[JCunningham]

could you look at yours and see if the top bushing got pushed down with the weight of the car? like i said befor with the top bushing not being fully seated the cradle is crooked. it will mess with the alignment and the alignment of the drive shaft. Im thinking that with time the weight of the car it could push the cradle up so the top bushing is bottomed out like it should be. Then your alignment will be off. I am a perfectionist. I even replace all the bolts and took my perfectly good BMR bushings out just to have it all GM. I use $250 snap on tq wrenches on everything. I even bought the Kent-Moore CH-51034-A Cradle Alignment Pins. and all Kent Moore ls/lt tools. I know I need help. There should be groups for people like me.

[RUQWIKR]

Originally Posted by JCunningham

could you look at yours and see if the top bushing got pushed down with the weight of the car? like i said befor with the top bushing not being fully seated the cradle is crooked. it will mess with the alignment and the alignment of the drive shaft. Im thinking that with time the weight of the car it could push the cradle up so the top bushing is bottomed out like it should be. Then your alignment will be off. I am a perfectionist. I even replace all the bolts and took my perfectly good BMR bushings out just to have it all GM. I use $250 snap on tq wrenches on everything. I even bought the Kent-Moore CH-51034-A Cradle Alignment Pins. and all Kent Moore ls/lt tools. I know I need help. There should be groups for people like me.

You're not the only one that click torques all fasteners, paint marks them for looking for movement, etc.

[MTSS1LE]

So I fell into the trap and am planning on converting my SS 1LE to full FEA. I've already purchased the DSSV struts used but unfortunately they don't have any hardware. I was able to look up the nuts and bolts for the knuckle mounts but I couldn't find the strut mount bolts. Does anyone know if these are carried over from the FE4?

[JCunningham]

id ask your dealer or call https://www.thatgmpartsguy.com/contact-us

[Fijititan]

Originally Posted by MTSS1LE

So I fell into the trap and am planning on converting my SS 1LE to full FEA. I've already purchased the DSSV struts used but unfortunately they don't have any hardware. I was able to look up the nuts and bolts for the knuckle mounts but I couldn't find the strut mount bolts. Does anyone know if these are carried over from the FE4?

Are you talking about the top mounting bolts? If you are, yes they are the same. I checked with the dealer. I’m doing the same swap this weekend. The only info I don’t have at the moment are the torque spec for the bolts from the strut to the wheel hub.

Top mounting GM bolt numbers:
1588730 long (this is for the GM performance strut brace which require longer bolts)
11602257 short (stock bolts)

[MTSS1LE]

Awesome thanks for checking on that. I think if you bought the zl1 1le lowering and handling kit it might've come with some instruction on installing them including the torque specs. Travislambert was that the case with your kit and would you be willing to share it to the rest of us? Otherwise the only other option is purchasing a helms manual or do a 3 day subscription here:

https://www.acdelcotds.com/subscriptions#

[czkn88pl]

Hi guys!

I also thinking to change something with my stock ZL1 suspension.
I'm using my car on street (not daily, but some weekends trips) and max. 10 times per year going to track day.
After reviewing this thread have some thoughts I should do if I want get better handling.

1. Change rear cradle bushings for this one from ZL1 1LE:
https://www.gmperformancemotor.com/parts/84341929.html
2. Install handling upgrade system from ZL1 1LE:
https://www.gmperformancemotor.com/parts/84352119.html
3. BMR sway bars for front and rear:
https://www.bmrsuspension.com/?page=...662&superpro=0
4. BMR sway bars end link kit:
https://www.bmrsuspension.com/?page=...611&superpro=0

Does some other parts from BMR (like control arms, toe rods, trailing arms) make sense for me when using car like I wrote above ?

Before reading this thread I wanted to change my suspension for DSSV or KW V3 , but right now thinking that FE4 with MRC is the best option for me, but also want to make it better.

[RUQWIKR]

Originally Posted by czkn88pl

Hi guys!

I also thinking to change something with my stock ZL1 suspension.
I'm using my car on street (not daily, but some weekends trips) and max. 10 times per year going to track day.
After reviewing this thread have some thoughts I should do if I want get better handling.

1. Change rear cradle bushings for this one from ZL1 1LE:
https://www.gmperformancemotor.com/parts/84341929.html
2. Install handling upgrade system from ZL1 1LE:
https://www.gmperformancemotor.com/parts/84352119.html
3. BMR sway bars for front and rear:
https://www.bmrsuspension.com/?page=...662&superpro=0
4. BMR sway bars end link kit:
https://www.bmrsuspension.com/?page=...611&superpro=0

Does some other parts from BMR (like control arms, toe rods, trailing arms) make sense for me when using car like I wrote above ?

Before reading this thread I wanted to change my suspension for DSSV or KW V3 , but right now thinking that FE4 with MRC is the best option for me, but also want to make it better.

On the ZL1 1LE "handling upgrade system" (PN 84352119), you only need the FEA front lower control links (84051643 / 44). All FE4 cars built after around January 2017 have the upgraded bushings in the rear knuckles. That has been discussed before in other threads.

[czkn88pl]

Originally Posted by RUQWIKR

On the ZL1 1LE "handling upgrade system" (PN 84352119), you only need the FEA front lower control links (84051643 / 44). All FE4 cars built after around January 2017 have the upgraded bushings in the rear knuckles. That has been discussed before in other threads.

