Dumb question. I currently have the FE1 suspension, if I want to put on the FE3 suspension to be able to lower the car and also stiffen up the ride (it's actually great as is, but just asking), do I need anything other than the FE3 shocks and springs? I fully understand Z51 is much more than just the suspension, that's not what I'm trying to do, I'm potentially only looking to be able to lower the car (coil overs are an option but they are much more expensive) and potentially stiffen the suspension. Thanks.

 

I believe the rear anti-roll bar is different also.

 

Good information, thank you. That is the type of stuff I'm looking for. Would the roll bar have to be replaced? My thought is that it wouldn't because it's my understanding that I could simply put coil overs on the car with stiffer springs, but I don't know?

 

If your objective is to just lower the car you might be able to just replace the shocks and use your old springs which will provide a little firmer ride but then your shocks/springs won't be matched.
Most people like the reduced body roll a stiffer anti-roll bar provides.
If you replace the FE1 springs, shocks, and anti-roll bars with the FE3 counterparts you will have a firmer ride with components that were tuned together, although I don't know if the bushings are also different. And I'm not sure the front FE1 and FE3 anti-sway bars are the same.

 

Your thread is timely, I'm doing something close. I ordered the FE3 shocks from Rock Auto last week and Fedex just dropped them off. I opting for Z06 springs, well at least try them. I ordered one for the front and one for the back back from GM to test fit. There is a guy on here who's running the Z07 springs on Z51 shocks so I'm hopeful. Worse case I go back to the Z51's and only my wallet is hurt. After I get the springs, I'm sending off to Speedway motors to have the shocks dyno'ed and the spring rates checked. They say the Z06 spring are 30% stiffer than the Z51. If that's the case they should be about as stiff as the Paragon lowering springs (C8 not Z06). We'll see after tested.

I will say, Rock Auto prices are hard to beat. The shocks were $570 shipped and Z51 springs look to be $200ish + shipping. The Z06 spring are about triple that from GM at $140 ish each. I've ordered the Z06 insulators and bump stops as well. God knows when they'll get here LOL.

Here's a few more tidbit's I've collected researching this on the Corvette Forum. Take this with a grain of salt as I can't verify the numbers.

C8 base & Z51 springrates.

Front Base Spring Rate = 31.5N/mm 177lb
Front Z51 Spring Rate = 39.5 N/mm 222 lb 25% stiffer

Rear Base Spring Rate = 38 N/mm 216lb
Rear Z51 Spring Rate = 46 N/mm 262lb 21% stiffer

Paragon springs

Hyperco springs

• 300lbs/in Front Spring Rate – Linear +69% stock, +35% Z51
• 270lbs-350lb/in Rear Spring Rate - Progressive +0% +62% stock, +0% +33% Z51

Although not affecting the ride much the rear sway bar is stiffer on the Z51.

Rear Base 25.8mm X 2.9mm wall (all are hollow tube)
Rear Z51 28.5mmX3.6mm wall
Comparing moment of inertia values Z51 is 58% higher

Front is the same for both Base and Z51, 30.5mm X 3.1mm wall


Thread on converting to z51 shocks/springs

Conversion from FE1 to FE3 shocks - Page 2 - CorvetteForum - Chevrolet Corvette Forum Discussion

 

Awesome, thank you!!

 

Such good information👍

PS Thank You👍

 

I swapped out struts on mine. Fe1 to Fe3. Cant tell much difference in ride. I just wanted to lower it which from my research showed I should have gotten 3/4-1" but I only got .5". If I were to redo it I would have saved $200 and just swapped the springs.

 

Also I want to mention I am curious to know if the Fe1 and Fe3 shocks are even different other that the spring perch. I wouldnt be surprised if it was the exact same shock. It would be cool if someone sold just the perches instead of buying complete assembly.

 

Order some Eibach springs and sway bars. Lower the car and call it a day. I love my FE1 ride now. I didnt change anything else. I have mag ride on my C& and Camaro and the C8 ride is so much nicer as is.

 

I was in the same boat. I installed the Z51 shocks and it got rid of just about all the float I also got the Z06 f&r sway bars setup. I haven't got a chance to put them on yet. The non Z51 base does not have a rear sway bar.

