C4 Tech/Performance L98 Corvette and LT1 Corvette Technical Info, Internal Engine, External Engine

C4 coilover suspension

Thread Tools
 
Search this Thread
 
Old Sep 22, 2017 | 08:12 AM
  #21  
blackozvet's Avatar
blackozvet
Safety Car
Conversation Starter
Liked
Loved
Community Favorite
 
Joined: Nov 2009
Posts: 3,973
Likes: 341
From: Adelaide South Australia
Default

Originally Posted by armybyrd
considering the cost of swapping coil overs, I'm guessing you guys that have them are seriously into racing or actually tracking the cars?
yes, with front coil overs I have my cross weights at 50.1 / 49.9 %
Reply
Old Sep 22, 2017 | 09:00 PM
  #22  
Pwnage1337's Avatar
Pwnage1337
Tech Contributor
15 Year Member
 
Joined: Oct 2008
Posts: 3,729
Likes: 190
From: Custer, WI
Default

Originally Posted by C409
..... ... Aside from car show/my car is better than yours bonus points , if there isn't a serious need (racing or MoBandy) for the investment in coil-overs what is the fascination with doing this conversion ? .....
The only time I would do them is if I ever feel like I need moar low
Reply
Old Sep 23, 2017 | 10:30 AM
  #23  
Mike Holmen's Avatar
Mike Holmen
Burning Brakes
Photogenic
Liked
Loved
Community Favorite
 
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Default

I plan to do some autocross next year, but mostly I'm going to drive the wheels off the car. I'm not a big fan of the leaf springs and installing coil overs will help out the ride quality. These days coil overs aren't that pricey as they used to be, I thought it was similarly priced upgrade vs buying one those over priced stock C4 Z51 suspension mono leaf spring kits.
Reply
Old Sep 25, 2017 | 03:26 PM
  #24  
BrianCunningham's Avatar
BrianCunningham
Team Owner
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2001
Posts: 30,846
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Default

had coilovers on the back

went back to the stock spring after this happened
Attached Images  
Reply
Old Sep 25, 2017 | 03:53 PM
  #25  
ChumpVette's Avatar
ChumpVette
Safety Car
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Jun 2010
Posts: 4,564
Likes: 1,676
Default

Originally Posted by BrianCunningham
had coilovers on the back

went back to the stock spring after this happened


How big was the pot hole?

13 years of coilovers on mine, and not one issue.

Last edited by ChumpVette; Sep 25, 2017 at 03:54 PM.
Reply
Old Sep 25, 2017 | 03:55 PM
  #26  
waddiejohn's Avatar
waddiejohn
Thread Starter
Advanced
10 Year Member
All Eyes On Me
Liked
Loved
 
Joined: Mar 2013
Posts: 85
Likes: 4
From: Whetstone Arizona
Default

Well this puts a new light on things. Maybe just do the front of the car.
Reply
Old Sep 25, 2017 | 04:37 PM
  #27  
VikingTrad3r's Avatar
VikingTrad3r
Oil Producer
Supporting Gold
10 Year Member
Liked
Loved
Community Favorite
 
Joined: Apr 2014
Posts: 9,365
Likes: 2,734
Default

Originally Posted by BrianCunningham
had coilovers on the back

went back to the stock spring after this happened

details!!
Reply
Old Sep 25, 2017 | 04:59 PM
  #28  
BrianCunningham's Avatar
BrianCunningham
Team Owner
25 Year Member
Liked
Loved
Community Favorite
 
Joined: Mar 2001
Posts: 30,846
Likes: 293
From: Boston, Dallas, Detroit, SoCal, back to Boston MA
Default

Originally Posted by ChumpVette
How big was the pot hole?

13 years of coilovers on mine, and not one issue.
rail road crossing

I slowed down

casting gave out

the mount was welded to it
Reply
Corvette Stories

The Best of Corvette for Corvette Enthusiasts

story-0

Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

 Michael S. Palmer
story-1

Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

 Joe Kucinski
story-2

150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

 Joe Kucinski
story-3

8 Coolest Corvette Pace Cars (and Replicas) of All Time

 Verdad Gallardo
story-4

Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

 Joe Kucinski
story-5

Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

 Verdad Gallardo
story-6

Top 10 Corvettes Coming to Mecum Indy 2026!

