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What would be a quiet exhaust for a 1998 3800 NA series 2 without trunk modification? by MulletproofMonk
Started on: 07-17-2015 04:27 PM
Replies: 17 (515 views)
Last post by: solotwo on 07-21-2015 11:12 PM
MulletproofMonk
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Report this Post07-17-2015 04:27 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
What would be a quiet exhaust for a 1998 3800 NA series 2 without trunk modification?

------------------
-Brian

My 87 GT Poly Suspension Upgrade (all pics) thread
Removing the roof panel
My HUD install thread
Modified stock air canister and base to 3.5 inch for 3800na

Isn't it strange that after a bombing, everyone blames the bomber, his upbringing, his environment, his culture, his mental state but … after a shooting, the problem is the gun?

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Darth Fiero
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Report this Post07-17-2015 04:42 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
Whatever OEM type "full-size" muffler you can find that will fit without modifying the trunk.

Aftermarket performance mufflers are notorious for promoting low frequency resonance noise (drone) to enter the cabin. This is what most people complain about when they go for a ride in the typical 3800 swapped Fiero that has performance exhaust. A restrictive stock type muffler is well suited at eliminating this low-frequency noise, but it comes at a price (ie: restricting the exhaust flow). I do not recommend using such mufflers on supercharged engines because the excessive backpressure can cause problems for the engine which can eventually lead to engine damage if not corrected.

But on a stock N/A engine, you should be ok. Beyond just the muffler, adding a cat and a resonator (if you can find the room) will quiet it down even more.

-ryan

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More is more. Less is not enough.

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[This message has been edited by Darth Fiero (edited 07-17-2015).]

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MulletproofMonk
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Report this Post07-17-2015 04:53 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:

Whatever OEM type "full-size" muffler you can find that will fit without modifying the trunk.

But on a stock N/A engine, you should be ok. Beyond just the muffler, adding a cat and a resonator (if you can find the room) will quiet it down even more.

-ryan


Anything you recommend? As always, my builds have followed your recommendations.
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Report this Post07-17-2015 04:54 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Custom headers and routing your exhaust the longer path of the stock Fiero exhaust, with both a cat and muffler in, will give you a quieter exhaust. You might be able to fit a resonator between the two under the cradle as well.
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MulletproofMonk
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Report this Post07-17-2015 05:01 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:

Custom headers and routing your exhaust the longer path of the stock Fiero exhaust, with both a cat and muffler in, will give you a quieter exhaust. You might be able to fit a resonator between the two under the cradle as well.


I might do that for the 3800sc, but this is just my 3800 NA daily driver so I dont want to go that expensive...
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Dennis LaGrua
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Report this Post07-17-2015 06:34 PM Click Here to See the Profile for Dennis LaGruaClick Here to Email Dennis LaGruaSend a Private Message to Dennis LaGruaEdit/Delete MessageReply w/QuoteDirect Link to This Post
All good ideas and info here.
I would say that a mini catalytic converter with the Spintech 343SC and exhaust resonator tips would give off a rumble but would be acceptable. You can fit that with a CAT without cutting the trunk or removing the heat shield. After trying the Afterburner and discovering that it was very loud I went to the Spintech with Heddman hot tips resonators. While the exhaust does have a strong sound and some interior drone its not deafening like the Afterburner. That muffler is the pits.
Lou and Blue just had an install done with an 18" Magnaflow muffler without trunk cutting. While that muffler is undoubtedly quieter, removal of the heat shield good or bad is just not my way of doing it. Your brake line runs along the rear trunk inner wall and excessive heat there concerns me. Unfounded concern, maybe, but I always err on the side of caution.

------------------
" THE BLACK PARALYZER" -87GT 3800SC Series III engine, custom ZZP /Frozen Boost Intercooler setup, 3.4" Pulley, Northstar TB, LS1 MAF, 3" Spintech/Heddman Exhaust, Autolite 104's, MSD wires, Custom CAI, 4T65eHD w. custom axles, HP Tuners VCM Suite.
"THE COLUSSUS"
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MulletproofMonk
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Report this Post07-17-2015 07:24 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Dennis LaGrua:
not deafening like the Afterburner. That muffler is the pits.
Lou and Blue just had an install done with an 18" Magnaflow muffler without trunk cutting. While that muffler is undoubtedly quieter, removal of the heat shield good or bad is just not my way of doing it. Your brake line runs along the rear trunk inner wall and excessive heat there concerns me. Unfounded concern, maybe, but I always err on the side of caution.


When i do my 3800sc i will probably take it to Ryan to have the trunk "massaged". I think most of us agree and caution.

I read Lou's thread and decided not to comment. Everyone says it is "just fine"... until it isn't and your car burns to the ground... too much money in my car to risk that....

[This message has been edited by MulletproofMonk (edited 07-18-2015).]

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Darth Fiero
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Report this Post07-18-2015 02:48 PM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by MulletproofMonk:


When i do my 3800sc i will probably take it to Ryan to have the trunk "massaged". I think most of us agree and caution. I read Lou's thread and decided not to comment. Everyone says it is "just fine"... until it isn't and your car burns to the ground... too much money in [i]my[/] car to risk that....



I wasn't suggesting in that other thread that the car would catch fire and burn to the ground if no heat shield was used. But, like a lot of other Fiero owners, I DO use my Fiero's trunk to haul luggage, chairs, other gear, etc. from time to time and it is very important none of this gets melted or burned. I've seen a lot of guys do swaps, remove the heat shield between the trunk and muffler, and end up with burned trunk carpet (or burned luggage) because they omitted the heat shield.

