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LT setup vs Y pipe w/ high flow cats

This is a discussion on LT setup vs Y pipe w/ high flow cats within the External Engine forums, part of the LSx Technical Help Section category; So has anybody here skipped out on the Long Tube headers and stayed with their Stock manifolds, but got high ...

  1. #1
    Member Guerrillakilla13's Avatar
    Join Date
    Feb 2011

    2002 Trans Am WS6

    LT setup vs Y pipe w/ high flow cats

    So has anybody here skipped out on the Long Tube headers and stayed with their Stock manifolds, but got high flow cats and a less restrictive Y pipe? If so, how do you like that setup?

    I'm trying to make a decision on if i should do LT's with high flow cats, or save a ton of money and just get a wider Y pipe with high flow cats. What do you all think?

  2. #2
    Moderator 98TransAmWs-6's Avatar
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    Apr 2010
    Fairfax, VA

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    98 TA WS6/ 01 C5 Corvette

    You won't see that much gain and honestly it wouldn't be worth the time. Sure you will gain some horse power but not enough to even compare to doing LTs. LT headers is where the gain is really at. That would be like upgrading to a Fast 102 but keeping a stock lid and TB. Just doing headers and cats won't work right either you will be creating a lot if turbulence and perhaps bottle necking the exhaust. I don't know how you would be saving a lot of money by doing this since my stainless headers and catted y were only $620. IMHO it is definitely not worth it to just do headers or y pipe you need to do both.
    Last edited by 98TransAmWs-6; 07-24-2012 at 10:06 AM.
    1998 Trans Am WS6 - Phantom
    421 CI LQ9, Tick Performance Custom Cam, TFS 255cc LS3 heads, Kooks 2" LT headers, Kooks 3" True Duals w/ high flow cats, FTP 104 lid, Speed Density Tune, 4" silicon tube, LS6 VCT, FAST 102 Intake, NW 102 TB, Oil Catch Can, SLP Bilstein Shocks w/ Vogtland Springs, CTS-V 4-piston Calipers w/C6 Z06 rotors, Stainless Steel Brake Lines, R1 concepts premium rotors, Hawk HP+ brake pads, VFN WSQ Hood, C5-R timing chain, SLP oil pump, E85 tune, Walbro 450 fuel pump, Deatschwerkz 95# injectors, Breathless performance headlights, Frost Tune, !HVAC.
    (Coming Soon) BMR DSL, UMI TQ Arm
    421 LQ9 14.8:1 on E85 Build/

  3. #3
    Join Date
    Apr 2012

    2001 trans am

    do them both use an ORY

  4. #4
    Senior Member Too Fast's Avatar
    Join Date
    Nov 2006

    2000 WS6 6spd Hooker LT

    +3 on LT/ORY. Emission testing a problem where you live?

  5. #5
    Super Moderator
    pajeff02's Avatar
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    Feb 2009
    Mansfield, PA

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    '02 WS.6 / '07 Suburban

    Just adding a Y-pipe isn't going to do a whole lot for you. Long tube headers are where the gains are at.

  6. #6
    Moderator Firebirdjones's Avatar
    Join Date
    May 2006
    Like the others have said, just jump right to a set of headers.

    I tried the Y-pipe replacement that SLP used to sell several years back. Stock manifolds otherwise. It was to replace the stock Y-pipe that is flattened on the driver side (I don't know if these are made any longer).

    I didn't gain squat, car ran the same MPH at the track. I even tried gutted cats for a while. Couldn't get any measurable performance gain there either. I'd guess the gutted cats did more harm than good having a huge open area the size of a mellon with a small 2 1/4" pipe on either end. Turbulance disrupting exhaust flow!!!

    In the end the long tube headers and off road Y pipe finally showed an improvement (about a tenth and ~2 mph) on an otherwise bone stock 02 SS. Start throwing camshafts and cylinder heads in the mix and you will likely see a larger improvement with exhaust mods.

  7. #7
    Former Mopar Man 2002ssslp's Avatar
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    Branchville, NJ

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    02 Camaro SS, 04 GTO

    1 3/4" LTH + 3" ORY + 3" in 3" out Borla = 25 to 30 gross hp
    My ride is a 2002 Camaro SS SLP #3296 with 30k, LTH, 3" Y, CME, Frost tune, K&N, ported TB, Blackwing lid, Bellows, MSD, Denso Iridium, and 85mm MAF, Bilsteins, Eibach springs, SLP strut brace, Adj. Panhard, TA Girdle, UMI, Pro 5.0, Nitto NT555
    My wife has a 2004 GTO with the rare SAP, 18" wheels, K&N Cold Air System, MSD, Ported TB, Frost tune, Denso Iridium, Flowmaster cat-back, 3200 Yank, 75k

  8. #8
    You've Seen The Butcher GoldenFlame's Avatar
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    May 2009

    2009 Silverado Z71
    2003 Corvette MN6 Black

    Ebay headers if you are on a super tight budget. My buddy's 98 Z has had them for 3 years, they're stainless. I'd do Ebay Headers, and a Texas Speed ORY, that's probably around $350 total. Then Add CATS if you really need them

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