View Poll Results: what's your choice will be ?
True Duals
209
65.11%
ORY & Catback
112
34.89%
Voters: 321. You may not vote on this poll
poll: true duals VS Ypipe & cat-back?.....
Originally Posted by Full-Force
Instead of pulling out books and digging up info on the net to make it sound like you are an exhaust engineer how about just posting up some plain old fashioned results.
Note the sponsor tag under the name ... I am the Engineering Director @ MagnaFlow Performance Exhaust.
How are you doing?
Originally Posted by oxidizr
Ummm ... I am an exhaust engineer ... and I will assure you nothign i wrote came from a book. It was very much so off the top of my head.
Note the sponsor tag under the name ... I am the Engineering Director @ MagnaFlow Performance Exhaust.
How are you doing?
Note the sponsor tag under the name ... I am the Engineering Director @ MagnaFlow Performance Exhaust.
How are you doing?
So you are saying a good Y-merge like the flowmaster and a 3.5 dump before the axle would be all I need? Thanks...
Well I put 420rwhp down with a flowmaster merge necked down to a 3 I-pipe with a cutout before the axle and hooker muffler outback. I spray 100 shot also and I am goin to switch it to a 150 shot soon. I have a sphon chassis mounted tq arm now but wanted duals but they want fit wiht that arm too well. So I am thinking about staying with the Y but dumping it. So thats why I was just interested in the difference in the 2 systems and if it was worth changing my tq arm for it or not? Thanks.
In my sig you will see a dyno for my truck.
Running through 1 7/8" Longtubes 2.5" collector with open cutouts at the collectors - 449/515
Running through 1 7/8" Longtubes 2.5" collector, dual 2.5" cat-less y-pipe, a 3" I pipe with a cutout open before the muffler - 440/514.
Runningn through 1 7/8" longtubes 2.5" colector, dual 2.5" cat-less y-pipe, a 3" I pipe through a 30" 5x8 Magnaflow muffler (street legal-noise consideration) - 435/510
Had i chosen to Longtube with a 3" collector Im sure a 3" y-pipe would have made for a smaller difference and not cost the 9 hp the dual 2.5" Y did.
Running through 1 7/8" Longtubes 2.5" collector with open cutouts at the collectors - 449/515
Running through 1 7/8" Longtubes 2.5" collector, dual 2.5" cat-less y-pipe, a 3" I pipe with a cutout open before the muffler - 440/514.
Runningn through 1 7/8" longtubes 2.5" colector, dual 2.5" cat-less y-pipe, a 3" I pipe through a 30" 5x8 Magnaflow muffler (street legal-noise consideration) - 435/510
Had i chosen to Longtube with a 3" collector Im sure a 3" y-pipe would have made for a smaller difference and not cost the 9 hp the dual 2.5" Y did.
Originally Posted by oxidizr
Ummm ... I am an exhaust engineer ... and I will assure you nothign i wrote came from a book. It was very much so off the top of my head.
Note the sponsor tag under the name ... I am the Engineering Director @ MagnaFlow Performance Exhaust.
How are you doing?
Note the sponsor tag under the name ... I am the Engineering Director @ MagnaFlow Performance Exhaust.
How are you doing?
so now why dont you tell me that a good y pipe and a magnflow catback will make same power than my duals
i hope you dont because someone who has posted in this thread has a dyno proven 15hp loss through the catback apposed to a cutout after the y
Building systems does NOT make you an engineer, it makes you a muffler shop tech ... what is your background?
I never claimed a good Y pipe + magnafllow cat-back would make the same power...
ugggg READ my post COMPLETELY.
...the loss was from a dual 2.5" Y not dual 3" ... stop reading what you want to and read the whole thing. I used a 30 inch long muffler to meet noise compliance SAE J1169 regulations. (If you truely understand SAE standard you will know that compliance means 95 dba measuread 20" 45* off the TIP of your exhaust outlet as measured @ 3/4 your peak RPM.) I can guarantee you a traditional true dual will not meet this standard with the mods you have on your car.
Open header or through the 2.5" Y pipe with 3" I (NOT 3" Y with 3.5" as we are talking about) netted a mere 9 HP and 1 lb-ft loss. the los was not observed from a 3" Y with 3.5" outlet.
The reason I never went to a large diameter Y was purely for the fact the truck made ~300 rwhp off the bottle (75-80% of the driving time) and ~450 rwhp on the bottle.
I never claimed a good Y pipe + magnafllow cat-back would make the same power...
