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3 inch vs 2.5 inch exhaust question #1032871 07/15/11 01:53 AM 07/15/11 01:53 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	My 69 road runner has been sporting a TTI complete long tube header system with 3 inch pipes connecting H-pipe into DynoMax mufflers and out the back for about 5 years. Since i lowered the car the exhaust system rubbs pretty much all the time and it was just plain aluminized pipe so it's looking pretty bad now. I was thinking of going to a 2.5 stainless system with their X-pipe and was wondering if anything will change for the better or worse with smaller diameter pipes?? The engine is the original 383 still in there. Any thoughts on what i might see differnt in performance if i go for the smaller pipes?

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032872 07/15/11 02:18 AM 07/15/11 02:18 AM
Joined: Apr 2007 Posts: 4,233 petaluma,ca. u.s.a. west master
west master Joined: Apr 2007 Posts: 4,233 petaluma,ca. u.s.a.	you prob won't notice much change,except it will be quieter. A stock engine may even run better as it will keep the exhaust hotter and move better. I wouldn't go to a 3" unless you plan to hot rod the engine.

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032873 07/15/11 02:26 AM 07/15/11 02:26 AM
Joined: Jan 2003 Posts: 70,126 Here DirectSubjection Tacohead. The First and Only
DirectSubjection Tacohead. The First and Only Joined: Jan 2003 Posts: 70,126 Here	Unless you are over the 500hp level, I bet you won't see a loss in performance. I asked a similar question years ago before I chose for my Duster. Ride eternal, shiny and chrome

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032874 07/15/11 02:31 AM 07/15/11 02:31 AM
Joined: Jan 2005 Posts: 3,699 Newport, Mi Evil Spirit master
Evil Spirit master Joined: Jan 2005 Posts: 3,699 Newport, Mi	Might even run better - a stock 383 should only need 2 1/2 duals with a crossover. The 3" might have actually been too large to scavenge properly. Free advice and worth every penny... Factory trained Slinky rewinder.........

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032875 07/15/11 02:46 AM 07/15/11 02:46 AM
Joined: Feb 2003 Posts: 10,216 Someplace you aren't S SomeCarGuy I Live Here
SomeCarGuy I Live Here S Joined: Feb 2003 Posts: 10,216 Someplace you aren't	The new system will be a nice package w/ a sotck or near stock engine. I had a low-po 383 that did very well w/ HP manifolds, 2.5 pipes, X pipe, and Magnaflows. Exhaust was 2.5 all the way to the bumper. I want my fair share

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032876 07/15/11 09:37 AM 07/15/11 09:37 AM
Joined: Mar 2008 Posts: 5,746 Ontario, Canada Dodgem master
Dodgem master Joined: Mar 2008 Posts: 5,746 Ontario, Canada	raise the car back up! scavaging is done in the first 12" of the header from the header flange at the head. 2 1/2 will be fine but that's a nice system on there now!

Re: 3 inch vs 2.5 inch exhaust question [Re: Dodgem] #1032877 07/15/11 10:19 AM 07/15/11 10:19 AM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Quote: raise the car back up! No way man, low and slow is the way to go! Ok so it's likes i may just go back to the 2.5 and try to find the stainless sttel pipes as myu car sits outside all the time and it's getting to look pretty rusty now.

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032878 07/15/11 10:24 AM 07/15/11 10:24 AM
Joined: Jan 2003 Posts: 4,727 Moved to N.E. Tennessee GomangoCuda master
GomangoCuda master Joined: Jan 2003 Posts: 4,727 Moved to N.E. Tennessee	Put a 440 in it and then the headers won't hang as low. In theory, there is no difference between theory and practice. In practice, there is.

Re: 3 inch vs 2.5 inch exhaust question [Re: DirectSubjection] #1032879 07/15/11 12:56 PM 07/15/11 12:56 PM
Joined: Apr 2005 Posts: 15,134 Kelowna, B.C. Canada D DPelletier I Live Here
DPelletier I Live Here D Joined: Apr 2005 Posts: 15,134 Kelowna, B.C. Canada	Quote: Unless you are over the 500hp level, I bet you won't see a loss in performance. I asked a similar question years ago before I chose for my Duster. Nowhere near enough flow requirement in a stockish 383 to need 3" exhaust; 2 1/2" mandrel bent is overkill.....but nice. Dave Last edited by DPelletier; 07/15/11 12:57 PM. 1970 Super Bee 440 Six Pack 1974 'Cuda 2008 Ram 3500 Diesel 2006 Ram 3500 Diesel 2004.5 Ram 2500 Diesel 2003 Ram 3500 Diesel 2006 Durango Limited [url] http://1970superbee.piczo.com [/url]

Re: 3 inch vs 2.5 inch exhaust question [Re: DPelletier] #1032880 07/15/11 01:04 PM 07/15/11 01:04 PM
Joined: Jan 2003 Posts: 4,727 Moved to N.E. Tennessee GomangoCuda master
GomangoCuda master Joined: Jan 2003 Posts: 4,727 Moved to N.E. Tennessee	Quote: Quote: Unless you are over the 500hp level, I bet you won't see a loss in performance. I asked a similar question years ago before I chose for my Duster. Nowhere near enough flow requirement in a stockish 383 to need 3" exhaust; 2 1/2" mandrel bent is overkill.....but nice. Dave It might in fact be quicker with 2 1/2". In theory, there is no difference between theory and practice. In practice, there is.

