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Exhaust options

  • have exhaust shop put some stock mufflers on and be done

    Votes: 3 37.5%
  • convert back to stock

    Votes: 3 37.5%
  • magnaflow mufflers

    Votes: 2 25.0%
1 - 19 of 19 Posts

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Discussion Starter · #1 ·
Not only do I want to quiet my exhaust down, but I may be trading the car soon and not sure if exhaust modification would deduct from trade in value. Anyway I'm looking at three options
1.) having the exhaust shop just put some stock mufflers on and be done
2.) change my entire exhaust back to the stock 2.25 setup
3.) put some magnaflow mufflers on

What do you guys think would be the best route to go ? btw, my current exhaust is 4 inch y-pipe w/ 4 inch magnaflow tips. cats/resonator are stock.
 

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8th Gen Antagonist
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Mods like that should add value, but 4 inch exhaust was a bad idea to begin with.
 

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8th Gen Antagonist
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I'm not sure if you have an SS or not, but anything past 2.5 inch starts to lower performance on the V6 motors, about 3 inch on the V8, 4 inch belongs on a massive diesel engine.
 

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Every 2nd Matters
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I'm not sure if you have an SS or not, but anything past 2.5 inch starts to lower performance on the V6 motors, about 3 inch on the V8, 4 inch belongs on a massive diesel engine.
What he said. And I miss clicked when I voted. I read it wrong and voted for only stock mufflers. In actuality I meant to click to return it to stock.
 

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Discussion Starter · #8 ·
I have the SS model. Does this have something to do with back pressure ? Every now and then someone would bring that up to me. Upon research some say it's only a myth
 

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Not back pressure, but scavenging.
 

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OEM LOL
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Yes, back pressure

4in will kill your lower end power but increase your upper end power

but you can get the same upper end power with a 3in exhaust and keep your low end power.

A double din will not increase your value unless it is a nav. unit.

my girlfriends dad is the used car manager for a huge buick gmc dealership and her uncle owns it.

With all my mods i have talked to him about it many times because i plan on trading my car in. Now my car is way over done i get that

but even just a performance exhaust will decrease the value because the car is messed with and harder to sell.

stock is always best unless it was a option on a car like a nav upgrade
 

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Discussion Starter · #11 ·
So, it's my understanding that dealers want completely unmolested vehicles, but would something as simple as painted grills and pillars also harm value ?
 

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Found this at http://www.veryuseful.com/mustang/tech/engine/exhaustScavenging.pdf

"2. Calculations and Comments by Dave Stadulis of SMSP Exhausts Relating Flywheel HP to Exhaust Cross-
Sectional Area (Diameter):
quote:
Here are the numbers for 16g tubing:
OD (in.)....ID (in.)...Area....%Increase......HP.......HP/in^2
2.25........2.120.......3.53.....0%...............200.......56.66
2.50........2.370.......4.41.....25%..............275.......62.34
2.75........2.620.......5.39.....22%..............318.......59.00
3.00........2.870.......6.47.....20%..............400.......61.83
OD is exhaust outer diameter, ID is inner diameter, Area is tube cross-sectional area, % Increase is
increase from the prior OD, HP is Flywheel hp, and HP/in^2 is hp per square inch cross-sectional
area.
For the 2.75 in. tube, I assumed 59 HP per square inch of flow area, I used Larry's numbers for the
others....you are talking HP at the crank :
2-1/4" for up to 200HP @ the crank, 2-1/2" for 275HP, 2-3/4 for 320HP...
or 60HP (at the crank) per square inch of (cross-sectional) flow area."

The idea is that you want to have a large enough pipe to lower back pressure for the rpm range you will normally drive in, and yet still have it small enough to create a vacuum strong enough to scavenge your exhaust gasses as quickly as possible, thus pulling more air and gas into the combustion chamber at a faster rate to create more power.
 

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OEM LOL
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So, it's my understanding that dealers want completely unmolested vehicles, but would something as simple as painted grills and pillars also harm value ?
yes because it narrows down the market on who they can sell the vehicle too.

I think your car is whited out if i remember correctly.

so now they would have to find someone who wants a flashy whited out car.

Think about it how many people who are driving impalas actually mod them?
or
how many would want it whited out

When you customize it and make it your own thats what you do you make it YOURS. now while people can appreciate it not many would wanna own it

If it was a high performance car or something like a camaro then alot of those guys customize them and want a customized car not so much with a impala which is a fleet queen
 

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Discussion Starter · #14 ·
So from what Papa and king have said, I basically have an exhaust that would only be sufficient(equal gain on the low and high end) on a turbo diesel. wow Thanks for the help guys
 

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And now you know. Because...

 

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I have the Magnaflow Catback exhaust and it works well on the Impala. It has low end power and high end power. I'm still surprised that it still looks good after a few years of our salty Canadian winters. I would think a good exhaust would add value to the vehicle.
 

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8th Gen Antagonist
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Now you're getting it! People always like to talk about back pressure, but the reality is that you don't want any. The problem is that the exhaust needs to create a sort of siphoning effect, basically sucking the exhaust out of the engine. This won't happen if the exhaust is too large, which is why that post of PapaD's shows a sharp gain, followed by a rapid decline in power output as the exhaust size is increased. That post unfortunately is not a solid reference though, since every engine will have it's own flow requirements.
 
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