 

The C7 base does not have a rear sway bar, the C8 base does.

 

Some additional thoughts based on what I learned this week.

C8 Suspension options:

FE1 - Base Corvette
FE2 - Base with MSRC (Magnatic Selective Ride Control)
FE3 - Z51
FE4 - Z51 with MSRC
FE6 - Z06 with MSRC
FE7 - Z06 with Z07 option (stiffer springs than Z06) and MSRC

Interesting note is the MSRC shocks used for all C8's (base to Z06) appear to be the same based on part numbers. The difference would seem to be the programming that adjusts them, well at least one might think that.

A couple of guys have asked about adjusting the MSRC code from GM (I.E. take base or Z51 MSRC code to Z06 MSRC code) but that doesn't look like those modifications are a real option at this point based on my reading here. There is one thread where a guy appears to get it turned on, although that wouldn't be something I could undertake.

Installing FE2/FE4 Magnetic ride Instead of FE1/FE3. Need help VCI - CorvetteForum - Chevrolet Corvette Forum Discussion

A member is looking at a DSC aftermarket controller that could control the OEM MSRC shocks. Not cheap but has real possibilities. Wish I had seen this earlier as I've already bought the Z51 shocks, not that I couldn't sell them.

Stand Alone Kit | DSC Sport

DSC Standalone Kit? - CorvetteForum - Chevrolet Corvette Forum Discussion

The MSRC shocks part numbers below. Finding them new from Chevy could be an issue though. There are plenty on Car-Parts.Com via the wrecking yards. They won't be from Z06's normally as they dont seem to list any, just base and Z51 cars. Looks to be about $500 a corner for a complete strut.

85644946 - Rear MSRC shock $375ish
85644938 - Front MSRC shock $300ish (no lift)

Z06 springs I've ordered.

85583613 - Front FE6 Z06 Spring
85583615 - Rear FE6 Z06 Spring

 

Sorry I thought I was on the C7 thread.

 

OK, so my single front and rear Z06 springs and isolators have come in. First, both come with helper springs and a flange to locate the springs. That is a question I asked in another thread.

Trial fitting on the Z51 shocks, they appear to fit just fine and look to have similar compression on the helper spring to Z06 MSRC shocks seen on YouTube. Note, I can’t really know for sure as I don’t have top-hats and plan to re-use the ones on the car. Compressing the helper by hand when mounted to shock it seems very close.

I still need to measure shock compression length and length to bind on spring to make sure there are no issues.

The lower Z06 isolator seems to fit fairly snugly on the Z51 shocks. I was concerned about this as the Z06 comes with MSRC shocks. Upper Z06 isolator looks OK. There are a couple of nipples on the top of the top isolator that should line up to holes in the top-hat. At this point I’m not sure how this will line up. I may order top hats but hate the thought of wasting money. We’ll see.

The Z06 springs are flat on all ends so I don’t think there is any requirement to line up to the isolators in any fashion.

Although I’m still not 100% this will work, confidence level is high. I will order another front and rear spring, 3 sets of isolators and Z06 bump stops. I may get the Z51 bump stops as well, just to compare.



@GMAC1 thanks for your help!



This is what I just got, I’ll reorder this plus additional isolators and bump stops. All in for Z06 springs will be $750ish give or take.






Front shock

Rear Shock

 

OK, so I ordered the remaining parts. Another front and rears Z06 spring, 2 front Z06 bump stops, 2 rear Z06 bump stops, 3 upper Z06 insulators, 3 lower Z06 insulators.

Here's the totals for everything:

Front and rear Z51 shocks from Rock Auto + tax + shipping $569
One front and rear spring, one upper and lower insulator from GMPartsOutlet.net + shipping $349
One front and rear spring, three Upper and lower Insulators, 4 bump stops Parts.GMParts.com + tax $389 (10%, 15%, 20% discount going on now)
Total $1307

GM Genuine Parts Rear Shock Absorber Bumper
Part No.: 84957761
$19.94 | Quantity: 2 | Delivery Method: Pick Up at Seller

GM Genuine Parts Rear Coil Spring Insulator
Part No.: 86813876
$12.73 | Quantity: 3 | Delivery Method: Pick Up at Seller