Re: 3 inch vs 2.5 inch exhaust question [Re: DPelletier] #1032881 07/15/11 01:05 PM 07/15/11 01:05 PM
Joined: Jan 2003 Posts: 16,376 D dogdays I Live Here
dogdays I Live Here D Joined: Jan 2003 Posts: 16,376	agreed. R.

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032882 07/15/11 01:16 PM 07/15/11 01:16 PM
Joined: Dec 2007 Posts: 18,157 Mass DAYCLONA I Live Here
DAYCLONA I Live Here Joined: Dec 2007 Posts: 18,157 Mass	2 1/4"....2 1/2" max on that 383 combo with a H pipe

Re: 3 inch vs 2.5 inch exhaust question [Re: DAYCLONA] #1032883 07/15/11 06:55 PM 07/15/11 06:55 PM
Joined: Jan 2003 Posts: 1,374 Houston,Tx. L Lee446 pro stock
Lee446 pro stock L Joined: Jan 2003 Posts: 1,374 Houston,Tx.	Stu, if you decide you want to sell the 3", please drop me a PM. I have a 493 b-body project that could use it. Thanks! Lee.

Re: 3 inch vs 2.5 inch exhaust question [Re: Lee446] #1032884 07/15/11 07:39 PM 07/15/11 07:39 PM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	Quote: Stu, if you decide you want to sell the 3", please drop me a PM. I have a 493 b-body project that could use it. Thanks! Lee. Ok Lee and yes i am going to sell it. The local muffler shop is going to make me a deal on the new exhaust system for parts only and free labor. All i have to do it put a little sign up saying they did the job and let people look under the car as advertizing. Now i am thinking of going to a side outlet exhaust using these SpinTech mufflers. 6731511-3393XR90C.jpg (319 downloads)

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032885 07/15/11 08:31 PM 07/15/11 08:31 PM
Joined: Apr 2007 Posts: 4,233 petaluma,ca. u.s.a. west master
west master Joined: Apr 2007 Posts: 4,233 petaluma,ca. u.s.a.	Quote: Ok Lee and yes i am going to sell it. The local muffler shop is going to make me a deal on the new exhaust system for parts only and free labor. All i have to do it put a little sign up saying they did the job and let people look under the car as advertizing. The luxuries of being a MOPAR celebrity,now go find a hemi builder and get comped a new motor.

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032886 07/15/11 08:35 PM 07/15/11 08:35 PM
Joined: Jan 2003 Posts: 20,622 Eagle, Idaho Neil The Doctor is in.
Neil The Doctor is in. Joined: Jan 2003 Posts: 20,622 Eagle, Idaho	On a Road Runner I think the rear exit exhaust would look a whole lot better. Side exit exhaust is more appropriate for the pony cars (cuda, challenger, mustang camaro). If you want to keep your exhaust pipes from rusting on the outside you can remove them, lightly spray the pipes with silver header paint. Once the paint dries roll the pipe system under the car on a creeper so it doesn't get scratched up, and then lift it into place and bolt it up. I did this to my old mustang with a can of vht. The paint will stink pretty good for the first few miles while the heat cures it.

Re: 3 inch vs 2.5 inch exhaust question [Re: Neil] #1032887 07/15/11 09:10 PM 07/15/11 09:10 PM
Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi... MidPenMopar OP Looking for fun? Keep looking
MidPenMopar OP Looking for fun? Keep looking Joined: Dec 2003 Posts: 36,840 South San Francisco, Californi...	I have always had rear exiting exhaust and just want to change up the look for awhile. The way i park in right up to my new custom garage door and when i start it it echos off the door as well as making watery condinsation marks. The side outlest should be cool and the car is so modifed anyway it's no biggie to me.

Re: 3 inch vs 2.5 inch exhaust question [Re: MidPenMopar] #1032888 07/15/11 10:20 PM 07/15/11 10:20 PM
Joined: Mar 2005 Posts: 3,144 Central NC gch master
gch master Joined: Mar 2005 Posts: 3,144 Central NC	It will be LOUD.

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