[Z06] Valve Train Sound Test: WCCH vs Stock Heads
02-17-2013, 07:09 PM
#1
Team Owner
Thread Starter
Valve Train Sound Test: WCCH vs Stock Heads
Well today my buddy Rich came over to check out how my WCCH heads (SS valves/dual springs/CHE rockers) sounded compared to his stock 2011 Z06.
I took some video. And he used a sound meter.
We compared cars in the same spot of my garage one right after. He tested from 5 locations around the perimeter of the motor as well as inside the cabin with the windows up. Testing was done at idle and at 2K RPM. Again, for consistency, I did my best to hold both motors at level rpm during that testing. I can tell you there is some variance as its impossible to hold rpm perfectly at 2K. We also both had our frc's off and both engines were completely warmed after driving.
I was supposed to get my CAT replaced yesterday but that didn't happen. I have a confirmed leak in the driver CAT so not sure if that can be heard or contributed sound levels.
My impression is that the stock motor is quieter but both have the same overall valve train component sounds. Rich can give his feed back on this.
STOCK IDLE
STOCK 2K RPM
WCCH IDLE
WCCH 2K RPM
WCCH HOOD DOWN (sorry this did not come out for stock)
DH
I took some video. And he used a sound meter.
We compared cars in the same spot of my garage one right after. He tested from 5 locations around the perimeter of the motor as well as inside the cabin with the windows up. Testing was done at idle and at 2K RPM. Again, for consistency, I did my best to hold both motors at level rpm during that testing. I can tell you there is some variance as its impossible to hold rpm perfectly at 2K. We also both had our frc's off and both engines were completely warmed after driving.
I was supposed to get my CAT replaced yesterday but that didn't happen. I have a confirmed leak in the driver CAT so not sure if that can be heard or contributed sound levels.
My impression is that the stock motor is quieter but both have the same overall valve train component sounds. Rich can give his feed back on this.
STOCK IDLE
STOCK 2K RPM
WCCH IDLE
WCCH 2K RPM
WCCH HOOD DOWN (sorry this did not come out for stock)
DH
Last edited by Dirty Howie; 02-17-2013 at 08:28 PM.
02-17-2013, 10:06 PM
#8
Melting Slicks
Here is the trabulated data:
Some representative examples;
Notes:
Meter used was a Radio Shack Sound Level Meter cat. no.33-200. Decibels are measured as a logarithmic unit (powers of 10) If you want to read more, go here : http://www.physicsclassroom.com/class/sound/u11l2b.cfm.
To keep it simple, an increase of 3 db doubles the level. The hearing threshold (silence) is 0 db.
Positions 1-5 were such that the meter micro phone was right at the edge of the engine compartment, pointing toward the center of the engine. Meter was placed on a piece of dense foam to isolate from any extraneous frequencies.
*Position 6 was in the driver’s seat and was very subjective, i.e. the meter reading varied significantly depending on where it was held.
"C" weighting covers 32-10k Hz; "A" weighting covers 500-10k Hz. This means you cut out a lot of low frequencies using "A" weighting. All measurements were made using "C" weighting except for additional interior samples to remove predominantly lower freqs present in the interior (notice the drastic difference between C and A weighting).
My personal impression: The new heads are louder, but not buy a significant amount. With the hood closed you could hardly tell a difference between the two vehicles.
Some representative examples;
Notes:
Meter used was a Radio Shack Sound Level Meter cat. no.33-200. Decibels are measured as a logarithmic unit (powers of 10) If you want to read more, go here : http://www.physicsclassroom.com/class/sound/u11l2b.cfm.
To keep it simple, an increase of 3 db doubles the level. The hearing threshold (silence) is 0 db.
Positions 1-5 were such that the meter micro phone was right at the edge of the engine compartment, pointing toward the center of the engine. Meter was placed on a piece of dense foam to isolate from any extraneous frequencies.
*Position 6 was in the driver’s seat and was very subjective, i.e. the meter reading varied significantly depending on where it was held.
"C" weighting covers 32-10k Hz; "A" weighting covers 500-10k Hz. This means you cut out a lot of low frequencies using "A" weighting. All measurements were made using "C" weighting except for additional interior samples to remove predominantly lower freqs present in the interior (notice the drastic difference between C and A weighting).
My personal impression: The new heads are louder, but not buy a significant amount. With the hood closed you could hardly tell a difference between the two vehicles.
