C-beam Delete?
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
C-beam Delete?
I've been thinking about deleting the C-beam in my C4 by making a trans crossmember that bolts to the frame on the bottom and a bracket that goes from the C-beam holes on the differential to the frame to keep it from rotating.
Has anyone done this? Anything particular I need to look out for? This is honestly the first IRS that I'm going to modify.
Has anyone done this? Anything particular I need to look out for? This is honestly the first IRS that I'm going to modify.
Melting Slicks
Joined: May 2014
Posts: 2,898
Likes: 592
From: New Port Richey FL
O.K. Why
In my book it is a proven system that is Fairly Light Weight, all this Bracketing & frames are going to reduce ground clearance to nothing and add weight. If your concerned about Driveline Twist/Defection of the Beam I am sure you could stiffen it by Aluminum Welding a flat plate on the flat side of beam.
In my book it is a proven system that is Fairly Light Weight, all this Bracketing & frames are going to reduce ground clearance to nothing and add weight. If your concerned about Driveline Twist/Defection of the Beam I am sure you could stiffen it by Aluminum Welding a flat plate on the flat side of beam.
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
The car has a TH400 and I would like to consider the possibility of eventually swapping out the Dana 36 for a Ford 8.8. Making a C-beam bracket to mount the 8.8 to the C-beam would be easy, but easier yet to just mount it to the frame.
The car already has a cage. A transmission crossmember would be a quick job.
The car already has a cage. A transmission crossmember would be a quick job.
Melting Slicks
Joined: May 2014
Posts: 2,898
Likes: 592
From: New Port Richey FL
The car has a TH400 and I would like to consider the possibility of eventually swapping out the Dana 36 for a Ford 8.8. Making a C-beam bracket to mount the 8.8 to the C-beam would be easy, but easier yet to just mount it to the frame.
The car already has a cage. A transmission crossmember would be a quick job.
The car already has a cage. A transmission crossmember would be a quick job.
Some photo's of what you have would help
Last edited by s carter; Mar 22, 2018 at 09:55 AM.
Le Mans Master
Joined: Sep 2013
Posts: 6,192
Likes: 750
From: near the thumb in the mitten
The cobra IRS is designed to bolt in on the mustang 4 link frame locations. So rear underbody would be a pattern to fab from. Since car is caged a cross member shouldn't be difficult. Running a engine and mid plates can help in layout in keeping every thing straight and centered. Good Luck.
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
Explorer 8.8 can be made to work with the factory C4 rear IRS setup fairly easy. A batwing/C-beam adapter would take me a weekend to finish but my biggest hassle would be axles. No need to do a subframe adaptation or anything like that.
If I'm going to fabricate a C-beam adapter, it seems the easier solution would be to just put a cross bar between the frame rails that the front of the differential bolts to, so I can delete the C-beam all together.
If I'm going to fabricate a C-beam adapter, it seems the easier solution would be to just put a cross bar between the frame rails that the front of the differential bolts to, so I can delete the C-beam all together.
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Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
Safety Car
Joined: Apr 2005
Posts: 3,624
Likes: 431
From: Dale City VA
The rear cross member will be easy as the frame rails are exposed.
The trans cross member will be a bit tougher but really not that difficult. The easiest access to the frame rails are from inside the car, right in front of the seats. You can make up a 3 piece cross member where 2 pieces welded to the frame rails and run along the floor thru the side of the trans tunnel.... then a center removable bar for the trans to bolt to. No ground clearance problems and I run 3.5" dual exhaust under it on my 84.
The above is the way my 84 with a Powerglide trans is done.
I have pics of the rear cross member in my car as I documented the straight rear 3 link suspension conversion really well.... I did not take any pics of the trans cross member but I will after this weekend as I have been asked about the trans cross member many times....
