The Dreaded Flowmaster Cat-Back
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From: Philadelphia, Pennsylvania
The Dreaded Flowmaster Cat-Back I finally got my car up on a lift today. I realized that I have the infamous Flowmaster cat-back on my Z28.
Can someone tell me why these systems have such a bad reputation? Do they really flow that bad? I'm looking to have some long tubes installed. Is the Flowmaster system so bad that I should get another cat-back, too?
What causes these systems to flow so bad? Can I modify it to improve the flow? I heard that there's baffles in these systems. Is that what causes the problem and can they be removed? If not and a new system is my only answer, what would be recommended?
Thanks.
Can someone tell me why these systems have such a bad reputation? Do they really flow that bad? I'm looking to have some long tubes installed. Is the Flowmaster system so bad that I should get another cat-back, too?
What causes these systems to flow so bad? Can I modify it to improve the flow? I heard that there's baffles in these systems. Is that what causes the problem and can they be removed? If not and a new system is my only answer, what would be recommended?
Thanks.
Depends what muffler youre talking about. Some have gained very little at the track with a cutout open vs closed on a flowmaster. Others have gained a bit after they replace a flowmaster with something else. But on most, the difference is miniscule.
I would keep it since its already there and see how you like how it sounds with the headers installed. I personally like how they sound on stock cars, but heard they loose their good sound with LTs.
I would keep it since its already there and see how you like how it sounds with the headers installed. I personally like how they sound on stock cars, but heard they loose their good sound with LTs.
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From: Schiller Park, ILL Member: #317
The Flowmaster chambered design is not the best in a crossflow (single in, dual out) configuration such as what is used for the F-body catback. However Flowmaster has several different lines of mufflers, not all of them are equal and certainly not all of them are "bad".
If you are concerned about flow but like the sound, you can always add a cheap cutout to the system.
Like most mufflers on the loud end of the spectrum, Flowmaster will produce some significant rasp (sort of a kazooing type sound) at certain RPMs when paired with an ORY. Headers aren't the reason for this sound, it's the ORY. If you add cats (or certain bullet mufflers) or go with true duals you won't have this issue.
If you are concerned about flow but like the sound, you can always add a cheap cutout to the system.
Like most mufflers on the loud end of the spectrum, Flowmaster will produce some significant rasp (sort of a kazooing type sound) at certain RPMs when paired with an ORY. Headers aren't the reason for this sound, it's the ORY. If you add cats (or certain bullet mufflers) or go with true duals you won't have this issue.
Flowmaster's even though popular have shown to not flow so well. I wouldn't waste the money on a new catback just swap in a better flowing muffler....or like said a cutout.
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Teching In
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From: Philadelphia, Pennsylvania
Any suggestions as to what muffler to use? The car is basically stock. As of right now, I have the cat-back, a lid, free ram air and a K&N filter. I plan on having long tubes installed and a ported throttle body. The car is my daily driver. Thanks for the info. I appreciate it.
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Teching In
Joined: Oct 2014
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From: Philadelphia, Pennsylvania
Depends what muffler youre talking about. Some have gained very little at the track with a cutout open vs closed on a flowmaster. Others have gained a bit after they replace a flowmaster with something else. But on most, the difference is miniscule.
I would keep it since its already there and see how you like how it sounds with the headers installed. I personally like how they sound on stock cars, but heard they loose their good sound with LTs.
I would keep it since its already there and see how you like how it sounds with the headers installed. I personally like how they sound on stock cars, but heard they loose their good sound with LTs.
Thread Starter
Teching In
Joined: Oct 2014
Posts: 16
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From: Philadelphia, Pennsylvania
The Flowmaster chambered design is not the best in a crossflow (single in, dual out) configuration such as what is used for the F-body catback. However Flowmaster has several different lines of mufflers, not all of them are equal and certainly not all of them are "bad".
If you are concerned about flow but like the sound, you can always add a cheap cutout to the system.
Like most mufflers on the loud end of the spectrum, Flowmaster will produce some significant rasp (sort of a kazooing type sound) at certain RPMs when paired with an ORY. Headers aren't the reason for this sound, it's the ORY. If you add cats (or certain bullet mufflers) or go with true duals you won't have this issue.
