Results 1 to 12 of 12

Thread: 2 1/2 vs 3 inch Exhaust

  1. #1
    Join Date
    Apr 2006
    Location
    Smyrna, DE
    Age
    67
    Posts
    1,750

    Question 2 1/2 vs 3 inch Exhaust

    What are the benefits of having 3" exhaust over the 2 1/2 inch exhaust to the rear?
    2004 MM (Black) #112 of 3213 (SOLD)
    2003 MM (BLACK #5444 of 7838 (FOR SALE)
    "BLACK MAMBA" (fomerly owned by Chris Wright)
    Cowl Induction Hood
    2.9 Whipple
    4.6 MMR Motor
    4L80E Trans
    Stainless 3" Exhaust
    631 RWHP/569 RWTQ
    AND-
    2018 Ford f-150 SuperCab Black
    3.3 L 4X4
    -AND-
    SLAYER1
    formerly owned by "Impala Slayer!! 2004 SB MM
    Kenne Belle 2.8 (Liquid Cooled), MMR "Boss 302" Block, Kooks Headers and cats, Accusump Pre-Oiler Dynamax VT mufflers, MBS 2 1/2" exhaust, 4.10's, 2800 stall, Argento 312 "Color" Powder coated wheels, Rears widened 1 1/2 ",650 HP/590 TQ on 93 Octane, M/M catch can, 3 pillar gauge (Boost, Fuel, air intake and coolant temp, custom console cover, S-55 treatment.

  2. #2
    Join Date
    Jan 2004
    Location
    Somewhere in the N.C. Triangle
    Age
    63
    Posts
    25,738
    An engine is like an air pump... more incoming air and more exhausted air is better.
    “When you can’t make them see the light, make them feel the heat.”
    Ronald Regan

    "The only way to deal with the Islamic State - these blood thirsty, blood-drunken, terrorists -
    is to kill them, keep on killing them, until you kill the last one, then you kill his pet goat."

    Lt. Colonel Ralph Peters

    “Be polite, be professional, but have a plan to kill everybody you meet.”
    "I come in peace. I didn't bring artillery. But I'm pleading with you, with tears in my eyes, if you **** with me, I'll kill you all"
    General James Mattis




  3. #3
    Join Date
    Nov 2002
    Location
    St. John, IN
    Age
    40
    Posts
    14,222
    Nothing
    /thread

  4. #4
    Join Date
    Apr 2006
    Location
    Smyrna, DE
    Age
    67
    Posts
    1,750
    I know there was supposedly some benefit to having some back pressure with the smaller exhaust but see some people running with the larger 3" exhaust all the way back. I wondered if there was a hp benefit to the larger exhaust.
    Last edited by vkirkend; 10-15-2014 at 08:22 AM. Reason: sp
    2004 MM (Black) #112 of 3213 (SOLD)
    2003 MM (BLACK #5444 of 7838 (FOR SALE)
    "BLACK MAMBA" (fomerly owned by Chris Wright)
    Cowl Induction Hood
    2.9 Whipple
    4.6 MMR Motor
    4L80E Trans
    Stainless 3" Exhaust
    631 RWHP/569 RWTQ
    AND-
    2018 Ford f-150 SuperCab Black
    3.3 L 4X4
    -AND-
    SLAYER1
    formerly owned by "Impala Slayer!! 2004 SB MM
    Kenne Belle 2.8 (Liquid Cooled), MMR "Boss 302" Block, Kooks Headers and cats, Accusump Pre-Oiler Dynamax VT mufflers, MBS 2 1/2" exhaust, 4.10's, 2800 stall, Argento 312 "Color" Powder coated wheels, Rears widened 1 1/2 ",650 HP/590 TQ on 93 Octane, M/M catch can, 3 pillar gauge (Boost, Fuel, air intake and coolant temp, custom console cover, S-55 treatment.

