GMCforum
For enthusiast of the Classic GMC Motorhome built from 1973 to 1978. A web-based mirror of the GMCnet mailing list.

Home » Public Forums » GMCnet » Quiet Exhaust Question?
[GMCnet] Re: Quiet Exhaust Question? [message #368562 is a reply to message #368561] Tue, 25 January 2022 11:08 Go to previous messageGo to previous message
jimk is currently offline  jimk   United States
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma:
Senior Member
On our Air Filter side of the business, we spent lot of time in Clean rooms
verifying noise using the DB meter and soon realized there were considerable
factors we had to explain.
Naturally we use data from a location that had the lowest DB.


---------- Forwarded message ---------
From: Todd Sullivan
Date: Tue, Jan 25, 2022 at 8:53 AM
Subject: [GMCnet] Re: Quiet Exhaust Question?
To:


Jim’s comment reminds me of a lesson learned while dune riding a dirt bike
with the fiberglass pole and flag required for visibility. If the
flag(which mounts via the rear axle) is installed on the muffler side the
hot gasses from the muffler quickly make short work of the fiberglass pole
despite the fact that the pole is several inches to more than a foot away
from the exhaust tip while underway.

Sully
Bellevue wa

On Tue, Jan 25, 2022 at 8:24 AM Jim Kanomata wrote:

> There is a reason why on a RV we prefer to exit to the side and down.
> When towing a car, it is preferable not to have the Hot air hitting
> directly onto them. Also less chance of bending the pipe tip. If you use a
> DB meter, the noise outside is the same if the pipe exits to the rear or
> side. Just sound different inside.
>
>
> On Tue, Jan 25, 2022 at 7:22 AM James Hupy wrote:
>
>> GM experimented with no mufflers, by denting the exhaust pipe as well as
>> the tailpipes. It was good when the cars were new, but the aftermarket
>> exhaust providers raised "HOLY NED" with them because they had to
provide
>> similar exhaust systems. What usually happened was that the OEM stuff
got
>> replaced from manifold flanges to end of tailpipe with conventional
>> systems. Customers were none to happy about the bills for that. GM
> changed
>> back in a couple of years. Then came "catastrophic convertes"
resonators,
>> etc.
>> Jim Hupy
>> Salem, Oregon
>>
>> On Tue, Jan 25, 2022, 7:13 AM Keith V wrote:
>>
>>> I fixed the rap by running the exhaust straight out the back rather
> than
>>> pointed out the pass side. I barely hear it at all now 🙂
>>> ________________________________
>>> From: Terry via Gmclist
>>> Sent: Sunday, January 23, 2022 4:51 PM
>>> To: gmclist@list.gmcnet.org
>>> Cc: Terry
>>> Subject: [GMCnet] Re: Quiet Exhaust Question?
>>>
>>> Mine is quiet with 2 mufflers up front and a long pipe to the right
> rear
>>> corner. Pipe is 2.5 inch diameter. If I ever woke anybody up in a
>> campground
>>> they must have been sleeping in the road. Maybe the insides of one or
>> both
>>> of your mufflers has corroded away and is not cancelling the sound
> wave.
>>> Headers up front are definitely louder than cast iron manifolds and I
>> also
>>> have those courtesy of the P.O.. I also have the fender liners
> installed.
>>> Sitting in the driver's seat I can barely hear the engine running.
> Engine
>>> tuning can make a big difference in the amount of sound emitted from
>>> headers, but usually will be accompanied by loss of normal power
output
>>> and poor fuel economy. If it runs well and smooth I would
check/replace
>> the
>>> mufflers first,especially since I have the equipment to tackle that
> job.
>> A
>>> resonator is just another muffler and will quiet it more (and
eliminate
>>> exhaust "crack") but also may cost just as much to procure and get
>>> installed as replacing the mufflers. Depends on where and how you
shop.
>>> --
>>> Terry Kelpien
>>>
>>> ASE Master Technician
>>>
>>> 73 Glacier 260
>>>
>>> Smithfield, Va.
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>> _______________________________________________
>>> GMCnet mailing list
>>> Unsubscribe or Change List Options:
>>>
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
>
>
> --
> Jim Kanomata ASE
> Applied/GMC, Newark,CA
> jimk@appliedairfilters.com
> http://www.gmcrvparts.com
> 1-800-752-7502
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:


--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:


Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
 
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Read Message
Previous Topic: Gmcnet forum rules
Next Topic: Grease Vs Silicon Grease Vs Dielectric Grease
Goto Forum:
  


Current Time: Tue Jul 02 11:06:22 CDT 2024

Total time taken to generate the page: 0.00731 seconds