a1sensei

A while back I read people recommending Reflectix under the carpet to reduce cockpit temps. I read a little about Reflectix and the "R" value was terrific! Seemed like the perfect stuff, thin and effective. I also saw "cool" pictures of people's resto-projects with the "Flash Gordon" look.

Then I used it. Right off I was dissapointed with the results. It looked cool, but the insulation seemed to do very little to stop heat. I wondered why, but recently was reading about different insulation types and uses for a construction project. It seems, Reflectix insulation is phenominal at reflecting RADIANT heat. To do this, it must be on the side of the barrier facing the heat source, with open air space in between. Otherwise it passes heat through easily. In other words, it would work great if you put it on the outside of your floorpans facing the exhaust pipes (until the under-car environment did it in). But, using it on the inside of the car, sandwiched between the floorpan and the carpet, it is useless.

This seems to confirm what I experienced. Just wanted to pass this along to keep others from throwing the money away. Stick with the stuff that is made for the purpose. God bless, Sensei

Stroker-427

Phisics again!!!!

A heat reflective material must be facing the heat source...... unless you like to keep your car's interiors very hot...... for a very long time!

Isn't a owen !!!!

SIXFOOTER

I never even concidered Reflectix for exactly that reason plus its basically shiny bubble wrap. Which means it will die under the foot traffic on the drivers side.
The best way to deal with it seems to be several thin layers of Lizard Skin on the engine side of the floor. I would also put on a couple layers on the inside and am useing NuPrene for sound proffing inside.
Wrapping the exhaust and Ceramic headers is annother big step to keep the floor cool.
Thats my recipe anyways, someday I'll even get to see if it works

onaqwst

dynomat extreme...... no problem and works great.....

OzzyTom

If you place a reflective material on the firewall side like I did, be certain it has a very high temp rating. The material I used (pictured above) was sourced from a commercial outlet specialising in heat insulation for the trucking industry. It has a fibreglass matting 3mm thick, with a reflective outer aluminium layer. It is bonded to the floor pan using high temp silicon adhesive. Product is rated at 800* celcius (~1470* F) which ensues it copes with the heat transmitted from the headers and exhaust pipes.

It made an immediate difference to the amount of heat entering the cabin...... I can drive my car with bare feet if I like... Could never do that before.

Wrencher

I used it with good results. As you said, the best effect is achieved on the outside (engine/trans side), but putting it on the inside as well the outside works very well for me. I have no heat issues except on the hottest days (over 100 dgrees) here in NorCal. Also, I was worried about the foot/heel area collapsing, but I haven't seen it and I drive it year 'round.

My main reason for using it was weight. Reflectix was king in that corner. All the other mats I looked at were HEAVY! My car was a porker when I got it, and since I'm not ever gonna meet any NCRS rules with this mistreated little darlin', I'm going for performance. No spare (I know, it's crash protection), lots of aluminum, any other ways to shed bulk, have shaved it down to 3,275 lbs. and I still have iron heads. It's free horsepower, but I still want some creature comforts, so I left the A/C in which is very heavy.

So if weight is not a concern, by all means go with something else, and if anyone knows of a (very) light alternative to this stuff, I'd love to hear about it.

Hans

vettfixr

This is what I did and it worked very well.

http://home.comcast.net/~vettfixr/page14.htm

Now, I believe that most of the heat in the cockpit of C3s is not the result of radiated heat but is caused by heat being drawn into the cockpit via the heat/AC system. I wrote a tech tip on this and, since this is the time of the year that we get a lot of heat posts, I usually recommend that people read it. This fix eliminated 95% of my cockpit heat.

https://www.corvetteforum.com/techti...=241&TopicID=3

jim2527

Actualy the bubbles create a non moving air space which is what provides the heat reduction....not the shineyness

My IR heat gun tells me there's upto a 25 degree reduction. Fact.

chevy69

Here is a recipe for lizard skin I used on my '38 dodge coupe:

http://forums.corvetteforum.com/show...de+lizard+skin

yellow 72

"It seems, Reflectix insulation is phenominal at reflecting RADIANT heat. To do this, it must be on the side of the barrier facing the heat source, with open air space in between."
________________________________________ __
Not according to the manufacturer....


http://204.11.91.9/images/uploads/di...age%20door.pdf

73, Dark Blue 454

I'll disagree. I can't imagine there would be a bit of difference depending which side of the floor-board the Reflectix is attached.

