Flowmaster cat back
Thread Starter
12 Second Club
Joined: Feb 2006
Posts: 993
Likes: 3
From: Waukesha,WI
Flowmaster cat back I bought my car used and the previous owner had installed a flowmaster cat back on it. i'm hearing horrible stories about how bad they flow. is it the cat back its self or the muffler? if its just the muffler who makes a better flowing muffler that i can just bolt up so i don't have to buy a new exhaust. i love the corsa look but i think i'll just put on tips. so i need a better flowing muffler and i don't care how loud it is just want flow and bolt right up.
they have a pair of corsa knock offs on ebay....look the same but are cheap. otherwise, i had flowmaster at first, liked the sound but once i put an ORY n headers i hated it. changed the exhaust to borla and noticed a difference in gains and wayyy better sound cause its adj.
TECH Apprentice
Joined: Dec 2004
Posts: 309
Likes: 0
From: Evansville, IN
You'll hear people claiming they gained 30+rwhp by switching from the Flowmaster catback, but is rarely based on firsthand experience. The 80-series muffler is the restriction, but don't be fooled into thinking every one of their mufflers is restrictive. The single chambers (10-series) flow extermely well, and have become the popular choice for true-dual setups. Buy your catback for sound, not performance.
TECH Apprentice
Joined: Dec 2004
Posts: 309
Likes: 0
From: Evansville, IN
I haven't heard one in person, and sound clips don't really sound the same at all. Most of the guys who are running them say it creates a unique sound that is similar to the old small-blocks. I'm sure someone who has single-chambers will post up soon.
Trending Topics
TECH Apprentice
Joined: Dec 2004
Posts: 309
Likes: 0
From: Evansville, IN
As far as I know, nobody on here is using a single-chamber with a y-pipe. Flowmaster doesn't make a 1-chamber catback for F-bodies, so it is going to weld in. Also, most of the guys running them in true dual setups have longtubes and often a cam as well. With stock manifolds it is going to sound quite a bit different. You put an emphasis on making it "bolt up," and this is a route that requires more than just bolting on a catback. You should probably do some reading of the stickies and such before you go dropping some money. Exhaust sound is a personal preference and not everyone is going to have the same taste as you. You need to find a sound you like.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo Thread Starter
12 Second Club
Joined: Feb 2006
Posts: 993
Likes: 3
From: Waukesha,WI
i pretty much have liked all the f-bodies i've heard with different exhausts except my buddies ss with LT's and a magnaflow no cats etc. it was to raspy. but i just want to gain some exhaust flow with a muffler i can put in the flowmasters place
I vote Hooker, although they have had some reliability issues over time, I think they are a great muffler. Some have problems with the baffles inside the muffler coming loose. If they do after a year or two, who cares, replace it. They are only $80!
The hooker muffler is fairly tame with stock manifolds but it has great tone and flows very well. Depending on the size difference between the Flomaster and Hooker, the muffler should bolt right up. You may want to look more into that. If they are different sizes, any exhaust shop can make it work for you.
If you plan on Longtubes in the future, that is where this muffler shines. It sounds great with Longtubes and ORY. I am hopefully replacing my flowmaster with one soon.
Good luck with your decision!
The hooker muffler is fairly tame with stock manifolds but it has great tone and flows very well. Depending on the size difference between the Flomaster and Hooker, the muffler should bolt right up. You may want to look more into that. If they are different sizes, any exhaust shop can make it work for you.
If you plan on Longtubes in the future, that is where this muffler shines. It sounds great with Longtubes and ORY. I am hopefully replacing my flowmaster with one soon.
Good luck with your decision!
