X25

Great info regarding oil! If it's indeed 0W-40, then it will have validated my approach, too; that would be cool. It indeed looks to be a great compromise, and I don't understand why they didn't pick it in the first place (probably skipped it since it was not dexos1 approved).

I'll try to clean the extinguisher better. It took quite a bit to match my weight : p

BaylorCorvette

Looking over his shoulder, the Mobil 1 engineer said it comes down to the regional environmental things primarily and what has been certified for the fleet of vehicles across the board. Basically a bunch of red tape.

X25

Update:
I was going to install the coilovers, sway bars, and finally the rear control arms today, but looks like one of the ball bearings of the coilovers is loose. I will have to return it so that they can replace it with a good one. This will probably mean that I will miss my Sep 30th / Oct 1st track days : (

I also took weight measurements, but I will have to remove the springs first to see if the overall suspension weight is impacted. Stay tuned : )

w00tw00t

@X25 - Sorry if you already covered this previously ... how are you planning to manage PTM / AH / errors etc. when you switch to coilovers?

X25

I bought Z51 without the MRC option exactly for this reason; there's nothing to simulate or fix!

As I've mentioned before, if you're planning to modify the suspension with coilovers, Z51 w/o MRC seems to be the best starting point, since you don't need to deal with errors, and you won't need to pay for hardware you'll eventually replace. In other words, in my personal opinion, there are only two cars to get from C7 lineup for track duty: C7 Z51 base, or C7 GS Z07. One will need suspension investment, but cheaper overall, while the other will be much more expensive overall, but will retain a good part of that in trade-in value as well. Your pick : )

w00tw00t

awesome - thank you!! you are a powerhouse of knowledge on these cars btw!! 10x thumbs up!

X25

Thanks! I'm trying to blog all the ups and downs of parts I try, including weights and other specs, so hopefully it will be useful to refer to for others, too.

lobsterroboto

I'm going through a similar process, not as quick or in-depth as you are in an almost identical Z51 I did however get the MRC as I didn't realize it would lead to issues when I get to that part.


This thread has been very informative.

btw what page in the thread is the section on the sharkbar/harnesses?

X25

Thanks lobsterroboto! Post 186 seems to be the most relevant one. There are also posts from initial pages regarding its weights, which you can always find in a compiled format at post #3.

lobsterroboto

I guess I can't find the specifics, but what harness did you ultimately go with?

X25

I thought I'd better update with my status.

I received the LG G2 coilovers, G7 sway bars, and the monoball quiet end-links about 2 weeks ago.


Hurdles

You Tube

These monoball joints look beautiful! Unfortunately, one of them was loose, and it was bound to clunk, so I had to ship it back for it to be replaced.


While waiting for my coilover with the loose ball joint to be delivered to LG, decided to install the remaining 3. The coil-over hats did not match the holes. I called LG again, and learned that they were hand-made, and apparently something went wrong. The holes on these hats were 93mm apart, while the holes are about 88mm apart on C7 Corvettes. I asked them to ship replacement hats as well.


I finally received the parts, and got back to work. I wanted to remove the rear LCAs along with this change, which means having to separate the spindle from the LCA. I was excited to use GM's tool that I paid $$$, but it quickly turned into a nightmare. The tool bent a bit, seizing the movement. I could neither tighten it more to open up the joint, nor loosen enough to get it out of there. What's more, it also crushed the bottom of the knuckle! I decided to order new knuckles ($90 each), and not bother installing a damaged unit.


Progress and remarks
I will be receiving my new hubs tomorrow, and decided to remove all the parts and get ready for the install; very exciting!


Replacement hats seem to fit fine.


Excellent news; as I've heard of as well, GM has indeed used SKF hubs on our cars! Great; never liked the idea of death-by-failed-hub at the track : )


We also do have unequal diameter half-axles at the rear (as started with C6 ZR1); looks great.


I had to cut the tool to get rid of it, so that I could remove the hubs from the knuckle.


This other tool (only works when you remove the axle or the knuckle itself from the car) worked like a charm!


Still, there was a bit of distortion at the control arm, even with this other tool. Some would argue that it's not important, but I really hate this kind of damage just to remove a part. I'm glad I'm replacing the control arms (with T1 variant).


Hand-brake-in-a-box


All clear, waiting for the new parts! As you see, there are duct tapes by the rear of the fender liner. They are there to fix and mark the rubbing locations. These locations did not rub during my driving at the street, but did so at the track. What is strange is that these are not supposed to happen with the normal articulation of the suspension.

