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Muffler types

Started by _LHoon_ , Jan 05 2009 02:07 PM

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11 replies to this topic

#1 _LHoon_

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Posted 05 January 2009 - 02:07 PM

Hey guys,
I am about to fabricate my LC exhaust system for a 450hp carbi 355ci, which will also see 150hp NOS.
It will be a twin 3 inch I will be using a pair of the following (already purchased) mufflers.

Magnaflow #11229
3inch, 4x9inch body, Offset (straight-through). This muffler is packed with sound absorbing material.
Posted Image

Hooker Aerochamber #21505
3inch, 5x8" body, Offset/centre (straight-through). This muffler has different volume chambers, but no sound absorbing material.
Posted Image

I have deliberately chosen two different types of mufflers. I want to target a wide spread of frequencies.

... here's my question:

Which muffler should I install at the front, and which one should be at the back of the car?
Will the muffler position have any significant influence on the exhaust note??
Similar to this question... some people install 'Resonators'. Are these normally fitted close to the engine?

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#2 TerrA LX

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Posted 05 January 2009 - 03:15 PM

I think resonator is another name for muffler AFAIK.
Type and style of muffler will dictate the volume of the exhaust note and placement does play a small part in the lower pitch/drone.

Edited by ALX76, 05 January 2009 - 03:15 PM.

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#3 _bon_scott_

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Posted 05 January 2009 - 04:36 PM

Resonators usually go at the back and don't really offer too much sound absorption compared to a true muffler. AFAIK they just reduce the drone of the exhaust by increasing the weight of the system and therefore lowering the drone frequency, similar to how sound deadening works in doors or the car body.

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#4 _LHoon_

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Posted 06 January 2009 - 08:24 AM

Thanks for your thoughts.

Got any suggestions as to which of the two mufflers I should place closest to the engine?

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#5 myss427

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Posted 06 January 2009 - 09:46 AM

Too close to the engine is the quickest way to loose horse power, mount them as far back as possible. Hot gasses expand, cool contract. If it has to be up front, mount resonators first, the straight through kind.

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#6 _LHoon_

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Posted 07 January 2009 - 12:27 PM

Too close to the engine is the quickest way to loose horse power, mount them as far back as possible. Hot gasses expand, cool contract. If it has to be up front, mount resonators first, the straight through kind.

Thanks, this is starting to make sense.

After the collectors I will bring the pipes together to make an X-Pipe, and then the first set of mufflers will be directly before the diff. The other set of mufflers will be after the diff, either side of the fuel tank.

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#7 _jbracefan1977_

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Posted 24 May 2009 - 10:55 AM

Too close to the engine is the quickest way to loose horse power, mount them as far back as possible. Hot gasses expand, cool contract. If it has to be up front, mount resonators first, the straight through kind.

I agree with�myss427. plus you cant go wrong with the 11229. you see, I have the magnaflow 11229 just installed and love it, they are cheaper on ebay but I wanted a warranty (the salt on the roads here in winter kills an exhaust) so I got it here magnaflow 11229 , or you can try one of the vendors here, they are always running sales/specials. either way its a great system and very easy to install. good luck� :3gears:

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#8 _LHoon_

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Posted 27 May 2009 - 09:13 PM

Thanks for all previous comments. I just thought I'd give you an update on what I ended up doing with my exhaust.

I positioned the Hooker Aerochambers before the diff and the Magnaflows after the diff. Also made an x-pipe just after the collectors. Once I started making the exhaust, I disovered that the Aerochambers are not reversible so they were more suited at the front.

I'm really happy with the result. It sounds awesome and the noise coming out the back isn't actually as loud as I expected. Altough there's a fair bit of mechanical noise coming from the front of the car, which I think is just because the motor has an aggressive solid camshaft and 11:1 compression.

Here are some pictures.

Posted Image

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#9 _Squarepants_

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Posted 27 May 2009 - 09:22 PM

Good to see you're wearing all the right protective gear there, including your Samoan Safety Sandles! :tease:

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#10 originalglenn

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Posted 27 May 2009 - 11:01 PM

nothing wrong with the sandals
they let you know when the carpets on fire

now a real question
why the x? is it just for strength?

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#11 Rockoz

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Posted 28 May 2009 - 02:13 PM

The X balances the sound out. It takes some of the bark out of the system. If put in the right place, can increase power as well.
To make this system even better you need to remove that restrictive bit at the front, other wise it is almost a waste of effort running the 3 inch to the rear.

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#12 _LHoon_

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Posted 28 May 2009 - 06:49 PM

Yeah unfortunately I'm only running 2.5 inch collectors at the moment because I still have the crappy 1 5/8" CastleAuto (CRS) extractors. Later when time and money permits I will get a custom set of 1 3/4" primary extractors feeding into 3 inch collectors.