Interiors, noise, and temp control - aka - NVH in a tin box with mud tires

[pippinmader]

Seems that as I get the bronco more refined and have the kids with me more I want it to be quieter inside and figure out some way to control floorboard temperatures. I saw Lars and maybe Tony are interested in some NVH improvements also so here is what I have found. I am hoping people can chime in with what has worked for them, or what hasn't!

Temperature control options:

• Reduce exhaust heat with ceramic coating or heat shields
  • Adding ceramic coating, especially inside the exhaust where it works the best, is either expensive or really difficult. If you want ceramic coating buy the components that way! Has anyone found a good way to DIY ceramic coating?
  • I am already on my third set of headers, should have spent more money and got ones that are ceramic coated from the start!
  • I bought some fiberglass/dimpled aluminum heat shield that I zip tied to the exhaust where it gets hottest - the results have not been amazing but at least it smells bad? Has anyone found a better solution?
• Thermal insulation on the floor using lizard skin or other conduction barriers
  • I added ceramic balloons to the Raptor liner when I sprayed it, and it doesn't work that good. It sounds like to get a good thermal barrier using lizard skin or similar it needs to be 1/2 inch thick! I could also add carpet but it would get pretty wet when it gets hosed out! lol!
• Radiant barrier on the floor like using gold foil on the bottom side!
  • If it is good enough for a McLaren it is good enough for a bronco! Broncos are precious metal right?
  • Summit racing makes some sounds deadening that has a foil top coat and a butyl backing. I am considering trying to put it on the bottom side of the floor boards to control both sounds and heat. I am hoping that if it is installed really carefully it won't trap moisture. Has anyone tried this?

Sound Control Options

• Weather stripping and sealing
  • From my experience with houses - air leaks let in a lot of noise. But I don't think there is much more I can do on this front for my build.
• Spray on options like lizard skin
  • I have heard good things, but it needs to be thick, there is a reason lizard skin comes in a 5 gallon bucket (or 3 gallons or whatever it is).
• stick on options like dynamat
  • Like I said above, I bought some of the Summit Racing brand stuff for my 1950 ford pickup and it says it works as a thermal barrier also, so I might try it?
• Carpet - Nope!

The one issue I am running into is I don't have an interior in the bronco to hid any of this stuff. It has bed liner on the tub and stone chip paint on the inside of the hard top. What are people running for headliners? I see there are stock style ones for pretty cheap or ABS ones for more $$$.


Am I missing anything? What has worked for you guys?

[CityHick]

A humorous anecdote before my real update:

When I bought my bronco it was fully carpeted. During my test drive I told the owner that it was by far the quietest EB that I'd driven, and had the most solid feel. As I began to tear it apart I found the reason why it was so quiet and solid. Someone in the past had covered the entire front section of flooring with asphalt roofing shingles, then a layer of 3/4" felt padding, and then a carpet kit. While I am not advocating for such measures, to this day it still holds the title of quietest EB interior in the history of EBs.

15 years ago everybody was spraying bedliner into their rigs so I followed the herd. It's good in concept but for the reasons you have outlined above it mostly sucks in practice. Maybe this is a factor of me being 45 and not 30 anymore, I don't tolerate the annoyances as well.

It is my nature to seek to quantify results with real numbers (I am a software engineer/operations geek so it's kinda my deal). So it makes no sense to me why I did not take some "before" measurements with regards to floorboard temps and sound levels. And without those figures I don't know how much of a point there is in me taking "after" measurements.

I'll provide some subjective observations about my experience with Dynamat products. Dynamat Extreme is a pretty damn nice product. I lined the footwells and covered it all up with a rubber floor several years ago. I will say that it helped with both noise and heat intrusion. I only went up as far as the angled portions of the front footwells at that time, with the dynamat. I should also say that I had several "holes" in my firewall that I did not pay much attention to. Primarily just bolt holes for oem bits and pieces that I removed long ago. It is basically foil/butyl with what's probably the world's best adhesive to stick it down.

