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Member -- Product Review
A special tip of the hat and thanks to Eric J. Miller, for writing and submitting this review!
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Advanced Thermal Products, Inc.
Sound/Thermal Blanket System
A Consumer Test Report
By Eric J. Miller
Upon purchasing my 2001 Dodge Ram 3500 dually, my wife had a few things to say. "IT'S TOO BIG - TOO UGLY - TOO LOUD. " Custom side paint and pin striping dropped the words "too ugly" from her description (especially with all the compliments we were getting) which left me with "too loud" and "too big". I could not do anything about the "too big" so I went after the "too loud".
Being a regular reader of the TDR Web Site, I discovered a forum post on sound/thermal blankets that are produced by Advanced Thermal Products Inc. (ATPI), a company in California. Although the person who posted had purchased parts of the system and was satisfied, there was no concise data on sound reduction. Their only response was the hood blanket and valve cover blanket seemed to be the most effective blankets of the set and they were satisfied.
Due to the expense of the ATPI blankets, I researched the price of boat engine sound reduction materials and found them to be too expensive considering all the fitting work I would have to do to. I decided the blankets offered by ATPI were probably the best route to go. After all, I only intended to spend about $400 for the valve cover and hood blankets. However, after talking to Tim Thompson at ATPI, I decided to go for the whole set at $850 including shipping to Pennsylvania. (You can see a picture of the blanket set in TDR Register - Issue 27, p. 111)
Company Address:
Advanced Thermal Products, Inc.
P. O. Box 15817
Santa Ana, California 92735-0817
Phone: (800) 826-8417
e-mail: timmer-t@atpwrap.com
Company Web Site:
www.atpwrap.com
Cost of the various components is:
#129CU 5900 Reflective Hood Blanket $270
#129CU 5901 Valve Cover Blanket $150
#129CU 5902 Turbo Manifold Blanket $250
#129CU 5903 Outlet Elbow Exhaust Blanket $140
#129CU 5904 Outlet Elbow Exhaust Blanket $85
Total = $805. 50
Product Quality and Theory
Let there be no misunderstanding - this is a quality product! Upon opening the shipment, I was quite impressed. Also, communication from Tim Thompson was of a most courteous and caring nature and produced the following background information. His company (ATPI) mainly produces sound/thermal blankets for commercial trucks, U. S. Coast Guard vessels, and some racecars. Their purpose is to increase thermal efficiency and decrease the sound level. As ATPI had a company Ram, it was decided to experiment on it. Others heard the resulting sound reduction and so production began. The hood blanket has an aluminum colored reflective outer shell with a sheet of sound deadening plastic sandwiched between. The valve cover blanket is constructed in a similar manner but is thicker and has a non-reflective black heat resistant material on the outside shell that looks similar to black nylon. The turbo/manifold and exhaust pipe blankets are constructed from the same black outer shell as the valve cover but have a wire mesh inner shell that holds a fibrous inner layer of insulation in place. Tim claimed the blankets reduced sound on their Ram by about 25% but he had not taken sound meter readings. He had no data to back up his claims, Tim mentioned he would appreciate a copy of my test study. Tim also mentioned their truck's water temperature had the habit of constantly fluctuating and the blankets steadied the needle. He felt more of the heat was going out the exhaust rather than being reflected into the engine compartment. Also, diesels like heat and the blankets help to maintain a good operating environment. He alluded to turbine temperature and "coking" if proper time was not allowed for cool-down. Also, most people who bought one or two blankets usually came back for the complete set. One item of very poor quality was a set of instructions - there were none in the box. I feel instructions with pictures are badly needed. A phone call to the company resulted in a very vague set of instructions. Tim tells me he is correcting this problem now with an mpeg file to be sent with each order.
Disclaimer
I am not associated with ATPI in any manner and take no responsibility for sound results on your particular truck. I am a technology teacher in a middle school and have used, what I feel, is a controlled environment to test my Ram. Next year, after 37 years of teaching, I plan to retire, place my Harley Road King in the back of the truck, pull a 35' travel trailer behind, gather my wife and begin touring the country.