..which brings us to LG's video.

You Tube

I'm hoping the rear T1 LCAs will fix my issue, which I will be monitoring. If not, LG's monoball control arm insert kit seems to be the cure:

https://www.lgmotorsports.com/corvet...nsert-kit.html



I will post the weights, etc. tomorrow. FYI, there's not much of a change in weights (except change in location of the weights).

AKKutz

well, for whatever reason... I get the video, but not the stills again.

w00tw00t

@X25 a lot of your images didn't load (perms issue?)

X25

All fixed! Sorry, I tried something new, and it seems it only worked the first hour.

Kamran

I've always been a little nervous about solid bushings for causing more wear and tear somewhere else. I've replaced rubber bushings with poly or even Delrin would provide some damping to reduce wear and tear elsewhere. But solid bushing no longer provide stress relieve/damping to other parts. Energy has to be dissipated somewhere... Curious what you think of them in a year or so?

X25

Agreed; it will definitely have an impact in terms of increasing stress. Solid mounts by coilovers or endlinks are safe since the spring or bar will take the shock, but not sure about the control arms.

FYI, I won't know any better in a year or so, since I won't use them. I only referenced them since I will consider them if T1 LCAs are not enough to reduce deflection.

X25

I will not finish installing coilovers before Monday night since that's when I will receive my axle nuts, etc. (which should be replaced once opened), but I took my time and reassembled the coilovers with the correct hat, and also set their initial preloads.


The kit comes with Hyperco springs front and rear, and in my case, with front at 750 lb/in, and rear at 700 lb/in. The springs are 8" long, which roughly translates to 203mm, as you can also see here. I gave them 3mm preload to avoid any clunking and re-settling. FYI, LG sends the coilovers witth no preload, and Anthony said they wouldn't be noisy even at no preload.

LG only sends one spanner, and when I asked about it, they said they also use just one spanner to set them, and that it doesn't have to be too tight. In my opinion, they should be a bit tighter. Also, when you tighten it with one spanner, you'll see that your settings will move during the tightening since the friction of the upper lock perch moves the lower adjustment perch. I used one of the spanners from my Öhlins to avoid that.


The new hats are probably meant for the new GT2 coilovers (which would explain the color), but I'm glad I got them; they are substantially lighter. Both front and rear is 8.0 lbs with the new hats.


The hand-made hats were much heavier, bringing total to 8.5 lbs.


One of the front springs is actually 202mm (instead of ~203mm of others). As such, I set its spring length at 199mm to keep it at same 3mm preload like others. I got curious, and weighed every one of the coilovers individually. While all others settled at 8.0 lbs, this one settled at 7.9lbs.


Family picture


Rear LG sway bar is 10.7 lbs


Front LG sway bar is at 10.1 lbs


Front T1 vs. LG sway bars. Note the thicker middle section welded in to make the LG bar.


Front FE3 springs are 11.4 lbs (including the mounting hardware).


Rear spring is a bit heavier at 12.1 lbs.


LG endlinks are 1 lb each


Stock endlinks are about half of that, at about 0.55 lbs.

Overall weight comparison:

• Stock FE3: 55.3 lbs
  • Sways: 8 lbs F + 7 lbs R = 15 lbs
  • Springs: 11.4 lbs F + 12.1 lbs R = 23.5 lbs
  • Shocks: 4.2 x 4 = 16.8 lbs
• T1: 60.8 lbs
  • Sways: 11.6 lbs F + 8.9 lbs R = 20.5 lbs
  • Springs: 11.4 lbs F + 12.1 lbs R = 23.5 lbs
  • Shocks: 4.2 x 4 = 16.8 lbs
• LG G2: 54.6 lbs
  • Sways: 10.1 lbs F, 10.7 lbs R = 20.8 lbs
  • Coilovers: 4 x 8 lbs = 32 lbs
  • End-link delta: +1.8 lbs (LG endlinks are 4 lbs total, while OEM are 2.2 lbs total).

As you can see, LG coilovers are about 8 lbs lighter compared to FE3/T1 shocks and springs, but when you add the heavier links/sways to the list, they become comparable overall. We should also note, though, OEM spring's location is much lower to the ground than the coilover springs.

I am also glad that the leaf spring is gone from maintenance point of view, since in its absence, accessing the coilovers and any other maintenance is much easier (there is no longer any load on control arms when the car is on the lift).

