Project Veloci

[MH3.0R]

Any reason for the offset muffler?

I think you've added too much restriction there.

Perhaps something like this would've been better>

http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=10993

The offset is needed to fit it in and as close to the current floor cavity so it does not hang down and scrap the lip of my driveway. It was recommended by Barry the fabricator. So, I am going with his recommendation.

[MH3.0R]

If the offset is essentially straight through it will be a solid solution to sound reduction and not cost anything in power

We did the same thing for a customer with 3.0SC in Mackay, works extremely well

I can confirm this is a straight through but with a kink between in and out of course. Good flow and increased suppression of the noise.

If it still not to my liking, then the stock rear mufflers will be gutted, a straight thru section added in stainless, then the cavity will be filled with fibrelgass, a custom made glass pack!

[ndlibgt]

why bother with the resonator? Why not just get a 3" straight through muffler? Quiet, non restrictive, win.

Probably should have taken this good piece of advice on board Mark.

My car was louder when it had the stock centre compared to 3" centre a muffler so I'd say your on the right path here.

[jaydece]

no lag? does it say diesel on the magnaflow box? hope that's not a particle filter type muffler?

[<GB>]

i got magna flow rear 2.5 in mufflers dunno what the center one is its straight though its louder than the mrt set up

[MH3.0R]

no lag? does it say diesel on the magnaflow box? hope that's not a particle filter type muffler?

Justin,

Photo of the box:



It is a performance muffler, and no Diesel or Particulate filter anywhere in sight, on the box, nor inside the muffler.

[MH3.0R]

i got magna flow rear 2.5 in mufflers dunno what the center one is its straight though its louder than the mrt set up

This is a front muffler at 3-inch in and out. After the Y, it reduces to 2.5 inch on each side. My custom mods to the stock rears will include new 2.5 inch in and out.

[MH3.0R]

Like to see a 1/4 wave resonator if it drones, doing the research on those, intriguing stuff
They're an alternative to, or used in conjuction with, a Center muff...

So BBB, done anymore research on the 1/4 wave stubs? They would be quite finicky on the size and position depending on what frequency one is trying to reduce. I reckon one would need to have a sort of sliding T joint so the stub can be varied in its location along the pipe at 90 degrees to the normal flow. Would be quite a technical setup and would need considerable R&D effort to get it right. Probably cheaper to just try different mufflers.

[jaydece]

cool no lag...its just that I saw it on the box....and was just wondering...

[<GB>]

i got magna flow rear 2.5 in mufflers dunno what the center one is its straight though its louder than the mrt set up

This is a front muffler at 3-inch in and out. After the Y, it reduces to 2.5 inch on each side. My custom mods to the stock rears will include new 2.5 inch in and out.

my front is a hot dog straight through 3 inch in and out then y its 2.5 each side which are magna flow straight though we went 2.5 cause 3in wouldnt bee needed and would betoo loud!! i wanna put a better mid one in too to shut mine up a little. i was shocked how much bruces shut up from his tune at idle though... my car seemed quiter when i got the springy tune at 100kmph

i got a muffler like yours on my patrol cause i didnt want straight though as its a bit louder

[bigBADbenny]

Ill be going the way Bruce suggested but starting with the 2nd cat, a 3" to 4" long taper 100cell cat for -5db... (Also from bestmufflers)
Ill add the center muff later if required.
The calculation for a 1/4 wave res (for a 4cyl at least) is:
1075/(((drone revs)x2)/60) .
I was also considering your trombone arrangement for testing
The res can go anywhere between headers and rear muffs.
There are some muffs that incorporate this type of res at the inlet.
Research here and around this article:
http://www.corner-carvers.com/forums/sh ... tcount=111
http://www.kcsr.org/showthread.php?t=131893
Quote: Yes, a 4-cyl generates 2 pulses per revolution instead of 4. So the math is
tube length in feet = 1075/(((drone revs)x2)/60)
http://www.6speedonline.com/forums/mid- ... ators.html
In a sense your offset mid does a similar thing, interupting the effective length of the exhaust.

Like to see a 1/4 wave resonator if it drones, doing the research on those, intriguing stuff
They're an alternative to, or used in conjuction with, a Center muff...

So BBB, done anymore research on the 1/4 wave stubs? They would be quite finicky on the size and position depending on what frequency one is trying to reduce. I reckon one would need to have a sort of sliding T joint so the stub can be varied in its location along the pipe at 90 degrees to the normal flow. Would be quite a technical setup and would need considerable R&D effort to get it right. Probably cheaper to just try different mufflers.

[jaydece]

my 5 cents....Just buy a varex already...

[MH3.0R]

cool no lag...its just that I saw it on the box....and was just wondering...

Ok, I did not spot that when I was looking at the box. But I did start Googleing the Petrol vs Diesel Mufflers and I get the impression there is no difference other than diesel muffs are supposed to be high flow where some petrol muffs have back pressure built in to the design. In the case of performance muffs, there should be little or no difference. I hope!

[MH3.0R]

The calculation for a 1/4 wave res (for a 4cyl at least) is:
1075/(((drone revs)x2)/60) .

I guess it would be 1075/(((drone revs)x3)/60) for a 6 cyl?

Research here and around this article:
http://www.corner-carvers.com/forums/sh ... tcount=111
http://www.kcsr.org/showthread.php?t=131893
http://www.6speedonline.com/forums/mid- ... ators.html

Very interesting reading, but they do the calculations based on the engine RPM, not the centre frequency of the measured sound. Should the calculation be based on the measured frequency or the engine rpm or does it translate to the same thing anyway? Mmmm....

[MH3.0R]

my 5 cents....Just buy a varex already...

Sorry, not my cup of tea there old chap. Want to do thing the hard way so one learns a jolly good lesson.