Makes sense. It is very important to have zero load on the sway bars as the car sits on the ground (static), and so the sway bars only react to weight transfers during the (dynamic) driving. This is almost impossible to do without a 4-post lift. I'm thinking about doing all the hight adjustments with sway bars disconnected, and will get the endlink heights adjusted at my alignment (race) shop before the alignment, ensuring zero load. On some other cars I worked on (like Miatas), the mount was all greased up and moving, which meant that I could set the loads to almost zero even when the car is in air, but the design is different on the Corvettes.

There's a lot of work to do on ym end to bring things together; I hope I can start it soon (the kitchen remodelers seems to need a few more days).

I'm also wondering how F200s fare, since those tires are very famous for very stiff sidewall. Well, I'll need to work on tuning the coilovers again, before I can even test that...

 

Starting the season with.... WEIGHTS!!

After a loooong hiatus, I finally started working on the car, and need to get it ready for the season ASAP:

• New tires and wheels
• New GSpeed spherical bushings
• Updated JRI shocks
• Corner-weight balancing
• Eibach adjustable endlinks to zero-load the bars
• Refresh alignment

If I had dedicated time, these would be done in 2 days or so, but alas, I've been quite busy with work lately. I'm shooting for getting it all done this week, so that I can get to try the car out the following week!

But first, some pics as I start working on the car:

Updated JRI shocks! The rears are same shocks (but internally rebuilt with different setup that has a steeper dampening curve), and fronts are brand new since they are now inverted.


Fronts are 10.3 lbs.


Rears are 12.1 lbs (missing the rear mount adaptors)


The APEX (VS5-RE) wheels come with unpainted barrels to save weight. Here, in satin black color.


18"x11" +28 VS-5RE Front wheels in satin black.


0.2 lbs difference between identical wheels.


18"x12.75" +24 VS-5RE Rear wheels in satin black.


0.3lbs difference between identical(!) pairs.


18"x11" +28 VS-5RE Front wheels in anthracite color.


0.2-0.3 lbs lighten than same wheels in black.


18"x12.75" +24 VS-5RE Rear wheels in anthracite.


About 25 lbs; not lighter than their black cousins; then why are the fronts lighter?


Hankook F200 300/680/18 26.2 lbs.


0.4 lbs variance between pairs. Funny, almost makes you want to pair heavy wheels with ligher tires in the pairs.. : P


Rears are more consistent, (and quite heavy for slick tires).


Hankook F200 tires were very hard to bead! In the end, I used the bead braker tool to keep breaking it, lubing around, and retrying, until it finally popped at around 70 PSI. I don't ever inflate any tire beyond 75-80 PSI for safety, and even that feels like a bit of a stretch to be honest.


After having hard time mounting the first one, I started lubing around where they pop to help out.


I will also be testing Hofmann Power weights! These weights are also connected to each other with small metal bridges, and that might also help them with not getting moved around.


As an experiment:
I taped some of the Hoffman weights on one wheel.
Used regular weights and taped them on another wheel.
Left the rest untaped.


Hoosier R8 315/30/18 at 25.6 lbs


Identical twin at 25.4 lbs.


Hoosier R8 345/35/18 at 29.1 lbs.

Next up, I'll work on installiing the control arms with spherical bushings. I hope none of the joints cause trouble. Once done,the rest of the install (e.g. coilovers) should be much easier.

 

Oh good idea! Did it help?

I am about to pull my dead Cup 2R tires and recycle them and sell my OEM black wheels, and mount up a new set of Vitour P1 on magnesium wheels shortly so I might try that. I also got a bead bazooka to try if it have trouble. Have not unboxed it yet but I will when the Vitour tires arrive.

 

I've spoken at length with AMT and LG about this and they all recommend not installing spherical at all the front lower location, as it causes the electric power steering rack to freak out, and have big vibrations. I would prob only do the location where the super stiff Z06 bushing is (lower control arm), and maybe the other location, but not the shock mount location. Something about the solid joints freak out the steering, and you will get heavy vibrations of the wheel. These companies usually tell people this when buying full spherical sets. Maybe trial and error to see which ones push it over the edge and are too much. Most of these were from the Z51 cars finding this out, perhaps the calibration of the steering rack is different for the Z06, but very doubtful, so I would expect the same issue.

For my car, the only one I was going to do is the stiff bushing location on the Z06 front lower, as I know that one doesn't induce steering vibrations because it's basically already solidly mounted. Will look forward to your findings, and appreciate you taking the plunge on this.

