94 LT1 Exhaust Question
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94 LT1 Exhaust Question I have a 94 Z28 with flowmasters. I like the way the car sounds, but I think I want it a little louder. I still have my cats on, and I looked under the car and it looks like 3inch pipes. I was thinking about going to the exhaust shop tomorrow to modify my set up a bit. What do some of you suggest I do? I want to keep the flowmasters, but should I make the pipes bigger? Possibly 4inch? (Or is that a waste of money) I basically want whatever is going to give my car it's best performance. I was thinking about gutting, or getting rid of the cat, but I don't want a check engine light on. Is there anyway this is possible? Thanks a lot, I hope to get some good ideas.
-Jay
-Jay
My 94 sounded mean as hell with the magnaflow catback w/out cats, I will never put cats on my car, sounds too good without it....i'd throw the cats off, mine never threw any codes because of it
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So, do you think the 3inch pipes that I already have are big enough? Do you really think it won't throw any codes or anything? How do you think the flowmasters would sound without cats? Pretty loud? Also, will it increase hp, or will I notice a difference at the track or anything? I personally doubt it, but I don't know too much about how restrictive the cats are. It would make sense that the car would be quicker with more air flow...
Hmm honestly I dont think it would make such a dramatic difference that you would notice anything. I am pretty sure the 3 inch piping is plenty...My piping was 3 inch on my magna flow and it sounded damn good and it was really loud too...you could hear me coming for quite some time lol I dont know how the flow masters will sound...in my experiences of hearing them and from just the way people talk I dont think they are the best to go with but its all in opinion I guess...so go with what you like...and if they dont sound too good when you pull the cats you can always get something else or have the cats put back in. But I know mine will never run cats ....
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People say not to go with flowmasters because "apparently" it doesn't give you as much performance. Although, they sound very good. (especially on mustangs) I'm a camaro guy, but mustang V8's with flowmasters sound nice. Anyway, I can't imagine the sound being much different, just louder. If that's the case, I wouldn't mind it at all. Does it end up smelling really bad out of the exhaust? I don't want to get a ticket or anything. I'm just trying to improve my exhaust a bit, not spend a bunch of money on magnaflows or something...Are you sure you can re-use your old cats?
P.S. If anyone else is reading this, feel free to give your opinion. Thanks
P.S. If anyone else is reading this, feel free to give your opinion. Thanks
If you're talking about 5.0s or 4.6 mustangs, your engine sounds a lot different.
Taking the cat off will increase flow, increase noise level (by a LOT) and change the tone, most people think it sounds better. Yes you will be able to smell exhaust a lot more than with a cat, but it's a great smell to a car guy lol.
Most exhaust shops will NOT remove a cat for you.. if you know someone then maybe you can do what I did, and got flanges made and a custom pipe to go in place of the cat, with flanges on both sides. This way when smog rolls around, I still have my cat.
Simply removing your cat might have the desired effect that you're looking for (louder and more tone) but as previously stated, unless you gut it yourself, you probably won't find someone to do it.
Flowmasters are the worst flowing of all the aftermarket muffler brands. However, on your engine (mostly stock) the difference is maybe 3-5 RWHP between your flowmaster, and say for example, my straight pipe setup. Not a whole lot. Flowmasters do sound nice however.
What model flowmaster do you have? You might simply be able to get a different model. The 40 series flows in my opinion are the loudest and bassiest, more than the 80s.
Talk to the exhaust guy and see if he has anything laying around, usually they have used mufflers just sitting around and you might be able to get something at a good deal. Mufflers never go bad, so used just means slightly dirty.
Taking the cat off will increase flow, increase noise level (by a LOT) and change the tone, most people think it sounds better. Yes you will be able to smell exhaust a lot more than with a cat, but it's a great smell to a car guy lol.
Most exhaust shops will NOT remove a cat for you.. if you know someone then maybe you can do what I did, and got flanges made and a custom pipe to go in place of the cat, with flanges on both sides. This way when smog rolls around, I still have my cat.