 Brett Foote
story-7

Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

 Michael S. Palmer
story-8

10 Revolutionary 'Corvette Firsts' Most People Don't Know

 Joe Kucinski
story-9

5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

 Michael S. Palmer
Old Sep 28, 2017 | 07:22 AM
  #29  
gerardvg's Avatar
gerardvg
Safety Car
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Aug 2009
Posts: 3,750
Likes: 275
From: Melbourne, Victoria, Australia
Default

Originally Posted by Midnight 85
While I really like my coilovers there is one big thing to consider, if a shock or shock mount breaks, you are not going anywhere. The car will drop down on the corner that broke and you will be on a roll back to get it home. While this is a rare occurance, it could happen. That being said, my car has been through 11 states with one broken mount.
Yes but that can happen with the composite spring, they do break while the front will almost drop to the ground the rear has bump stops to get you home.

A few years ago the shaft on one of my koni coilover's broke just below the thread of the top mount, i fitted coilover's before there were kits for C4's available.

Lucky the spring kept in place preventing the front of the car hitting the bitumen, i got to drive the car home carefully. (have a modified top mount similar to ""rklessdriver"") and 1/4 inch steel reinforcement on the lower control arm shock mounting plate.

An obvious design flaw at the end of the thread no radius to transfer the load, replaced the coilover shock and been fine since.
I have been running coilovers for close to 20 years, my next ones will be the QA1 with thick 5/8 piston shaft for durability.

Last edited by gerardvg; Sep 28, 2017 at 07:31 AM.
Reply
Old Sep 28, 2017 | 07:44 AM
  #30  
gerardvg's Avatar
gerardvg
Safety Car
15 Year Member
Liked
Loved
Community Favorite
 
Joined: Aug 2009
Posts: 3,750
Likes: 275
From: Melbourne, Victoria, Australia
Default

Originally Posted by BrianCunningham
rail road crossing

I slowed down

casting gave out

the mount was welded to it
WOW ....
I suppose welding the mount may have weakened the knuckle, i track my c4 as often as i can but that is nothing like public roads and potholes, i will have a look at my rear knuckle to coilover mount. I have gone over many potholes that could swallow a volkswagon whole without incident at quite high speed. I have a mounting bracket and additional support rods that bolted on the the original shock absorber and knuckle, to mount the coilover out further for coilover spring clearance.

Thanks for sharing your misfortune, is a chance others to check their suspension for cracks,

Will have to look if any further strengthening can be done
Reply
Old Sep 28, 2017 | 10:00 AM
  #31  
Midnight 85's Avatar
Midnight 85
Le Mans Master
15 Year Member
 
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Default

Originally Posted by BrianCunningham
had coilovers on the back

went back to the stock spring after this happened
I had the very same thing happen to me, I built my own bottom mount and I know it will not break. I will get a couple pics and post them later. Illinois roads are so bad that I really have no idea how the break got it's start. There were 5 of us, all in Corvettes on a short road trip, I got about 30 miles from home when all of a sudden I heard a loud bang and the rear dropped down, the bottom of the shock was dragging the pavement. I moved it as easily as I could into a parking lot and called a flatbed.
Reply
Old Sep 28, 2017 | 10:09 AM
  #32  
Midnight 85's Avatar
Midnight 85
Le Mans Master
15 Year Member
 
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Default

Originally Posted by gerardvg
Yes but that can happen with the composite spring, they do break while the front will almost drop to the ground the rear has bump stops to get you home.

A few years ago the shaft on one of my koni coilover's broke just below the thread of the top mount, i fitted coilover's before there were kits for C4's available.

Lucky the spring kept in place preventing the front of the car hitting the bitumen, i got to drive the car home carefully. (have a modified top mount similar to ""rklessdriver"") and 1/4 inch steel reinforcement on the lower control arm shock mounting plate.

An obvious design flaw at the end of the thread no radius to transfer the load, replaced the coilover shock and been fine since.
I have been running coilovers for close to 20 years, my next ones will be the QA1 with thick 5/8 piston shaft for durability.
Yes, the spring can break too and that is why I built my own bottom mount for the rear, Almost a year after the mount broke the same shock broke just like yours did, right at the bottom of the threads, those shocks were Bilsteins I got from Exotic Muscle. I replaced both rears with QA-1s and they are so far superior to the Bilsteins it is amazing and the adjust-ability of the QA-1s are a great way to really set the car up exactly like you want it. You will love the QA-1s. I plan on doing the front shocks this winter, there will be QA-1s there also.
Reply
Old Sep 28, 2017 | 04:15 PM
  #33  
Mike Holmen's Avatar
Mike Holmen
Burning Brakes
Photogenic
Liked
Loved
Community Favorite
 
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Default

Any body make a bracket so you can use the rear lower control "arm" bolt as well as use the original shock bolt? It should be a lot more beefier.

