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By chance has anyone on this site changed the gear ratio of a 1989-1996 Q45 differential? My project is to change the 3.54 gears in a Q45 differential to the 4.08 gears from a NA 300ZX. The Q45 differential is currently installed behind an LT1 and 700r4 transmission in a 1976 280Z. Thank you to anyone who may be able to give me some information.

I'm not sure if this belongs in the drive-train or brakes section, but with black Friday coming up I thought I'd throw it here since It gets more views, MODS feel free to move it. I'm new to IRS suspension and I'm really having trouble wrapping my head around how a diff swap will affect the car. I've read the FAQ's and I think a q45 diff is the way I want to go. As I said I'm having trouble visualizing how this all goes together, is there a picture or some kind of diagram with all the components like the half shafts and companion flange? and all that other stuff and how it all connects? my biggest question is will it affect my brakes? I want to get set from silverminemotors if they have a black Friday sale, but I'm worried that a diff swap would change the hub, or something to make the brakes no longer fit. I'm sorry that this is a probably a pretty silly question, but there's a lot of new terms I don't know, and its hard for me to understand it in word form. I get the difference between the short and long nose diffs and how they are mounted, but everything beyond that confuses me. 1. Is there a diagram or laid out and labeled image of how the q45 or similar diff connects to the 240z stuff? 2. Would a q45 swap affect my aftermarket brake choices? Thanks Guys!

Hi everyone, I've been using this site for research along the way gearing up for my build. I just created an account, and this is my 1st post. I'm excited to interact and share my experience as I go with those I've mooched off of for so long! I've done a trial fit to check that the motor/oil pan/trans all lines up ok- so far so good! I'm now in the process of the final build on my 383, and about to pull the trigger on my suspension/brakes/hubs/axles etc. I figured I'd give up some info for critique from the experts (that's you guys!). I think I've ironed out most of the kinks of the build in my head, but maybe someone can catch me before I make stupid and expensive mistakes. 1st, a little history on the car/theme- I moved to san diego 5 years ago from Philadelphia, and I never knew such fun roads could exist! So I decided I needed a car that was more fun to drive, and after test driving a lot of cars, I bought an rx8. This was not even on my list of potential vehicles, but the salesman offered a fun test drive, so I bit. After driving such a light car, I can vow to never have a heavy "fun car" again! The rx8 was a hoot, but it didn't scratch my hot rod itch. After some digging, I came across the z cars. Amazingly lightweight, awesome weight distribution, ample underhood room, ginormous transmission tunnel, manual rack and pinion, strut suspension- I'm so in!!! Ok, now all I need to do is find one, being from philly, I've barely ever seen one- salty roads and weather wiped them all away long before my time. I figured I'd save up, and find a good specimen even if it took months. It took a day...I found a clean 69k mile, 1 owner, original orange county car for $1300 an hour from home- done! Ever since I've been reading and researching for the proper combination of parts that will satiate my "requirements" as a driver. It needs to be fast- stupid fast. It needs to handle- and not make me wish I had something else. It needs to look great- which Z's do!. It needs to be affordable- I'm not a "rich guy". (I could have bought a restored 63 corvette with a 9000rpm 302 or something if I were rich!) In all honesty, I'm really happy about the path I'm headed down with this car, and it really seems like a no compromise plan for not "classic muscle car" money, and it will be faster, handle better, and in my opinion, even look better. I can't decide if I really liked the 240 that much off the bat, or if I fell in love with it after staring and dreaming...I think it was both! Ok enough blabbering about why I'm doing this, and onto the technicals- This will be a street/strip car. Street because it would be a sin to build a drag car with the roads in san diego. Strip because theres no point of a car (imo) that you can't let fly. So the plan is as follows, 383, 11:1, brodix track1 heads, solid roller cam, single plane, holley 850hp carb (I build engines, that's the easy part). Should be about 550 horse on motor and pull to 7200 rpm, coming in around 2300rpm, trying to make it a canyon carver and a strip terror is tough for a cam designer, but my man says he has it covered... T56 6spd trans with aluminum flywheel and Ram powergrip hd clutch, good to 650hp as per Ram, and thats for a 3600lb car. R200 from q45, with techno toy tuning backing plates allowing q45 hubs, eliminating stub axles and flanges, while using q45 cv's with chromoly axles, and q45 brakes. Techno toy coilovers all around with tokico illiminas, 5 lug front hubs, and 300mm 4 piston brake kit. MSA sway bar kit, and quick ratio bump steer spacers. Possibly "zpowersteering's" electric steering assist kit. I have a shop on board to do the roll bar. For wheels I'm thinking 16x8, 5x4.5, 0 offset American Racing Torq Thrust II's polished. For tires, 225/50r16 front and 245/50r16 rear, maybe 45 series, not sure on that yet, need to do some measuring. I'm planning to use vintage air's system for AC, because the last thing I want is to get the car done, and loathe driving it because I don't want to stick the the seat. Soooo, what do you guys think??? I'd like to call out rebekahsz on this one, she always seems to have good input on stuff I've read before, plus the front tires are off the ground in the signature thumbnail Sorry that was so long winded everybody, I guess I've never had a chance to say all that to anyone that I thought would care before... please feel free to tell me if I'm barking up the wrong tree with any of the parts I've chosen, or if you have any better ideas, all I have so far is the motor, transmission, and car. The techno toy order is ready, and I'll probably order it next week after I build the car in my head 10 more times haha. (Ps- the body isn't as bad as it looks, just red paint flaking to the original yellow beneath. I think that's why I got it so cheap, in the craigslist ad, it looked like bondo everywhere!) Thanks to all who have any input or recommendations in advance.