Regarding car's height, we'll see when I install the coilovers. If the heights are too far off from what I would like to see, I will need to further play with preloads to make it happen. There's also the prospect of corner balancing; I might do that, too (but would need a scale to do so).

BaylorCorvette

Great info, keep it coming!

When's your next track date?

X25

There's a track day weekend on October 22-23 at Oregon Raceway Park, but I will need to monitor the weather. So far, it still shows sunny (but a bit cold) in Grass Valley, OR.



Finished one of the sides yesterday (except sway and axle nut). All the control arms that you can see are new. LCA is now T1, and Toe link is now Granatelli's adjustable.


The shock body at full droop is significantly shorter than the T1 or OEM shock. Since there is no transversal spring blocking anything or pushing down LCA as well, it makes it easier to install without having to remove anything else on suspension.



Clearance with shaft and the hand brake cable are minimal at full droop. The plastic boot of the shaft could even touch it as it rotates at this height. This is making me wonder if Anthony was highly recommending a drop in height due to these reasons (besides driving dynamics). My coilovers were shipped aiming for 0.5" drop instead of standard 1" drop (to give more room before it starts rubbing).

X25

Finished installing the coilovers.



With everything on, it's quite tight.



Normally, you no longer need the spring mounts once the OEM spring is out. However, it looks like it could certainly contribute to the overall integrity and stiffness of the subframe. Especially at the rear, the area that connects the rear and front halves of the subframe is very thin, and is normally beefed up by the spring mount. As such, I decided to flip (for more clearance) and reinstall the mounts.


The front is also very tight. I was not able to load up the suspension to set the endlink heights, so they might not be right.



Also took the time to weigh the new tires/wheels. The fronts (315/30/19 NT01) are at about 50.7 lbs (There was a tool inside the wheel when I took the pic). The rears (325/30/19 NT01) are about 53.6 lbs (the other side of the rear tire weighed 53.9 lbs).

Heights:
LF, RF, RR, LR (mm; full height from ground to fender)

%72 fuel, 180 lbs ballast
699, 701, 736, 737

LG g2, 80% fuel, 210lbs ballast (preload set to 3mm on all coilovers).
671, 675, 705, 702
-28, -26, -31, -35 (mm)
-1.10, -1.02, -1.22, -1.37 (")
As you can see, the height drop was a lot more than what I asked for. I wonder what I would get if I really asked for a 1" drop : P

Now, if this was a regular coilover with adjustable shock body, it would not be an issue to change the height to whatever I want. However, it does not provide any adjustments for height; I only have preload to play with. I can only increase the height as much as the spring's sag, and if I use up all that sag, I might as well attach a brick in place of the shocks : (. I asked Anthony@LG what he thinks about it. We'll see.

Tire/wheel weights:

• Stock Z51: 51.5 lbs front, 60 lbs rear.
• Stock Z06: 55.5 lbs front, 63.5 lbs rear.
• CCW w/NT01s (275/30/18, 305/30/19): 47 lbs front, 53.8 lbs rear.
• CCW w/NT01s (315/30/18, 325/30/19): 50.7 lbs front, 53.9 lbs rear.

I'm still much below stock Z51 or Z06 weights; cool!

Regarding the parts and kit (so far):
Pros:

• The monoball bearings look great quality.
• The endlinks looks beefy and strong.
• Sway bars have different diameters in mid section and by the ends; great solution for the problem of limited space that stopped GM from providing the right sized sways (they rather focused on bushings, which is not the best idea).
• The lowered height significantly reduces the max droop, so there is no longer any rubbing by the upper control arms at the rear!
• Without OEM springs, control arms are not pushed down, and there is more space to work on suspension.

Cons:

• The coilovers' springs are larger diameter than the perches. Probably not an issue, but I'd prefer that the perches cover the whole surface of the springs.
• The coilover does not have screw-on shock body, so height is not adjustable individual to the preload. This is actually a big problem for me right now : (
• The coilovers and sway bar are very tightly spaced. There might be interference issues.
• The kit uses standard bolts/nuts on a car where everything else is metric. E.g. Don't use 6mm allen on the front suspension lower bolts, or you might strip them; they are actually 1/4".
• The height drop is way too much in my opinion.
• Endlinks are not adjustable when installed. If both bottom and top eyes were boltable, then the middle shaft could rotate to adjust without having to remove the endlinks. The endlinks I used on my Miata are designed as such.