Building a replacement exhaust system

[White Lincoln]

I would like to replace the exhaust setup I have now.

Will it effect the V6 using 2.5" pipe? As I understand exhaust, there has to be some pressure on the exhaust (but I could be wrong). I would like to go to true dual exhaust with an X-pipe and either keep the current mufflers or replace them. The muffler depends on the size of the pipe. The CAT forward is a 2.0" pipe and currently have 2.25" from the CAT back.

 

[theterminator93]

Exhaust upgrades 101

Upgrading the exhaust on your MN12 isn't difficult, but you need to have realistic expectations on what will change when you start upgrading pipes or swapping mufflers. The factory exhaust and mufflers are not terribly restrictive, especially with stock (or near-stock) powertrains. The...

forum.birdcats.com

Pressure = bad
Velocity to create scavenging = good
Too much velocity = pressure buildup

Basically there is a sweet spot. Too small, and you end up creating pressure which restricts power (try breathing through a straw). Too large, and you lose the benefits of scavenging.


IMO, 2" diameter is more than sufficient on the 3.8 N/A.

 

[White Lincoln]

Exhaust upgrades 101

Upgrading the exhaust on your MN12 isn't difficult, but you need to have realistic expectations on what will change when you start upgrading pipes or swapping mufflers. The factory exhaust and mufflers are not terribly restrictive, especially with stock (or near-stock) powertrains. The...

forum.birdcats.com

Pressure = bad
Velocity to create scavenging = good

IMO, 2" diameter is more than sufficient on the 3.8 N/A.

Thanks for the info Terminator.
Unfortunately, TruBendz does not make a 2" dual exhaust kit, only 2.25" and 2.5". If a 2.25" is going to cause issues on a stock V6, I guess I can learn to weld. YIKES! Or make the exhaust out of aluminum and use a MAP torch to solder the connections. A pipe bender for 2-3" is NOT CHEAP and I have not seen any for sale in my area yet. If I could get a new or used welder and pipe bender for under $300, that I would do.

 

[MadMikeyL]

What is the reason for replacing the exhaust? If you are looking for a good sound, you pretty much aren’t going to get that out of the 3.8. They just are not a good sounding engine, and with larger exhaust they tend to drone at highway speeds. If you are looking for performance, your money is better spent elsewhere as the 3.8NA will never be a powerhouse, and you would need to be making significantly more power before the stock exhaust really becomes a restriction. If you just want the look of the dual pipes, get a stock rear section off a V8 car in the junkyard, it will bolt right up to the stock front section on your V6.

 

[White Lincoln]

What is the reason for replacing the exhaust? If you are looking for a good sound, you pretty much aren’t going to get that out of the 3.8. They just are not a good sounding engine, and with larger exhaust they tend to drone at highway speeds. If you are looking for performance, your money is better spent elsewhere as the 3.8NA will never be a powerhouse, and you would need to be making significantly more power before the stock exhaust really becomes a restriction. If you just want the look of the dual pipes, get a stock rear section off a V8 car in the junkyard, it will bolt right up to the stock front section on your V6.

LMAO... let me find some pics... CAT forward is fine, CAT back is from a V8 Cougar and the mufflers input are not 2.25" OEM size (2.5"), as suggested in the advertisement when I bought them. The CAT forward to CAT back is 2.0" to 2.25". I think its a mess and I believe is part of my rattle when the car is cold. Once I drive around for 5 minutes or so, the rattle goes away. I am thinking the exhaust tubing is swelling with the heat and sealing up any loose areas that might rattle when cold. I thought about taking the car to a mechanic and see if they can find the rattles, but the last time I drove with a mechanic, they said "what rattles? I don't hear any rattles...". That was the end of thinking someone else might know what it is.

 

[MadMikeyL]

Ah, I see. Ok, so in your case I would get the 2.25” dual kit from truebendz, a Magnaflow 2.25” dual inlet/outlet muffler with the built-in X-pipe, and a pair of 2.25” Dynomax turbo mufflers. The setup then would be your front pipe sections, into the Magnaflow mid-mounted, then out of the mid-mount to the trubendz pipes, out yo the back and then into the turbo mufflers, and have it all welded together, not clamped! If you want to make it easier to remove for service, you can add a pair of flanges right in front of or behind the mid-mount muffler, but again those should be welded in place. That setup should keep it pretty quiet, not drone, and resolve your exhaust rattles.

 

[White Lincoln]

Thanks for the suggestions, that helps too. I was wondering what type of pipe you would recommend, aluminum OR stainless steel?

I received the O2 sensors tonight and installed them. I drove the car around till the engine was at normal temp. Plugged in my Snap-On scanner with the Ford, GM, Chrysler up to 93 (my car was made 12/93) and the results where codes 137 /173 rich... frack.

 

[XR7-4.6]

You mean aluminIZED vs stainless Steel? Aluminum would not last very long as an exhaust system, it would literally melt! In the rust belt long term durability stainless all the way, in non-salt climates/fair weather driver situations aluminized mild steel however is fine.

 

[White Lincoln]

Oops... I stand corrected. "2.25 Inch Aluminized"... DOH!

 

[1997ThunderbirdLXV6]

Probably unrelated, but in the spirit of considering all possibilities:

I used to have an annoying rattle from just below the driver, particularly when cold. It ended up being the left/rear O2 sensor connector which kept hitting the underbody.