A calculated dual 3" y into a 3.5" I and a cutout will net you the same power as the sytem you describe and will pass through your g load brace and wont bang your floorboard like the 4". In just about any instance i can think of the power you are making wiht your car does not justify 4" exhaust.
...the loss was from a dual 2.5" Y not dual 3" ... stop reading what you want to and read the whole thing. I used a 30 inch long muffler to meet noise compliance SAE J1169 regulations. (If you truely understand SAE standard you will know that compliance means 95 dba measuread 20" 45* off the TIP of your exhaust outlet as measured @ 3/4 your peak RPM.) I can guarantee you a traditional true dual will not meet this standard with the mods you have on your car.
Open header or through the 2.5" Y pipe with 3" I (NOT 3" Y with 3.5" as we are talking about) netted a mere 9 HP and 1 lb-ft loss. the los was not observed from a 3" Y with 3.5" outlet.
The reason I never went to a large diameter Y was purely for the fact the truck made ~300 rwhp off the bottle (75-80% of the driving time) and ~450 rwhp on the bottle.
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by oxidizr
I used a 30 inch long muffler to meet noise compliance SAE J1169 regulations. (If you truely understand SAE standard you will know that compliance means 95 dba measuread 20" 45* off the TIP of your exhaust outlet as measured @ 3/4 your peak RPM.) I can guarantee you a traditional true dual will not meet this standard with the mods you have on your car.
Most of us don't have to worry about dealing bullcrap like noise compliance.
I might be missing something here, but why is it that you need to meet a noise standard and not emissions?
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
Originally Posted by blkZ28spt
Most of us don't have to worry about dealing bullcrap like noise compliance.
I might be missing something here, but why is it that you need to meet a noise standard and not emissions?
I might be missing something here, but why is it that you need to meet a noise standard and not emissions?
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by ShevrolayZ28
Maybe because he designs catbacks, and catbacks have nothing to do with polution emissions.
Umm, did you read all the posts?
He is talking about systems with longtubes, Y-pipes and cat-backs. Unless those longtubes have built in cats, at the factory location, and were never mentioned (not to mention AIR/EGR hookups) it has everything to do with emissions.
Originally Posted by blkZ28spt
Umm, did you read all the posts?
He is talking about systems with longtubes, Y-pipes and cat-backs. Unless those longtubes have built in cats, at the factory location, and were never mentioned (not to mention AIR/EGR hookups) it has everything to do with emissions.
He is talking about systems with longtubes, Y-pipes and cat-backs. Unless those longtubes have built in cats, at the factory location, and were never mentioned (not to mention AIR/EGR hookups) it has everything to do with emissions.
No offense intended, I thought perhaps you might not have read the thread.
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by ShevrolayZ28
Well, the thread starter asked about sound, so the rest of us are discussing sound, not emissions.
No offense intended, I thought perhaps you might not have read the thread.
No offense intended, I thought perhaps you might not have read the thread.
The discussion has turned to power, and has been discussing that for some time.
oxidizr said that his longtubes, y-pipe and cat-back setup would pass a certain noise compliance. That made me wonder what the situation is that would call for noise compliance but not emission compliance.
OFF TOPIC ...
I used the illustration with my truck to show HOW LITTLE even a 2.5" y pipe has over an OPEN header. I never contended a street-legal cat-back would outperform a illegal true dual.
I listed the last values to show even further how little a noise complaiant exhaust has over a vehicle with NO exhaust. I'm sorry but, but when you already have 430-450 rwhp ... traction will dictate your ability to "win" a traffic light race NOT 15 rwhp.
The reason i made the point regarding street noise compliant is this:
How many time have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust system.
So you ask why i even mentioned noise compliance vs emissions? THAT is why.
I used the illustration with my truck to show HOW LITTLE even a 2.5" y pipe has over an OPEN header. I never contended a street-legal cat-back would outperform a illegal true dual.
I listed the last values to show even further how little a noise complaiant exhaust has over a vehicle with NO exhaust. I'm sorry but, but when you already have 430-450 rwhp ... traction will dictate your ability to "win" a traffic light race NOT 15 rwhp.
The reason i made the point regarding street noise compliant is this:
How many time have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust system.
So you ask why i even mentioned noise compliance vs emissions? THAT is why.
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by oxidizr
OFF TOPIC ...
I used the illustration with my truck to show HOW LITTLE even a 2.5" y pipe has over an OPEN header. I never contended a street-legal cat-back would outperform a illegal true dual.
