Upgraded to Nismo coilover - how to adjust rear shock's rebound setting from inside?

[2023MTOreo]

Happy New Year!

on my 2023 performance MT i've upgraded the oem shocks with the Nismo coilover setup. after some adjustments the front and rear ride height dropped about an inch which is perfect for me. the shop where i had the work done adjusted the front and rear rebound settings to 12 out of 16 click. 16 being the hardest. even at 12 this is still a little stiff and wandering a bit for me especially on the uneven, rough freeway. btw i also had the alignment done after all the suspension works done a few weeks after so i don't think it's off alignment. my 2020 VW GTI with stock shocks and Eiback lower springs feels a lot more solid, steady, stable at high speed than my current Z's setup.

i know how to adjust the front shocks' rebound setting with the included adjustment wheel. i took out the rear trim pieces today hoping to find a similar method to adjust the rear rebound setting but there's a black piece of rubber covering the top of the rear shocks (see attached pic) i didn't find an easy way to remove or peel back the rubber piece unless cutting into it which i rather not do at this time. Question - is there an easy way to adjust the Nismo rear shock? T.I.A

 

[eculley]

Unfortunately there is no way to adjust it while it's mounted, unless you do what you do not want to do and cut a hole in the cap. There are extended adjusters you can use to fish through the cap, trim and carpet that makes adjustments easier without having to take them off.

Assuming they were adjusted for pre-load, and the bushings were "clocked" when the struts were installed? And you got an alignment? All of these things play a massive part in how the car drives in the end.

 

[2023MTOreo]

Thanks for your reply. I'll look into an aftermarket extended adjuster. from the ones i saw the extension is screwed to the adjustment wheel. i may need to get 2 more nismo rebound adjustment wheels for each rear shock and saving the one that came with the kit for the 2 front struts.

i didn't know that rear setup needs preload adjustment since the springs are separated from the shocks/dampers. i searched a bit online and saw some writeup and video on this subject so that helped a lot. the shop i used is specialized in japanese sport cars so i hope they did all the right steps. i didn't hear any metal clanging sounds so i think the springs at least have some preload. i'll try to adjust the shocks damping settings for now. if they are still stiff after all that then i'll make a visit to the shop for options.

 

[D2M]

On the Nismo coilovers the rear preload is no adjustable separately. If you adjust the spring collar on the rear spring you will be changing the rear ride height, affecting the bump travel. As long as you are not too low and riding on or close to the bump stops you will be ok. Post a side profile pic of the car if you want to se if the height is too low or not.

That rubber cap you see has a small lip that sandwiches between the shock mount and the body. You can try to pull it off by force but might damage the cap and definitely wont be able to get it back in. That cap should have been omitted anyway when they installed the shocks so you can get to the adjuster.

 

[eculley]

The rear won't need pre-load adjusted but the front may (depending on how Nismo ships the coils). This was a recommendation regarding the car not riding correctly.

 

[D2M]

There is no separate preload adjustment on the Nismo coilovers at all. When you rotate the spring collar front or rear you are raising/lowering the ride height. So if they are set too low in ride height they will loose all the bump travel and be bouncing on the bump stops.

 

[2023MTOreo]

my Nismo coilver kit came uncalibrated. Without any adjustment the rear was high and the front was very low. after the shop made some adjustment the front and rear almost the same and acceptable to me. i'm attaching 2 pics, 1 at the shop before any adjustment made with nismo default settings out of the box and 1 after the shop made adjustment. front measurement from ground to bottom of wheel well is 27 and 3/8. the rear is at 27". when i sit in the car the front is lower a little bit, maybe to 27 and 1/4.

i cut an X over the plastic cap over the rear shocks to get to the top of the rear shock adjustment. both front and rear are now set at 8 out of 16 clicks. it rides softer and more compliant but still a little stiff which i think it's ok. i'll keep at this setting and testing it more on various roads to narrow down on one that's acceptable to me.

Thanks for all your feedbacks!!

 

[eculley]

Did you install the coilovers initially or was it the shop? The first shot looks like the rear wasn't clocked, and then it was realized and corrected in the second photo. Meaning, everything was torqued down while it was still lifted and components were still at full droop. Glad it's sorted.. would love some thoughts on the coils now that youve got them dialed in!

 

[D2M]

Ride height looks fine, not too low. At 27" rear you could maybe go up slightly to get more bump travel. you said you started at 10 clicks then went to 8. Try like 2 or 3, always start soft and work your way up if needed, stiffer isn't always better, especially if you are on a street tire and just cruising around.

A while back I contacted ST ( the manufacturers of the Nismo coilovers ) to get the spring rates on these. The front is a 12K and the rear is a progressive variable rate, I'm guessing around 10/12K. At those rates the car should ride like a dream, thats not stiff at all for this car, just enough to give a sporty feel.

 

[2023MTOreo]

Did you install the coilovers initially or was it the shop? The first shot looks like the rear wasn't clocked, and then it was realized and corrected in the second photo. Meaning, everything was torqued down while it was still lifted and components were still at full droop. Glad it's sorted.. would love some thoughts on the coils now that youve got them dialed in!

