Belly Pan Danger –Belly Pan Owners Must Read

[justme1969]

I really love those metal pans, very nice! Diddnt your old piks show sides open by 2+"? thats sorta strange to develope that much heat.
Return to tank systems generate heat also. the constant pumping is great for ethenol fuels removing water vapors and such but add grill block and a sealed engine compartment where heat must exit pans cavity and blow across the tank ill bet she gets warmish.

[aardvarcus]

Yes, the sides are open, more like 4+” as you can still access and use the lifting points on the car with the pan in place.

I am beginning to think the bare aluminum is part of the root of the problem. I think the reflectivity of the bare aluminum is reflecting the radiant heat from the exhaust back up to the underside of the car, which is mainly all dark surfaces. Then as the underside of the car heats up, in turn the aluminum heats up, and because it has such low emissivity the only heat loss is due to convection/conduction.

I am now considering painting the aluminum. (I should have just bought pre painted aluminum like I originally planned….) It looks like I can get aluminum primer from the local big box, which is white. I could leave the bottom white and then second coat the top surface facing the exhaust with a flat black. That should absorb instead of reflect the heat. Then the heated aluminum pan can dissipate the heat to the air flowing under the pan. The primer is good to 200 degrees in use, and hopefully I won’t be anywhere near that limit.

[kach22i]

Wasn't there a thread which mentioned that metal insect screen will block air flow passing over it much like a solid, yet allow radiant heat to escape?

[aardvarcus]

Thank you everyone for all your help and useful advice. Yesterday I pulled over to check the temp of my gas tank and car underbody, and became uncomfortable with how warm everything was getting. Thus the rear middle section of the pan covering the gas tank came off. When I got home, the middle section and engine section were also removed. I have driven three trips in this configuration, and I have already noticed a 10% hit in MPG as compared to the same trips driven yesterday or in the past week. Note that my front fascia/splitter is already as low as the underbody, thus I already have an air dam.
It is time to scrap my initial plan completely, and focus on BellyPan 2.0. My front most piece on the nose and rearmost piece behind the muffler will stay unchanged for now. I hope to modify and mainly reuse the pan section that goes under the engine bay. On the middle section, I plan to have completely separate left and right pans, and leave the area around the exhaust completely exposed initially. I may go back and add screen or mesh covering, but just to get something back functionally I will focus on getting the sides back together and hopefully my MPG back up. I will also focus on version 2.0 on better integration of the edges to the car’s body.

[pacobeagle]

Would this help at all?
Thermo-Tec : Kevlar Muffler Cover

[whatmaycome14]

Any update to this?

[aardvarcus]

I have been working on the car, but not on the bellypan. I have had a few electrical issues, and on Friday I discovered where the previous owner had hacked up the factory harnesses of the car and installed an aftermarket alarm system. I have half the interior stripped out of the car trying to return the car back to factory. Spent all weekend doing that and building a new relay wiring harness for the headlights, another project necessary due to inferior workmanship from the previous owner.

After I fix all wiring issues, I am going to start on my grill block and radiator intake combo, which will also form the first 1/5 of my belly pan. Belly pan will start back up when those items are done.

My only update is to reiterate: please do not put your belly pan under the exhaust sections of the car. It isn’t about whether or not the material can withstand the temperature; it turns that trapped area into an oven and heats up everything down there. My aluminum sheeting was fine temperature wise, it was just the parts up under the car that weren't fine. The last straw on my under exhaust belly pan was when the front section (nowhere near the gas tank) would heat up the front part of the cars belly so much you couldn’t hold your hands on the bolt bolting the seat to the floor after only 30 minutes of driving. It will melt, shrink, or warp plastic parts.