If you are concerned about flow but like the sound, you can always add a cheap cutout to the system.
Like most mufflers on the loud end of the spectrum, Flowmaster will produce some significant rasp (sort of a kazooing type sound) at certain RPMs when paired with an ORY. Headers aren't the reason for this sound, it's the ORY. If you add cats (or certain bullet mufflers) or go with true duals you won't have this issue.
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Any suggestions as to what muffler to use? The car is basically stock. As of right now, I have the cat-back, a lid, free ram air and a K&N filter. I plan on having long tubes installed and a ported throttle body. The car is my daily driver. Thanks for the info. I appreciate it.
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From: Philadelphia, Pennsylvania
If you have the cross-flow style catback, there are several good options for muffler replacements.
I found the rear section of a Magnaflow catback with stainless tips and went with that because I needed something quieter to keep the car under the sound limit at local road courses. Love the sounds and it flows well.
Since I didn't want to sacrafice the ability to be "loud" when I wanted it, I installed a cutout in the intermediate pipe with the angled tip to help reduce rasp in the system. Love it. Loud + tone + no rasp = exactly what I wanted out of the exhaust setup when there was no sound restriction in place.
If you search on youtube for "2002 Camaro SS Road Atlanta" or "2002 Camaro SS Atlanta Motorsports Park" there are a few videos if you want to get a feel for what it sounds like.
I found the rear section of a Magnaflow catback with stainless tips and went with that because I needed something quieter to keep the car under the sound limit at local road courses. Love the sounds and it flows well.
Since I didn't want to sacrafice the ability to be "loud" when I wanted it, I installed a cutout in the intermediate pipe with the angled tip to help reduce rasp in the system. Love it. Loud + tone + no rasp = exactly what I wanted out of the exhaust setup when there was no sound restriction in place.
If you search on youtube for "2002 Camaro SS Road Atlanta" or "2002 Camaro SS Atlanta Motorsports Park" there are a few videos if you want to get a feel for what it sounds like.
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If you have the cross-flow style catback, there are several good options for muffler replacements.
I found the rear section of a Magnaflow catback with stainless tips and went with that because I needed something quieter to keep the car under the sound limit at local road courses. Love the sounds and it flows well.
Since I didn't want to sacrafice the ability to be "loud" when I wanted it, I installed a cutout in the intermediate pipe with the angled tip to help reduce rasp in the system. Love it. Loud + tone + no rasp = exactly what I wanted out of the exhaust setup when there was no sound restriction in place.
If you search on youtube for "2002 Camaro SS Road Atlanta" or "2002 Camaro SS Atlanta Motorsports Park" there are a few videos if you want to get a feel for what it sounds like.
I found the rear section of a Magnaflow catback with stainless tips and went with that because I needed something quieter to keep the car under the sound limit at local road courses. Love the sounds and it flows well.
Since I didn't want to sacrafice the ability to be "loud" when I wanted it, I installed a cutout in the intermediate pipe with the angled tip to help reduce rasp in the system. Love it. Loud + tone + no rasp = exactly what I wanted out of the exhaust setup when there was no sound restriction in place.
If you search on youtube for "2002 Camaro SS Road Atlanta" or "2002 Camaro SS Atlanta Motorsports Park" there are a few videos if you want to get a feel for what it sounds like.
If I bought a MagnaFlow catback for my TransAm LS1, would it be noticeably louder than stock? I want something louder than it is now, but not something as loud as the redneck straight-pipe my Camaro LT1 was like when I bought it. I'm a Harley guy, and everyone in my neighborhood rides their choppers to work in the morning so no one really cares if I have a little bit more dB in the car. (I went from straight pipe to MagnaFlow on that car, so I don't know what the Camaro sounded like stock.)
What I always wanted is that intimidating roar as the whole car shook on crank when I used to detail this C6 Z06. I realize I don't have the power of an LS7, but if I could even come close to that kind of roar it would be great.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
If I bought a MagnaFlow catback for my TransAm LS1, would it be noticeably louder than stock? I want something louder than it is now, but not something as loud as the redneck straight-pipe my Camaro LT1 was like when I bought it. I'm a Harley guy, and everyone in my neighborhood rides their choppers to work in the morning so no one really cares if I have a little bit more dB in the car. (I went from straight pipe to MagnaFlow on that car, so I don't know what the Camaro sounded like stock.)
What I always wanted is that intimidating roar as the whole car shook on crank when I used to detail this C6 Z06. I realize I don't have the power of an LS7, but if I could even come close to that kind of roar it would be great.
What I always wanted is that intimidating roar as the whole car shook on crank when I used to detail this C6 Z06. I realize I don't have the power of an LS7, but if I could even come close to that kind of roar it would be great.
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If your car is otherwise stock (including stock cats and manifolds) then a simple Magnaflow catback won't give it the sort of "intimidating roar" that you have described. Magnaflow, while definitely louder than stock, is pretty docile on the overall scale of aftermarket systems, which is great for super aggressive setups with an ORY that needs to be quieted down for track or local noise requirements. If you intend to keep the stock cats and a stock engine, I would suggest something more aggressive than Magnaflow to suit your desire.....perhaps the SLP LMI or II or something similar, or even just a cutout on the stock system.
Also, I looked up the SLP LoudMouth II and that sounds just awesome in some of the videos, I might go that route.
SORRY FOR HIJACKING YOUR THREAD, I WILL LEAVE NOW. lol
Last edited by SouthernRex; Sep 25, 2015 at 06:16 PM.
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From: HAmpton Roads VA
I started with a stock exhaust, but my neighbor had a set of flowmasters on his ls1 car. I really didn't like the way they sounded so I started listening to sound clips of different set ups.
I currently have LT's with and ORY "no cats" and the SLP Loud Mouth II cat back. The car is loud, but doesn't drone inside. I will say that I don't daily drive the car, but it is nowhere near as loud as all the Harley's that fly past my house.
There are a couple places on this sight that you can listen to different exhaust clips from other members and their setups..... Listen for what you like and do what you want.
I know that my stock exhaust with the LM2 cat back had a lot of rasp and backfire.... for some reason I dont get that with the LT's and no cats.
I currently have LT's with and ORY "no cats" and the SLP Loud Mouth II cat back. The car is loud, but doesn't drone inside. I will say that I don't daily drive the car, but it is nowhere near as loud as all the Harley's that fly past my house.
There are a couple places on this sight that you can listen to different exhaust clips from other members and their setups..... Listen for what you like and do what you want.
I know that my stock exhaust with the LM2 cat back had a lot of rasp and backfire.... for some reason I dont get that with the LT's and no cats.
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
This is exactly the opposite of what just about every LM I or II user has reported (including myself.) They usually sound great and rasp-free with the stock cats and manifolds, but as soon as you add an ORY you get that awful kazoo on crack sound that most of us refer to as rasp. Perhaps we just use the term "rasp" to describe different things.
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From: HAmpton Roads VA
A set? Meaning two? Did he have a custom true dual setup or was this LS1 car something other than an F-body?
This is exactly the opposite of what just about every LM I or II user has reported (including myself.) They usually sound great and rasp-free with the stock cats and manifolds, but as soon as you add an ORY you get that awful kazoo on crack sound that most of us refer to as rasp. Perhaps we just use the term "rasp" to describe different things.
This is exactly the opposite of what just about every LM I or II user has reported (including myself.) They usually sound great and rasp-free with the stock cats and manifolds, but as soon as you add an ORY you get that awful kazoo on crack sound that most of us refer to as rasp. Perhaps we just use the term "rasp" to describe different things.
As for the exhaust sound before and after full exhaust install I was very surprised. When I had my stock manifolds/cats and stock Y-pipe with just the LM II cat back the car had a bit more bass and less rasp, but backfired and burbled and popped A LOT!
I was warned that the car was only going to get louder and pop more. I agree the car has a higher pitch rasp in the mid to high RPM range but the majority of the backfire and popping is gone.
As stated before it is loud, but i don't get a lot of drone especially on the highway in high gear.
My car had high miles when i got it so it may be that the cat's were shot.