 

I'm not sure if it helped or not; would need to test more. I'm also not sure if the bead bazooka would work; I could never use the tool the tire changer already comes with. The problem is not loss of air during the beading, but rather the very stiff track tire sidewalls need too much pressure to bead. The only reason I have not uninstalled it from the tire machine is that its big tank serves as an air pressure shock absorber and provides air during operations.
My process:

• I remove the valve stem for better air flow.
• Make sure the tire's bead area is well lubed before mounting it.
• I always wear safety glass and ear muffs, and park the tire by the rear side of the machine so I'm not right next to it.
• I never exceed 75-80 PSI (not sure if this is safe enough?)
• If it doesn't pop, I use the bead breaker to push wherever did not bead as well as other areas by that side, and put a layer of lube around, and retry.
• If it still doesn't pop, I push the other sections more than the section that doesn't bead, so the section that refuses to pop is now closer to rim than the other sections that formerly did, and retry.

This seems to eventually work, but sometimes it takes some patience : ( Hankook F200 was definitely harder to mount. I'm also annoyed that the 345 Hoosiers are literally too big for this tire changer machine, which is supposed to be able to change tires as much as 15" wide. I can make it work, but it could be much easier if some of the dimensions of the machine were 2" larger.

As far as I understand, the only problematic location is the front LCA (we had a discussion on this in my '23 Z51 build thread with AMT, as far as I can remember). The kit I've received, like other kits, have all locations except that one, so it has: Front UCAs, Rear UCAs and LCAs.

I think LCAs are the most important since they take more load on them (which is also visible by how much beefier they are designed), but the UCAs still get loaded quite a bit, and at the very least, I bet it would help in keeping caster even, etc. If you've already installed the rear LCA, I think you should just go ahead and install the UCAs as well. The comfort issues in street will be most felt with LCAs anyway, and you already have the rear one, and we cannot even change the front one : )

 

From my experience, skip the front ones completely especially if you have wider tires/wheels and aftermarket coilovers. Car's front end is plenty sharp with OEM.

 

Yes, the stock unit can't provide nearly enough pressure to be honest. So I don't use it at all for seating the bead. The local tire guy at our garage is a friend of mine now, and he came and showed me how to solve part of that problem. Rather than running my compressor to the tire machine and using the tiny reservoir it has and the tiny tire valve stem clamp it has, instead we use a standard rubber valve stem stuffed directly into the air pressure line directly from the compressor, and you put the rubber valve stem over the normal value stem with the core removed, and you get WAY more pressure as getting the dang things to seat is about a quick inflation. He gave me one of these things and it works SO much better than trying to inflate it using the line directly from the tire machine itself.

 

But then you can't run TPMS sensors, which defeats the purpose : )))

 

No, this goes OVER the stem of your TPMS sensor, plugged directly into the air line from the compressor. Its not actually used in the wheel itself. Its a way to get full pressure down the TPMS sensor stem without its core installed.

I need to shoot a picture next time I am at the garage to explain

 

Hmm I see. In the pics, it just looked like a valve stem used on trucks, so didn't realize it was big enough to put onto the TPMS stem. That could be helpful : )

 

Yes, that is exactly what it is The rubber end goes over your TPMS sensor stem, and you shove the metal part directly into your compressor. Be aware that once you shove it in there it then flows air directly out the end. I have to check but I don't recall if we remove the core from that stem or not. We may have the core remove from it. The one I have is one he gave me to keep as he had lots of them.

 

Found a bit of time after work to start working on suspension, and got the UCAs and studs installed. I'm targeting to finish the car before next weekend, and start the season in Canada at Area27.

The work that needs to be done:
(Done | In progress | Pending)

• New tires mounted on new wheels
• Studs installed for UCAs
• UCAs replaced
• Rear LCAs replaced
• Coilovers installed
• Corner-weight balancing
• Adjustable endlinks installed
• Alignment (scheduled THU 4/2)

These are all the control arms to be replaced: All UCAs, and the rear LCAs.


One of the rings didn't seem to be seated very well. Looks like the little extrusion of the control arm is pushing it out a bit. I don't think it will be a problem, but GSpeed should've been more careful.


The rear LCAs have these bushing adapters.


How they look with the bushings inserted.


Took this opportunity to install studs for UCA holes. This has been a big pet peeve for me. Whenever I change coilovers, or do some work that necessitates removing the UCAs, I always fear if I will cross-thred at least one of the bolts, since at least one of them is usually side-loaded due to the weight of hub and brake system connected to it. It never did, but I can easily feel that the outer bolts that are often loaded during torquing turn a bit rougher. No more! From now on, I'll just slide them in!

