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00:36:41 - 12/20/2024
General Dakota Board
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alexG
Dodge Dakota
JOIN HERE
1/07/2009
19:49:50
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 Subject: Cat-Back Exhaust
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Message:
Own a 04 QC 4.7L auto. I'm planning on installing a gibson exhaust kit. I've heard that with the dual exhaust you actually lose power, or atleast not gain as much as the single exhaust kits. Does any body have any input as to which is better. By that i mean more powerful.
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JasonB
Dodge Dakota
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1/07/2009
20:23:25
|  RE: Cat-Back Exhaust
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See the chart here
http://www.autobarn.net/flamthexki.html
Read this
http://www.nsxprime.com/FAQ/Miscellaneous/exhausttheory.htm
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alexG
Dodge Dakota
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1/07/2009
20:52:53
| RE: Cat-Back Exhaust
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Apparently you're trying to sell me on flowmaster, and if you'd would read the the exhaust theory page, you'll find that it claims flowmaster to be one of the worst flowing mufflers.
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Kowalski
GenIII
1/08/2009
11:12:19
| RE: Cat-Back Exhaust
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That could vary with the aplication. Since you want more power, you'll get more bang for the buck by replacing the resrictive y-pipe insted. The difference between single or dual exhaust comes down to proper pipe sizing. Go too big with either and the exhaust pulse at the exhaust valve will slow down too much for proper exhaust scavaging, loosing low end torque. No one has ever reported dynoing a significant gain from a cat back swap of either type here without also doing other mods.
Lead, follow, or get out of the way
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TexasTodd
GenIII
1/08/2009
15:43:19
|  RE: Cat-Back Exhaust
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Message:
Alex,
Your goal here is to gain power?
Other the the advice form Kow.., (y-pipe), SAVE your money. ALL you're doing is buying a different sound, and RARELY any increased HP or TQ.
Before and after dynos don't lie (especially when there are done by an independent party)
Butt (rear end) dynos are proportional to the money you spent. 'It feels faster!'
I'm STILL waiting, for that INDEPENDENT before and after dyno of a K&N CAI, that has any gains. (not the manufacturers)
On my 01 4.7, it came with the California emmissions exhaust, which is a pre-cat in each header, with an 02 sensor before and after each cat. 4 total.
This actually helps with the A/F mixture, amoung other things.
Then the LARGE 3rd cat, which has a restrictive metal screen completely over the forward end of the cat, with NO 02 sensors!
I hope you're wondering why I'm telling you all this. Well yes, you read the article on exhaust systems, right?
Well, I, (and others) have re-located our 3rd cat to somewhere more convenient, like say, the trash can!
So I have some minor mods, (and an Excellent RW dyno), and no third cat.
Because there is no 02 sensors, the engine runs THE SAME! AND NO MIL lights! NONE. AND, it always passes my yearly inspections here in Texas. They actually drive your vehicle (brake and chasis check), look at all the lights, and hook it up to the 'puter port. NO codes,-passes!
By removing the 3rd cat, if you have one, it frees up some of the restriction (that screen mainly), and sounds lower, with a MILD rumble.
People are amazed when I tell them it's a 'stock' exhaust.
Having the cat removed and a aluminized pipe weld in cost me $30! (shop in San Antnio)
I've been on these boards since before ordering the build on my 01, 4.7, QC. I quickly learned about independent dyno proven mods, and fad of the month mods.
That's why I'LL never get a 'cat-back' exhaust, until maybe my stocker rusted out! They're basically worthless for 'power'. TQ or HP.
Now, some people do get them just for the sound, and hat's off to them. Some of them sound pretty nice, just not in MY neighborhood! LOL
Look into to a shop fabbed y-pipe, thats slighlty less restricive. i.e. -Kow's advice.
You want PROVEN hp and TQ increases for free?- Get rid of that balt driven fan and clutch!!!!
The stocker electric will nearly always do the trick, especially with a 180 t-stat.
01 SLT QC, two tone paint,
OEM fender flares
Cab high Leer cap w/ double slider window,
Infinity sound,
Tire and handling pack,
R/T sway bars
Trailer towing pack,
4.7 manual,
HO cams,
HO intake,
180 degree Thermostat
Ported the stock 68mm TB,
Homebrew 'true' CAI, w/ K&N
No belt driven clutch or cooling fan
No third cat.
SuperChips Tuner
Max dyno, NO short belts, etc.
227 RW HP
300 RW TQ
Drive it like its paid for!
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