I listed the last values to show even further how little a noise complaiant exhaust has over a vehicle with NO exhaust. I'm sorry but, but when you already have 430-450 rwhp ... traction will dictate your ability to "win" a traffic light race NOT 15 rwhp.
The reason i made the point regarding street noise compliant is this:
How many time have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust system.
So you ask why i even mentioned noise compliance vs emissions? THAT is why.
I used the illustration with my truck to show HOW LITTLE even a 2.5" y pipe has over an OPEN header. I never contended a street-legal cat-back would outperform a illegal true dual.
I listed the last values to show even further how little a noise complaiant exhaust has over a vehicle with NO exhaust. I'm sorry but, but when you already have 430-450 rwhp ... traction will dictate your ability to "win" a traffic light race NOT 15 rwhp.
The reason i made the point regarding street noise compliant is this:
How many time have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust system.
So you ask why i even mentioned noise compliance vs emissions? THAT is why.
What makes a y-pipe setup legal and duals illegal?
A car with duals has "no exhaust"? I beg to differ. Open headers may be no exhaust, duals are definately an exhaust. If you insist it exit out the rear to be considered as existing, you can take 2.5" or even 3" duals out the back with adequate ground clearance.
Police officers can't see whether or not you have cats. You telling me that if I drove by you, you could SEE that I didn't have cats?
I have been running longtubes to true duals for two and a half years. I have been pulled over probably about a half dozen times in the Camaro during that time. I received one ticket that was complete bullcrap, which was not even a moving violation. I received one warning for "defective exhaust" because it was too loud. If it wasn't for the fact that this occured at 1:30 AM on a college campus I wouldn't have even recieved that warning. There are people with y-pipe setups every bit as loud as my car, and people with duals which are quieter.
BTW: I even passed emissions with my exhaust set up as is.
Originally Posted by blkZ28spt
What makes a y-pipe setup legal and duals illegal?
A car with duals has "no exhaust"? I beg to differ. Open headers may be no exhaust, duals are definately an exhaust. If you insist it exit out the rear to be considered as existing, you can take 2.5" or even 3" duals out the back with adequate ground clearance.
I listed three dyno results:
1. My truck open header ... NO EXHAUST
2. My truck with 2.5" cat-less y pipe and 3" I with cutout before muffler open
3. My truck with 2.5" cat-less y pipe and 3" I with cutout before muffler closed through a noise compliant muffler.
This is where i derived my NO exhasut vs compliant cat-back info!!!! #1 vs #3
Police officers can't see whether or not you have cats. You telling me that if I drove by you, you could SEE that I didn't have cats?
this is what i wrote:
"How many times have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust system."
My point is that NO ONE can see ... so sound is what catches a would be cops attention. You don't jsut get emissions violation tickets unless they are acompanied by illegal speed contest or some sort of noise abatement issue.
I have been running longtubes to true duals for two and a half years. I have been pulled over probably about a half dozen times in the Camaro during that time. I received one ticket that was complete bullcrap, which was not even a moving violation. I received one warning for "defective exhaust" because it was too loud. If it wasn't for the fact that this occured at 1:30 AM on a college campus I wouldn't have even recieved that warning.
There are people with y-pipe setups every bit as loud as my car, and people with duals which are quieter.
I'm not debating noise ... BACK on topic ... a 4" I pipe is over kill for 400 rwhp and a properly designed Y pipe system can produce as much power as a true dual.
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by oxidizr
You will have to look at local state laws of which some prohibit altered exit locations.
Nobody cares that my exhaust exits under the car. Even the emissions testing facility employees couldn't have cared less.
Originally Posted by oxidizr
this is what i wrote:
"How many times have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust systeem.
"How many times have you been pulled over because a law officer SAW your non-legal cats or absence of any?
I am willing to be to bet that a noise violation issue led them to look at you a little more carefully, maybe even led them to pull you over or more over led them to believe you had a "modified" exhaust systeem.
Originally Posted by oxidizr
And I have never been pulled over in the past 3 years ... hmmm 6 vs 0... now there is something.
Do you think you could drive through a college town at 1:30 am on a saturday night, multiple times, without getting pulled over?
Originally Posted by oxidizr
I'm not debating noise
Originally Posted by oxidizr
... BACK on topic ... a 4" I pipe is over kill for 400 rwhp and a properly designed Y pipe system can produce as much power as a true dual.