I didn't install the coilover. the shop did. all i could do is to adjust the rebound settings using the included adjustment wheel (basically a small allen wrench with 6 numbers marked on it).

i think you could be right that the rear wasn't clocked initially that's why it looked way high up, even higher than factory height. i'll definitely leave some feedback about my trial and errors and thoughts on the Nismo coilover kit once i feel i have the car's suspension all worked out.

today i went to the softest setting and counted the number of clicks (no sound heard, just visual "clicks" from eyeballing the marked number on the adjustment wheel moving). i did this a few times from softest to hardest and the number of "clicks" is actually 20 not 16 as documented!! all 4 corners behaved the same. all have about 20 clicks instead of 16. strange!! anyway i settled on 5 clicks from the softest - so technically only 1/4 of the most stiff setting. going over bumps on surface streets seems to be bearable and still stiffer than oem shocks. however at freeway speed or a little faster (80, 85 mph) on uneven parts of the freeway, or when going over white round bumps of the lanes the car still has side movements! my tire pressure on left and right tires about 1 psi (different). i just got the alignment done last week after the car had all the suspension works done and driven around for 2 weeks. the alignment shop could only adjust the front toe and not the front camber or caster. i'll create another post for my alignment question in order to keep the comments on the original topic.

 

[2023MTOreo]

Ride height looks fine, not too low. At 27" rear you could maybe go up slightly to get more bump travel. you said you started at 10 clicks then went to 8. Try like 2 or 3, always start soft and work your way up if needed, stiffer isn't always better, especially if you are on a street tire and just cruising around.

A while back I contacted ST ( the manufacturers of the Nismo coilovers ) to get the spring rates on these. The front is a 12K and the rear is a progressive variable rate, I'm guessing around 10/12K. At those rates the car should ride like a dream, thats not stiff at all for this car, just enough to give a sporty feel.

yes, i went from softest and dialed in at 5 out of 20 clicks (20 clicks being the hardest). as noted in my previous comment for some reasons i have 20 clicks settings instead of the documented 16 clicks. currently i'm ok with the rebound behavior - just don't know why the car still have side movement on uneven road at freeway speeds.

do you think if i raise the rear to another 1/4" or 3/8", the rear will be less bouncy/stiff and more compliant but yet at the same time give me the extra stability when i take corners/curves 2x faster than the posted speed limit? btw i have the Z1 rear sway bar set at the soft setting (outter hole). for the rear, i would have to take back to the shop for them to raise it a little more. at the shop i saw both rear tires had to be off and jacked up high in order to get to the adjustment rings on the shocks then drop back down with the tires on to check for correct height. this may involve more than 1 go and i definitely not setup to do this at home. especially when the Nismo kit didn't come with the adjustment wrench - or someone forgot to put 1 in the box. the shop had to use their own when i asked for the wrench back.

 

[D2M]

So here is the thing with these cars. In the rear the shock has a very similar motion ratio as the wheel ( the wheel and shock move almost the same distance up and down ) so you have a small window to set the travel of the shock to operate correctly. With the Nismo coils the spring adjuster directly affects the travel as they are not adjustable separately.

If you are going over a bump and it seems to get very harsh suddenly then you are most likely bottoming out and hitting the rear bump stop, thus you will need to raise the rear up to gain more up travel with the wheel. With a soft rear spring it,s easy to blow through the rear travel quickly and bottom out the shock. Also these cars have a lot of torque thus under WOT acceleration the rear will squat and take up a portion of the up travel making the car even easier to bottom out hitting a bump under hard acceleration. So if you are feeling harshness over bumps when accelerating hard it needs to go up. You should be able to achieve a desirable setup with the Nismo coils, it might take a few tries.

 

[2023MTOreo]

thanks again for your inputs. i had to read it twice to fully understand the concept. i guess i'll go back to the shop and have them raise the rear to be the same height with the front (from 27" to another 1/4" or 3/8"). i wonder this little gain will make any difference with the side movements but at least i try.

i've always used lower springs with oem shocks and upgraded sway bars before on my other cars and have been happy with their suspension performance so far. on this Z i just thought maybe i'd splurge this time and go with coilovers since it's a more expensive car. i should have done more thorough research on different types of coilover and pick the one with easier adjustment on springs and shocks. not to say the nismo coilover is a bad product but maybe it's not totally right for my personal preference.

 

[chadgigachad]

I'm looking into removing/cutting this rubber cap, does anyone have a part number for the rubber cap and removal instructions?

 

[chadgigachad]

I'm looking into removing/cutting this rubber cap, does anyone have a part number for the rubber cap and removal instructions?

https://www.z1motorsports.com/rear-...70z-g37-g35-sedan-rear-shock-cap-p-13655.html

I believe this part is the rubber cap. No idea how to remove it, so I suppose when I go with coilovers in the distant future, I'll just cut them inplace.