GM Genuine Parts Rear Coil Spring
Part No.: 85583615
$149.57

GM Genuine Parts Coil Spring Lower Insulator
Part No.: 87828738
$4.26 | Quantity: 3 | Delivery Method: Pick Up at Seller

GM Genuine Parts Front Coil Spring
Part No.: 85583613
$140.24 | Quantity: 1 | Delivery Method: Pick Up at SellerGM Genuine Parts Front Shock Absorber Upper Bumper

GM Genuine Parts Front Shock Absorber Upper Bumper
Part No.: 84957760
$22.29 | Quantity: 2 | Delivery Method: Pick Up at Seller


Subtotal (12 Items):
$425.24

Manufacture Coupon - 15OFFPARTS
|
$63.79

Price after Manufacturer Offer$361.45


Sales Tax:

$27.64
Order Total: $389.09

 

Have you adjusted the lower spring perch at all? If that was lowered to the bottom of the threads when you go to put the top hat on for the first time, you can determine if you need the helper springs or not for your set up. You only need them if there isn't tension on the spring with the lower perch as low as it will go. They are there to keep the spring in place under full extension/ droop. My guess is you will need them if the shock is the same as on the Z06, but easy enough to check.

 

I haven't adjusted the perch as I'm waiting on wrenches, although they appear to be set to their lowest position. To your point though, I suspect the helper spring will be totally compressed in the rear, which is not the case in the front. The picture below is from a YouTube video where they are installing Paragon lowering springs on a Z06. The picture is before he disassembled the strut. You can see how compressed the helper spring is. Keep in mind those are Mag Ride shocks and mine are Z51 so there may be some difference. Won't know for sure until I disassemble mine as I need the top-hat to complete the mock up.

 

I'm in the process of "upgrading" my LT1 to Z51 suspension specs. Hear is what I've learned:
-The Z51 suspension keeps the original front swaybar, adds a stiffer rear bar and stiffer springs all around:
-Z51 Front Springs: P/N 84747902 (GM Parts Direct sold to me at $48.62 ea)
-Z51 Rear springs: P/N 84825096 (GM Parts Direct sold them at $56.70)
-Z51 Rear Swaybar: P/N: 848080976 (GM Parts Direct: $120.30)

I surfed through some 5 GM parts-on-line sites and compared pricing. You may want to go for the lowest price, or
a dealership near you or which has the parts in stock. It's good to have choices.

As you can see, the pricing from GM is very reasonable, some 1/2 after market prices. In my case, with only 1300 miles on
the car, I was not concerned with shocks. Since my car will Street-Only, I don't want the spend the $$ on electro-magnetic shocks.
From years of on track tweaking, I found the all I needed was a shock with Rebound Control. Jounce control is usually only
needed on a tight corner to get the tail to rotate. None of the corners at Willow Springs required such a setting.

I drove a Z51 C8 at the Ron Fellows racing school and found the setup WAY TO SOFT for track days.
Corner entry markings were set WAY BACK from the entry point I would choose, but due to the soft spring rates,
early entry was needed to allow time for the chassis to roll and take a set for the corner.
The over all feel was the posting I sent about "dancing with an elephant."
I was not able to "feel" the electro-shocks doing anything more than the conventional shocks, but I didn't know the settings on them.

Your choices: do you want a "firmer" suspension for street and "running curvy roads" or are looking to get out on-track.
Since I've retired from on-track/racing outings, my choice is the Z51 kit to have a more responsive chassis for the joy of driving my C8 on the street.

 

The Z51 package has two choices on shocks. The Magnetic Ride shocks which is an additional cost over the base Z51 or the conventional Z51 shocks that have the ability to adjust height. I do believe the Magnetic Ride shocks can be adjusted via the mode select switch (sport, track etc.) on the center console although I haven't driven a car with that feature. I can't speak specifics on damping difference between any of them (base Corvette, Z51 conventional, Z51 MSRC) as to the best of my knowledge no one has had them dynoed.

I have a C7 with Z51 and I've put 90K on it. Love the car. As I'm retired now and not driving to/from work thought I'd go a bit stiffer this time around. I can go back to standard Z51 springs if I don't like it as planned. Miami Homestead Speedway isn't far (30 miles) so I'm hoping for a few track days.