't think of a better place for it to be. I quit using welded diff's many years ago after breaking lots of stub axles, and I was never a big fan of dragging the rear wheels around anyway, especially in the rain (turn pig, turn! *%$#*). I have driven a "Quaiffe like" R200 (actually it was an original Gleason Torsen) on the track in an ITS 280Z and liked it. We always ran the factory clutch type LSD's in the R180's in the ITS 240Z's. With the R180 we had serious bad heat problems but only when we got above 3.70 ratios. Spent a whole season changing clutches, shims, preloads, lubes, etc. puking fluids the whole time. Even had Jasen Jasensky set up a couple diffs for us (quick trivia- who knows who this is?) to no avail. One time had a tranny temp gauge on the diff and after 8 laps at Road A the needle wrapped itself completely around and then broke off (325 degree gauge). Finally settled on a combination of Redline diff lube and BG additive before we could go a full race. We decided it was the gear ratio and not the diffs that tipped the heat generated minus head shed scale to the positive. An R200 would give you more cooling surface area for the same work input, so that might be another reason to go R200. You could swap the Quaiffe or factory LSD between ring and pinions once you get them set up, we had a couple LSD's we swapped around amongst several case/ring/pinion sets. Your real problem is going to be brakes. Lemme know when you get to that part of the build. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 21, 2005 Share Posted November 21, 2005 Jasen Jasensky Engine guy for Sharp. What do I win? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted November 21, 2005 Share Posted November 21, 2005 One time had a tranny temp gauge on the diff and after 8 laps at Road A the needle wrapped itself completely around and then broke off (325 degree gauge). Finally settled on a combination of Redline diff lube and BG additive before we could go a full race. We decided it was the gear ratio and not the diffs that tipped the heat generated minus head shed scale to the positive. Out of curiosity katman, did you ever try "REMming" the gears? If you thought it was the gear ratio that caused the heat issues this may be helpful. It's basically a high tech polishing of the gears. Supposed to reduce operating temps, and reduce friction to the point where you can see a hp increase on the dyno. I never personally saw any actual evidence of the benefits, just the advertisers claims that it did so. Never had any complaints about it either... When I was selling diff parts I had a couple gears remmed for customers. They came back looking like they were chromed. I found a website that has pics, but they REALLY don't do the final surface finish justice. http://www.mrracingequipment.com/M&R%20Racing%20Equipment%20-%20rem.htm It is supposed to be effective, but the best part is once you've had it done you can brag to all your racing buddies how you just got a rem job and they didn't. 1 Quote Link to comment Share on other sites More sharing options...
mom'sZ Posted November 21, 2005 Author Share Posted November 21, 2005 me thinks you are stuck with the R200. The R200 it is then. Finally settled on a combination of Redline diff lube and BG additive before we could go a full race. I had read that little jewel of info in one of your posts on IT.com You could swap the Quaiffe or factory LSD between ring and pinions once you get them set up, we had a couple LSD's we swapped around amongst several case/ring/pinion sets. perfect Your real problem is going to be brakes. Lemme know when you get to that part of the build. Thanks Katman, I had been waiting for you to weight in on this subject and I appreciate the help Quote Link to comment Share on other sites More sharing options...
katman Posted November 21, 2005 Share Posted November 21, 2005 Engine guy for Sharp. What do I win? Diff and tranny guy for Sharp. John Caldwell was their engine builder if I'm not mistaken. Close enough, you win a beer next time I see you. Of course you know that Caldwell once roomed with Mark Womack's brother, and Mark of course founded Sunbelt Performance Engines, now owned by jim Thompson, builder of your last motor. Quote Link to comment Share on other sites More sharing options...
katman Posted November 21, 2005 Share Posted November 21, 2005 Out of curiosity katman, did you ever try "REMming" the gears? We didn't try that- but if I end up in that situation again we'll look into it. Thanks for the tip. We were convinced it was the LSD and didn't really come to grips with the gears possibility until the season postmortem. By then we fixed it. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 21, 2005 Share Posted November 21, 2005 John Caldwell and John Knepp built motors for the BRE (Brock) team here on the west coast. They eventually became Electramotive and John Knepp still does engine management stuff (along with selling CAD software): http://www.electramotive.com/. John Caldwell went on to found Caldwell Development, Inc. (CDI) in Vista, CA and built lots of high performance engines including the Viper V10 engines that won Le Mans a few times, many of the Nissan VG and VQ engines that won SCORE, IMSA, and the later Nissan turbo GTP engines. John shut CDI down a few years ago and gave away the last two Electramotive built L6 turbo engines (damn!) that he had lying around his shop for years. I don't know if Caldwell also supplied engines to the Sharp team, but I'm guessing they didn't for competitive reasons. Quote Link to comment Share on other sites More sharing options...
johnc Posted November 21, 2005 Share Posted November 21, 2005 Another old Z racer guy that has been coming around my shop lately is Pat Vasquez. For those that might not know the name, he is the guy who started Kaminari and he stops by in his red 260Z that still has the original wide body kit on it. Quote Link to comment Share on other sites More sharing options...
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