Just getting started on my build and trying to figure out if I should modify the frame and remove the cross braces in the trunk. If anyone has done this and had success without much flex after removing the cross brasses please let me know where you welded the supports.
Is this actually worth the hassle? I think it will look cleaner but don't want to compromise the integrity of the trunk section by removing the braces.
I removed mine. Right or wrong, I assumed the lower trunk floor would help keep things rigid and square, and frankly, there's so little bracing back there, I didn't think the absence or presence of those small bits of frame would mean much in a rear collision.
Built an early MkIII years ago, sold years ago. Back after 18 years to build a MkIV Build Thread Here Partners: Levy Racing, Summit Racing, LMR, Breeze, Forte's Parts, Speedhut, ReplicaParts
MkIV Complete Kit Ordered 4/18/23, Delivered 7/11/23, Boss 427W, Edelbrock Pro Flo 4, TKX (.68 5th), IRS, Wilwood Brakes, 18" Halibrands, Toyo R888R Tires, Custom Speedhut Gauges
I kept mine as-is, as Rich mentioned. "Legacy" builders pointed out that the small triangle partition helped to retain "show-n-shine" products from other trunk items...if that's a consideration.
I saw it as a challenge to precisely cut the drop sections of the panels for the best fitment around those frame tubes
I removed the left diagonal brace and added an additional brace along the right side of the drop trunk. I also made provisions for a battery mounted to the left of the drop trunk.
The very early Mk4s had a dropped trunk without the diagonals (I built one of the first 50 for a customer) but FFR soon found that without them the rear wouldn’t stay square so they went back in. As Rich said they are there for a reason.
I have a fairly early Mk IV that was constructed shortly after the change Jeff mentioned above. My online manual I had purchased from FFR didn’t match my frame. I called FFR and they informed me that the frame had been strengthened to prevent it twisting.
I wanted the extra room without the frames in the way so I modified the trunk area frames. Here are a few pictures.
A storage compartment was also added in front of the newly created dropped area. I use this for tools and a small grease gun.
HTH
Norm
Last edited by Norm B; 01-13-2025 at 11:37 PM.
Mk4 base kit 7721, 331 Stroker, Holley Sniper EFI, Wipers, Heater, Whitby Soft Top, Drop trunk mod and more
Add me to the "Factory Five put them there for a reason" camp. I've done multiple builds and have installed the trunk mod in each including in a Gen 3 Coupe. Where the tubing is thicker than the material used in the Roadster. With the thousands of miles and multiple seasons for each, I haven't found the braces across the opening to be a big deal. Easy to use for the kinds of things typically in there -- tools, detailing misc, inflator, sun screen, towels, my wife's sweater or coat (important ), you name it. Builders welding in replacement braces is perhaps better than removing completely. But not my preference plus I don't weld.
Last edited by edwardb; 01-12-2025 at 09:25 PM.
Build 1: Mk3 Roadster #5125. Sold 11/08/2014. Build 2: Mk4 Roadster #7750. Sold 04/10/2017. Build Thread Build 3: Mk4 Roadster 20th Anniversary #8674. Sold 09/07/2020. Build Thread and Video. Build 4: Gen 3 Type 65 Coupe #59. Gen 3 Coyote. Legal 03/04/2020. Build Thread and Video Build 5: 35 Hot Rod Truck #138. LS3 and 4L65E auto. Rcvd 01/05/2021. Legal 04/20/2023. Build Thread. Sold 11/9/2023.
With the mod I made my wife’s clothes for a road trip go in a regular suitcase and mine in a duffle bag. Both easily fit in the trunk along with the Whitby soft top and car cover. No need to pack stuff around the bars. It is stronger than the original Mk IV by a long shot and I bet every bit as strong as the FFR mod.
There is no real strength in that area until you hit the 2x3 frames that the roll bar rear legs attach too. The rest looks like a crumple zone with, unfortunately, a fuel tank hanging in it. Kind of like the Pinto.
One of the reasons I went with two roll bars was to provide protection in a rear end accident, especially from the pickup trucks so popular in Alberta, where I lived when I first built the car.
Mk4 base kit 7721, 331 Stroker, Holley Sniper EFI, Wipers, Heater, Whitby Soft Top, Drop trunk mod and more
The braces are there to support the aluminum floor. Without them it flaps up and down. I removed my braces before I removed the floor and found this out. No other structural value.
I cut mine out, but then welded them back in a lower configuration. replicated the same design in the new floor of my framework. The gas tank butts up against the bottom of it with a rubber gasket between the metals.
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MkIV Roadster build: Gen 2 Coyote, IRS, TKO600. Ordered 10/24/18. Delivered 1/29/19. Engine installed 8/8/21. First start 9/12/21. First go-kart 9/17/21. Off to paint 4/11/22. Back from paint 12/30/22. Build thread here.
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), you name it. Builders welding in replacement braces is perhaps better than removing completely. But not my preference plus I don't weld.
Originally Posted by PG_Cobra