Here are some of the rear.
https://i.imgur.com/onNanOm.jpg
https://i.imgur.com/DynsOXI.jpg
https://i.imgur.com/gnCYIKy.jpg
https://i.imgur.com/Av5IPQo.jpg
Will
The trans cross member will be a bit tougher but really not that difficult. The easiest access to the frame rails are from inside the car, right in front of the seats. You can make up a 3 piece cross member where 2 pieces welded to the frame rails and run along the floor thru the side of the trans tunnel.... then a center removable bar for the trans to bolt to. No ground clearance problems and I run 3.5" dual exhaust under it on my 84.
The above is the way my 84 with a Powerglide trans is done.
I have pics of the rear cross member in my car as I documented the straight rear 3 link suspension conversion really well.... I did not take any pics of the trans cross member but I will after this weekend as I have been asked about the trans cross member many times....
Here are some of the rear.
https://i.imgur.com/onNanOm.jpg
https://i.imgur.com/DynsOXI.jpg
https://i.imgur.com/gnCYIKy.jpg
https://i.imgur.com/Av5IPQo.jpg
Will
Last edited by rklessdriver; Mar 22, 2018 at 01:52 PM.
Pro
Joined: Sep 2019
Posts: 716
Likes: 135
From: Buchanan, Michigan
The rear cross member will be easy as the frame rails are exposed.
The trans cross member will be a bit tougher but really not that difficult. The easiest access to the frame rails are from inside the car, right in front of the seats. You can make up a 3 piece cross member where 2 pieces welded to the frame rails and run along the floor thru the side of the trans tunnel.... then a center removable bar for the trans to bolt to. No ground clearance problems and I run 3.5" dual exhaust under it on my 84.
The above is the way my 84 with a Powerglide trans is done.
I have pics of the rear cross member in my car as I documented the straight rear 3 link suspension conversion really well.... I did not take any pics of the trans cross member but I will after this weekend as I have been asked about the trans cross member many times....
Here are some of the rear.
https://i.imgur.com/onNanOm.jpg
https://i.imgur.com/DynsOXI.jpg
https://i.imgur.com/gnCYIKy.jpg
https://i.imgur.com/Av5IPQo.jpg
Will
The trans cross member will be a bit tougher but really not that difficult. The easiest access to the frame rails are from inside the car, right in front of the seats. You can make up a 3 piece cross member where 2 pieces welded to the frame rails and run along the floor thru the side of the trans tunnel.... then a center removable bar for the trans to bolt to. No ground clearance problems and I run 3.5" dual exhaust under it on my 84.
The above is the way my 84 with a Powerglide trans is done.
I have pics of the rear cross member in my car as I documented the straight rear 3 link suspension conversion really well.... I did not take any pics of the trans cross member but I will after this weekend as I have been asked about the trans cross member many times....
Here are some of the rear.
https://i.imgur.com/onNanOm.jpg
https://i.imgur.com/DynsOXI.jpg
https://i.imgur.com/gnCYIKy.jpg
https://i.imgur.com/Av5IPQo.jpg
Will
I realize this is an old thread, was hoping maybe as you're doing oil change and or maintenance we could get some updated pics of all this stuff before it gets lost in internet limbo. Very valuable tech info for the group. As always thanks for the good tech you share with us c4 guys! 😁
Pro
Joined: Sep 2019
Posts: 716
Likes: 135
From: Buchanan, Michigan
I was hoping for some close ups of the front crossmember, maybe when he does an oil change in the future? From all I've read seems Will has more experience with these cars than the next 15 forum members combined. Be a shame to not have some of this stuff documented for posterity sake.
Thread Starter
Burning Brakes
Joined: Sep 2016
Posts: 1,133
Likes: 319
From: Ohio
As much as I still want to delete the C-beam, probably not an option again this year. Budget is super thin lately.
I did manage to go 5s in the 1/8th on a Dana 36. Its tired and worn out, but still kicking.
I did manage to go 5s in the 1/8th on a Dana 36. Its tired and worn out, but still kicking.