body and interior How Loud Is Your Car At 70Mph?

[jgerry2002]

Another part that is good for some noise reduction is the "heat sheild" (should be called noise shield) that goes over the stock header (tii or stock).

 

Typically these are thrown out as they appear to be some hp robbing, evil looking emissions device. Which is not the case.

 

I put this back on my '74 tii and it made a BIG difference in cabin noise, especially on the highway.

[LimeySteve]

I think it should be mentioned that the iPhone decibel meters are not very good. Mine reads over 90dB when i'm simply talking at a normal tone in  a quite room 3 feet away from the phone. earplugs are a good idea... I use them while working, maybe I should just keep them in full time

my Droid sound meter reads 75 Db 3 ft away conversation in a not so quiet office.So I'd say the droid one is pretty good.

[ndog]

Iam going to borrow our shop db meter and compare it to my phone iam not so sure its a app-able kind of measurement mi phone said 97db

[hegedus]

72 tii on HWY 280 in SF Bay Area.

 

78 Db as measured by SPL Meter app on iPhone.  With 5 speed at 3200 rpm.

[jgerock]

I'm going to get the iPhone app to check my tii.  My left ear hurt after driving to Vintage 2008, but that most likely was caused more by the wind buffeting into the car than the Ansa muffler (4 speed and 3.64 diff).

 

 

[LimeySteve]

Ear plus are a good idea to prevent inner ear damage from the wind buffeting , I always wear then in my 32 Ford Roadster when on the freeway, you can hear more of the car & I'm refreshed not beaten up when I arrive at my destination, regardless of car noise , the wind will f up your inner ear.

[gliding_serpent2]

... loud enough to feel that I am going REALLY fast. 

[PatAllen]

My automatic is very quiet. i went totaly dumb fussy when i restored this car about that. i kept all the original deadening possible as close to oem, and added few more where it seemed to miss some. note the speedo is in kph and off by about 10kph.

 

Edited May 13, 2013 by PatAllen

[diathermic]

Another part that is good for some noise reduction is the "heat sheild" (should be called noise shield) that goes over the stock header (tii or stock).

 

Typically these are thrown out as they appear to be some hp robbing, evil looking emissions device. Which is not the case.

 

I put this back on my '74 tii and it made a BIG difference in cabin noise, especially on the highway.

Do you have a picture of this heat shield?  I had been curious about the noise effects of theses things and am glad to hear your have noticed a difference.  Most modern cars have lots of sheet metal shielding over their exhaust and I was wondering how much of it was for heat and how much was for noise.

Also curious as to the effects of wrapping exhausts with the heat wrap most folks use in Turbo set-ups.  I was thinking it would dampen sound a lot, but don't like the thought of these wraps making the headers heat up even more than they already do by preventing the headers from radiating their heat.

Edited May 13, 2013 by diathermic

[bnam]

I don't believe that the heat shield has any impact on noise.  The original cast iron exhaust is heavy and probably has more noise absorbing qualities than the thin heat shield.

[visionaut]

Loud enough that I either need to crank the stereo up 2 notches, or turn it off and enjoy the amazing ambient 'symphony'. 

 

Not often being outside the car as it's driving about, I've heard often from friends that they can hear me coming/going a block away...

[jgerry2002]

Look at the shape of this part that attaches to the header. I believe it to be more than a heat shield. All I can say was there is a noticeable drop in db (wish I had an iphone or something to measure this) in the cabin when i put this part back on. There is something going on the with resonance coming off the header. It changes / reflects that sound away from the cabin.

 

#8 here -> http://www.realoem.com/bmw/showparts.do?model=2231&mospid=47131&btnr=11_2399&hg=11&fg=50

 

 

I don't believe that the heat shield has any impact on noise.  The original cast iron exhaust is heavy and probably has more noise absorbing qualities than the thin heat shield.

Edited May 14, 2013 by jgerry2002

[Guest_anonymous]

87db. 40dcoe w/itg air filters, stahl pattern header, ansa center, ansa oem style muffler. 5speed, 3.91 lsd. Fred flinstone floor pans, crack house window seals, no deadening whatsoever or even an attempt to quiet the interior. Well maybe listening to some Iron Maiden's Piece of Mind helps a bit.

[Slightly Larger Roundies]

, crack house window seals, 

 

 

^^^  Classic.

[BDB]

diathermic,

 

interesting study!  once i get my bmw roadworthy this weekend, i'll post my results.  i have a carb'd 4 speed, so yes, it is teeth gnashing annoying how much noise this car makes at freeway (70mph) speeds.  i usually don't take long highway drives with the BMW.  it also gives me motivation to install the 5 speed trannies I have in my garage!  that's my late summer project.