stick152

I started out doing my heat shielding project about three weeks ago. I had originally figured on doing the tub, cockpit floors and doors but got a wild hair and decided to keep going.

I was having some heat issues with the roof arch (it got hot to touch in the afternoons) and, on the very hot days when the car was sitting in the direct sun for a while, the AC would take about 10 minutes to really start getting cold. If I was parked in the shade, even when it was over 90* outside, it'd start blowing cold almost immediately. So, I decided to try heat shielding the dash pad and attached HVAC duct to see what kind of difference it would make.

Here are some numbers for the before and after for the dash insulation. Both times, the car was parked in the sun with the windows up and no sun shade in the windshield.

Before insulation:
Outside air temp: 90*
Interior car air temp: 115*
Interior temp in center air duct: 130*

After insulation:
Outside air temp: 90*
Interior car air temp: 115*
Interior temp in center air duct: 117*

The biggest difference that I notice now is that when I turn on the AC, it gets cold FAST! It's also blowing close to the same temps from all air vents (far left side, center, far right side).

The temps are as follows:
AC set to 70* with dual control set in center and OAT at 98*
Center duct temp: 42*
Left side duct: 48*
Right side duct: 48*
I left the digital thermometer in each duct until the temp appeared to be stable - about three minutes.

Unfortunately, I didn't have a chance (i.e., didn't think to) to check the vent temps before pulling out the dash to do the insulation.

As for the roof arch, after insulating that it no longer gets warmer than the ambient air temp in the car. Since doing all this heat shielding, I've noticed a much more comfortable cockpit (temperature-wise) and the AC hardly runs above two bars on the fan speed to keep the car nice and cool.

In case anyone's interested, it took two-and-a-bit rolls of Reflectix (at $21-ish a roll at HD) and three rolls of silver tape ($3-ish) for the entire car (tub, riser, floor panels, tunnel, doors, arch, dash pad, and HVAC ducting).

So all that being said, here's the procedure:

My mechanic-in-training helped me pull out all the trim and dash pad.


Here's the denuded roof arch:


When insulating the roof arch trim, there are some cutouts that you need to be sure to make. Two for the velcro attachments at the back, several for the clips that hold the front edges in place and one for the cutout for the rear targa latch. These look kindof rough in the pics, but I trimmed them up for a better fit before installation.



Here's the finished roof arch trim piece:


Now on to the rear speaker surrounds / trim pieces. To get these out, I detached the top of the hatch struts one at a time, slid the trim piece over the strut and re attached the strut (I didn't re-clip the strut - just let the weight of the hatch hold it in place).

Top of the hatch strut with clip and defroster connector:


Spring clip pliers work best for removing the spring clip (duh, right?) but if you don't have any handy, a pair of long needle-nose with fine tips will work nicely.


If you have problems getting this trim piece to turn loose, it's probably this freakin' thing!


Here's this trim piece all insulated. I didn't insulate the portion around the speakers and the bottom edge because that portion of the car was already insulated from my previous insulation work.


On to the dash pad! This part took for freakin' EVER! The dash pad itself was a breeze, but that HVAC duct was a bugger to get just right. There are all kinds of compound curves and facets, so I just took my time and got the best fit possible.

If you haven't already seen it, here's what the underside of the dash pad looks like (after three or four beers and things start looking blurry)


Reflectix is pretty darn easy to work with. It folds nicely and makes it a breeze to just press fit and rough cut. Once you get it to that stage, you can just clean up the fit and tack into place with small tape strips. Here's some of the progression.




To do the cut-out for the defroster hole, I just used a pocket knife with a long, skinny and SHARP blade and cut it out being EXTREMELY careful not to cut any of the leather or the rubber-ish edging that the defroster grill sits on.


Here's the dash pad insulation all cut out and tacked down.


When doing the final edge taping, I find it easier to pre-cut my tape before starting. It's a personal preference, but it seems to go much faster for me.


Now on to the HVAC duct:


I got pretty in to doing this part and forgot to take pictures of my progress along the way. However, I did take this one of the first panel placed on. Basically, it could be used as an example of how I did one face at a time...


Through the magic of the internet, here it is TWO FREAKIN' HOURS LATER!

Here's the bottom side:


And here's the front:


Here she is, fully assembled and ready to be installed:



So to sum up the benefits of this portion of my heat shielding project...
* I saw a 13* temp improvement directly under the dash pad in the center vent.
* My AC starts blowing cold air much more quickly and the temps between the side vents are even (don't know if they were before though).
* The AC hardly has to work at all now to keep the car cool.
* The under-dash electronics don't have to deal with as much heat.
* My daughter and I got some papa-daughter time (working on the vette no less). We had a lot of fun and she's learning how to work on a vette!

Was it worth all the work? For me, yes. For someone else, maybe not.

imavettegirl

boy, that looked like a lot of work!

lucky131969

Yep, that would have been the most important piece of info. The temp you are seeing out of the center duct is what you should be getting anyway ~40-45 degrees depending on temp/humidity. In your case, if you installed the insulation, and reduced the radiation or conduction from the dash pad, it's just gets down to that temp quicker....not any colder.

The two most important benefits from this task are sound deadening, and quality time with your daughter.

stick152

The getting to temp quicker was my biggest motivating factor. There should be less heat transference through the ducting after insulating, but without the non-insulation numbers I don't know how much of an improvement there may have been for the temp at the side vents. Guess I could just remove it all, take the temps and put it back

stick152

It was! But my daughter and I had a lot of fun doing it, and she really liked getting to see what was under the dash pad. Seein' her turning a ratchet did my heart all kinds of good