# Swapping Z31 rear suspension **URL:** \ **Category:** Canada Nissan Automotive\ **Created:** [February 21, 2005, 1:11pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405 "2005-02-21T13:11:47Z")\ **Posts on this page:** 20\ **Page:** 1
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [February 21, 2005, 1:11pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/1 "2005-02-21T13:11:47Z")
Well myself and Andru finished up swapping all of the rear suspension out of the '87 parts car into my '84. We hit a few…well ok, many snags along the way. If the guys on [Z31.com](http://Z31.com) had told us about certain parts not swapping between the rear suspension assemblies we may not have spent so much time trying to swap the brakes/diffs/axles. In the end we ended up having to put everything from the parts car, including the brakes, cross member, diff, springs, control arms sway bars…etc. The realization about 3/4 of the way through that we could have just dropped the whole assemblies out and been done in under 2 hours was a bit of a piss off…but we moved on. Live and learn. The next time we’re pulling suspension out, it’s going to go much smoother. :drinkers: If anyone needs tips on swapping Z31 suspension, myself and Andru are full of them now! Matt P.S. Thanks again for all your help Dru! 😃 ---
**Author:** ![Nis240](https://avatars.discourse-cdn.com/v4/letter/n/a9a28c/32.png) [@Nis240](https://forums.speedlife.net/u/Nis240)\ **Post date:** [February 21, 2005, 4:25pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/2 "2005-02-21T16:25:08Z")
Vented rear brakes are always better than solid. ---
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [February 21, 2005, 5:50pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/3 "2005-02-21T17:50:33Z")
That they are. Despite them being about 3/4" smaller in diamater, I expect them to brake much better than the stock ones. The front brakes are the same between the two cars. ---
**Author:** ![1mns13](https://avatars.discourse-cdn.com/v4/letter/1/8491ac/32.png) [@1mns13](https://forums.speedlife.net/u/1mns13)\ **Post date:** [February 22, 2005, 3:06pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/4 "2005-02-22T15:06:56Z")
Why did you swap the suspension in the first place? ---
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [February 22, 2005, 5:14pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/5 "2005-02-22T17:14:37Z")
Wider stance and didn’t you ever see my car squat like a girl peeing in the woods? On the plus side I have the good condition, shorter geared diff that should shave a 1/2 sec off my 1/4 mile time all by itself. :partyman: ---
**Author:** ![1mns13](https://avatars.discourse-cdn.com/v4/letter/1/8491ac/32.png) [@1mns13](https://forums.speedlife.net/u/1mns13)\ **Post date:** [February 23, 2005, 7:19am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/6 "2005-02-23T07:19:56Z")
I didn’t realize z31s had two different rear tracks. I figured the antiquated suspension design was the cause of the squat problem. So which years have have the best rear suspension? ---
**Author:** ![Zazam](https://avatars.discourse-cdn.com/v4/letter/z/f9ae1b/32.png) [@Zazam](https://forums.speedlife.net/u/Zazam)\ **Post date:** [February 23, 2005, 7:25am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/7 "2005-02-23T07:25:04Z")
> [@1mns13](#): > > I didn’t realize z31s had two different rear tracks. I figured the antiquated suspension design was the cause of the squat problem. So which years have have the best rear suspension? Actually the 88-89 NA: 3.9 open diff :yeah:but the 87 NA was what we had wich had a 3.7 open diff And Matt no problem! More then likely I’ll need a hand install some of my goodies within the next 2 months :partyman: ---
**Author:** ![1mns13](https://avatars.discourse-cdn.com/v4/letter/1/8491ac/32.png) [@1mns13](https://forums.speedlife.net/u/1mns13)\ **Post date:** [February 23, 2005, 7:59am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/8 "2005-02-23T07:59:05Z")
I knew about the diffs. Matt stated a wider track and less squat. Meaning updated components. ---
**Author:** ![RS13](https://avatars.discourse-cdn.com/v4/letter/r/46a35a/32.png) [@RS13](https://forums.speedlife.net/u/RS13)\ **Post date:** [February 23, 2005, 9:31am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/9 "2005-02-23T09:31:33Z")
it is still a 4000 punds beast. you gonna get squat no matter what :finger :alright: ---
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [February 23, 2005, 11:51am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/10 "2005-02-23T11:51:49Z")
The hubs on the 87+ all are 10mm wider on each side. Swapping the suspension in helps with my camber issues as well as a 20mm wider track. It brings the tires nicely out to the edge of the fender. :E Matt P.S. the car only weighs 3000lb, less once I strip some of the crap out of it. :finga: P.P.S. 3.54 stock diff ran a 13.8, new 3.7 diff is capable of 95.6% of that with all other factors being equal. 13.811 x 0.956 = 13.203s. Isn’t gearing wonderful? :E ---
