Saturday I took a friend out for a spin in the GTM since he was bothering me about it so much. Not that I’m going to turn down a chance to take the car out for a nice cruise. After a bit, I started to get on the go-pedal. As I hit 90mph this loud, I mean LOUD, repetitive banging noise erupted from the front of the car. At first I thought it was the engine so I slowed down right away. Noise vanished. Hit the gas again, brought it up to 90 and the noise started right back up. Throttle response was fine, no power loss, and this time I could tell it was definitely in the front of the car somewhere. As I gradually slowed the noise got ‘slower’ and then vanished. I assumed the tire was rubbing on something that had broken loose, as it sounded like aluminum banging against something.

I got the car into the garage and looked around and did not find anything out of the ordinary. Odd. Later that night I went back out to the garage and peered through the mesh in the nose/mouth at the front of the car and saw ‘it’. I remembered that earlier in the drive that day I had scraped the pavement with the underside of the car when I hit a dip in the road. I figured it was the skid bars that had scraped, but I was wrong. The bottom portion of the radiator cowl aluminum had to have been flexing from air buffeting into the radiator and when I hit the dip in the road the front edge of the very middle of the aluminum bit into the pavement hard, ripping a couple inch long tear down the middle of itself. In hindsight, I had always wondered about that aluminum as it was always very pliable, and really wasn’t surprised that this had happened. I reached under the car and ‘shook’ the aluminum and found it was now extremely weakened and would easily ‘bow’ upwards into the bottom edge of the radiator. Couple that weakness with air pressure at 90mph+ speeds and it created one hell of a racket.

To fix the aluminum I had to figure out a way to support it so it wouldn’t bow and flex under air pressure. I created two aluminum brackets that would mount to the side of the radiator cowl, and to the bottom aluminum piece as the solution. A bend in the aluminum was added for support/rigidity, and to direct air up into the radiator. I jacked up the aluminum panel that needed support to parallel (relative to the ground) and set to attaching the brackets. Once riveted in place, I pulled the jack out and the aluminum held its now supported parallel position very well. The bottom of the radiator cowl is now very sturdy and does not flex and move around. To strengthen the ‘torn’ aluminum in the middle I riveted a flat aluminum piece in place to add rigidity (not pictured).

Took the GTM out today and hit triple digits a handful of times and, thankfully, heard no more of that god-awful noise.

Tonight I finished attaching the diffuser to the frame. I slid the jack in under the diffuser and jacked the bottom of the diffuser up against the frame so I could drill a few holes and rivet it into place. The diffuser I have was quite a bit off in its design so the bottom of the diffuser does not sit flush to the frame. Not a big deal though, as I used the jack to push the end of it against the frame and sunk a handful of heavy duty 3/4″ long rivets into it to hold it into place. I pulled on it pretty hard to ensure it would hold up.

With the diffuser in place I installed the pedal box cover. This piece is not mentioned in the manual at all – it was just buried in within the aluminum parts. I don’t believe it was labeled in the parts list, either. This piece is meant to prevent water/air from getting into the driver footbox, but rather than silicone it in place I placed some double-sided tape under the panel edges to ‘seal’ it in case I ever need to remove it in the future.

Instead of using the FFR provided rear-view mirror I decided to use the Corvette rear-view since it has driver and passenger map lights built in. To utilize this lighting, I had to run a ground wire, and the white ‘dome light’ wire from the Painless fusebox up to the center of the windshield where the mirror will be. Not an easy task with the roll-bar padding/fabric in place! I ended up snaking a coat hanger down the pillar under the fabric with a hook bent on the end. Once I got it down behind the dash I was able to hook the mirror wires and pull them up the pillar. I then pushed the wires on top of the front halo bar (sandwiched between the roof and halo bar) and ran them to the center of the windshield. Tested the mirror wiring to ensure it will work – good.

Since my car stereo has a really great iPhone interface, I mounted a nice iPhone holster on the driver side for easy access. This holster is actually designed to mount on vents, but I just unscrewed and removed the mounting mechanism it uses and affixed it to the tunnel vinyl with heavy-duty double-sided tape. Perfect setup.