Test Background
To begin, beside the description above, my truck has an auto transmission with 4. 10 rear. I also installed Bosch 275 RV Injectors and a VA Box. It has a leather interior - I feel I should note this as it might reflect on sound absorption when compared to a cloth interior. Also, I used a professional quality Simpson Sound Meter placed in the "slow mode" (averages readings over a period of time to eliminate "spikes") and I calibrated the meter both before and after each test at 94 dBA to double check its accuracy. The meter is "A Scale" calibrated to most closely resemble hearing of the human ear. External vehicle meter readings were taken 1 foot outside the right front wheel well. Engine compartment readings were taken with the meter 15" from the valve cover - facing it while being held directly inside the right hand battery. Readings within the cab were taken with the sound meter placed on the leather seat beside me in the exact center of the passenger compartment. The fan control for the heater A/C system was turned off so as not to interfere. The engine was warmed up. Highway testing was done at 60 MPH (1900 RPM) on a slightly worn 35 year old cement 4 lane highway with a 1 to 2 degree incline. 3 Month old stock 235 tires were on the truck. All highway tests were recorded at the exact same spot.
Decibel (dBA) Relationship
As the test is based on decibel "A Scale" readings (dBA), I feel you should have some sense of dBA relationships. A whisper is 40 dBA, normal conversation is approximately 65 dbA, potential damage to the ear begins at 92. To bring all this home to our front seat, set your air conditioning at its normal position and the fan at its lowest setting and turn off the engine. The lowest fan speed will emit 48 dBA, the next highest speed will emit 54 dBA, the next highest 60 dBA, and the highest setting 68 dBA which just happens to be the dBA of road noise when my truck is coasting at 60 MPH on the cement highway. To further clarify this, I would like to quote Robert Patton from his article "Noise Reduction Project" in TDR Magazine - Issue 26, p. 76. Robert states the relationship quite well when he writes "The measure of a decibel's effects are progressive: a 3 dBA drop equals about one-half the sound power, but is only the threshold of what the average person can perceive as "quieter". It takes a 10-dBA reduction for a person to declare that something is "twice as quiet. "
The Test
In the Spring I mentioned on our web site forum that I was ordering the ATPI blankets and would write a thorough report on them. A few of you e-mailed me asking what stock sound levels were on the truck at present. One astute "Ram'er" said he felt a blanket should be made for the engine sump as he felt a lot of noise was coming from there and would I take a measurement at that point. He was right - 101 decibels!!!
Stock Readings
So here is the amount of noise I purchased for $35, 000. I can't tell you the dBA of my truck being unloaded from the carrier, but I can give you the following info with no ATPI blankets installed. With the truck sitting on my asphalt driveway, the shift lever in "Park", and warmed up -
1 foot in front of the radiator the decibel level is 88, 1 foot outside the right front wheel well 87, at the tailpipe in the back of the truck 77, the sump is 101, and the sound level inside the cab is 62.
Under the hood and 15 inches away from the valve cover the sound is 102 dBA. If you drop the shift lever into gear with your foot on the break and the engine at idle, it creates an increases of : In front of radiator +3, right front wheel +5 (Now at level potentially damaging to ears), cab interior +2. If the engine is cold, add another 4 dBA to the cab interior.
Blanket Testing
So let's add ATPI blankets and see what the dollar buys. Although I took 9 different meter readings from different positions as each blanket was installed, I will not bore you with that info and simply focus on cab interior sound. I will address idle speed in gear, mild acceleration through the gears, and speed at 60 MPH / 1900 RPM.
<h3>DbA Readings</h3>
Valve Cover Blanket
Idle in gear: 64 to 63. 5 = . 5 dBA reduction
Mild acceleration through gears: 74 to 71 = 3 dBA reduction
60 MPH: 73 to 72 = 1 dBA reduction
Valve Cover Blanket + Hood Blanket
Idle in gear: 63. 5 to 62 = 1. 5 dBA reduction
Mild acceleration through gears: 71 to 70. 5 = . 5 dBA reduction
60 MPH: Remained at 72 = No difference (Surprising)
Valve Cover Blanket + Hood Blanket + Turbo/Manifold Blanket
Idle in gear: 62 to 61= 1 dBA reduction
Mild acceleration through gears: 70. 5 to 70 = . 5 dBA reduction
60 MPH: 72 to 69. 5 = 1. 5 dBA reduction
Note: I feel the turbo/manifold blanket is one of the three best blankets of the set to invest in, as it took away about 80% of the turbo "whine".
Valve Cover Blanket + Hood Blanket + Turbo/Manifold Blanket + Both Exhaust
Pipe Blankets (complete set)
Idle in gear: 61 to 59 = 2 dBA reduction
Mild acceleration through gears: 70 to 68 = 2 dBA reduction
60 MPH: 70. 5 to 69. 5 = 1 dBA reduction
Note: The two exhaust pipe blankets are the next best buy as they took away the most noise while also preventing the floor on the passenger side from
getting hot.