**Author:** ![1mns13](https://avatars.discourse-cdn.com/v4/letter/1/8491ac/32.png) [@1mns13](https://forums.speedlife.net/u/1mns13)\ **Post date:** [February 23, 2005, 12:06pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/11 "2005-02-23T12:06:45Z")
Thanks for the info Matt. You may experience a hint more understter at low speeds, but if that new rear end has lsd, a stab of throttle,will cure it. ---
**Author:** ![Inzane](https://avatars.discourse-cdn.com/v4/letter/i/b38774/32.png) [@Inzane](https://forums.speedlife.net/u/Inzane)\ **Post date:** [February 23, 2005, 12:28pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/12 "2005-02-23T12:28:35Z")
> [@Chromedragon](#): > > didn’t you ever see my car squat like a girl peeing in the woods? In drag racing, you WANT a RWD car to squat. (that’s part of the reason Mustangs are so easy to launch well). The squat aspect allows you better weight transfer to the rear (driving) wheels. In fact a lot of my problem at Bud Park is the Z32’s ANTI-squat suspension geometry. Its better overall for other situations of course, but not ideal for drag-racing. My car’s inability to squat is part of the reason for the difficulty in launching and the wheel-hop that I’ve experienced. ---
**Author:** ![sil\_eightyRPS13](https://avatars.discourse-cdn.com/v4/letter/s/2bfe46/32.png) [@sil\_eightyRPS13](https://forums.speedlife.net/u/sil_eightyRPS13)\ **Post date:** [March 8, 2005, 10:02pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/13 "2005-03-08T22:02:32Z")
> [@Inzane](#): > > My car’s inability to squat is part of the reason for the difficulty in launching and the wheel-hop that I’ve experienced. not really… some setups make the muscle cars stand up, rather than squat… and clutch control will help stop wheel hop! 😉 ---
**Author:** ![Inzane](https://avatars.discourse-cdn.com/v4/letter/i/b38774/32.png) [@Inzane](https://forums.speedlife.net/u/Inzane)\ **Post date:** [March 10, 2005, 5:20pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/14 "2005-03-10T17:20:24Z")
> [@sil\_eightyRPS13](#): > > not really… some setups make the muscle cars stand up, rather than squat… > and clutch control will help stop wheel hop! 😉 That’s nice but you’re ignoring the physics of weight transfer. And how long are you going to be able to slip an organic street disc clutch before its toast? ---
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [March 10, 2005, 6:38pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/15 "2005-03-10T18:38:03Z")
So it seems that the parts car we were originally told was an 87 is actually an 88. That means the diff that I stuck in the car is a 3.9, not a 3.7. How that will fare at the track, we’ll have to wait and see. :w00t: ---
**Author:** ![1mns13](https://avatars.discourse-cdn.com/v4/letter/1/8491ac/32.png) [@1mns13](https://forums.speedlife.net/u/1mns13)\ **Post date:** [March 10, 2005, 7:48pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/16 "2005-03-10T19:48:58Z")
> [@Chromedragon](#): > > So it seems that the parts car we were originally told was an 87 is actually an 88. always check the 10th digit of the vin for year. ---
**Author:** ![RS13](https://avatars.discourse-cdn.com/v4/letter/r/46a35a/32.png) [@RS13](https://forums.speedlife.net/u/RS13)\ **Post date:** [March 10, 2005, 7:55pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/17 "2005-03-10T19:55:36Z")
or was the vin taken off with a scredriver??? :E ---
**Author:** ![Jason\_Lange](https://avatars.discourse-cdn.com/v4/letter/j/65b543/32.png) [@Jason\_Lange](https://forums.speedlife.net/u/Jason_Lange)\ **Post date:** [March 10, 2005, 9:44pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/18 "2005-03-10T21:44:11Z")
I think the 3.90 will work well for you. It might get you into a chunk of 5th. ---
**Author:** ![Inzane](https://avatars.discourse-cdn.com/v4/letter/i/b38774/32.png) [@Inzane](https://forums.speedlife.net/u/Inzane)\ **Post date:** [March 10, 2005, 9:57pm UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/19 "2005-03-10T21:57:10Z")
> [@Chromedragon](#): > > That means the diff that I stuck in the car is a 3.9, not a 3.7. Even better! :E ---
**Author:** ![Chromedragon](https://avatars.discourse-cdn.com/v4/letter/c/ba8739/32.png) [@Chromedragon](https://forums.speedlife.net/u/Chromedragon)\ **Post date:** [March 11, 2005, 12:08am UTC](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405/20 "2005-03-11T00:08:58Z")
> [@1mns13](#): > > [quote=Chromedragon]So it seems that the parts car we were originally told was an 87 is actually an 88. always check the 10th digit of the vin for year.[/quote] They were parts cars, I wasn’t too concerned about the exact year so I just took the guy’s word for it. It all turned out well in the end though! The car really gets down now! 😃 [Next page](https://forums.speedlife.net/t/swapping-z31-rear-suspension/138405.md?page=2)