That having been said, dobey's suggestion of running aftermarket headers that allow you to route the exhaust system like stock Fiero DOES in fact give you enough room to add a cat and possibly a resonator. But it is a more expensive option. For a cheaper option, I did see once where a guy modified a chambered performance muffler (like a flowmaster) and actually welded a mini (spun) catalytic converter inside of it - and that's definitely an option. BUT this probably is NOT an option you can use most OEM type mufflers that are assembled by the factory rolling and crimping the ends. You would need a muffler that was welded together at the factory to do this, and most of these are only found in the aftermarket as louder performance mufflers.

On a side note, I suppose you could always weld some short length resonators to the outlet(s) of a welded performance muffler to quiet it as well.
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MulletproofMonk
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Report this Post07-18-2015 03:17 PM Click Here to See the Profile for MulletproofMonkClick Here to visit MulletproofMonk's HomePageSend a Private Message to MulletproofMonkEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:
I wasn't suggesting in that other thread that the car would catch fire and burn to the ground if no heat shield was used.


Sorry if it read that way. I wasn't saying that you were saying the car would catch fire, I was just saying that I hear people say it's fine and it probably is 9 out of 10 times... It's that 1 in 10 that makes me nervous because it's probably me...

An example is me pulling the front springs on the Fieros. I have never restrained them from popping out and never had a problem with them hitting me. So the last time I did one to install poly I stood back and pushed the control arm down with a pipe. Needless to say the spring shot out 4 feet and only stopped because it hit the chair my phone was on. Again, I was the 9 out of 10. If I had been the 1 out of 10 it would have hurt... http://www.fiero.nl/forum/F...L/094633-3.html#p112
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Report this Post07-18-2015 06:22 PM Click Here to See the Profile for PaulJKSend a Private Message to PaulJKEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:

Beyond just the muffler, adding a cat and a resonator (if you can find the room) will quiet it down even more.



Yep. My 3800SC has cat and cut out trunk. I went under the car and measured the space available. Then went to Summit racing website and shopped using their SEARCH. You can put in the inlet and outlet configuration. Selected the biggest muffler that would fit and had it installed - cadillac i think. At highway speed, you can't even hear the exhaust.
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Report this Post07-18-2015 08:26 PM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:
That having been said, dobey's suggestion of running aftermarket headers that allow you to route the exhaust system like stock Fiero DOES in fact give you enough room to add a cat and possibly a resonator. But it is a more expensive option.


I don't think it would be more expensive. Custom headers would be, but it should possible to use the F-body manifolds and have an exhaust made just from the Y-pipe back. A decent shop will probably charge around $600-800 to do that, or to build the short exhaust with lots of tight curves off the rear.
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Report this Post07-18-2015 11:03 PM Click Here to See the Profile for Neils88Click Here to Email Neils88Send a Private Message to Neils88Edit/Delete MessageReply w/QuoteDirect Link to This Post
Jones Full Boar Quiet Tone mufflers, available at Summit for under $70, have a great sound without being too loud. Decent performance too. They also come in a 13" case length, with either one or two outlets so perfect for a Fiero without cutting the trunk. Lots of size options too. I have one on my 4.9 and absolutely love the sound. I'm not into noisy exhausts and was happy with the result.

Edit: just to note, I also have a Catco high flow catalytic converter as well.

[This message has been edited by Neils88 (edited 07-18-2015).]

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Report this Post07-19-2015 12:25 AM Click Here to See the Profile for ltlfrariClick Here to visit ltlfrari's HomePageClick Here to Email ltlfrariSend a Private Message to ltlfrariEdit/Delete MessageReply w/QuoteDirect Link to This Post
CC insert. Worked wonders for the noise level on my dohc swap.

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Report this Post07-20-2015 12:47 AM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


it should possible to use the F-body manifolds and have an exhaust made just from the Y-pipe back.


A stock F-body Y-pipe will fit and work in a Fiero???
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Report this Post07-20-2015 06:51 AM Click Here to See the Profile for dobeySend a Private Message to dobeyEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Darth Fiero:
A stock F-body Y-pipe will fit and work in a Fiero???


No, the Y has to be made too. Sorry if I worded that oddly.
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Report this Post07-20-2015 10:10 AM Click Here to See the Profile for steve308Send a Private Message to steve308Edit/Delete MessageReply w/QuoteDirect Link to This Post


Jones full boar -- 13" can 18" tip to tip total length pipe to pipe

At Summit ---Two types the full boar (loud) and full boar 'quite tone'

As close as I've seen to the OE FIERO muffler size.

[This message has been edited by steve308 (edited 07-20-2015).]

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Darth Fiero
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Report this Post07-21-2015 01:41 AM Click Here to See the Profile for Darth FieroClick Here to visit Darth Fiero's HomePageClick Here to Email Darth FieroSend a Private Message to Darth FieroEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by dobey:


No, the Y has to be made too. Sorry if I worded that oddly.


I didn't think it would work, but I wanted confirmation since I have never attempted to use F-body manifolds in a Fiero swap.

Anyway, another thing to consider is the quality of exhaust system you are going to get from an exhaust shop down on the corner. Every exhaust shop (or auto repair shop that did custom exhaust bending) I've been to only has the type of pipe bender that puts the crush bends (or crimps) in the pipes. These crush bends are horrible for flow. Probably not a big deal for an N/A engine, but if you are looking for the best performance possible, then you are going to want mandrel bends. If you cannot find an exhaust shop that has a mandrel bending machine, then that is pretty much going to limit your options to ordering the individual mandrel bends from Summit or Jegs and either welding them together yourself to construct your exhaust system or having someone else do it for you.
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Report this Post07-21-2015 11:12 PM Click Here to See the Profile for solotwoSend a Private Message to solotwoEdit/Delete MessageReply w/QuoteDirect Link to This Post
Flowmaster 80 IS loud at 70!
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