Thank for your reply. I have MY2018. Then I shall have already this one from this kit "rear knuckles complete with stiffer bushings and ball joints" ??
Then I need only 84051643 / 44 ?

[RUQWIKR]

Originally Posted by czkn88pl

Thank for your reply. I have MY2018. Then I shall have already this one from this kit "rear knuckles complete with stiffer bushings and ball joints" ??
Then I need only 84051643 / 44 ?

Yes - just talking parts from that kit PN.

If it was my car, I'd just do the front lower links and rear cradle bushings to start. Until you are VERY advanced pace on track, and know exactly what type of corner entry, mid-corner, corner exit style you prefer, I would not mess with the sway bar rates. Then, you can fine tune the suspension to your personal liking.

It's your car, so, change to your liking now or in the future.

[travislambert]

Originally Posted by czkn88pl

Thank for your reply. I have MY2018. Then I shall have already this one from this kit "rear knuckles complete with stiffer bushings and ball joints" ??
Then I need only 84051643 / 44 ?

These cars are in a delicate balance and are basically perfect from the factory. That makes them incredibly difficult to improve upon by just changing a part here and there.

I'm as guilty as anybody when it comes to this. More than once I found myself lusting over upgrades only to invest a bunch of money and time for no meaningful benefit.

One upgrade I don't regret at all was BMR upper+lower trailing arms and toe links. There are a couple of hard double-apex right hand turns at PittRace where my left rear tire kept rubbing the liner. I even had a shiny spot on the body where the tire flexed over and rubbed. I installed the single adjustable trailing arms as well as the double-adjustable toe rods and that problem went away.

As has already been mentioned, have a particular goal in mind for each change while keeping in mind the parts you already have are really, really, good.

[czkn88pl]

Originally Posted by travislambert

These cars are in a delicate balance and are basically perfect from the factory. That makes them incredibly difficult to improve upon by just changing a part here and there.

I'm as guilty as anybody when it comes to this. More than once I found myself lusting over upgrades only to invest a bunch of money and time for no meaningful benefit.

One upgrade I don't regret at all was BMR upper+lower trailing arms and toe links. There are a couple of hard double-apex right hand turns at PittRace where my left rear tire kept rubbing the liner. I even had a shiny spot on the body where the tire flexed over and rubbed. I installed the single adjustable trailing arms as well as the double-adjustable toe rods and that problem went away.

As has already been mentioned, have a particular goal in mind for each change while keeping in mind the parts you already have are really, really, good.

OEM control arms, toe rods, trailing arms, etc. are not specially good quality. Even on street I have problems with drive because I can't drive straight and is always fight with the car . Handling it's not good.

I read at this thread that really much difference makes changing rear cradle bushings. It's true ? Shall I start with it first ?

[TRZ06]

Originally Posted by czkn88pl

OEM control arms, toe rods, trailing arms, etc. are not specially good quality. Even on street I have problems with drive because I can't drive straight and is always fight with the car . Handling it's not good.

I read at this thread that really much difference makes changing rear cradle bushings. It's true ? Shall I start with it first ?

YES, the rear cradle bushings will resolve your issues. That is the ONLY weak point in the ZL1 & SS 1LE suspension from a handling perspective.

In fact, if you look at the parts list, most of the suspension pieces are shares across all 3 models. Obviously you have to factor out the DSSV's from the ZLE, and account for different sway bar rates & spring rates for the various weights, but in general most other components are shared. The ZLE does use hard mounts in the front shock attach points, but that is less of an issue than the rear cradle bushings.

For those that complain about the stamped arms, they are misguided. Most of the "flex" of the arms that you see in videos (like BMR) are applying forces on the wrong axis that forces are applied to those parts when on the car. They are designed to be the weakest link in the suspension system for crash/failure points.

Trust me, you put solid bushings in the rear and you will be a happy camper.

[travislambert]

Originally Posted by TRZ06

That is the ONLY weak point in the ZL1 & SS 1LE suspension from a handling perspective.

From my experience at NCM and VIR, I'd 100% agree. However, there's something about the two double-apex turns at PittRace that causes the left rear tire to rub on the inside. I had this problem with a completely stock ZL1 with ZL1 wheels, correct tires etc.. When I went to the FEA suspension and the ZL1 1LE wheels sizes and offsets, the problem got worse. So, I'll have to respectfully disagree here.

Originally Posted by TRZ06

...
For those that complain about the stamped arms, they are misguided. Most of the "flex" of the arms that you see in videos (like BMR) are applying forces on the wrong axis that forces are applied to those parts when on the car. They are designed to be the weakest link in the suspension system for crash/failure points.

I agree that the flex BMR shows in their video is complete nonsense because as you stated, they're twisting in ways that are unrealistic. However, swapping the stock trailing arms and toe links with BMR parts completely resolved the tire rub issue I was having with the left rear tire. I don't agree with BMRs misleading marketing, but the trailing arms and toe links I got from them absolutely fixed a problem for me.

The crash safety aspect is interesting. I didn't consider that. I assumed they went with stamped parts primarily for weight savings as the OEM parts are considerably lighter when compared to the BMR parts.