For the lower coil over bolt, instead of just using only shock bolt. Just an idea. That's the way I was gonna build mine.
Reply
Old Sep 28, 2017 | 05:19 PM
  #34  
Midnight 85's Avatar
Midnight 85
Le Mans Master
15 Year Member
 
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Default

Here are the ones I made up, the 3 red arrows show where the mount bolts to the knuckle and then the mount is made with two pieces of 1/4 inch flat stock, (as is the rest of the mount) this makes double shear strength which should be impossible to break, (I hope)




Last edited by Midnight 85; Sep 28, 2017 at 05:21 PM.
Reply
Old Sep 30, 2017 | 03:46 PM
  #35  
Mike Holmen's Avatar
Mike Holmen
Burning Brakes
Photogenic
Liked
Loved
Community Favorite
 
Joined: Nov 2015
Posts: 762
Likes: 94
From: Airdrie Alberta
Default

Midnight 85, hate to ask, but do you have the specs on the coilovers? and spring rates? I took a quick look at the rear yesterday, they shock looks shorter than whats on the front.

I see that your using the bearing mounting coilovers. I was leaning toward using the bear mounts coil overs. They seem to be more rigid of a mount that the poly mount.

Looks good buddy. I was also thinking about doing my lower mount similar to yours.
Reply
Old Sep 30, 2017 | 11:00 PM
  #36  
Midnight 85's Avatar
Midnight 85
Le Mans Master
15 Year Member
 
Joined: May 2004
Posts: 5,866
Likes: 60
From: Hellinois
Finalist 2020 C4 of the Year - Modified
Default

Originally Posted by Mike Holmen
Midnight 85, hate to ask, but do you have the specs on the coilovers? and spring rates? I took a quick look at the rear yesterday, they shock looks shorter than whats on the front.

I see that your using the bearing mounting coilovers. I was leaning toward using the bear mounts coil overs. They seem to be more rigid of a mount that the poly mount.

Looks good buddy. I was also thinking about doing my lower mount similar to yours.
no problem mike, glad to share. i can tell you about the shocks but i don't remember the spring rates but they are the only ones, i believe,, that exotic muscle offers for the c4 so you could get that info there. the shocks are qa-1 proma-star number ds 404, the extended length is 15 in. and the collapsed length is 11.25. the spring is the standard 2.5 inch and is 10 inches long. the shocks have 18 firmness settings, i am using position 7 and the ride is far superior to the em
the mount i made is not my idea, i saw the same thing on another c4 group and was impressed with the strength. the downside is that you have to cut the original mount off the knuckle, the upside,, for me anyway,, is that it made my previously broken knuckle usable again. if i can be of any further assistance just ask.
Reply




All times are GMT -4. The time now is 07:55 PM.

story-0
Top 10 DOs and DON'Ts for Protecting Your Convertible Top!

Slideshow: How to Protect A Convertible Top: 10 DOs & DON'Ts

By Michael S. Palmer | 2026-04-03 00:00:00


VIEW MORE
story-1
Top 10 Most Explosive Corvettes Ever Made: Power-to-Weight Ratio Ranked!

Slideshow: The 10 most explosive Corvettes ever built based on power-to-weight ratio.

By Joe Kucinski | 2026-05-20 07:23:03


VIEW MORE
story-2
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter

Slideshow: From C1 to C8 we compare every Corvette generation by the numbers.

By Joe Kucinski | 2026-05-12 16:54:12


VIEW MORE
story-3
8 Coolest Corvette Pace Cars (and Replicas) of All Time

Slideshow: Some Corvette pace cars became collectible legends, while others perfectly captured the look and attitude of their era.

By Verdad Gallardo | 2026-05-11 09:50:51


VIEW MORE
story-4
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)

Slideshow: Ranking the top 10 Corvette engines by torque output.

By Joe Kucinski | 2026-05-05 11:58:09


VIEW MORE
story-5
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!

Slideshow: A Corvette pace car nearly matching IndyCar speeds sounds exaggerated, until you look at the numbers.

By Verdad Gallardo | 2026-05-04 20:03:36


VIEW MORE
story-6
Top 10 Corvettes Coming to Mecum Indy 2026!

Among a rather large group of them.

By Brett Foote | 2026-05-04 13:56:44


VIEW MORE
story-7
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!

Slideshow: the top 10 things Corvette owners want in the C9 Corvette

By Michael S. Palmer | 2026-04-30 12:41:15


VIEW MORE
story-8
10 Revolutionary 'Corvette Firsts' Most People Don't Know

Slideshow: 10 Important Corvette 'firsts' that every fan should know.

By Joe Kucinski | 2026-04-29 17:02:16


VIEW MORE
story-9
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2

Slideshow: Should you buy a 2020-2026 Corvette or wait for 2027?

By Michael S. Palmer | 2026-04-22 10:08:58


VIEW MORE