Club Cobra

Club Cobra (http://www.clubcobra.com/forums/)
-   ERA---Speak with Bob Putnam (http://www.clubcobra.com/forums/era-speak-bob-putnam/)
-   -   db measurements sidepipe FIA (http://www.clubcobra.com/forums/era-speak-bob-putnam/131403-db-measurements-sidepipe-fia.html)

J.Jensen 10-20-2014 06:44 AM
db measurements sidepipe FIA
 
Have anyone done any measurements of the noise on their ERAs?

The Norwegian regulations for amateur built vehicles dictates the vehicle must meet a European sound regulation. The maximum sound level is 87db.

The microphone is to be placed 20" from the exhaust outlet, at a 45 degree angle in the direction that puts the mic the furthest away from the body.

Throttle is applied to bring the engine up to 3/4 of peak power rpm, or if that rpm is not available, 3/4 of engines maximum contructed? rpm. Say rev limiter anyone?

I´m guessing open pipes are definitely out the window, how quiet are the quiet ones at say, 4000 rpm for a 289/302/331?

Rick Parker 10-20-2014 09:25 AM
Sort of makes it sound like a 66 Mustang on the showroom floor. (:

patrickt 10-20-2014 02:09 PM
Quote:
Originally Posted by J.Jensen (Post 1323078)
Have anyone done any measurements of the noise on their ERAs?

The Norwegian regulations for amateur built vehicles dictates the vehicle must meet a European sound regulation. The maximum sound level is 87db.
That's going to be a toughie.... I have the "quiet type" pipes on my ERA and she idles at just under 95 decibels.

http://www.clubcobra.com/photopost/d...0/sound001.jpg

DanEC 10-20-2014 04:29 PM
87 db is pretty low. You would probably have to use a reverse flow undercar mufflers with a side exit and then I'm not sure it can be met. Those regulator guys can kind of put a damper on fun. :(

J.Jensen 10-20-2014 06:57 PM
Could the pipe be filled with some type of wool or something to muffle it just for the inspection and take the pipe off and remove it after the paperwork is done?

patrickt 10-20-2014 07:43 PM
Quote:
Originally Posted by J.Jensen (Post 1323139)
Could the pipe be filled with some type of wool or something to muffle it just for the inspection and take the pipe off and remove it after the paperwork is done?
Maybe. I've seen some small block Cobras that were pretty quiet (too quiet). Since you're asking about small block FIAs, that might work to get you by.

strictlypersonl 10-21-2014 08:58 AM
Generally, the 427 exhaust is considerably louder than the FIA. If necessary, however, there is quite a bit of room in the FIA down-pipe where some extra silencing material can be positioned. Permanently, of course. :rolleyes:

J.Jensen 10-21-2014 09:05 AM
God no, permanent would suck. But a downpipe could maybe be replaced for an open one - to keep the silent for reinstallation for the annual inspections (every two years)?

ERA174 10-28-2014 10:31 PM
If the government inspection is going to incorporate an analysis of the exhaust gases, as well as decibel output, then you will need to retune the engine for the test. So, have a street exhaust/tune and track only exhaust/tune, that you can switch between. If you are not experienced with converting between the two, have the company you pay to do the tuning/exhaust work show you how to convert between the two.

*13* 10-29-2014 03:11 AM
My 289 has fairly low compression & would probably be considered quiet next to most. I have the sidepipes with the "cherry bomb" style center piece. If you keep the RPMs down its reasonable. @ 3000-4000 rpm it's not going to be quiet on any meter.

J.Jensen 10-29-2014 04:23 AM
Quote:
Originally Posted by ERA174 (Post 1324140)
If the government inspection is going to incorporate an analysis of the exhaust gases, as well as decibel output, then you will need to retune the engine for the test. So, have a street exhaust/tune and track only exhaust/tune, that you can switch between. If you are not experienced with converting between the two, have the company you pay to do the tuning/exhaust work show you how to convert between the two.
No exhaust gas analysis. Only requirement is no colored smoke on acceleration :D


All times are GMT -7. The time now is 04:24 PM.

Powered by vBulletin® Version 3.8.0
Copyright ©2000 - 2025, Jelsoft Enterprises Ltd.
Search Engine Friendly URLs by vBSEO 3.6.0
The representations expressed are the representations and opinions of the clubcobra.com forum members and do not necessarily reflect the opinions and viewpoints of the site owners, moderators, Shelby American, any other replica manufacturer, Ford Motor Company. This website has been planned and developed by clubcobra.com and its forum members and should not be construed as being endorsed by Ford Motor Company, or Shelby American or any other manufacturer unless expressly noted by that entity. "Cobra" and the Cobra logo are registered trademarks for Ford Motor Co., Inc. clubcobra.com forum members agree not to post any copyrighted material unless the copyrighted material is owned by you. Although we do not and cannot review the messages posted and are not responsible for the content of any of these messages, we reserve the right to delete any message for any reason whatsoever. You remain solely responsible for the content of your messages, and you agree to indemnify and hold us harmless with respect to any claim based upon transmission of your message(s). Thank you for visiting clubcobra.com. For full policy documentation refer to the following link: