Thumper Posted March 21, 2006 Share Posted March 21, 2006 What would be better for 1/4 mile times a 300zx lsd or to weld the diff up for an all out drag car. This car would be trailered to and from the track. I would not be worried about reliability or turns only getting down the 1/4 mile the fastest. Btw my car is a street car and I would never do this to my car just asking cause I think of these things randomly. Thanks Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 21, 2006 Share Posted March 21, 2006 Welded. You don't ever need differentiation when you're going in a straight line. Quote Link to comment Share on other sites More sharing options...
Scottie-GNZ Posted March 21, 2006 Share Posted March 21, 2006 Welded. You don't ever need differentiation when you're going in a straight line. Agreed. Most all full-time drag cars run a spool, effectively the same thing as welding the spider gears. Make sure that diff is completely cleaned out of all lubricants and you get good penetration on the welds. Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted March 22, 2006 Share Posted March 22, 2006 You could even go with a lighter R180 if you weld the diff. Quote Link to comment Share on other sites More sharing options...
proxlamus© Posted March 22, 2006 Share Posted March 22, 2006 hmmm very interestn... I haven't done a search yet... but is there a thread or a site which has a greta write up on how to weld up a differential?? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 22, 2006 Share Posted March 22, 2006 I believe John Coffey has gone into it. Preload the side gears and use a particular type of filler rod is what I recall from that thread. Search and you should find it. Quote Link to comment Share on other sites More sharing options...
5foot2 Posted March 22, 2006 Share Posted March 22, 2006 If it's a real race car, I'd say go solid rear, a four link and a spool. You might also check with the sanctioning body. Some don't allow welded diffs. Quote Link to comment Share on other sites More sharing options...
PUSHER Posted March 22, 2006 Share Posted March 22, 2006 speaking of spools, where can I get one for our r200s? Quote Link to comment Share on other sites More sharing options...
JMortensen Posted March 22, 2006 Share Posted March 22, 2006 I don't think anyone makes a spool for the R200. Quote Link to comment Share on other sites More sharing options...
Thumper Posted March 22, 2006 Author Share Posted March 22, 2006 If it's a real race car, I'd say go solid rear, a four link and a spool. You might also check with the sanctioning body. Some don't allow welded diffs. Nah this would be a poor man's drag car if anything. But this does look like something I will do someday. Thanks Quote Link to comment Share on other sites More sharing options...
Bluto Posted March 22, 2006 Share Posted March 22, 2006 I just installed a welded diff into my z this weekend. This is my daily driver. I have heard the good and bad, and figured if I could live with open exhaust for 3 months (turbo motor)I could deal with anything. The thing that stood out in my mind when deciding to do this was remembering when phil(prreith on this board) was having issues with his quaif at a track day event at black hawk. after talking to other Z racers and hearing that they were all using welded rears as opposed to some sort of lsd. I had a friend weld my diff up for me, I have a 175amp mig in the shop but the friend welds cranes together /bow... He used 110,000lb tensile strength 1/16th flux core wire so I have the utmost confidence in this rear end(plus I beat the piss out of it in front of my shop after the install.) After the install I did figure 8's in gravel for a good 10 minutes just make sure everything was well lubed and not on the verge of grenading. After I had built my confidence abit It was off to the pavement for the worst abuse my transmission had seen since the stock l28 was removed and the turbo motor was swapped in.. No more 1 wheel peel for me, No sir! The tires do squeak alot but I am ok with this, it is especially noticeable in gas stations and store parking lots. makes me giggle, Im giggling now just thinking about it. I have to admit, I hadn't seen johnc's thread prior to this and I wish I had. I will have to go back and find it. The diff was cleaned very well but there was no talk of preloading the gears. The spiders were preheated with a rosebud. This was to ease/aid in the welding process and ensure everything was as oil/moisture free as possible. And, I love it, straight line acceleration is more improved than I imagined it could be. Acceleration out of turns is also much improved( I will admit that some of this can be attributed to driver enthusiasm). While cruising the steering feels abit stiffer but just barely noticeably. I had also read that parallel parking can be more difficult.... yes, definitely. ( I have to do this every time I park at home.. haha) Lack of power steering really shows its ugly face here, this will surely have me considering power steering when I move on to meaty beefy big and bouncy(Who album or song title comes to mind??) front wheels. I am altogether very happy I made the swap(especially since I had a ujoint going out on my other axles, r180 =>r200) and will be pulling the diff from my 510 to have the same thing done. I had planned on posting pics and will do so when I bring the digi camera home from the shop. Hope this helps, Sam Quote Link to comment Share on other sites More sharing options...
