Loryde520 Posted July 30, 2016 Report Share Posted July 30, 2016 I finally have had a chance to run my truck out on the hiway, and it sucks! I'm at 3200 rpm at 57 mph. I went to look at a dogleg 5 spd out of a 200sx last night and am now at a crossroads at what I should do. Do I go for the 5 spd swap or look at maybe different gears in the rear. I've done alot of reading on here about the swap, and I am somewhat aware of the problems I may incur, but shouldn't be too difficult. The only question I have is will my driveshaft fit? It was custom made 1 piece with a 510 yolk on it. My question is, will the dust flange on the yolk slide into the dust flange on the back of the dogleg 5 spd? I currently have a 510 4spd. behind my L20B, and that tranny doesn't have the dust flange on the tail where the yolk slips in. Or, should I leave the 4 spd. and maybe look for some taller gears? Thanks in advance to any ideas! Quote Link to comment
bananahamuck Posted July 30, 2016 Report Share Posted July 30, 2016 It should fit inside that shield ,, My .02 would be if your running low profile tires ,, do the 5speed swap AND switch rear gear to 3.90 .. 2 Quote Link to comment
datzenmike Posted July 30, 2016 Report Share Posted July 30, 2016 Well the 510 and the 200sx dogleg have identical 1 through 4 gears but a 14.6% over drive if you were at 3,200 @ 57 MPH you will now be 2,736 RPMs. Just keep in mind that you can't keep lowering RPMs forever and still be able to make enough power to push through the air and climb hills at high speed. The good news is it will drive exactly the same in the lower 4 gears as before. You are running a 4.375 differential in your 521, so a 3.70 differential (close to 14.5% different) will also drop your 3,200 RPMs down to about the same amount. HOWEVER this will affect your acceleration in ALL the gears and be sluggish. If you carry heavy loads often this isn't the way to go. It is the fastest, easiest and cheapest option. . Quote Link to comment
bananahamuck Posted July 30, 2016 Report Share Posted July 30, 2016 I wouldn't go as high as 3.70.,,,,,,,,,, 3.90 or even 4.11 would be in the butter zone for a L20b at hiway speeds.. Freeway speeds out where we are is 70+ so that's where 3.90 comes from... Quote Link to comment
hobospyder Posted July 30, 2016 Report Share Posted July 30, 2016 3.9 rear end is optimal for gas mileage/speed though ain't it mike? What do we get those out of? Quote Link to comment
EastBay521 Posted July 30, 2016 Report Share Posted July 30, 2016 It should fit inside that shield ,, My .02 would be if your running low profile tires ,, do the 5speed swap AND switch rear gear to 3.90 .. I loved the dogleg and 3.9 rear in my 521. cruised 80 in 5th. rpms kinda high near 4k but that where my L18 likes to be. Doing the speed limit and driving it nice i got a good 22mpg depending on the wind Quote Link to comment
flatcat19 Posted July 31, 2016 Report Share Posted July 31, 2016 Lower gear ratio may even help prolong the life of the dogleg, especially one strapped behind an L20B. Quote Link to comment
Loryde520 Posted July 31, 2016 Author Report Share Posted July 31, 2016 Lower gear ratio may even help prolong the life of the dogleg, especially one strapped behind an L20B. Should I not run the dogleg behind my L20? Quote Link to comment
TENDRIL Posted July 31, 2016 Report Share Posted July 31, 2016 its life most likely started behind a l20. I had one in my wagon behind a pretty peppy l20b did just fine. they are however known to have some weakness compared to the zx ones everyone wants Quote Link to comment
datzenmike Posted July 31, 2016 Report Share Posted July 31, 2016 The dogleg came on L20Bs. The 71B is built for truck or 6 cylinder use so is much stronger. Nicer shift pattern too. Quote Link to comment
flatcat19 Posted July 31, 2016 Report Share Posted July 31, 2016 Should I not run the dogleg behind my L20?Run it. You'll be fine. I have 2 doglegs currently. Will be installing one come winter. I was told, by a Datsun owner I have tons of respect for, to replace main bearing before installing. Quote Link to comment
EastBay521 Posted July 31, 2016 Report Share Posted July 31, 2016 All this talk of doglegs just reminded me I have a tired one that any one can have for free. shifted fine but would whine in 3rd and 5th 1 Quote Link to comment
EastBay521 Posted July 31, 2016 Report Share Posted July 31, 2016 I wana say it would whine in 4th aswell Quote Link to comment
datzenmike Posted July 31, 2016 Report Share Posted July 31, 2016 Forth 'gear' isn't really a gear as power is transmitted straight through the transmission in a straight line to the driveshaft. There is little side load so the bearings that support the mainshaft are usually more quiet. ALL other gears transmit power through the counter shaft. Under load, the main and counter shafts tend to be forced apart and the bearing have to work harder and wear out sooner. Growling in 1,2,3,and 5 but quieter in 4th would be the counter bearings. The FS5W63A dogleg has 63mm between main and countershaft centers. This limits the maximum diameters of the bearings that can fit between the shafts that support them. An FS5W71B has 71mm for larger bearings. Quote Link to comment
MikeRL411 Posted July 31, 2016 Report Share Posted July 31, 2016 Eggs have 'yolkes' transmissions and drive trains have "yokes." 1 Quote Link to comment
bilzbobaggins Posted July 31, 2016 Report Share Posted July 31, 2016 All this talk of doglegs just reminded me I have a tired one that any one can have for free. shifted fine but would whine in 3rd and 5th Why am I way the fuck over here. :/ Quote Link to comment
EastBay521 Posted July 31, 2016 Report Share Posted July 31, 2016 Because its way cheaper than here in the bay area? 1 Quote Link to comment
KoHeartsGPA Posted July 31, 2016 Report Share Posted July 31, 2016 I got so used to my 4spd behind my L20b that I literally just ignore my 5spd sitting on one of my work bench....3600 rpms @ 60mph and 4500 @ about 75 just doesn't bother me one bit....my engine likes it above 3000 rpms anyway.... 1 Quote Link to comment
Loryde520 Posted July 31, 2016 Author Report Share Posted July 31, 2016 Eggs have 'yolkes' transmissions and drive trains have "yokes." Now you're makin want some bacon and eggs. Screw the dogleg!! Quote Link to comment
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