Nissan 370Z Forum - View Single Post

HapaZ · 02-15-2018, 12:09 PM

Hi All,

I've noticed a few posts around these parts referencing the Z1 subframe bushing insert kit but few people writing up their experience of them. So after two weeks of daily driving and a weekend of canyon carving here we go...

The kit I'm referencing:
https://www.z1motorsports.com/z1-pro...s-p-12015.html

Review
Shipping/Packaging:
Z1 has always been on top of their shipping game and I didn't have any problems with their standard shipping. The collars were wrapped and in a padded envelope.

Material:
Nice aluminum, but it's not like you're going to be looking at these very often once they're on the car.

Install:
The installation took me about 90 minutes, with about 20 minutes of being under the car scratching my head. The instructions could have been clearer with pictures of the parts referenced, but honestly this was not a difficult install with an electric impact wrench and a bit of patience. With my aftermarket cat-back I did not need to drop my muffler or any pipes behind, despite instructions stating the this needed to be done. The top collars on the rear-most section of the subframe gave me a bit of trouble because they needed to be clocked just right so that they would drop down into the empty space on the existing stock bushing. Since I couldn't see the space from the top, I ended up using my pinky finger to feel the orientation of the void and then slowly rotated the top collar when I inserted it. In hind-sight, it may be possible to see the orientation of the voids when looking through the bottom of the bushing - I wasn't that smart when I did the install.

NVH:
On-road I don't notice any additional NVH from these bushings. I have a fairly loud exhaust set up and it's possible I didn't notice any while driving because it was drowned out. So I'll keep the jury out on that one other than to say if there is any additional on-road NVH it's got to be pretty mild. When I do hear the inserts is when backing out of my driveway, however. I have a steep angle coming off my curb that usually lifts an inside rear wheel when entering/exiting. I do hear a very mild creaking noise when I go over this section of my driveway. I assume this is due to some movement that's caused by the twisting of the subframe or chassis. It's really not bad and again I do not hear this while I'm driving with both rear wheels on the road.

Performance:
Ok now for what you've all been waiting for. The simple answer is that yes they do make a difference, but only in some circumstances. The video Z1 posted about the movement of the differential and the subframe is a really good visual representation of what happens when going on/off throttle. I have a whiteline differential bushing and when doing a max acceleration shift from 1st to 2nd (and 2nd to 3rd to a lesser extent) now with these collars there is a smaller delay from the time the shift is completed to the time you feel the car push you back in your seat. When quickly hitting the gas while driving there is also a quicker response in the time it takes to translate power to the ground from the time you press the pedal, but the difference isn't quite as dramatic as what I feel doing a quick 1st to 2nd shift. I also notice that on engine braking the response is similarly quicker. Here the time I take my foot off the gas to the time I feel the car actually respond is less. If I had to take a guess, I'd say I went from maybe 1/4 of a second delay to 1/8th. This isn't an instrumented test here, but I can definitely feel a difference. I can also feel a difference when accelerating hard out of a corner. Occasionally, I'd feel a slight or brief side-side movement that was not caused by losing tire traction. Spencer at Z1 describes this as a "penguin shimmy" in their video and this kit eliminates it pretty well. It feels like the rear-end is more consistent when coming out of a corner hard on the gas.

Value:
For $150 and a short install I'm happy with my purchase. The difference isn't as dramatic as a front sway bar or a solid alignment, but if you've already done a fair bit of suspension modding these can be a nice upgrade. This is also one of the few modifications I've done that didn't cause me to bleed at some point during the install. At the end of the day, this purchase got me to spend some time connecting with my car for a pretty small price. So I'm sure that after driving for another month or two I'll forget what it felt like stock, but I'm okay with that. For the past two weeks I've enjoyed the process and for me that's worth it!

02-15-2018, 12:09 PM	#1 (permalink)
HapaZ Base Member Join Date: Sep 2014 Location: NorCal Posts: 242 Drives: 2012 370z Base Coupe Rep Power: 10	Z1 Subframe Bushing Insert/Collar Review Hi All, I've noticed a few posts around these parts referencing the Z1 subframe bushing insert kit but few people writing up their experience of them. So after two weeks of daily driving and a weekend of canyon carving here we go... The kit I'm referencing: https://www.z1motorsports.com/z1-pro...s-p-12015.html Review Shipping/Packaging: Z1 has always been on top of their shipping game and I didn't have any problems with their standard shipping. The collars were wrapped and in a padded envelope. Material: Nice aluminum, but it's not like you're going to be looking at these very often once they're on the car. Install: The installation took me about 90 minutes, with about 20 minutes of being under the car scratching my head. The instructions could have been clearer with pictures of the parts referenced, but honestly this was not a difficult install with an electric impact wrench and a bit of patience. With my aftermarket cat-back I did not need to drop my muffler or any pipes behind, despite instructions stating the this needed to be done. The top collars on the rear-most section of the subframe gave me a bit of trouble because they needed to be clocked just right so that they would drop down into the empty space on the existing stock bushing. Since I couldn't see the space from the top, I ended up using my pinky finger to feel the orientation of the void and then slowly rotated the top collar when I inserted it. In hind-sight, it may be possible to see the orientation of the voids when looking through the bottom of the bushing - I wasn't that smart when I did the install. NVH: On-road I don't notice any additional NVH from these bushings. I have a fairly loud exhaust set up and it's possible I didn't notice any while driving because it was drowned out. So I'll keep the jury out on that one other than to say if there is any additional on-road NVH it's got to be pretty mild. When I do hear the inserts is when backing out of my driveway, however. I have a steep angle coming off my curb that usually lifts an inside rear wheel when entering/exiting. I do hear a very mild creaking noise when I go over this section of my driveway. I assume this is due to some movement that's caused by the twisting of the subframe or chassis. It's really not bad and again I do not hear this while I'm driving with both rear wheels on the road. Performance: Ok now for what you've all been waiting for. The simple answer is that yes they do make a difference, but only in some circumstances. The video Z1 posted about the movement of the differential and the subframe is a really good visual representation of what happens when going on/off throttle. I have a whiteline differential bushing and when doing a max acceleration shift from 1st to 2nd (and 2nd to 3rd to a lesser extent) now with these collars there is a smaller delay from the time the shift is completed to the time you feel the car push you back in your seat. When quickly hitting the gas while driving there is also a quicker response in the time it takes to translate power to the ground from the time you press the pedal, but the difference isn't quite as dramatic as what I feel doing a quick 1st to 2nd shift. I also notice that on engine braking the response is similarly quicker. Here the time I take my foot off the gas to the time I feel the car actually respond is less. If I had to take a guess, I'd say I went from maybe 1/4 of a second delay to 1/8th. This isn't an instrumented test here, but I can definitely feel a difference. I can also feel a difference when accelerating hard out of a corner. Occasionally, I'd feel a slight or brief side-side movement that was not caused by losing tire traction. Spencer at Z1 describes this as a "penguin shimmy" in their video and this kit eliminates it pretty well. It feels like the rear-end is more consistent when coming out of a corner hard on the gas. Value: For $150 and a short install I'm happy with my purchase. The difference isn't as dramatic as a front sway bar or a solid alignment, but if you've already done a fair bit of suspension modding these can be a nice upgrade. This is also one of the few modifications I've done that didn't cause me to bleed at some point during the install. At the end of the day, this purchase got me to spend some time connecting with my car for a pretty small price. So I'm sure that after driving for another month or two I'll forget what it felt like stock, but I'm okay with that. For the past two weeks I've enjoyed the process and for me that's worth it! Last edited by HapaZ; 02-15-2018 at 01:58 PM.