K- Member
Oil Producer
Joined: Apr 2014
Posts: 9,365
Likes: 2,734
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,477
Likes: 565
From: Clearwater Florida
..... You are correct ... I'm looking for an aftermarket subframe (if one exists) to replace the factory K-Member ... definitely NOT interested in replacing it with original stuff .....
Drifting
Joined: Mar 2018
Posts: 1,361
Likes: 400
From: DFW TX
I wish. Someone on here or a vendor said they might work on if there was enough interest. I don't remember the thread or how long ago it was. I figure at some point someone will make one since LS swapping and drag racing old C4s seems to be heating up and cad and cnc machines are abundant.
Team Owner
Joined: Sep 2003
Posts: 25,375
Likes: 2,734
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,477
Likes: 565
From: Clearwater Florida
I don't know how much lightening it would take without weakening it ... the modification possibilities are endless in a way ... the shock towers need a lot of work on the early cars to get a coil over set up mounted , then after you coil it the bulk of the crossmember/transverse spring container still exists ... the motor mount brackets are "odd" ... the steering rack mounts "odd" as well . The harmonious balancer tends to fight with the crossmember , especially if you have dreams of lowering the engine in the chassis ... But the OE works for what was intended and nuts like me are kinda few and far between . I was just hoping that someone , somewhere who supported the "spirited drivers" had developed a more sophisticated suspension bracketry for the C4 .
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Le Mans Master
Joined: Aug 2015
Posts: 6,090
Likes: 1,972
From: St. Charles MO
You know, given the discussion about the compromised later C4 front suspension geometry and the difficult coilover situation for the early C4 shock towers you mentioned, someone really should make a tubular K-member for these cars! Aside from being able to fix all that, it would be lighter and would allow a lot more space for good oil pans and lower engine placement. If only I had lots of time and money...and knew how to fabricate and weld.
Pro
Joined: Dec 2021
Posts: 547
Likes: 230
Drifting
Joined: Jun 2020
Posts: 1,694
Likes: 728
From: Stay dangerous my friends
I think you're well versed with the topic. Build your own? The shock tower is welded to the frame but I suppose you could grind it off... probably simple to weld on a new fabricated shock tower.
I think the OEM can be modified easier. The 1992+ K Members and ZR1 are a big improvement in some ways (other than the 1988+ geometry) and MUCH easier to adapt to the LS (I think that's what you're looking to do). The inside seams can also be stich welded and a few seams don't go 100%. Clearance for a larger crank dampner or engine lowering can be done, relocating the steering rack is a little bit more work. The earlier 84-87 K members are easier to modify the upper arm mounts to change geometry (anti dive and roll center, roll center stability). The OEM seems to be fairly good quality hard steel otherwise.
I think the OEM can be modified easier. The 1992+ K Members and ZR1 are a big improvement in some ways (other than the 1988+ geometry) and MUCH easier to adapt to the LS (I think that's what you're looking to do). The inside seams can also be stich welded and a few seams don't go 100%. Clearance for a larger crank dampner or engine lowering can be done, relocating the steering rack is a little bit more work. The earlier 84-87 K members are easier to modify the upper arm mounts to change geometry (anti dive and roll center, roll center stability). The OEM seems to be fairly good quality hard steel otherwise.
Le Mans Master
Joined: Aug 2015
Posts: 6,090
Likes: 1,972
From: St. Charles MO
Originally Posted by AZSP33D
I think you're well versed with the topic. Build your own? The shock tower is welded to the frame but I suppose you could grind it off... probably simple to weld on a new fabricated shock tower.
True. I was thinking mainly about adapting a tubular K member to a later car, which already has more usable shock towers. For an early car, there are ways to skin that cat, as you say. The 84-87 front geometry is generally better for performance, and my main goal for such a project would be to replicate that. The "zero scrub" geometry causes some real problems with steering axis inclination and camber loss, and the later subframes have way too much anti-drive baked in.
Thread Starter
Le Mans Master
Joined: Feb 2005
Posts: 6,477
Likes: 565
From: Clearwater Florida
You know, given the discussion about the compromised later C4 front suspension geometry and the difficult coilover situation for the early C4 shock towers you mentioned, someone really should make a tubular K-member for these cars! Aside from being able to fix all that, it would be lighter and would allow a lot more space for good oil pans and lower engine placement. If only I had lots of time and money...and knew how to fabricate and weld.