Vehicle manufacturers use sound-deadening material on the floor pans to, you guessed it, deaden sound coming into the interior. Racecars don’t need this stuff and it can be a pain to remove.

You are a racer, which means you are a bit nutty. What I mean is you lie in bed at night and obsess over minute details of your car. The front toe setting is 1/32 of an inch off. Your differential fluid viscosity is too thick. The car is one pound too heavy. These are the things that only racers concern themselves with. This month’s Toolshed Engineer is going to help you lose that one extra pound that your racecar has, and we are going to do it with … science!

Unless you drive a formula car or a sports racer, most of us race a machine originally designed and manufactured for passenger transportation. That means it has a bunch of stuff that isn’t needed for racing around a track, namely sound-deadening material glued to a floor pan. Racecar drivers want their cars loud and light and this gooey, hard-to-remove stuff serves neither of those purposes. So, we want to get rid of this unneeded evil. If you have ever tried to use a putty knife and simply scrape the sound-deadening material off, you have realized that this material is seemingly welded to the floor pan. I’ve tried everything, elbow grease, chisels, hammers, and it is useless. The stuff simply won’t go away.

Most race shops have a torch handy, and you can heat the material up to the point where it becomes a black gummy mess that you can scrape off. You will burn most of your clothes off in the process, make an awfully smelly, smoky mess as you try to get all of this material off of the floor pan. Instead of using fire, you can use ice to solve your problem.

Not just any ice will fix your predicament. It has to be dry ice. Pick up a block of dry ice — a seven pound block costs around $20 — set it on the floor pan and wait a minute. It will cool the sound deadening material to the point where the adhesive is no longer affective. Then grab a big mallet and start pounding on the floor pan. Voila! The vibration of the mallet impact knocks the pesky sound deadening material right off the floor pan in little easy-to-clean-up chunks. Yes, science is awesome!

Be careful though, dry ice is dangerous stuff to work with. If it touches your skin it will burn you, badly because it registers at -109 degrees Fahrenheit. Use large leather welding gloves to handle the material. Once you have the right gloves and a nice big hammer, the process is easy. With one block of dry ice and 10 minutes, I was able to clear out the entire hatchback area out of an Acura Integra. The process is simple — and kind of fun.

Here is some “I-learned-the-hard-way” advice. 1) Use a large-faced mallet as opposed to a smaller metal or woodworking hammer. The dry ice makes the sound deadening material extremely brittle, but it also makes the floor pan brittle too when the temperatures are so low. I actually put a hammer through a floor pan with some overzealous whacking. 2) Before you go crazy making your racecar as light as possible, find out what your minimum class weight is. There is no point in taking away evenly distributed, low-center-of-gravity, safely mounted, weight from a car, just to have to add 10 pounds of weight in another manner to get the car to legal weight. We all want the lightest car possible, but sometimes looking at the bigger picture can save you a bunch of unnecessary work and expense.

When all is said and done and every square inch of sound deadening material is removed from the floor pan, you will be glad to know you have removed about the same weight as a bottle of water. I know, I know, you’re a racer and every ounce of weight counts. Plus, you won’t be able to sleep at night until every sliver of this stuff is removed from your floor pan. I get it. Sweet dreams and happy pounding. I’ll see you at the track.

Here is a pile of all of your hard work, the debris of sound-deadening material removed from the floor pan. If you took the time to weigh all the pieces, trust me, you will be pretty disappointed in the actual weight loss.
Here is a pile of all of your hard work, the debris of sound-deadening material removed from the floor pan. If you took the time to weigh all the pieces, trust me, you will be pretty disappointed in the actual weight loss.
Boom! There it is, a job well done. All the unwanted sound-deadening material is vanished. Amazing what science can do.
Boom! There it is, a job well done. All the unwanted sound-deadening material is vanished. Amazing what science can do.
Be careful with heat. Many times an O.E.M. fuel tank is just below the floor pan you are melting away to get rid of sound-deadening material. You don’t want to go boom!
Be careful with heat. Many times an O.E.M. fuel tank is just below the floor pan you are melting away to get rid of sound-deadening material. You don’t want to go boom!
Now that things are cooled down and lost their adhesive attributes, get the BFH and pound away. The pieces of sound deadening material will fly right off the metal. Science is awesome!
Now that things are cooled down and lost their adhesive attributes, get the BFH and pound away. The pieces of sound deadening material will fly right off the metal. Science is awesome!
 If you have all the time in the world and you are a glutton for punishment you can use a scraper and slowly scrape off the material after it is heated. Monotonous and boring. Use science instead.
If you have all the time in the world and you are a glutton for punishment you can use a scraper and slowly scrape off the material after it is heated. Monotonous and boring. Use science instead.
Dry ice blocks cool the metal and sound-deadening material to a temperature where adhesive doesn’t work anymore and the material becomes brittle. Move the pieces around, wait a minute or two and then pound away with a hammer. You can clear an entire trunk in about 5 to 10 minutes.
Dry ice blocks cool the metal and sound-deadening material to a temperature where adhesive doesn’t work anymore and the material becomes brittle. Move the pieces around, wait a minute or two and then pound away with a hammer. You can clear an entire trunk in about 5 to 10 minutes.
 Leather welding gloves, a hammer and dry ice is all you need to get rid of the sound-deadening material. The gloves are the most important tool for safety. Dry ice will burn you, just like regular heat can burn you. Do not make direct contact with the skin.
Leather welding gloves, a hammer and dry ice is all you need to get rid of the sound-deadening material. The gloves are the most important tool for safety. Dry ice will burn you, just like regular heat can burn you. Do not make direct contact with the skin.
Heed the warnings on the dry ice packaging. Yes, this stuff can burn you. Yes, this stuff can suffocate you. And most importantly do not eat it — not that anyone would, but obviously some moron did, which is why there is a warning label on the packaging. Thank you, Darwin.
Heed the warnings on the dry ice packaging. Yes, this stuff can burn you. Yes, this stuff can suffocate you. And most importantly do not eat it — not that anyone would, but obviously some moron did, which is why there is a warning label on the packaging. Thank you, Darwin.

 

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Image courtesy of Rob Krider