  5. #5
    Join Date
    Apr 2011
    Location
    Statesville, NC
    Age
    28
    Posts
    2,164
    i thought the general rule was 1" total for every 100 horsepower,

    so only if your were planning on making 600+ RWHP would 3" exhaust be necessary

  6. #6
    Join Date
    Jul 2008
    Location
    North Georgia
    Posts
    3,989
    Quote Originally Posted by jwibbity View Post
    i thought the general rule was 1" total for every 100 horsepower,

    so only if your were planning on making 600+ RWHP would 3" exhaust be necessary

    +1^^^^^^^^^

  7. #7
    Join Date
    Nov 2012
    Location
    Southeastern PA
    Age
    58
    Posts
    1,102
    Quote Originally Posted by jwibbity View Post
    i thought the general rule was 1" total for every 100 horsepower,

    so only if your were planning on making 600+ RWHP would 3" exhaust be necessary
    How do nine-inch tips figure into that ? I mostly see them on cars making about 125 hp, is that one inch of can per 15 hp ?
    "Moonbeam McSwine"


    2003 DBP, fresh off an Iowa corn farm.
    "Pretty much stock, except for the blower."


    "Devil Girl"

    2004 DTR w/ Light Flint
    Every factory option - Moonroof, all that stuff.

  8. #8
    Join Date
    Jun 2007
    Location
    Bethlehem, PA
    Age
    38
    Posts
    2,756
    Quote Originally Posted by jwibbity View Post
    i thought the general rule was 1" total for every 100 horsepower,

    so only if your were planning on making 600+ RWHP would 3" exhaust be necessary
    It's a good thing I went full 3"
    2003 DBP # 153 Whipple 3.4 in coming soon
    2004 Black Trilogy #43

  9. #9
    Join Date
    Jul 2011
    Location
    Upper Marlboro
    Age
    62
    Posts
    1,579
    Quote Originally Posted by Comin' in Hot View Post
    It's a good thing I went full 3"
    Yepp ---the old rule of thumb was'' big block' pushing 600 hp can accommodate 3'' exhaust
    Roger that

    Assembled 8/25/03. In service 11/5/03.[Safford Lincoln Mercury] . Returned from Service to Dundalk Lincoln Mercury 7/12/11 Adopted and reassigned to Street Duty 7/29/11 .at Car Center [Waldorf Ford] /Waldorf MD. # 27 of 997 silver burch #103 of 3214 Sold Oct 17, 2015. Replaced with 2016 XLT Explorer with 3:66 gear 4WD [ interceptor package] In addition 2015 -V6 Mustang added to the corral April 17,2015 with Roush upgrades .

  10. #10
    Join Date
    Feb 2012
    Location
    harrison twp,mi
    Posts
    8,636
    Y'all must be running race cars!!!!
    Those were the days.........

    DANG THEY'RE CUTE!!!!!!
    Smile and Nod
    I love THIS bar

  11. #11
    Join Date
    Jun 2005
    Location
    North East PA
    Age
    37
    Posts
    1,175
    fopr most people's MM 2.5" is fine... but if you plan to run big power & Big boost / CFM then the #" exhaust is less restrictice. but if you havent had your headsw redone (port & polished) then the exhaust will not make a difference...

    If you cant get the xtra air flow thru the engine....

  12. #12
    Not much better for either one if you still running stock manifolds that's where its choking these engines .

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Similar Threads

  1. 17 inch skinnies and 15 inch rear wheels and drag radials
    By MarauderPU in forum Tires & Wheels
    Replies: 1
    Last Post: 05-23-2013, 05:54 PM
  2. For Sale 4 inch Exhaust extension NIB Box Never opened
    By Mercguy04 in forum Marauder-specific Parts for Sale
    Replies: 9
    Last Post: 03-28-2012, 12:31 PM
  3. Megs 4 inch non resonated Exhaust Tips, New!
    By 96fleetwood in forum Marauder-specific Parts for Sale
    Replies: 11
    Last Post: 12-02-2011, 04:37 AM
  4. Replies: 17
    Last Post: 10-28-2008, 04:14 AM
  5. I wanted to put either 22 inch or 24 inch rims on
    By My04isnice in forum Tires & Wheels
    Replies: 38
    Last Post: 08-23-2007, 10:30 AM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •