Powertrix oilover conversion needs.


  • Powertrix oilover conversion needs.

    Well, I'm selling the 89T and will be spending some of the money on the Shiro. I've decided to install Powertrix coilovers as I got a discount on taking over the deposit from a member who had to back out due to selling his car. I never had plans for coils before, I really haven't pay much attention to how you guys were doing it and what additional parts I may need beyond the kit from Powertrix. They are doing the welding on the spindles as part of the buy, and it seems like I remember that they include front camber adjustment plates.

    I ordered the (R/T) coilovers with 8k/6k springs, what else will I need? I am not a track or drift guy and will be doing the majority of my driving on the street and in the city with an occasional trip to the country/mountain roads. I would like to order what I need soon so I can do everything at one time.



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215

  • #2
    Just need the coilovers. Once the welding is done they'll bolt in.

  • #3
    Get some bumpsteer spacers from ASCO to compensate for being lower in the front. You may want to consider doing the rear camber mod and finding a way to get more rear toe adjustment too if you plan to go decently low. The front camber plates maxed out get me to around -3.4 in the front btw. I'd recommend running 4f 3r damping to start with.


    Dont give up, build your dream Z

  • #4
    ASCO is sold out of bump steer spacers. I already did the slotted trailing arm mount/cross member camber mod, what about rear camber plates?



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215

  • #5
    Hah the rear strut has no bearing on camber, so no camber plates there…

  • #6
    You'll only need bumpsteer spacers if you lower significantly enough to need correction to control arm angle.

  • #7
    the bump steer spacers are all you would want. I still have not done the rear camber mod. I just did the coils and the spacers.

  • #8
    reddzx;346765 wrote: Well, I'm selling the 89T and will be spending some of the money on the Shiro. I've decided to install Powertrix coilovers as I got a discount on taking over the deposit from a member who had to back out due to selling his car. I never had plans for coils before, I really haven't pay much attention to how you guys were doing it and what additional parts I may need beyond the kit from Powertrix. They are doing the welding on the spindles as part of the buy, and it seems like I remember that they include front camber adjustment plates.

    I ordered the (R/T) coilovers with 8k/6k springs, what else will I need? I am not a track or drift guy and will be doing the majority of my driving on the street and in the city with an occasional trip to the country/mountain roads. I would like to order what I need soon so I can do everything at one time.


    Most people have touched upon the basics. Bump Steer Spacers are almost a must. The proper name is Roll Center Adjusters (RCA) and Stance sells these as well. This will correct some geometry issues with the front LCA. You would actually benefit from these with ST springs as well.

    Rear camber mod, which is sounds like you have already done. Hopefully its enough, and the stock rear toe adjustment has enough to get you back withing specification at your desired ride height.

    Wheels and tires. Tires play a huge roll in suspension setup. When going with coilovers it is recommended to use a 17" wheel with lower profile tires. Sidewall flex, lets say in your 225/50/16, will make the car feel bouncy. Now you can run higher PSI and set your dampers to the stiffer side to compensate, but this will create a harsher ride quality. This is the main reason people complain their coilovers are garbage and dont like them. They overlook one of the most important aspects of suspension and just want a lower ride height.

    What people dont talk about. Front tension rods. The lower you go in the front, the stock front tension rods start to twist putting a lot of stress on themselves and the LCA. In the past people have stress cracked LCA tear the tension rod area. Kouki tension rods actually have an extra piece spot welded to this area (kouki tension rod will put more stress on the LCA than zenki ones). In my cars I weld a plate over a portion of the LCA to box them in for rigidity. After market adjustable tension rods come with a end link which allows the tension rod to rotate without putting additional stress on the LCA



    I would say the top 3 would be the basics and the 4th is an FYI situation.

    Being realistic I really don't think you are going to like them
    . Depending on ride height you will have to be very conscious about driveways with your front lip, and the ride is going to stiffer than what you are used too. If your back is not up to par, its going to feel the side effects. I would highly recommend keeping your ST setup complete so you are able to bolt it back in.
    86na - BlueZ
    Shiro #366 - Kouki Monster
    85t - Mr Tickles

  • #9
    Thanks Adam, your honesty is appreciated. I am not going to slam it and I have already become driveway conscious just with the 89T on ST's.

    What 17" wheel offset and tire size would you recommend?

    I still have the SS springs also and may keep the ST/Bilstein combo just in case.



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215

  • #10
    reddzx;346842 wrote: Thanks Adam, your honesty is appreciated. I am not going to slam it and I have already become driveway conscious just with the 89T on ST's.

    What 17" wheel offset and tire size would you recommend?

    I still have the SS springs also and may keep the ST/Bilstein combo just in case.
    What I meant was you want to run a minimum 17" wheel. 350z 18s will also work out nicely as well.

    I keep preaching but most 17x9 mustang wheels really fit the bill on the z31. Be it Cobra R's, SCs, or FR500 they all look good. 245/45 or 255/40 tire works really well with this combination (and is not stretched). Most mustang wheels come +24 offset, you are going to need a spacer in the front to clear the coilover (if you have 1" spacers try them first). Rears will bolt up fine, but you may need a spacer depending on desired aesthetics. Run -2 to -2.5 degrees of camber up front, and you may need to bend over the 2 tabs that hold the fender liner in. I was able to just remove the screws and bend the tabs upward with a dead blow hammer + heat. This holds the liners in place with no issues and really easy to do.
    86na - BlueZ
    Shiro #366 - Kouki Monster
    85t - Mr Tickles

  • #11
    adamvann3;346844 wrote: What I meant was you want to run a minimum 17" wheel. 350z 18s will also work out nicely as well.

    I keep preaching but most 17x9 mustang wheels really fit the bill on the z31. Be it Cobra R's, SCs, or FR500 they all look good. 245/45 or 255/40 tire works really well with this combination (and is not stretched). Most mustang wheels come +24 offset, you are going to need a spacer in the front to clear the coilover (if you have 1" spacers try them first). Rears will bolt up fine, but you may need a spacer depending on desired aesthetics. Run -2 to -2.5 degrees of camber up front, and you may need to bend over the 2 tabs that hold the fender liner in. I was able to just remove the screws and bend the tabs upward with a dead blow hammer + heat. This holds the liners in place with no issues and really easy to do.
    I'm running full 88T suspension in the front of my 86, with ST springs and Bilsteins. I have a set of 03 Cobra wheels on mine (genuine Ford, not reps, if that makes a difference for offsets). They fit great with a 5mm spacer in front and 10mm in rear. I'm running a 235 width tire in the front, but have space for a bunch more. When it needs replacing I'll probably do a 245 or 255. Rear is a 275 and there's still plenty of space back there as well.
    Prius… because Pretentious wouldn't fit across the back of the car…

    Cheap, Fast, Reliable - pick any two

    My 1986 Turbo Build

  • #12
    jaqattack02;346845 wrote: I'm running full 88T suspension in the front of my 86, with ST springs and Bilsteins. I have a set of 03 Cobra wheels on mine (genuine Ford, not reps, if that makes a difference for offsets). They fit great with a 5mm spacer in front and 10mm in rear. I'm running a 235 width tire in the front, but have space for a bunch more. When it needs replacing I'll probably do a 245 or 255. Rear is a 275 and there's still plenty of space back there as well.
    Reps and genuine run the same offsets. You have to remember with stock front you just need to clear the front strut housing. With coilovers you now need to clear the spring perch + spring and need lower offset to do so. I love 235/40 tires on 17x9 wheels, but its a minor stretch (hardly noticeable) but I also know this is not Tim's style or preference. At 17x9+2 235/40 I was barely able to fit a pinky width between my tire and coilover perch. With coilovers you want your 9" wheel to be close to 0 offset, maybe towards the negative side depending on tire width.
    86na - BlueZ
    Shiro #366 - Kouki Monster
    85t - Mr Tickles

  • #13
    Thanks, this is precisely the kind of Information I need.



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215

  • #14
    9.5s and 255s made me go with 15mm spacers at +22 offset.
    Usual Z31 suspect: Garage Queen (aka broken)

  • #15
    300zxturboftw;346864 wrote: 9.5s and 255s made me go with 15mm spacers at +22 offset.
    front or back?



    1988 300ZX Turbo, Shiro Special #760
    1988 300ZX Turbo Automatic (wife's car)
    1991 Hard-body 2WD

    http://zccw.org/zccw/?page_id=1215