JMiller138

Have 911T (71) and want to reduce noise level in the car. Anyone know of a quieter muffler than the stock muffler.

Also anyone successful at reducing the engine noise using added insulation or sound panels. Would love any help here - the noise level is making me want to sell it - don't want it to come to that!!!

Thanks
Jim

Tom F

Your muffler may just be a mess inside. Why not have someone who knows them evaluate it, and buy a new one if that's what is indicated? The factory exhaust system is the best system I've seen, except for the SSI heat exchangers which are better, but still use a stock muffler. You could it an exhaust from a '75-'79 car (but not one that had thermal reactors), but it would be expensive (if new), a mess (if used) and cause a power loss (regardless).

JMiller138

Tom

I have no idea how old the muffler is, it is rusty on the outside. I repaced the heat exchangers with SSI's last year. How do you tell if the muffler inside is bad. All I know is it is extremely hard to hear the radio at 55+ mph, is that normal? So people have suggested the high noise level is due to the high tip speed of the cooling fan. Thanks for the response
Jim

Matt Chamblin

Dyna Mat or one of the other sound absorption pads would be your best bet. To really bring the sound level down though, you will need to pull the floor carpets, and the rear seats, to kill road noise as well.

A quieter than stock muffler? Good luck. The majority of people purchasing aftermarket muffs, want more noise. But you could give the guys at GHL a call. They can make muffs loud or quiet.

You could always just upgrade your speakers or add an amplifier, if music is your priority. In my cars, radio takes a back seat to the awesome sound the engine puts out.

JMiller138

Matt

Thanks for the sugestions. Regarding sound levels. I tested the noise level using a meter from work and found the car produced 105 dba at 70 mph. OHSA reguires hearing protection for levels over 86 dba. I know this because we have adhere to this stuff at work. Who is GHL?

Jim

Rick C

These figures were reported for a 1984 3.2 in Car & Driver back then:

Idle = 59 db
Max = 83 db
70 = 75 db

Can't imagine that an earlier 911 would be 105db unless the muffler was shot.

tchanson

Jim,

105 db? Yikes! No wonder you can't hear your radio...

I agree with Tom and Rick's above comments that it sounds like your current factory muffler is shot, which is entirely possible after 31 years of service.

To my knowledge, GHL does not manufacture any systems for pre '78 applications. Why not try the<a href="http://www.pelicanparts.com/catalog/shopcart/911E/por_911E_exhaus_main.htm" target="_blank"> OEM style</a> exhaust (manufactured by Ansa/Dansk) that Pelican sells? Can't beat the price at roughly $250, if this is what you're looking for.

Good luck,
Tim

Matt Chamblin

[quote]Originally posted by JMiller138:
<strong>Matt

Thanks for the sugestions. Regarding sound levels. I tested the noise level using a meter from work and found the car produced 105 dba at 70 mph. OHSA reguires hearing protection for levels over 86 dba. I know this because we have adhere to this stuff at work. Who is GHL?

Jim</strong><hr></blockquote>

Jim, GHL is a quality aftermarket exhaust manufacture. I have no affiliation, just a happy customer. You can purchase there products from Pelican Parts.

As far as you sound levels go, was that with the windows up or down? I know in my SC the db's are higher with the windows up, due to the leaking weather seals. But it does sound like you muffler is shot, and due for replacement.

I know all about OSHA's sound levels, I use to drive a fire engine that produced 105 db @ 55 mph. I got my department to install A/C and headsets because of the OSHA regs.

JMiller138

The db measurments were with the windows up. The wind noise is another thing I would like to solve. I replaced the door seals and bought the little plasic parts kit you can use to plug holes in the doors but still the air noise is a pain. Any ideas you have about that also would be appreciated.

I see you have multiple 911's, do you find that the cars get quieter as years went on.

Jim

Steve W

Jim, 105 dba?? There is something wrong with your muffler, for sure. The baffles must be blown and rusted out inside. If its old, and rusty on the outside, chances are the guts aren't stainless either and have rusted out long ago. The stock muffler is pretty quiet, just like any other stock 911. A stock muffler mated with SSIs on a 911 should be no louder than 75 dba 70 mph.

JMiller138

Thanks to all for the help

I have ordered a ANSA/Dansk muffler from Pelican, I'll report back with the results. If it is quieter I will be a very happy man.

Jim

JMiller138

Well I installed the new Ansa/Dansk muller and it did reduce the noise level quite a bit. I now have a level of 77 dba at 70 mph, very close to the 75 db that was quoted in one of the the above messages.

Thanks for all the help
Jim

Matt Chamblin

That's a big improvement over the 105db's you had previously. <img src="graemlins/beerchug.gif" border="0" alt="[cheers]" />

tryan

going to sell your old muffler on ebay. just kiddimg