When I tore things apart this year for my transmission/transfer case swap, knowing that I had a good 6 months of delays ahead of me, I set about addressing these holes. I welded some closed, and sealed the others with bolts, washers, and RTV. I extended the Dynamat up as far as I could on the vertical firewall surface. I then covered all of the first layer of Dynamat Extreme with Dynamat Dynaliner. It is 1/2" closed cell foam with an adhesive backing. I covered the firewall, transmission tunnel, and floors with it as well, and then put the rubber WH floormat down.

I have only about an hour's worth of seat time with this new setup but so far I am very pleased. I am hearing very little sound coming into the cab from the engine bay anymore. This is with me running around with factory doors and a bikini top, no hard top, so it is hard to say since I have road noise to compete with... but its noticeably quieter. The heat issue is going to require some more seat time to assess. I haven't driven it during the hottest parts of the day yet, but so far it feels quite a bit less warm around the feet.

I was reading threads on classic about heat shielding the exhaust and I think it was Lars who mentioned installing some aluminum sheeting on standoffs from the floorboards, above the exhaust pipes. I will probably do something similar with mine, at least along the areas nearest to the engine and to where people ride. I had a heat shield on a muffler long ago, which was basically just a formed piece of aluminum strapped to the muffler. it seemed to help with heat issues, but it rattled no matter what I did to it...

I hope this provides some help.

[pippinmader]

I wonder what length nails I should use to install the roofing shingles? 7/8 inch should extend far enough into the engine compartment to hold right?

Speaking of bad ideas - I did also try making my own insulation for the exhaust using high temperature exhaust manifold paint and more of those ceramic beads. It was rated to 1200 F but it was an utter failure! It didn't seem to keep interior temperatures down and burned off in a smokey mess in the first 100 miles.

All kidding aside, I am likely to add as much dynamat or "SummitMat" as I can, but I don't really want to add a rubber floor so that makes it complicated. Any thoughts about putting it on the bottom of the floor? There is probably space up under the dash to add some that should help. If I add it to the hard top it will require that I add a headliner. I will also likely add some to inside the doors just because it would be fairly easy.

[Lars]

I need to post up some photos of my heat shields. Won't happen tonight, bedtime is calling my name. But briefly, I made them out of .063 half hard 1100 series aluminum sheet (soft, crack resistant, malleable). All mounted on standoffs on the underside of the body. A huge piece above the muffler, and more recently a section above the passenger side header. The difference in heat entering the cab is remarkable.

I have rubber floor mats with carpet insulation underneath. Over the 20-ish years since I had evil bedliner sprayed in, the exhaust heat has mostly cooked it off where the exhaust system passes close to the body. And on trips, with stuff piled in the back, I could reach my hand down behind the passenger seat and the floor was waaayyy too hot to touch. Likewise the floor on the passenger side of the transmission tunnel. With the heat shields in place, the floor barely gets lukewarm.

There is a reason modern vehicles have heat shields above the exhausts. What I described above is easy to fabricate (and I promise I'll post pix) and well worth the effort. Note that the heat shields do nothing for noise, but the reduction in heat is astounding considering the (lack of) effort required to fab and install them.

[pippinmader]

I have thought some about heat shields, do you think they would work as well if they were attached directly to the exhaust? I would rather not drill into my floor (it took a long time to weld up all those holes!) I was thinking of forming little 1" standoffs and riveting semicircular heat shield (aluminum?) to them. Or is that design more likely to vibrate and make noise?
What about embossed aluminum? My Tundra uses that stuff on a lot of components like the starter, makes it a real PITA to change the starter. The fiberglass and adhesive backed stuff seems like it would hold water, but maybe the exhaust heat will cook it off?
https://www.summitracing.com/parts/dei-050503
https://www.summitracing.com/parts/sum-350301

[plug ugly]

Ive tried it all, and my rig is still HOT. Ive got ceramic insulation under a bed lined tub inside and out. I have heat shielding above as much exhaust as possible, I have coated headers, wrapped exhaust and stick on insulation on the tunnel covers. It still gets hot since there is very little air movement with the belly pans and close tolerances to the motor, auto tans and exhaust. Im looking at insulated floor mats to stop burning my feet since I wear flip flops every day

[pippinmader]

Has anyone used this kind of headliner?
QuietRide Solutions BRONCO 6677-FCHK Bronco Headliner AcoustiShield ABS Plastic Full Cab 1966-1977 (cjponyparts.com)

It is currently $5 off!!! lol