I'm still not sold on the second part of that statement, though.
I don't carea bout the legality of your exhaust system you simply asked a question to which i answered. ex: Michigan State vehicle code - section 707/707c Muffler in good working order and in constant operation & Tail pipe and resonator if orginally equipped.... goes onto elaborate about decible levels.
You are beyond capacity to understand .... YOU brought up noise .. i was only talking about noise in MY applciation not between Y and true dual ...
Again I would enthrall you to read the ENTIRE thread...
I design compliant exhaust systems and am very versed on vehicle codes and their requirements (this one took me a whopping 2 secs to google)
If you agree that 4" is too big that is half my point .... the other half is that configuration has little to do with that and it has more to do with proper sizing and use of equipment ... it is a matter of total caulated flow.
You are beyond capacity to understand .... YOU brought up noise .. i was only talking about noise in MY applciation not between Y and true dual ...
Again I would enthrall you to read the ENTIRE thread...
I design compliant exhaust systems and am very versed on vehicle codes and their requirements (this one took me a whopping 2 secs to google)
If you agree that 4" is too big that is half my point .... the other half is that configuration has little to do with that and it has more to do with proper sizing and use of equipment ... it is a matter of total caulated flow.
Last edited by oxidizr; Feb 26, 2006 at 08:44 PM.
TECH Resident
Joined: Sep 2004
Posts: 797
Likes: 0
From: Clarksville, Tn
So I hope this helps out a lil, in August I put together a TD system on my car. Now I have a clearance problem(You get what you pay for, $75 installed). But that will be be fixed as soon as I can raise the bullets up a lil more, they hang kinda low right now.
I dont have the problem of fumes in my car, or creeping into my car.....
They are loud, but that is what I WANTED.....they dump just before the axle and I have my turn downs pointed at a 45 degree angle inward towards each other to reduce any drone that may occour....so far I dont think I have had that problem.
I dont have problems with the police for excessive noise, matter of fact I drive through town poast the PD all the time just to see if they do say anything(2nd gear @35 mph)
One last thing, I love the way it sounds, people look hard and I get compliments all the time. I cannot wait until I can get my cam in....MS3 is cam of choice.....
Have fun Gents...I truely enjoy threads like these.....:USA:
I dont have the problem of fumes in my car, or creeping into my car.....
They are loud, but that is what I WANTED.....they dump just before the axle and I have my turn downs pointed at a 45 degree angle inward towards each other to reduce any drone that may occour....so far I dont think I have had that problem.
I dont have problems with the police for excessive noise, matter of fact I drive through town poast the PD all the time just to see if they do say anything(2nd gear @35 mph)
One last thing, I love the way it sounds, people look hard and I get compliments all the time. I cannot wait until I can get my cam in....MS3 is cam of choice.....
Have fun Gents...I truely enjoy threads like these.....:USA:
11 Second Club
Joined: Feb 2003
Posts: 5,524
Likes: 1
From: The South
Originally Posted by 00TAProject
So I hope this helps out a lil, in August I put together a TD system on my car. Now I have a clearance problem(You get what you pay for, $75 installed). But that will be be fixed as soon as I can raise the bullets up a lil more, they hang kinda low right now.
I dont have the problem of fumes in my car, or creeping into my car.....
They are loud, but that is what I WANTED.....they dump just before the axle and I have my turn downs pointed at a 45 degree angle inward towards each other to reduce any drone that may occour....so far I dont think I have had that problem.
I dont have problems with the police for excessive noise, matter of fact I drive through town poast the PD all the time just to see if they do say anything(2nd gear @35 mph)
One last thing, I love the way it sounds, people look hard and I get compliments all the time. I cannot wait until I can get my cam in....MS3 is cam of choice.....
Have fun Gents...I truely enjoy threads like these.....:USA:
I dont have the problem of fumes in my car, or creeping into my car.....
They are loud, but that is what I WANTED.....they dump just before the axle and I have my turn downs pointed at a 45 degree angle inward towards each other to reduce any drone that may occour....so far I dont think I have had that problem.
I dont have problems with the police for excessive noise, matter of fact I drive through town poast the PD all the time just to see if they do say anything(2nd gear @35 mph)
One last thing, I love the way it sounds, people look hard and I get compliments all the time. I cannot wait until I can get my cam in....MS3 is cam of choice.....
Have fun Gents...I truely enjoy threads like these.....:USA:
The cam will make as big of a difference vs the stock cam as the exhaust did vs stock.