Simply removing your cat might have the desired effect that you're looking for (louder and more tone) but as previously stated, unless you gut it yourself, you probably won't find someone to do it.
Flowmasters are the worst flowing of all the aftermarket muffler brands. However, on your engine (mostly stock) the difference is maybe 3-5 RWHP between your flowmaster, and say for example, my straight pipe setup. Not a whole lot. Flowmasters do sound nice however.
What model flowmaster do you have? You might simply be able to get a different model. The 40 series flows in my opinion are the loudest and bassiest, more than the 80s.
Talk to the exhaust guy and see if he has anything laying around, usually they have used mufflers just sitting around and you might be able to get something at a good deal. Mufflers never go bad, so used just means slightly dirty.
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I just got the car, but I believe it is 40 series flowmasters. I do know someone to take my cat off. He took mine off of my old car. I just wanted to get some imput on this car, because I don't know how it will act up, or if engine lights will come on. So, are you suggesting gutting the cat, or just removing them and putting a pipe there? I just want to do whatever will give me the best flow and sound the best. I don't want the car obnoxiously loud. I mean, I want to be able to pull up next to a cop at a light and not have him think I don't have a cat and give me a ticket, you know?
By the way, I wasn't saying my car sounded anything like a mustang. I was just saying mustangs sound very good with flowmasters.
I'm also not looking to invest any money in a different exhaust type. Like I said, I'm pretty sure they are 40 series. They sound pretty good right now and have been on the car ever since 1994. They are just not as loud as I would like them to be...
How much of a HP difference do you think I would get on the dyno taking the cat off and replacing it with a pipe? Also, should I consider a different set up with the exhaust? Like, what would a good layout be with my flowmasters. I'm all for the sound. The 3HP on the dyno isn't really worth the money to me for a different brand...
By the way, I wasn't saying my car sounded anything like a mustang. I was just saying mustangs sound very good with flowmasters.
I'm also not looking to invest any money in a different exhaust type. Like I said, I'm pretty sure they are 40 series. They sound pretty good right now and have been on the car ever since 1994. They are just not as loud as I would like them to be...
How much of a HP difference do you think I would get on the dyno taking the cat off and replacing it with a pipe? Also, should I consider a different set up with the exhaust? Like, what would a good layout be with my flowmasters. I'm all for the sound. The 3HP on the dyno isn't really worth the money to me for a different brand...
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From: I-L-L-I-N-O-I-S
He has a '94, so his car's PCM is OBD1. 
OBD1 should not throw any codes with an offroad pipe (ORP) in place of the cat. I did not get an SES light when I removed the cat on my '95 (also OBD1).
As far as the difference between the cat & ORP...Yeah, an ORP will make your Flowmaster a little louder at idle and a lot louder in the higher rpms...The sound will also get a little raspy/tinny that way...Usually longtube headers and an offroad Y-pipe (no cats) cause horrible rasp through a Flowmaster...Just depends upon your set-up though (some systems sound better without cats than others)...Like you, I currently have a 3" Flowmaster cat-back (80 series dual outlet) on my stock internal LT1 and it is unbelievably QUIET at idle, cruise, whereever! Even with my Mac headers + highflow cat!! So, I'm going to eventually try the ORP to see how I like the sound. For the time being though, I absolutely LOVE my Flowtech cutout (that thing is 10x louder than the Flowmaster at any rpm and sounds downright DEEP & MEAN).
Nothing is going to "outflow" it either. Seriously, BEST $60 (including installation) I've ever spent. 
Definitely a nice alternative to my Flowmaster system when I want to be very loud and have the best flow possible...
BTW, are you sure your car has the 40 series muffler? Because the 40 series wasn't made for the F-bodies (it can be made to fit though) and it is only a single outlet on the drivers side. The 80 series with dual outlets is the crossflow replacement muffler that was designed for the '82-'02 3rd & 4th gens (it's the same muffler that comes in all of the 3" American Thunder cat-back systems we use).