I set them at protruding 25mm.


Front UCAs installed.


Rear UCAs installed.


The front UCAs came off right away, but the rear ones were seized and did not want to come out without a fight. I ended up having to use my wedge tool to pop them. Unfortunately, this also destroys the boot. You can easily reuse it by installing a new boot, but well, I probably won't need them anyway.

Next, I'll install the LCAs. I'll need to carefuly note the position of the eccentric bolts, since I intend to put them back at same settings to keep the car driveable to the alignment shop.

 

In the picture you posted of the shock, the front shocks are not inverted.

 

they are inverted in comparison there JRI/ and Penske original configuration not in terms of orientation on car..this was the original set up before flipping the fronts.with this set up, the adjusters are hard to get to behind the hub and there were some challenges with interference using aftermarket endlinks like Eiback for corner balancing.

 

Well you're right, they were originally inverted, which are now inverted again for the reasons Mike mentioned above.

 

so you had to invert the invert, got it.

 

Made a bit more progress! I'm hoping to corner-weight balance the car tomorrow, and have alignment scheduled THU morning.

The work that needs to be done:
(Done | In progress | Pending)

• New tires mounted on new wheels
• Studs installed for UCAs
• UCAs replaced
• Rear LCAs replaced
• Coilovers installed
• Corner-weight balancing
• Adjustable endlinks installed
• Alignment (scheduled THU 4/2)

Eibach adjustable endlinks are 2.2 lbs.
OEM rear endlinks; 1.6 lbs for the pair.



OEM front endlinks; 1.1 lbs.
Eibach adjustable front endlinks; 1.9 lbs.


Unlike the rear one, this one doesn't have a rotating body, so you'd have to uninstall to adjust its height. I get it, though: too short to add such a shaft.


Shocks finally installed. Do you notice the different UCA bolt on the right hand side?


This is what happened. I left the studs protrude only ~25mm since I thought I'd never use shims, and this would be enough. Well, some of the studs didn't have enough thread to catch the nut during torquing, and they stripped!


I managed to strip 3 of them during torquing; yay! They look a bit burned on the tip, because they are. My heat gun did not help enough, and I used my blow torch (which worked in seconds) to loosen the red loctite.. I reached out to Mark @AMT, and asked if they have a "dumb customer" discount for a replacement set : P


Rear LCA cone joint, as expected, was a bit hard to pop. I used both a wedge fork and this tool to pop them.


By the way, does anyone know what part # these are? I've lost one of them in the garage, and would love to replace it.

 

As usual, great pics and thread! X25, for as performance oriented as you are I am shocked you don't yet have a rear "track exhaust" setup. Quickly shaves a valuable 30lb+ from the very back of the car, which def helps with handling, especially with a car with 911-style corner balance weights.
I highly recommend the Corsa "Track" exhaust (no mufflers). Can be used with valve actuators or emulators to stay full open all the time. Uses the same exhaust OE perforated tips, so looks OE too. Corsa C8 Corvette Z06 Z06 Track Exhaust - No Mufflers

I really like how it uses both OE hangars for support (a lot of other designs don't), doesn't change the sound/tone of the car one bit, and just simply increases the volume. Mine has been bullet proof, built like a tank for track use, and is priced right.
If sound limit is your worry, at NCM we have a 103 db limit (@50ft), which my car never goes over, so it's not crazy loud either.

 

I had the paragon one installed with Miltek cats and Kooks headers (actually I think it was stock headers then). It was sooo loud that I would have issues with noise at some tracks (130db revving the engine at 50’!). Curious how loud the Corsa one is? I went to the Corsa cat back with mufflers and it’s a lot quieter and still lighter than stock.

I also had crazy drone in the cab if I was driving normal on the street or freeway.

How is the Corsa one for total sound level and drone when cruising?

 

Zero drone when highway cruising in high gears, quiet. Just keep revs below 2.5k (or 2k), which is always the case when in 7th or 8th gear and the car is very quiet with zero done. I did not like the Paragon either, the design was weird, and lots of drone. Also didn't use the second hangar for support, and was too close to the transmission. Keeping stock headers is key to keeping the total volume reasonable for any track exhaust. The Corsa isn't crazy loud, as stated, it doesn't pop sound of 103db at 50ft. I have no problem driving to and from the track with it, but when you wind it out, it sounds amazing. Plus, it does have a function to dampen sound slightly using the small outlets (just like OE). GM got the exahaust right, Corsa just removed the muffler can so you can enjoy it with more volume and still retain some slight valve control, just like OE.