thehelix112 Posted March 22, 2006 Share Posted March 22, 2006 Sam, I really noticed the understeer tendencies of the locked diff. Don't kid yourself, its shocking! You can however overcome it a little by increasing the rate of the rear ARB relative to the front. I also noticed a big improvement when I added more camber to the front of the car, front end is more than happy to turn now. Dave Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted March 22, 2006 Share Posted March 22, 2006 The JTR manual covers this topic. They even give the type of filler rod to use with your stick welder. They did say it must be a stick welder. Will be anxious to hear how you like the welded diff the first time you try to accelerate on a curving, wet on ramp. Have heard bad things about how tail happy welded diffs can be on a wet street. Quote Link to comment Share on other sites More sharing options...
dr_hunt Posted March 22, 2006 Share Posted March 22, 2006 Well, I've never had a welded diff, but we used to fill the teeth on the spider gears with brass and re-install them on circle track cars. The brass is soft and is easy to braze on the spider gears. Although I'm going to assume that this loads the cross pin alot and may be prone to breaking a cross pin. Welding is probably alot better if your going to be on pavement. I run detroit lockers in both the cars and personally wouldn't have anything else, cause if it's good enough for nascar, it's good enough for me. Quote Link to comment Share on other sites More sharing options...
Bluto Posted March 22, 2006 Share Posted March 22, 2006 I don't have any delusions about poor condition handling with this set up, my daily driver last winter was a mustang svo, certainly not the torquiest thing out there but the rear end was still plenty tight(tighter than any of the GT's ive owned) the first few times we had sloppy weather found me pointing in the wrong direction more times than I care to admit.. I swore I would never drive a datsun in the winter again(my first Z rusted to little pieces in a few short Illinois winters) so this will be just one thing to help me stick to that. As for wet weather, spring is here and Ill be prepared(I hope!). As for adjusting the rest of the car to compensate for the under steer, the only new bushings on the car are the mustache bar bush's so I'm starting with a clean slate(or perhaps a 20 year old ragged out slate.. haha) and will be swapping everything over gradually until I take the Z off the road to begin body work once the 510 is street worthy. Sam Quote Link to comment Share on other sites More sharing options...
Bluto Posted March 23, 2006 Share Posted March 23, 2006 a few pics, one of the diff, another of the results... lol http://album.hybridz.org/showphoto.php?photo=6432&cat=500 grenaded both outer u-joints and tweeked my halfshafts. Sam Quote Link to comment Share on other sites More sharing options...
Clifton Posted March 23, 2006 Share Posted March 23, 2006 I've mig'd atleast 6 diffs. 2 for me and the rest for friends. Never preheated and everyone of them has held. I weld the side gears to the carrier and then fill between the spiders a little. We have broke axles and Birfields (CV's) These are all in dedicated rockcrawlers so they see alot of abuse. Quote Link to comment Share on other sites More sharing options...
510six Posted March 24, 2006 Share Posted March 24, 2006 I wouldn`t use the R180 for dragstrip duty.I have a collection of broken R180 stub axels from hooking up on a sticky track.I drove around for a bit in a R180 with a welded diff with my old N20 motor and it was entertaing as times.I ended up buying a LSD.Then a R200 with a NISMO LSD , LOTS of hard drag launches later the diff still works great. Quote Link to comment Share on other sites More sharing options...
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