datsunlover Posted August 2, 2004 Share Posted August 2, 2004 First off, I did search, and I got some info from this site; http://zhome.com/ thanks to that search. Anyway, I have a 75 280z with a 4 gear (3.545 ratio acording to the chart) and I plan on swaping in a 5-speed and rear end from a 198? zx 2+2. From what I can see in the listings, (dont know exact year of my doner car, but either way, 80 2+2s had a 3.9, and 81-84 had a 3.9) it looks like a 3.9 rear end I'll be swaping in. What I am wondering here, is this going to be a bad thing? IE; will I be slower on take off, but still buzzy on the highway? As it is now, the thing goes like a scared rabbit from a stop, but after 60mph it's just loud and gas hungry (3K rpm)... also my rear end is clunking/leaking, so a teardown is probly needed anyway.. Sorry if this sounds stupid, but I've been staring at ratios and numbers for a while here.. and Im just confused now.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 2, 2004 Share Posted August 2, 2004 http://www.geocities.com/z_design_studio/transmission.html IME for a N/A car the closer ratios are MUCH better than the lower 1st and 2nd gear. The gap from 2nd to 3rd is huge on the 4 speeds and early 5 speeds. Much better in the ZX 5 speed. Quote Link to comment Share on other sites More sharing options...
e_racer1999 Posted August 2, 2004 Share Posted August 2, 2004 you're going to be seeing the same acceleration (if not better) with the R200/5speed combination because the z has a 3.36 diff in it. (while the R200 is going to have a 3.9?) the big differences occur in the gearing in the tranny. the easiest way to get the conversion is by multiplying the individual gears in the tranny by the differential gear. the higher the number the more acceleration you're going to get (by sacrificing the top speed in that gear). EDIT: or do THAT! you beat me to the punch! Quote Link to comment Share on other sites More sharing options...
datsunlover Posted August 2, 2004 Author Share Posted August 2, 2004 Cool.. thats what I was thinking first.. but then I confused myself and thought that the 5 speed might 'slow' me down.. And yes, the 2nd to 3d is AWEFULL in my 4 gear Z. It actually drops too much (Im running 195/60/14s.. yah yah, I know too small.. it's all I got right now!) and you can feel a big drop in the rate of acceleration untill it gets back above 3500. Even if I wind 2nd to 6K rpm, it doesnt seam to help.. and just burns more gas I just got back from the car (had to get a towwing co. friend of mine with an unlock kit) and verified that it is a 1981.. so I'm assuming it's got the 3.9 R200.. Oh ya..just currious.. this 5 speed will bolt right up to my engine right? I am assuming it will, but I dont like assuming.. makes an a$$ of....well, you know. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 2, 2004 Share Posted August 2, 2004 Should bolt right up, but you need to use the pressure plate and the throwout bearing collar from the same car. Use the 280 stuff or the 240 stuff, but don't mix and match. I'd use the 280 stuff because it has a slightly stronger pressure plate. Quote Link to comment Share on other sites More sharing options...
datsunlover Posted August 2, 2004 Author Share Posted August 2, 2004 Great! Thanks man.. shoot.. you've helped me out a lot lately on here! I'm still workin on that sway bar thing BTW, should have it figured out by tomorrow I think.. Quote Link to comment Share on other sites More sharing options...
JMortensen Posted August 2, 2004 Share Posted August 2, 2004 No problem. You've just been asking more questions I know the answer to as of late. Quote Link to comment Share on other sites More sharing options...
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