Project Matador C4
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
When I saw the thread title I was going to post a pic of an old AMC Matador, then I saw you're SERIOUS about this.
I'll stay tuned for sure now.
My suggestion would be to do some bracing of the front suspension (I'm thinking angle braces for the upper control arm mounts) and any other torsional stiffness improvements. Chassis stiffness of the C4 was great when they were new, but compared to current new cars it's just average.
Speaking of which, since you have it torn down this far (if I were you) I'd weld in the targa top (and I mean fully weld the entire front and rear mating joints) to get rid of the bolt system. I think that done correctly it would make a significant difference in chassis stiffness.
I'll stay tuned for sure now.
My suggestion would be to do some bracing of the front suspension (I'm thinking angle braces for the upper control arm mounts) and any other torsional stiffness improvements. Chassis stiffness of the C4 was great when they were new, but compared to current new cars it's just average.
Speaking of which, since you have it torn down this far (if I were you) I'd weld in the targa top (and I mean fully weld the entire front and rear mating joints) to get rid of the bolt system. I think that done correctly it would make a significant difference in chassis stiffness.
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
From: Drayden Maryland
When I saw the thread title I was going to post a pic of an old AMC Matador, then I saw you're SERIOUS about this.
I'll stay tuned for sure now.
My suggestion would be to do some bracing of the front suspension (I'm thinking angle braces for the upper control arm mounts) and any other torsional stiffness improvements. Chassis stiffness of the C4 was great when they were new, but compared to current new cars it's just average.
Speaking of which, since you have it torn down this far (if I were you) I'd weld in the targa top (and I mean fully weld the entire front and rear mating joints) to get rid of the bolt system. I think that done correctly it would make a significant difference in chassis stiffness.
I'll stay tuned for sure now.
My suggestion would be to do some bracing of the front suspension (I'm thinking angle braces for the upper control arm mounts) and any other torsional stiffness improvements. Chassis stiffness of the C4 was great when they were new, but compared to current new cars it's just average.
Speaking of which, since you have it torn down this far (if I were you) I'd weld in the targa top (and I mean fully weld the entire front and rear mating joints) to get rid of the bolt system. I think that done correctly it would make a significant difference in chassis stiffness.
Thanks for the picture!
Last edited by TGM; Apr 9, 2013 at 03:11 PM.
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
That looks good, but I'd make sure to pick up the front frame section ahead of the steering with an L shaped bar tying in at the firewall where your drawing shows the upper bar attaching - and if there is any way you can connect the left and right sides of that, say across the top of the radiator area, that would really help a lot.
The front suspension braces usually brace the upper a-arm mounts, that's why I was suggesting the welded gussets.
The front suspension braces usually brace the upper a-arm mounts, that's why I was suggesting the welded gussets.
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
From: Drayden Maryland
That looks good, but I'd make sure to pick up the front frame section ahead of the steering with an L shaped bar tying in at the firewall where your drawing shows the upper bar attaching - and if there is any way you can connect the left and right sides of that, say across the top of the radiator area, that would really help a lot.
The front suspension braces usually brace the upper a-arm mounts, that's why I was suggesting the welded gussets.
The front suspension braces usually brace the upper a-arm mounts, that's why I was suggesting the welded gussets.
I was thinking about that and other things to do. I was just sharing some of the plans I was going to do. Thanks for the input. 
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
From: Drayden Maryland
Update!
I got the firewall completely off and now she is in the nude! You can see where I stopped sanding last year! I'm glad I wasted my time since I changed my mind and now I want to send it in for media blasting and powder coating.
Progress is going to be slow since the wife wants to look for a house!
So for now I'm just selling parts to save up for the roll bars and frame mods.
Progress is going to be slow since the wife wants to look for a house! So for now I'm just selling parts to save up for the roll bars and frame mods.
Burning Brakes
Joined: Dec 2007
Posts: 1,125
Likes: 8
From: Taft TN
If I was going that far....I would junk the c4 suspension. It would have c6 suspension with a torque tube and the tunnel. I've measured and it will fit with a few mods and shorten the torque tube. 
Safety Car
Joined: Mar 2005
Posts: 4,471
Likes: 1,224
From: Fredonia WI
2025 Corvette of the Year Finalist - Unmodified
2024 C7 of the Year Winner - Unmodified
2023 C4 of the Year Finalist- Modified
2020 C4 of the Year Finalist - Modified
2019 C4 of Year Finalist (performance mods)
2018 C4 of Year Finalist
Excellent project!
What in the world? Where would you possibly shove an O2 into the slave cylinder? Not that I doubt you ... we've all seen crazy stuff from PO's.
What in the world? Where would you possibly shove an O2 into the slave cylinder? Not that I doubt you ... we've all seen crazy stuff from PO's.