02-17-2013, 10:46 PM
#9
Team Owner
Thread Starter
Here is the trabulated data:
Some representative examples;
Notes:
Meter used was a Radio Shack Sound Level Meter cat. no.33-200. Decibels are measured as a logarithmic unit (powers of 10) If you want to read more, go here : http://www.physicsclassroom.com/class/sound/u11l2b.cfm.
To keep it simple, an increase of 3 db doubles the level. The hearing threshold (silence) is 0 db.
Positions 1-5 were such that the meter micro phone was right at the edge of the engine compartment, pointing toward the center of the engine. Meter was placed on a piece of dense foam to isolate from any extraneous frequencies.
*Position 6 was in the driver’s seat and was very subjective, i.e. the meter reading varied significantly depending on where it was held.
"C" weighting covers 32-10k Hz; "A" weighting covers 500-10k Hz. This means you cut out a lot of low frequencies using "A" weighting. All measurements were made using "C" weighting except for additional interior samples to remove predominantly lower freqs present in the interior (notice the drastic difference between C and A weighting).
My personal impression: The new heads are louder, but not buy a significant amount. With the hood closed you could hardly tell a difference between the two vehicles.
Some representative examples;
Notes:
Meter used was a Radio Shack Sound Level Meter cat. no.33-200. Decibels are measured as a logarithmic unit (powers of 10) If you want to read more, go here : http://www.physicsclassroom.com/class/sound/u11l2b.cfm.
To keep it simple, an increase of 3 db doubles the level. The hearing threshold (silence) is 0 db.
Positions 1-5 were such that the meter micro phone was right at the edge of the engine compartment, pointing toward the center of the engine. Meter was placed on a piece of dense foam to isolate from any extraneous frequencies.
*Position 6 was in the driver’s seat and was very subjective, i.e. the meter reading varied significantly depending on where it was held.
"C" weighting covers 32-10k Hz; "A" weighting covers 500-10k Hz. This means you cut out a lot of low frequencies using "A" weighting. All measurements were made using "C" weighting except for additional interior samples to remove predominantly lower freqs present in the interior (notice the drastic difference between C and A weighting).
My personal impression: The new heads are louder, but not buy a significant amount. With the hood closed you could hardly tell a difference between the two vehicles.
My new motor now has 34K miles and 1K miles with the new heads.
DH
02-17-2013, 11:02 PM
#10
Very nice job Rich. And you too Howie. Both of you guys did a good job with this comparison and documenting it, using actual video as well as a sound level meter. An actual measurement in decibels of one setup vs another, complete with video, so that people can get a good idea as to what to expect should they decide to go this route.
02-17-2013, 11:16 PM
#11
Team Owner
Thread Starter
Very nice job Rich. And you too Howie. Both of you guys did a good job with this comparison and documenting it, using actual video as well as a sound level meter. An actual measurement in decibels of one setup vs another, complete with video, so that people can get a good idea as to what to expect should they decide to go this route.
Hopefully it will be helpful for some members.
DH
02-18-2013, 11:23 AM
#13
Melting Slicks
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Thanks for the information. I am doing the WCCH heads one week from today. I was a little concerned about Clogan's comment about the louder heads. This really helps. Question, Howie's exhaust system has close to 100,000 more miles of use than Minkster's. I would think it would surely be a little louder. Thanks again.
Mine has B & B PRT's which are louder than stock.
Mark
Mine has B & B PRT's which are louder than stock.
Mark
Last edited by MarkC; 02-18-2013 at 05:50 PM.
02-18-2013, 04:27 PM
#14
Team Owner
Thread Starter
02-18-2013, 04:31 PM
#15
Team Owner
Thread Starter
Thanks for the information. I am doing the WCCH heads one week from today. I was a little concerned about Clogan's comment about the louder heads. This really helps. Question, Howie's exhaust system has close to 100,000 more miles of use than Minkster's. I would think it would surely be a little louder. Thanks again.
Mine has B & B PRT's which are lounder than stock.
Mark
Mine has B & B PRT's which are lounder than stock.
Mark
Rich has stock but different (ZR1 I think) exhaust. But I really don't think his meter is picking that up.
I think if you listen and compare the videos you will have a very good idea of what to expect. The camera sound level is static and was placed exactly the same on both cars.
DH
02-18-2013, 05:20 PM
#20
Team Owner
Thread Starter