'Radiant heat' means heat is transferred from one body to another without the two bodies being in contact,..the sun on your roof for instance. The heat source(s), exhaust, engine, transmission, etc, are not in contact with the floor board, or shouldn't be, so the layer of air exists between the heat source and Reflectix.

If you've sealed your cockpit with Reflectix and you still have a problem, I'd guess you have warm air from the cowl coming through your vents and kick panels.

My opinion.

a1sensei

Well if a manufacturer says their product does something, it MUST be true!

"Radient Barriers: It is easy to get excited when you first learn that foil-faced bubblepack has an R-value of 9.8 for only 3/8" of thickness... Reflective barriers are very good at reflecting heat waves traveling through the air, but there has to be an air space for the insulation to work. Touch the surface of the barrier and the heat from your hand will easily conduct through the material..."

Living Homes: Integrated Design and Construction
Thomas J. Elpel
HOPS Press, LCC
5th Edition Copyright January 2005

a1sensei

I put it on my fiberglass t-top panels (interior panel was off). As soon as the sun hit the t-top panel, you could reach up and touch the reflectix and it felt pretty much as hot as the bare panels felt without the insulation. Just about anything would have worked better (fiberglass, styrofoam, jute). God bless, Sensei

WillEE

I guess I'd rather pay $25 for Reflectix vs. the $300+ for the other stuff that is based on same principal which allegedly doesn't work and also weighs a ton. I did a test on a piece of reflectix - took a lighter to the bottom of and was pretty impressed on how it handled the heat. I've never seen reflectix installed on the outside of a house - although would probably provide better results if done that way. Maybe a scientific test is in order here - time to get out the bunson burner. I just think that the manufacturers who are making the pre-cut sheets are making a killing/ripping us off bigtime - practically a $100/yd for this stuff that is custom cut and as a result is not covering 1/3 of the surface area. I was very dissapointed with what I got from a Corvette Parts dealer for $100 which was for the front of the car. That's why I did the back, door panels and also a 2nd layer in the front for $25 total. I suppose it's all just heresay until someone actually does a test and compares the various products.

SanDiegoPaul

Baloney I say!

Reflectix was the best thing I ever did to my '76. If your heat is conducting, then something is touching the underbelly that shouldn't. Radiant heat won't get it hot enough to burn you through reflectix. It cooled down my car big time.

And before I used it, I read hundreds of posts over the years from others that had used it.

a1sensei

Not on the outside of the house, on the outside of the living space.

Red70vette

I put reflectix in my car over the winter and it is working fine so far. We haven't had any real hot weather but I have driven the car and gotten it up to temp many times. Definite large reduction in cockpit temps. I won't argue the science but it works well for me.

70BBvert

At the risk of over simplification there are three components to heat transfer, radiation, convection, conduction. Reduce any component and it will reduce the temps in the cockpit.

Radiation - need an gap and a shiny surface to reflect the energy away. I don't think reflectix on the inside will help at all

Conductive - need air spaces to disrupt heat transfer. Most likely the mode that reflectix is effective at

Convective - probably minimal anyway in this case since air currents aren't set up from under the car to inside the cabin. Other than those described by Vettfixr, which is more air leakage than convective heat transfer.

Just my $.02, you guys made me type to much already

Jim

CCrane65

Which is exactly what I did. I reasoned that putting a heat barrier under the carpet means the heat was trapped between the floorboard and the barrier.

To me it makes more sense to try and stop the heat from entering the car through the floorboard in the first place.

Think about it, the floorboard is still hot even though you put a barrier on top of it. So why not put the barrier between the floorboard and the heat source.

I used commercial waterproof heating/air conditioning tape to seal the Reflectix all up.

The elements won't have too much opportunity to destroy my Reflectix since my car is not a daily driver.

It works very well.

Unfortunately, I have heat coming from the vents even with the blower switch off. I know what I have to do, I just am avoiding it.

cc