Perceived Sound Versus Actual Sound
Regardless of what the meter reads, we do not hear like the meter - even when set on the "A Scale". Our ears might "perceive" two sounds of the same intensity as being different - one more pleasing than the other to the ear. An example might be two model airplane engines - one a 2 -cycle and one a 4-cycle. The 2-cycle has a higher "pitch" and is much more annoying while the 4-cycle has a lower pitch and is much more pleasing to the ear. I believe the blankets on my truck took away some of that higher tapping pitch of the valves for I "perceive" a better sound within the cab. For you "bombers", you'll still knock'em dead at the traffic lights for that sump is still blasting 101 dBA, which works its way through the wheel wells and reflects off the road.
Turbo Cool-down
One accessory I would recommend if you should purchase the blankets is a "Diesel Turbo Life Saver" from Geno's. When I reach my driveway and am ready to park the truck, the EGT's (pre turbo) are 450 degrees. With the blankets installed it takes 3 minutes to bring the temperature down to 300 and 4 minutes to "bottom out" the needle. With the timer installed, I simply hold in the "time-set" button until it beeps 3 or 4 times (sets the minutes I desire from one to five) pull my key out of the ignition, shut the door, hit the keyless remote alarm button, and walk away. This sets the alarm and when the engine stops, the alarm vibrations mode also sets. (I have a Chapman Alarm System that took the original installer 20 minutes to correct after I installed the timer. )
Notes & Conclusion
You will notice the greatest difference in sound reduction with a cold engine or while accelerating through the lower gears. With my 4. 10 rear at 60 MPH & 1900 RPM with the truck unloaded, the blankets reduced the sound to 1. 5 dBA above road noise and eliminated about 80% of the turbo whine. While pulling a 4000 lb. boat, the dBA increased to 73 at 60 MPH which was the same as the truck unloaded without blankets installed. In Robert Patton's "Noise Reduction Project", (TDR Register - Issue 26, p. 76) his goal was to achieve a 3 dBA reduction but he could only achieve a reduction of 1 dBA at road speed. His cost in materials was under $300. By comparison, I spent $850 and obtained "in-cab" reductions of 3. 5 dBA at a roadpeed of 60 MPH, a 6 dBA reduction going through the gears with mild acceleration, and a 5 dBA reduction at idle in gear. Exterior noise was reduced by approximately 4 dBA in the various locations measured. My ears "perceive" this to be about a 25% sound reduction in the cab. The actual meter readings I have documented reasonably verify this. If I wanted to save $270, I would not purchase the hood blanket as this seemed to be the least effective of all the blankets. However, it looks quite impressive with the hood up. Is it worth it? Would I purchase them again? Under my particular circumstances with the truck I own, my sensitive ears, and my wife complaining - yup! She now only complains about the noise others hear outside the cab when I pull up to the gym at 5:30 in the morning and let the turbo cool down. I can live with this!
Installation tips if you plan to purchase
Hood blanket - The original cardboard hood insulator is held in place with 15 V-shaped plastic push clips. Do not cut these off as they are $3 each. Use a small screwdriver to bend the one "free" leg of the insert pin toward the other and carefully pull out. When you reinsert these pins around the edge where the blanket is hemmed, you will need to cut away one or more of the layers on the underside as the blanket is too thick for the pins to lock into some of the holes. Valve Cover Blanket - As you face the engine from the front, I found this cover could best be inserted by tilting it toward the left a bit as I pushed it back over the valve cover. This is a tight fit to get it under the back of the engine compartment. I then needed to probe with a wooden dowel to unfold the rear of the blanket where the edge in the back had rolled under itself. Turbo/Manifold Blanket - I replaced two of the 2" springs with 4" springs so they could reach where I felt they should go. I'm not sure I have it secured properly as pictures and instructions are badly needed here. About an 8" piece of wire should be used to fish the springs up through the manifold. As my EGT sensor was installed pre-turbo, I had to cut the blanket with a model knife and pair of tin snips and simply fold it back around the sensor and exiting wire. I am not sure if they have a special blanket for manifolds with exhaust brakes installed. Exhaust Pipe Blankets - I found the blanket that covers the exhaust pipe downward could best be inserted from the bottom upward. However, I had to change the two top springs from 2" to 4" to get them fastened. (ATPI sent me the additional springs with no charge upon request. ) The blanket on the pipe under the floor was no problem.
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[This message has been edited by ToolManTimTaylor1 (edited 05-22-2001). ]
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