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Would I gain any HP by replacing my Flowmaster cat

This is a discussion on Would I gain any HP by replacing my Flowmaster cat within the External Engine forums, part of the LSx Technical Help Section category; I bought my black 99TA with a cat back Flow Master and I have been reading that it doesn't react ...

  1. #1
    BLKHWK Durango's Avatar
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    Would I gain any HP by replacing my Flowmaster cat

    I bought my black 99TA with a cat back Flow Master and I have been reading that it doesn't react well with an LS1 engine. Back pressure not as much flow is my understanding

    My question is would I gain any HP or torque by replacing my cat back with a different one?
    If yes by how much?
    If yes. could I just change out my flow master muffler? I don't know if anything lines up but those chrome tips coming out of the back look nice.

    Instead of spending $400 or $600 on a new cat back I could buy an LS6 intake or headers etc...Would that be a better investment?

    I only have an SLP lid that I really just ordered a KN filter and the cat back...

    I like the sound that I have now but performance for my money is what I'm looking for first. I am new as an LS1 owner and I would appreciate some help with dyno facts would be even nicer.

    Cheers

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    Senior Member 00z28bubba's Avatar
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    electric cut-out. cheap and if their is a noticable difference in a flowmaster catback vs another catback you will get it with the cut-out open. and you would still have plenty of money to play with maybe an intake or headers or whatever route you choose. manual cut-outs are cheaper and electric are easier to use once installed. i pm'd you a link to one i think there are cheaper for this kind but you just have to search for them though.
    Last edited by 00z28bubba; 12-14-2008 at 06:31 PM.

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    BLKHWK Durango's Avatar
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    Quote Originally Posted by 00z28bubba View Post
    electric cut-out. cheap and if their is a noticable difference in a flowmaster catback vs another catback you will get it with the cut-out open. and you would still have plenty of money to play with maybe an intake or headers or whatever route you choose. manual cut-outs are cheaper and electric are easier to use once installed. i pm'd you a link to one i think there are cheaper for this kind but you just have to search for them though.
    Cheers

    I'm going to try to learn about them I really never heard of them.

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    Auto Painter RyanJM's Avatar
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    I has a Flowmaster catback

    I didn't notice any great gain with different cat backs. I got rid of my flowmaster because of sound.It was great stock but with the long tube headers and off road y pipe it was too raspy. I have the new slp power-flo, not raspy and quite at cruising on the highway but loud when you want ti to be. The hp gain may be 2 or 3 hp nothing that you'll notice. You can swap it out with a magnaflow of the same size or dynomax for a couple hundred with install.. Simple cut and weld and keep the same tips.
    Spend your money on a LS6 intake(check your local speed shop I got a nice used for for a few hundred with install) or ASP pulleys($220), get a lot more power from that than changing out the flowmaster. I only paid $250 for my aftermarket WS6 ram air hood on my Trans Am. I found a big difference with the long tube headers and y pipe. Pacesetters are pretty cheap and I got a set of hookers with off road ypipe for $500 used with install at a local shop.
    I just sold them for $200 when I got my new QTP headers. Lots of better things to worry about that the catback if you want more power.

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    ROWDY BURNS jsteele90's Avatar
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    my flowmaster robs my car of around 17hp and 22 tq on my last dynotune comparing runs with the cutout and cutout closed

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    BLKHWK Durango's Avatar
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    Quote Originally Posted by jsteele90 View Post
    my flowmaster robs my car of around 17hp and 22 tq on my last dynotune comparing runs with the cutout and cutout closed
    Wow! You mean to tell me that I would gain 17hp by putting an electric cut out on my car and just leave the Flowmaster for my everyday driving. Thanks for the info

  7. #7
    BLKHWK Durango's Avatar
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    Quote Originally Posted by RyanJM View Post
    I didn't notice any great gain with different cat backs. I got rid of my flowmaster because of sound.It was great stock but with the long tube headers and off road y pipe it was too raspy. I have the new slp power-flo, not raspy and quite at cruising on the highway but loud when you want ti to be. The hp gain may be 2 or 3 hp nothing that you'll notice. You can swap it out with a magnaflow of the same size or dynomax for a couple hundred with install.. Simple cut and weld and keep the same tips.
    Spend your money on a LS6 intake(check your local speed shop I got a nice used for for a few hundred with install) or ASP pulleys($220), get a lot more power from that than changing out the flowmaster. I only paid $250 for my aftermarket WS6 ram air hood on my Trans Am. I found a big difference with the long tube headers and y pipe. Pacesetters are pretty cheap and I got a set of hookers with off road ypipe for $500 used with install at a local shop.
    I just sold them for $200 when I got my new QTP headers. Lots of better things to worry about that the catback if you want more power.
    Man we don't get deals like that over here I would do all of that in a hearth beat at those prices. I'll look around the 2 major speed shops around here for the LS6 intake for sure but can I change the intake for now and nothing else or do I have to put headers and y pipe with it. I was told that a corvette headers are as good if not better than anything else to put on my car if I swap the intake is that true?

  8. #8
    Junior Member MR NOS's Avatar
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    cat back is not that much important use your money in other staff don't wastt it on cat back flomaster is good but there is other staff is better like borla and b&b
    Last edited by MR NOS; 12-18-2008 at 07:27 AM.

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    Senior Member Zboner's Avatar
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    Corvette headers? its the same LS1 manifolds(basically trying to sell you the same thing you have already) get some pacesetters or Kooks(stainless)

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    BLKHWK Durango's Avatar
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    Quote Originally Posted by Zboner View Post
    Corvette headers? its the same LS1 manifolds(basically trying to sell you the same thing you have already) get some pacesetters or Kooks(stainless)

    Thanks

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    She Moderator KahanaReef's Avatar
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    I can't get away with LT's here in CA. I also have Flowmaster catbacks. What's the average cost to have electric cutout installed?

  12. #12
    cutting and welding mark21742's Avatar
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    Quote Originally Posted by KahanaReef View Post
    I can't get away with LT's here in CA. I also have Flowmaster catbacks. What's the average cost to have electric cutout installed?
    if you lived close to me I'd do it for a 6 pack look for a friend with a sawzall and a welder....a shop shouldn't charge that much though

  13. #13
    She Moderator KahanaReef's Avatar
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    Quote Originally Posted by mark21742 View Post
    if you lived close to me I'd do it for a 6 pack look for a friend with a sawzall and a welder....a shop shouldn't charge that much though
    Heh... thanks

    I'll look into it.

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    Veteran 0rion's Avatar
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    I paid a shop $20 to weld my cutout in. I ran the electric part of it myself. Pretty easy really. It's by far my favorite mod on the whole car.

  15. #15
    She Moderator KahanaReef's Avatar
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    I am assuming that as long as it's closed, it won't affect a smog pass... Am I wrong? or, is it one of those 'if they don't do a visual' things?

    And, which is best to buy?

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