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Flowmaster catback + 440 RWHP car

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Old Aug 22, 2008 | 10:13 AM
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Default Flowmaster catback + 440 RWHP car

How much restriction is a flowmaster catback on a car that has made 440+ HP thru it already?
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Old Aug 22, 2008 | 11:19 AM
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I wouldnt say its a restriction at all, it just doesnt flow as well as other catbacks
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Old Aug 22, 2008 | 11:55 AM
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The flowmaster catbacks are known for going on a stock LS1 car and actually slowing it down. FYI.
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Old Aug 22, 2008 | 12:02 PM
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Originally Posted by b00sted
The flowmaster catbacks are known for going on a stock LS1 car and actually slowing it down. FYI.
No, they are not.
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Old Aug 22, 2008 | 12:07 PM
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They pretty much give a 0 hp increase over the stock exhaust so you're probably leaving about 15rwhp on the table.
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Old Aug 22, 2008 | 12:18 PM
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remove the muffler and find out, it wouldn't take long to do. i'd guess you're losing <5whp using that MUFFLER over another. replace it with a magnaflow and see what happens.
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Old Aug 22, 2008 | 05:07 PM
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I dont see you losing to much over another muffler if you do something get a cut-out all that BS about oh the flowmaster slows you down is just rumor BS tell them post a dyno graph or something if it slows down that much prove it. I said it before I only seen one guy with a dyno run same day same car flowmaster vs cut-out and he only lost 8hp with the cut-out closed and that was all top end.
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Old Aug 22, 2008 | 05:15 PM
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yeah i cant see you picking up more than 5-8hp switching.
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Old Aug 22, 2008 | 05:16 PM
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Okay, I think we need a little bit of reality here - the flowmaster for fbodies does flow less than other catbacks, and it has been shown time and time again on this board from ppl that have switched.
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Old Aug 22, 2008 | 05:20 PM
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I've done the test back to back on a heads/cam car. Flowmaster robbed 22 rwhp vs. a cutout on a 460 rwhp car. Switched on a Hooker Aerochamber, and picked back up the 20 rwhp.

The Flowmaster sounds decent (if you like sounding like a pickup truck), but is quite possibly (aside from Corsa or B&B Tri-Flow) the worst flowing catback and/or muffler available for F-bodies.
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Old Aug 22, 2008 | 05:20 PM
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real talk I only found one dude that posted a graph that was consistant same day runs same car, everything else I seen is someone saying oh my sister in laws baby cousin had a flowmaster on his LS1 and he lost 20 hp lol get the **** out of here with that BS once I see the proof I'll believe it all that other **** is for the birds. Dude get a cut out its like 40 bucks from jegs instead of spending like 300 on a new cat-back to gain like 4 hp if that
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Old Aug 22, 2008 | 05:21 PM
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Originally Posted by JonCR96Z
No, they are not.
Apparently...Yes, they are.
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Old Aug 22, 2008 | 08:10 PM
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Originally Posted by ChevyRyda99LS1
real talk I only found one dude that posted a graph that was consistant same day runs same car, everything else I seen is someone saying oh my sister in laws baby cousin had a flowmaster on his LS1 and he lost 20 hp lol get the **** out of here with that BS once I see the proof I'll believe it all that other **** is for the birds. Dude get a cut out its like 40 bucks from jegs instead of spending like 300 on a new cat-back to gain like 4 hp if that
a sponsor isn't going to bullshit about that noob. dyno graphs have been posted here to back his statment hurt. don't be all butthurt cause you have the worst catback for our cars.
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Old Aug 22, 2008 | 08:12 PM
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Originally Posted by Damian
I've done the test back to back on a heads/cam car. Flowmaster robbed 22 rwhp vs. a cutout on a 460 rwhp car. Switched on a Hooker Aerochamber, and picked back up the 20 rwhp.

The Flowmaster sounds decent (if you like sounding like a pickup truck), but is quite possibly (aside from Corsa or B&B Tri-Flow) the worst flowing catback and/or muffler available for F-bodies.
I haven't heard of Corsa flowing bad??! I've always heard that Corsa flows real well! What testing have you done with Corsa?
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Old Aug 22, 2008 | 11:38 PM
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Originally Posted by Chase22
Apparently...Yes, they are.
Ok, show me some proof that someone put a flowmaster on a stock car and it slowed down, dumbfuck.

I didn't say that it was the best muffler out there. I sure don't run one. But there's no case where someone put one on a stock car and it slowed down, atleast without some other factor.

Even if that was the case its not "known" for causing stock cars to slow down. You and the guy that posted that before need to READ the threads and UNDERSTAND them before you post something.

Sorry, if this seems like an attack on you, but it was. Don't call someone out with expecting it back.

Jon
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Old Aug 22, 2008 | 11:44 PM
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It nothing about getting but hurt I could care less I'm fine with the flows sounds good as **** and car runs strong the thing is you lames are trying to feed him this bullshit like he is going to gain so much by switching out the flowmaster its not worth spending a extra 300 for like 3 hp thats why I suggested getting a cut out if its that much of a problem, and I like I said before if you got the proof post the graphs until then eat a dick
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Old Aug 23, 2008 | 12:39 AM
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The muffler that Flowmaster uses in the F-body cat-back makes it one of the worst flowing cat backs. They make some average flowing mufflers, but the one used for our cars aren't one of them. Just get a magnaflow cat back, one of the best flowing exhausts, cheap, all stainless.
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Old Aug 23, 2008 | 12:53 AM
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Thanks to those with real imformation.

I don't really like the sound, so I'm probably going to go with a Mangaflow, like on my bolt on car.
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Old Aug 23, 2008 | 12:56 AM
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Originally Posted by ChevyRyda99LS1
It nothing about getting but hurt I could care less I'm fine with the flows sounds good as **** and car runs strong the thing is you lames are trying to feed him this bullshit like he is going to gain so much by switching out the flowmaster its not worth spending a extra 300 for like 3 hp thats why I suggested getting a cut out if its that much of a problem, and I like I said before if you got the proof post the graphs until then eat a dick
https://ls1tech.com/forums/generation-iii-external-engine/890131-dyno-results-flowmaster-cb-vs-e-cutout.html

You even posted in that thread.

And try using proper grammar.
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Old Aug 23, 2008 | 07:31 AM
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Originally Posted by Damian
I've done the test back to back on a heads/cam car. Flowmaster robbed 22 rwhp vs. a cutout on a 460 rwhp car. Switched on a Hooker Aerochamber, and picked back up the 20 rwhp.

The Flowmaster sounds decent (if you like sounding like a pickup truck), but is quite possibly (aside from Corsa or B&B Tri-Flow) the worst flowing catback and/or muffler available for F-bodies.
My feelings exactly, and the reason all three of my Fbodies have ended up with Hookers in the end.
I dynoed my old LE setup with the hooker VS the cutout and found a difference of 3rwhp (VS open cutout).

Last edited by James Montigny; Aug 23, 2008 at 07:48 AM.
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