Lastly, for some reason FFR leaves a nice ugly gap between the engine cover and dash console. They don’t tell you to cover it, nor do they supply a piece to cover this gap. To fix this a cover has to be made. I cut a piece of cardboard and bent it to fit over the console and engine cover edges to get a basic measurement of the aluminum piece I would need. I have a handful of aluminum scrap left over from the build so I cut a piece to match the cardboard and bent it to match the tunnel sides. 1/4″ holes were drilled on each side, and then the tunnel frame holes were drilled out and rivnuts were installed. I trimmed the aluminum piece a bit more, then covered the top with some 1/4″ Dynamat for padding.  Left over suede from the build was used to cover it. Bolted back in place, the cover actually makes for a nice elbow rest since it’s padded fairly well. Not bad.

This should have been a straight forward 30-minute task, but it ended up taking quite a bit longer. The manual doesn’t have you mount the handle to the supplied bracket aluminum until you run the cables. In reality, it is much easier to mount the handle first, then run the cables. It also took a while to figure out how to use the bracket, as it is not pictured in the manual and they do not tell you where to  mount it or how to use it.  I ended up mounting it in the corner by the door hinge, putting it well out of the way of everything. To use the bracket you need to bend the ‘tabs’ back, and then press the handle onto them. Once the cables were ran, it took a while to figure out how to clamp them out of the way without the hood latches being pulled open too much by the tightened cables.

Knocked out a few quick and easy tasks. The rear view camera, which is really a complete license plate bracket, was mounted. Just have to solder the lighting wires for the license plate led lights that hold the bracket on and this will be done. After this I riveted the e-brake trim plate into place, then set to doing the front wheel well closeouts for the driver side. Straight forward stuff without any surprises.

With the radio installed, shift box re-welded into place, wiring organized, and console trim plate prepped, I felt it was finally time to get the center console and passenger dash in.

First thing I had to do was rivet the passenger dash pod to the center console. It was previously held in place with clecko pins. With the passenger pod joined to the console, I then attached the trim plate to the console.  Before getting started on installing the console/dash I vacuumed out the passenger footbox, cleaned the aluminum panels that will be underneath the dash, and secured the wiper closeout box in place.

Everything cleaned up, I set the console into place and set to attaching the air ducts to the dash vents. Two above the radio, one on the passenger pod, and two defrost ducts. I found the trick to doing the dash vents is to pull off the foam that is glued around the outer edge of the vent that you have to push the duct hose over, and cut a line down the middle of the duct hose through 2-3 wire rings so that it can be pulled over the vent easier. With the hose in place, I pulled on some zip ties to secure it. Defrost ducts are a little easier to attach the hoses to. After attaching all the hosing I connected up the hazard and fog lights switches, plugged in the climate control wire harness, and mounted the ignition switch and window switches.  The console/dash was then pushed down into place and secured at the base with a single 1/4-20″ screw on each side. Tested all the switches and climate controls with success.

All that is left to do with the interior at this point is mount the driver’s dash pod, interior lighting, mirror (when windshield is in), gauges, and seats.

Shane @ VRaptor Speedworks made up a nice tunnel closeout panel for those of us that include radios in our builds. The FFR supplied aluminum closes the tunnel off, but does not allow for a radio to be installed at the same time. Shane’s closeout piece works great. To get it to fit with my double-din unit I had to cut out a square for the wiring harness to pass through, and a few holes for the antenna and camera inputs to plug in through. The camera/antenna holes were protected with grommets, while I covered the wiring harness hole with duct tape, then put some slits in it so the wires can pass through, while still keeping things somewhat sealed. With everything set in place, the closeout was screwed into the frame and the radio was plugged in. I then test fit the dash to make sure the radio fit well and actuated open/shut without interference from the closeout panel. Good to go!

Ryan also stopped out and re-welded the shift box into place so now I can get the switches and everything in without interference.

With the mesh silicone’d into place and camera installed I was ready to install the nose aluminum (radiator cowl and nose underbody). Straight forward install since I mocked it all up previously.

With the side louvers in I was able to finally install the last closeout panels into the rear wheel wells. Kind of tough to get these fit properly, but once in they fit pretty well and create a good seal with the body.

I got my hands on a Corvette washer fluid spray nozzle finally so I was able to connect the washer fluid hose to that and clip it to the wiper arm. The hose is tucked into the wiper arm and zip tied at the base to keep it from pulling out when the wiper arm travels.  The hose is then routed through a hole drilled in the body beneath the wiper so it is nearly invisible. I used some adhesive-backed loom clips to secure the hose under the body cowl.

After doing the side duct louvers I installed the first 2 of 3 close-out panels in the driver-side rear wheel well. Once the louvers are cured and checked for sturdiness I will install the final closeout on each side.