Dakota Durango Forum banner

1 - 13 of 13 Posts

·
Registered
Joined
·
46 Posts
Discussion Starter #1
I have an '02 Dakota with the 4.7, I am trying to get a grip on what my exhaust options are.

Since I am at work, I can't go crawling around underneath, so I thought some of you might know some of this.

From the Catalytic Converter back (Catback?) what is the diamater of the tail pipe, stock.

Can I just make the diamater bigger (like go from 2 to 2.5, or 2.5 to 3) and add a more free flowing muffler to increase power, and let the engine "breathe Better" ?

Do I need to buy a prefabed kit, or can I go to a muffler shop and have them run and bend pipes for me?

If I DON'T replace my catalytic converter with a high flow one, is replacing the exhaust a waste of time and money?

Exhaust is the next place I am looking to increase power, so I want to better understand it.

Thanks in advance for the help!
 

·
Home Owner....
Joined
·
2,565 Posts
for the 4.7, pipe size afte the cat is usally 1.5 inches. the cat is already a higher flowing model and upping to a 2 or 2.5 inch cat back system is a great mod and well worth the cash, jsut be careful of your local SMOG laws if you upgrade the cat.

you can get a pre made kit or have your local shop fab one up for ya. your option, also a good idea to replace your downpipes in front of your cat(s), a very restrictive area on these trucks.
 

·
Registered
Joined
·
46 Posts
Discussion Starter #3
"Down Pipes" ??

This is in FRONT of the Catalytic converter, this sounds complicated, can I replace these without adding headers?


:help:
 

·
Home Owner....
Joined
·
2,565 Posts
afsigma21 said:
"Down Pipes" ??

This is in FRONT of the Catalytic converter, this sounds complicated, can I replace these without adding headers?


:help:
yap, it can be done without using headers. Headers are really not needed with the 4.7, your stock mannifolds flow just as well, if not better anyways.

your local muffler shop can fab up a new set of downpipes/y-pipe (same thing) when they do the rest of your system.
 

·
I like trucks
Joined
·
3,171 Posts
The 4.7's have 1.5 inch exhaust after the cat?
 

·
Home Owner....
Joined
·
2,565 Posts
T.j. said:
The 4.7's have 1.5 inch exhaust after the cat?
thats just a guess.... someone correct me, i may indeed be wrong on this :help:
 

·
Yes it's a lowered 4X4
Joined
·
2,307 Posts
WTF 1.5" after the Cat this is not a honda civic LOL!!! The stock pipes are 2.5"

If you plan on keeping a single exit exhaust then dont replace your exhaust system with a cat-back. It's a waste of money. Just get a high flow muffler and exhaust tip. The 2.5" pipes are more than enough. If you plan on going with a SI/DO system then use 2.25" pipes to keep your low-end torque.
 

·
I like trucks
Joined
·
3,171 Posts
Lol I was gonna say, no wonder the 4.7's benefit from exhaust. Lol I think the exhaust on my atv is 1.5''.
 

·
Registered
Joined
·
46 Posts
Discussion Starter #9
After reading the posts, and crawling around the truck, it all makes MUCH more sense now.

Thanks for all the input, and yes, I measured, the stock pipes are 2.5.


Now, where to find that extra 20HP or so I am looking for.... :huh:
 

·
Home Owner....
Joined
·
2,565 Posts
Anthony said:
WTF 1.5" after the Cat this is not a honda civic LOL!!! The stock pipes are 2.5"
thanx for the correction.... :biggthump

from the back of one it didnt look that big...
 

·
Home Owner....
Joined
·
2,565 Posts
afsigma21 said:
Now, where to find that extra 20HP or so I am looking for.... :huh:
well, call up Sam P at www.socaldakota.com and get the HO intake and HO cams....

then grab a Superchips programmer. thats all that is avail without grabbing a power adder of some sort.

the lil 4.7 is not well liked by the after market :cussing: :rant:
 

·
Registered
Joined
·
5,099 Posts
well you will not see 20hp from a cat back, you might see 3hp, but it will sound better.
 

·
Registered
Joined
·
12 Posts
I don't know if they've changed much from 2000 to 2004, but I just had mine apart and found 2.5 after the cat. I did install Gibsons single 3 inch cat back system and didn't notice much difference at all. In fact it feels like I lost low end :cussing: Actulaly another change was the level of drone at (1800 to 2400)rpm and vibration felt in the cab.Very unsatisfied with the company .Not much quality there of thinking went into it.Tell what be very careful how much you open it up. Fuel injected motors are a different animal when it comes to mods. You need back (some) pressure.
 
1 - 13 of 13 Posts
Top