I do recognize that this topic has been documented many times before, and believe it or not, I've read most (if not all) articles pertaining to this, on this site and others. But it is clear as mud. Here is my guarantee: if I can find help here, I will make a VERY PRECISE and WELL PHOTOGRAPHED swap so that others in the future aren't as confused as me. I own a 1971 240z, and I want to drop the the R200 that came out of a '94 Q45 (there has been even people speculating that the Q45 had a R230, but from most sources, it is an R200). I've retained the inner CVs with a 6-bolt flange pattern - the halfshaft axles and outer CVs are gone. Someone I know is parting a 1979 280ZX, and the diff has already been picked by someone else. I was thinking I could grab the moustache bar, front diff mount and rear control arm hanger, but some documentation suggested that only up to 1988 280Z (not X) moustache bars would bolt in. Will a 1979 280ZX moustache bar bolt into my 1971 240z and accept the R200 from the Q45? Is the front diff mount and rear control arm hanger worth picking from this 280ZX? As apparently the CVs weren't implemented in the N/A 280ZX (this car has u-joints), I'd like to use other CVs. Someone else has Z32 300ZX (n/a) half-shaft axles - they have a 5-bolt flange on the differential side, and just the one-piece CV/stub axles on the other (is there a proper name for this?). some documentation says that the Q45 CVs accept 30-toothed splines, which the Z32 TT has, but not the N/A version (which has 29). Really Nissan, REALLY? There has been some articles suggesting that pathfinder axles are a good fit (length-wise, tooth-count wise) - keeping in mind, I still need two wheel-side CVs on the 30-tooth splined axles. Then there are the dreaded stub-axles. Can I use the 280ZX stub axles and companion flanges in the 240z? On the companion flange side (CV-side), what bolt pattern will I be expecting? 6-hole (3 pairs)? Seems like I'll need to find either the proper outer CV to mate to it, or machine an adapter (which will affect the overall length). I am aware that several companies offer kits that would make my life easier, but I don't have thousands of dollars to throw at the rear end of the car right now. As a bonus question; is it worth getting the rear brakes off the 280ZX? I see many people have done it, except adapters must be machined to hang the calipers. Are the 280ZX housings the same, and could the whole thing be swapped into the 240z control arms? thanks so much, Sim http://www.geocities.com/jasonparuta/diffswap.html http://forums.hybridz.org/topic/70534-r-200-spline-counts-and-mystery-hlsd/