Mike
OBD1 should not throw any codes with an offroad pipe (ORP) in place of the cat. I did not get an SES light when I removed the cat on my '95 (also OBD1).As far as the difference between the cat & ORP...Yeah, an ORP will make your Flowmaster a little louder at idle and a lot louder in the higher rpms...The sound will also get a little raspy/tinny that way...Usually longtube headers and an offroad Y-pipe (no cats) cause horrible rasp through a Flowmaster...Just depends upon your set-up though (some systems sound better without cats than others)...Like you, I currently have a 3" Flowmaster cat-back (80 series dual outlet) on my stock internal LT1 and it is unbelievably QUIET at idle, cruise, whereever! Even with my Mac headers + highflow cat!! So, I'm going to eventually try the ORP to see how I like the sound. For the time being though, I absolutely LOVE my Flowtech cutout (that thing is 10x louder than the Flowmaster at any rpm and sounds downright DEEP & MEAN).
Nothing is going to "outflow" it either. Seriously, BEST $60 (including installation) I've ever spent. Definitely a nice alternative to my Flowmaster system when I want to be very loud and have the best flow possible... BTW, are you sure your car has the 40 series muffler? Because the 40 series wasn't made for the F-bodies (it can be made to fit though) and it is only a single outlet on the drivers side. The 80 series with dual outlets is the crossflow replacement muffler that was designed for the '82-'02 3rd & 4th gens (it's the same muffler that comes in all of the 3" American Thunder cat-back systems we use).
Mike
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So, what should I do? Should I get an ORP (off road pipe) in place of the cat, or should I just keep the cat on and not mess with it? How many cats do I have by the way?
The car is pretty loud when I rev it up. Also, I'm not sure that it was 40 series. I guess it could be 80. The guy just told me it's been on since 1994. When I rev it up high, it makes like a gargle sound. It's pretty cool. I just wonder how much the (ORP) will effect the sound and if it will be too much...Plus, do you think I will gain any HP. Do you feel that you did?
Also, I don't know if your 95 Z28 A4 has a lot done, but what have you ran with it? Did you ever run a high 13 with some basic bolt ons? If so, let me know what you did, so I can get on it. Thanks,
-Jay
The car is pretty loud when I rev it up. Also, I'm not sure that it was 40 series. I guess it could be 80. The guy just told me it's been on since 1994. When I rev it up high, it makes like a gargle sound. It's pretty cool. I just wonder how much the (ORP) will effect the sound and if it will be too much...Plus, do you think I will gain any HP. Do you feel that you did?
Also, I don't know if your 95 Z28 A4 has a lot done, but what have you ran with it? Did you ever run a high 13 with some basic bolt ons? If so, let me know what you did, so I can get on it.
Thanks,-Jay
Originally Posted by Camaro 0wner
So, what should I do? Should I get an ORP (off road pipe) in place of the cat, or should I just keep the cat on and not mess with it? How many cats do I have by the way?
The car is pretty loud when I rev it up. Also, I'm not sure that it was 40 series. I guess it could be 80. The guy just told me it's been on since 1994. When I rev it up high, it makes like a gargle sound. It's pretty cool. I just wonder how much the (ORP) will effect the sound and if it will be too much...Plus, do you think I will gain any HP. Do you feel that you did?
Also, I don't know if your 95 Z28 A4 has a lot done, but what have you ran with it? Did you ever run a high 13 with some basic bolt ons? If so, let me know what you did, so I can get on it. Thanks,
-Jay
The car is pretty loud when I rev it up. Also, I'm not sure that it was 40 series. I guess it could be 80. The guy just told me it's been on since 1994. When I rev it up high, it makes like a gargle sound. It's pretty cool. I just wonder how much the (ORP) will effect the sound and if it will be too much...Plus, do you think I will gain any HP. Do you feel that you did?
Also, I don't know if your 95 Z28 A4 has a lot done, but what have you ran with it? Did you ever run a high 13 with some basic bolt ons? If so, let me know what you did, so I can get on it.
Thanks,-Jay
Definitely get some kind of off road y-pipe or something. I'd say go without cats...it sounds better...louders...and all around meaner!