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Melting Slicks
Joined: Jun 2011
Posts: 2,383
Likes: 385
From: Leland , North Carolina
Le Mans Master
Joined: Nov 2009
Posts: 6,882
Likes: 234
From: Bangkok, Thailand
I agree. One of the guys on here with a dedicated C4 race car said that if he modded his suspension more it wouldn't be a C4 anymore - but a stock C5 z06 will pull away from him on a road course. OF course, chassis stiffness of the C5/6 is a big part of the improvement as well.
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
From: Drayden Maryland
if I started buying all the extra parts! I would love to see it though!I'm shooting to match or beat the C6 Supernatural LM GT2. It was built off the C4 chassis and it was a killer track car. Yes I know in 95.
I know its going to be hard to match it in a street car but I'm in for the challenge. Making a dream into reality! Plus we have the technology to build a race car from the 90s. We can buy aluminum block engines and build carbon fiber components at our finger tips!COPO I have to say I love the work you did on your C4!
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
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From: Drayden Maryland
shakedown067 posted a thead http://forums.corvetteforum.com/c4-t...post1583607969 showed how much movement there is in the batwing. I came up with a solution to give more support. I will be doing this mod on my car!
Le Mans Master
Joined: Dec 2003
Posts: 5,768
Likes: 33
From: Van Steel Corvettes
St. Jude Donor '12-'13
Burning Brakes
Joined: Aug 2005
Posts: 1,172
Likes: 9
From: '88 TPI L98/HotCam Powell, Ohio
Nice project! I don't envy you on the hours ahead.....
I would recommend not using 1.5" x .095" DOM for your cage. I know you may not end up racing with NASA or SCCA but you may want to sell the car to someone down the road that will. A poor cage will hurt the value in the long run. Even if you go with just a 4 pt. for now.
Here are the basic size requirements for NASA (SCCA also):
2501 - 3000 lb Car
1.500” x 0.120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
*****
1.750” x 0.120” ERW* (No issuance of log books for cars with ERW cages) *Note- Specifications listed only for
reference for inspection of grandfathered vehicles.
3001 - 4000 lbs
1.750” x .120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
No ERW allowed
And here is a link to the full rules (Go to 15.6 for cages)
http://www.nasaproracing.com/rules/ccr.pdf
I would recommend not using 1.5" x .095" DOM for your cage. I know you may not end up racing with NASA or SCCA but you may want to sell the car to someone down the road that will. A poor cage will hurt the value in the long run. Even if you go with just a 4 pt. for now.
Here are the basic size requirements for NASA (SCCA also):
2501 - 3000 lb Car
1.500” x 0.120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
*****
1.750” x 0.120” ERW* (No issuance of log books for cars with ERW cages) *Note- Specifications listed only for
reference for inspection of grandfathered vehicles.
3001 - 4000 lbs
1.750” x .120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
No ERW allowed
And here is a link to the full rules (Go to 15.6 for cages)
http://www.nasaproracing.com/rules/ccr.pdf
Thread Starter
Intermediate
Joined: Jan 2013
Posts: 45
Likes: 0
From: Drayden Maryland
Nice project! I don't envy you on the hours ahead.....
I would recommend not using 1.5" x .095" DOM for your cage. I know you may not end up racing with NASA or SCCA but you may want to sell the car to someone down the road that will. A poor cage will hurt the value in the long run. Even if you go with just a 4 pt. for now.
Here are the basic size requirements for NASA (SCCA also):
2501 - 3000 lb Car
1.500” x 0.120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
*****
1.750” x 0.120” ERW* (No issuance of log books for cars with ERW cages) *Note- Specifications listed only for
reference for inspection of grandfathered vehicles.
3001 - 4000 lbs
1.750” x .120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
No ERW allowed
And here is a link to the full rules (Go to 15.6 for cages)
http://www.nasaproracing.com/rules/ccr.pdf
I would recommend not using 1.5" x .095" DOM for your cage. I know you may not end up racing with NASA or SCCA but you may want to sell the car to someone down the road that will. A poor cage will hurt the value in the long run. Even if you go with just a 4 pt. for now.
Here are the basic size requirements for NASA (SCCA also):
2501 - 3000 lb Car
1.500” x 0.120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
*****
1.750” x 0.120” ERW* (No issuance of log books for cars with ERW cages) *Note- Specifications listed only for
reference for inspection of grandfathered vehicles.
3001 - 4000 lbs
1.750” x .120” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM
No ERW allowed
And here is a link to the full rules (Go to 15.6 for cages)
http://www.nasaproracing.com/rules/ccr.pdf
I know it's a crazy weight goal! But I have been crunching weight numbers on a excel sheet for each part. So far I have 2257 lbs without body. I have almost all the parts listed with custom roll bars. The birdcage has to weigh around 350-400 lbs because I can lift the front and back. I also added weight to some parts to make sure im not underestimating. Most of the body's weight is in the hood and doors.
Now if my weight starts going above 2500 lbs I will be putting 1.750” x 0.095” Seamless Alloy (4130), Seamless mild steel (CDS Mechanical) or DOM. I will say I'm going to be surprised if I get it under 2500lbs.
Thanks for keeping my hopes high! 