TECH Fanatic
Joined: May 2005
Posts: 1,135
Likes: 1
From: The 'Burgh, PA
Hooker is the 
! One of the only LS1 mufflers that adds a deep tone and not just volume. 2 years on mine and counting - no probs. It is pretty quiet with stock manifolds and cats unless you are "gettin' after it"
! One of the only LS1 mufflers that adds a deep tone and not just volume. 2 years on mine and counting - no probs. It is pretty quiet with stock manifolds and cats unless you are "gettin' after it" 
I had a flowmaster on my t/a when I bought it (along with the dreaded hypertech). I replaced mine with a hooker cat back system when I put on long tube headers. If your flowmaster is still in good shape and not starting to rust much I would get an electric cutout installed on your current system and use it if/when you race. The flowmaster does look and sound pretty damn good so that's why I wouldn't just completely ditch it. I would doubt that for stock or bolt on ls1s the flowmaster is reducing power by more then 10 rhwp over any other cat back.
This is my .02
This is my .02
TECH Senior Member
iTrader: (10)
Joined: May 2005
Posts: 5,353
Likes: 2
From: Bossier city,LA barksdale AFB
They call them flowdisasters for a reason! back In the day they were about all you could get while all the other company's updated their technology they didn't!
i got a 40 series (american thunder) and I love the sound, but im on stock manifolds and Y but I think the 40 AT cat-back is an improvment over stock either way. I dont think flowmaster is as bad as everyone makes it to be but I know the 80 series is restrictive
Teching In
Joined: Aug 2006
Posts: 40
Likes: 0
Im so sick of hearing people saying that you "lose power" with flow master! I personaly think its BS and I'll tell you why. I know 3 F bodys that have it and there car responds to mods and dynos just like everyone elses. My car personaly dynod 311 hp and 327 ft lbs of torque. Thats with just an MTI clear lid and flowmaster cat back and Y pipe. My car went 13.01 at 108 MPH with the factory 245's with just the lid,coldair and flowmaster. I have a friend that has a comp cam dont remember the specs though, hooker headers and flowmaster and hes making 380 hp and went 12.4 on some drag radials. and I have a friend with a 383 stroker and hes making 420 hp and 448 ft lbs of torque. I know that if you had something like the SLP loud mouth with that glass pack muffler that sounds like crap its gonna obviously flow better but I think thats the only one that you would see a power difference. I think that everyone can agree that any cat back you go with will give you 8-10 hp and thats it. You should deffinatley just buy a cat back for sound and thats it. My car runs strong and so does everyone elses that has flow master that I know. So Id say if you like the sound dont swap it. If you want power do a cut out because that will give you more power then having any kind of muffler on there.
Last edited by nvrlast; Sep 4, 2006 at 10:44 AM.
I agree somewhat, we are not seeing whos bolton car has the most horsepower here. Personally, on my setup in sig, I can not feel much difference at all when I open or close the cutout. But the 80 series is known to be the worst flowing muffler for our cars, period. If you like the sound, keep it and have a cutout installed, it's cheap and sounds good. My flowmaster doesnt sound very good with LT's so I am going with a different setup in the near future.
i have a flowmaster cat-back as well, i love the way it sounds, real crisp and assertive, but its not LOUD LOUD, but you know im around.
and i know these 80- series suck for flow, end of story, thats just how it is, flowmasters are engineered for sound more so than performance.
i also just bought LT's and ORY so i dont know how i will like it with the full exhaust, i guess we'll just see if i am gunna swap out the muffler or not.
and i know these 80- series suck for flow, end of story, thats just how it is, flowmasters are engineered for sound more so than performance.
i also just bought LT's and ORY so i dont know how i will like it with the full exhaust, i guess we'll just see if i am gunna swap out the muffler or not.
TECH Senior Member
iTrader: (1)
Joined: Apr 2005
Posts: 8,807
Likes: 0
From: Vancouver,[KITSILANO].B.C. Canada *WestCoast*
Originally Posted by DansRedz28
They call them flowdisasters for a reason! back In the day they were about all you could get while all the other company's updated their technology they didn't!
the only Flowmaster that does not flow as well as others is the 80 series CROSSFLOW....the others are not the straight through design ........the DELTA-FLOW design is as good as the others..maybe a couple-3-hp less......but the others do not have the "signature sound".....WHICH MILLIONS LOVE.....Including most DRAG RACERS....CIRCLE TRACK...including ALL WINGED racers......and any other racer "worth his salt" .....oh yeah, that is an old expression you also might learn...