1994 LT1s don't have after-cat O2's. if you have the money, invest in a good header/y-pipe setup. i don't know where you live, so i can't say gut the cat, but a drop out with flanges on both ends would work
i have a 94 LT1 camaro with a flowmaster, gutted cat, and mid length headers and it sounds nasty as hell, but not raspy or crappy at all. sets off alarms a pretty good way away. the reason people say borla is better is because they are straight through design giving more horsepower. but in my opinion it is worth the couple hp to get the sound you want bc you can make up hp somewhere else. flowmaster just controls the sound by routing it through chambers. but if you have a 94 that means you dont have an o2 sensor after the cat so just gut the cat or better yet take it off and put a cutout there and a pipe to take up the space. and im pretty sure but not positive that the exhause pipe is not 3 inch, if not its damn close, im going to go measure mine now actually.
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Originally Posted by LT1MAN
i have a 94 LT1 camaro with a flowmaster, gutted cat, and mid length headers and it sounds nasty as hell, but not raspy or crappy at all. sets off alarms a pretty good way away. the reason people say borla is better is because they are straight through design giving more horsepower. but in my opinion it is worth the couple hp to get the sound you want bc you can make up hp somewhere else. flowmaster just controls the sound by routing it through chambers. but if you have a 94 that means you dont have an o2 sensor after the cat so just gut the cat or better yet take it off and put a cutout there and a pipe to take up the space. and im pretty sure but not positive that the exhause pipe is not 3 inch, if not its damn close, im going to go measure mine now actually.
How much are cutouts? I really don't think I have the money for all that right now. I would rather just take the cat out and put a pipe there.
By the way, I live in the St.pete area. Is that bad for cops? Someone mentioned where I lived or something...
-Jay
I never got pulled over for noise pollution and there is a precinct within 10 minutes from my house and past by it all the time. I don't think many cops are gonna waste their time to get down and look if you have a cat lol But like I said, I would haul *** by the station with it screaming...never got a ticket for noise pollution....or speeding 
your best bet would probably be a set of headers with an off-road Y-pipe (ORY). That will definetly make that flowmaster sound a LOT meaner.
At idle that car isn't that much louder without the cat. My setup isn't extremely loud. It's definetly noticeable, and people WILL look at you just idling there because off the bass, but it isn't annoyingly loud. If you want really loud just pull the cat out and run an open Y lol.
I think putting an ORP there will solve your problem for now. But Headers will make it sound even better.
At idle that car isn't that much louder without the cat. My setup isn't extremely loud. It's definetly noticeable, and people WILL look at you just idling there because off the bass, but it isn't annoyingly loud. If you want really loud just pull the cat out and run an open Y lol.
I think putting an ORP there will solve your problem for now. But Headers will make it sound even better.
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Alright guys, I just got back from the muffler shop and I got the cat removed. They just put a ORP in place of the cat. It sounds awesome. Not to loud at idle, just a little louder then before. But, when you rev it up, it sounds pretty mean. I got on it once on the way here from about 50ish and I didn't really notice a difference. If anything, it felt slower lol. Is that possible? I think it's just me though. The car sounds pretty damn good and I wasn't really paying too much attention to the speedo.
Thanks for all your opinions, it really helped out!
-Jay
Thanks for all your opinions, it really helped out!
-Jay
Originally Posted by Camaro 0wner
Alright guys, I just got back from the muffler shop and I got the cat removed. They just put a ORP in place of the cat. It sounds awesome. Not to loud at idle, just a little louder then before. But, when you rev it up, it sounds pretty mean. I got on it once on the way here from about 50ish and I didn't really notice a difference. If anything, it felt slower lol. Is that possible? I think it's just me though. The car sounds pretty damn good and I wasn't really paying too much attention to the speedo.
Thanks for all your opinions, it really helped out!
-Jay
Thanks for all your opinions, it really helped out!
-Jay
Glad to hear you just got rid of the cat!
It probably felt slower because you were expecting some differences and it didnt really change lol thats my best guess. 