Ozdat Home Feature Cars Ozdat Classifieds Event Calander Links Trade Link Tech Resource Merchandise Donate Web Mail
It is currently Thu Mar 28, 2024 10:16 pm

All times are UTC+11:00




Post new topic  Reply to topic  [ 35 posts ]  Go to page « 1 2 3 »
Author Message
PostPosted: Sun Jan 29, 2017 12:35 am 
Offline
User avatar

Joined: Sat Jul 09, 2005 6:54 pm
Posts: 1380
Location: Blue Mountains, NSW
Unfortunately the twin loop design just won't fit neatly with the limited space. I had looked into that one already. Not only does it pass the sound twice through the mufflers, the proper ones should have the sound waves re-entering the chamber 180 deg out of phase to the ones coming into the muffler for the first time. They will effectively collide with each other and cancel each other out.

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18


Top
   
PostPosted: Sun Jan 29, 2017 2:01 am 
Offline
Donating Member
Donating Member
User avatar

Joined: Wed Feb 18, 2004 4:13 pm
Posts: 608
as long as it meets legal noise limits when open it would be.


Top
   
PostPosted: Sun Jan 29, 2017 4:19 pm 
Offline

Joined: Sat Jun 11, 2011 11:08 pm
Posts: 283
Try a aero chamber muffler. I put a small 9" long one in my Mrs ute with a cammed l67 and it sounds pretty blood stock lol. They reduce volume A LOT.


Top
   
PostPosted: Mon Jan 30, 2017 8:58 am 
Offline
Moderator
User avatar

Joined: Sat Oct 30, 2004 2:28 pm
Posts: 5357
Location: Melbourne, Australia
Did you notice any power decrease?
Are they straight through?

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun


Top
   
PostPosted: Mon Jan 30, 2017 10:13 am 
Offline

Joined: Fri Dec 19, 2003 4:16 pm
Posts: 75
Location: WARWICK, Q.
Makes your Datto sound like a V8 lol.
https://www.youtube.com/watch?v=k67iEZZg0g0

_________________
Richard..........http://www.youtube.com/watch?v=rqM9_Wq-TKc


Top
   
PostPosted: Mon Jan 30, 2017 10:32 pm 
Offline
Donating Member
Donating Member

Joined: Mon Aug 05, 2013 9:22 am
Posts: 95
Looks cool and sounds nice too but, what's a tuning tube? Is it adjustable/tuneable and how does it cancel amplitude?


Top
   
PostPosted: Tue Jan 31, 2017 2:36 pm 
Offline
Moderator
User avatar

Joined: Sat Oct 30, 2004 2:28 pm
Posts: 5357
Location: Melbourne, Australia
I've always wondered how these work with different capacity engines with different cylinders with different revs.
I assume there is a small Helmholtz resonator somewhere in there
Helmholtz resonators work with only specific frequencies and the associated harmonics. It's just a way of absorbing the energy using the existing energy out of phase.

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun


Top
   
PostPosted: Tue Jan 31, 2017 2:47 pm 
Offline
User avatar

Joined: Sat Jul 09, 2005 6:54 pm
Posts: 1380
Location: Blue Mountains, NSW
That's pretty much what i want to create within a standard muffler. Calculating the size needed isn't as simple as a 1/4 wave resonator though!

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18


Top
   
PostPosted: Fri Feb 03, 2017 5:21 pm 
Offline

Joined: Fri May 11, 2007 5:34 pm
Posts: 1901
Location: Coffs Harbour, NSW
I am running a twin 2.5" in/out Varex muffler on my XR8 ute, pity they're not legal, but it works perfectly, quiet over the whole rev range with it closed apart from a deep idle, loud as hell with it open.

_________________
http://www.healingchambers.com.au


Top
   
PostPosted: Sun Apr 09, 2017 7:25 pm 
Offline

Joined: Tue Aug 09, 2005 11:56 am
Posts: 15
Location: adelaide
I have made my sr20 1600 exhaust front to back with the intention of it being as quiet as possible at lower revs or idle. It is a full 3 inch with a 24 inch hotdog down the center and the biggest muffler I could possibly fit out the back. I bought a dynomax VT from the states as the configuration I was after wasn't sold locally. The difference with these mufflers is they have a light spring loaded valve on the exit. It is the quietest modified datsun I have heard at idle but sounds like a straight through muffler at full noise. The only thing I haven't tested yet is how it effects turbo response but it's a pretty light spring so I can't see it being much.

_________________
Mark


Top
   
PostPosted: Mon Apr 10, 2017 10:15 am 
Offline
Moderator
User avatar

Joined: Sat Oct 30, 2004 2:28 pm
Posts: 5357
Location: Melbourne, Australia
Good information to know.
I'm google searching the muffler as I type this!

_________________
1972 Datsun 1600, S14 SR20DET Engineered (204rwkW @ 17psi.)
viewtopic.php?t=6579
#SR20Datsun @SR20Datsun


Top
   
PostPosted: Tue Apr 11, 2017 8:43 pm 
Offline

Joined: Tue Aug 09, 2005 11:56 am
Posts: 15
Location: adelaide
It can sound a little fluffy at idle due to the valve but it reminds me of a stock 1600.

If your interested enough I can chuck a clip up of it on my YouTube channel.

_________________
Mark


Top
   
PostPosted: Wed Apr 12, 2017 9:13 am 
Offline
User avatar

Joined: Sat Jul 09, 2005 6:54 pm
Posts: 1380
Location: Blue Mountains, NSW
I think a sound clip would be good. Very surprised that you managed to fit a 600mm long hot dog in the middle. I built one that big and it was a very tight fit. I want happy with it so i cut it back out. My exhaust is tucked up very high.

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18


Top
   
PostPosted: Wed Apr 12, 2017 7:01 pm 
Offline

Joined: Tue Aug 09, 2005 11:56 am
Posts: 15
Location: adelaide
I have the Datsport solid gearbox crossmember with the exhaust provision which gave me a bit of extra room.

Here is the you tube link https://youtu.be/3iUsG9yzIHI

Now before anyone flames me I am well aware of how unreliable the phone db meters are but it is hard to gauge how quiet it is just with the video of it.

_________________
Mark


Top
   
PostPosted: Wed Apr 12, 2017 9:00 pm 
Offline
User avatar

Joined: Sat Jul 09, 2005 6:54 pm
Posts: 1380
Location: Blue Mountains, NSW
I have my own gearbox cross member. But it would need to sit between the prop shaft and the floor behind the gearbox. Thanks for the vid.
Does sound quiet at idle. What's the in cabin noise like when accelerating and cruising?

_________________
Ongoing Project: 1972 Datsun 510 S13 SR20Det. http://ozdat.com/forum/viewtopic.php?f=33&t=17898
New Daily: D22 Navara (The new workhorse)
Retired 12/2016: MY98 Subaru Impreza RX
Previous Car: Restored Green 1972 Datsun 510, Hot L18


Top
   
Display posts from previous:  Sort by  
Post new topic  Reply to topic  [ 35 posts ]  Go to page « 1 2 3 »

All times are UTC+11:00


Who is online

Users browsing this forum: Google [Bot] and 4 guests


You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot post attachments in this forum

Jump to: 

Powered by phpBB® Forum Software © phpBB Limited