Silent but deadly...
06-04-2009, 12:17 AM
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Silent but deadly...
I want a catback exhaust as I mentioned before that is silent, but will give a lot more flow.
Clearly having it silent means a few less hp.
My question is, which is better:
-2 1/4 catback with 2 1/4 resonator and 2 1/4 stock muffler
-2 1/4 catback with 2 1/4 resonator and 2 1/2 stock muffer
-2 1/4 catback piping up to a 2 1/2 resonator then 2 1/2 piping to a 2 1/2 stock muffer
I know people say to keep it all one size, but stepping it up at a point (at the resonator) and retaining it should actually help retain an even better flow especially when using a stock style muffler. It is kind of like the breath through the straw theory but I just shortened the straw considerably which in itslef does make it a little easier to breath.
I do not want to get a Flowmaster or Magnaflow, I want it to sound stock yet get me a little more high end while retaining or possibly increasing lows and mids.
When I modify the cat, it would then become 2 1/4 and so would the downpipe.
I want the Racing Solutions shorty header to finalize it.
Anyone here have a set-up where they sound stock yet got some good gain on their catback?
Clearly having it silent means a few less hp.
My question is, which is better:
-2 1/4 catback with 2 1/4 resonator and 2 1/4 stock muffler
-2 1/4 catback with 2 1/4 resonator and 2 1/2 stock muffer
-2 1/4 catback piping up to a 2 1/2 resonator then 2 1/2 piping to a 2 1/2 stock muffer
I know people say to keep it all one size, but stepping it up at a point (at the resonator) and retaining it should actually help retain an even better flow especially when using a stock style muffler. It is kind of like the breath through the straw theory but I just shortened the straw considerably which in itslef does make it a little easier to breath.
I do not want to get a Flowmaster or Magnaflow, I want it to sound stock yet get me a little more high end while retaining or possibly increasing lows and mids.
When I modify the cat, it would then become 2 1/4 and so would the downpipe.
I want the Racing Solutions shorty header to finalize it.
Anyone here have a set-up where they sound stock yet got some good gain on their catback?
06-04-2009, 04:18 PM
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Youre theory is actually backwards, you will get better power with the rear of the exhaust slightly smaller than the parts closer to the engine, here is a good reference citing that: Cobb Tuning
Also being quiet doesnt mean less HP, longer resignators and mufflers help that, longer resignator(s) deepen the tone while a longer straight through style muffler will keep it quiet assuming those designs are of good quality. Depending on your mods list(or wishful mods list) you shouldnt waste time with 2.25 piping but go with 2.5 all the way through or like the stock SS/SC exhaust bottle neck it near the end.
Also being quiet doesnt mean less HP, longer resignators and mufflers help that, longer resignator(s) deepen the tone while a longer straight through style muffler will keep it quiet assuming those designs are of good quality. Depending on your mods list(or wishful mods list) you shouldnt waste time with 2.25 piping but go with 2.5 all the way through or like the stock SS/SC exhaust bottle neck it near the end.
06-04-2009, 08:01 PM
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2 and 1/4" is plenty for a 2.2, considering its a 50% increase in size over stock.
And by making your exhaust even bigger than that, you would slow down the exhaust flow and lose low end torque, the kind you use to drive normally. The only reason that you can upgrade to the larger pipe and still get gains is that the mufflers and resonators are typically flow through design which eliminates restriction, but also make it louder. This negates the reduced speed of the exhaust flow to some extent.
Whatever exhaust you do get, its not going to give you a big gain, maybe 5-10 HP at most. Also, while some aftermarket ones are quiter than others, not really sure why you would want a silent one. If you do get a silent one, you will only hear engine whine in the high RPM's.
And by making your exhaust even bigger than that, you would slow down the exhaust flow and lose low end torque, the kind you use to drive normally. The only reason that you can upgrade to the larger pipe and still get gains is that the mufflers and resonators are typically flow through design which eliminates restriction, but also make it louder. This negates the reduced speed of the exhaust flow to some extent.
Whatever exhaust you do get, its not going to give you a big gain, maybe 5-10 HP at most. Also, while some aftermarket ones are quiter than others, not really sure why you would want a silent one. If you do get a silent one, you will only hear engine whine in the high RPM's.
06-04-2009, 08:16 PM
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I have 3"...but mine is not stock sounding hahahaha
loosing that to drive normally...you dont need it to drive normaly, and it gets GREAT gas milage, but gives you what you want in the higher end (where you want it when racing)...so i think its a GREAT idea 
2 and 1/4" is plenty for a 2.2, considering its a 50% increase in size over stock.
And by making your exhaust even bigger than that, you would slow down the exhaust flow and lose low end torque, the kind you use to drive normally. The only reason that you can upgrade to the larger pipe and still get gains is that the mufflers and resonators are typically flow through design which eliminates restriction, but also make it louder. This negates the reduced speed of the exhaust flow to some extent.
Whatever exhaust you do get, its not going to give you a big gain, maybe 5-10 HP at most. Also, while some aftermarket ones are quiter than others, not really sure why you would want a silent one. If you do get a silent one, you will only hear engine whine in the high RPM's.
And by making your exhaust even bigger than that, you would slow down the exhaust flow and lose low end torque, the kind you use to drive normally. The only reason that you can upgrade to the larger pipe and still get gains is that the mufflers and resonators are typically flow through design which eliminates restriction, but also make it louder. This negates the reduced speed of the exhaust flow to some extent.
Whatever exhaust you do get, its not going to give you a big gain, maybe 5-10 HP at most. Also, while some aftermarket ones are quiter than others, not really sure why you would want a silent one. If you do get a silent one, you will only hear engine whine in the high RPM's.
Last edited by NWAE Cobalt; 06-04-2009 at 08:16 PM. Reason: Automerged Doublepost
06-04-2009, 08:18 PM
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So youre saying stock exhaust is 1-1/8 in diameter? I dont even remember my stock exhaust but I dont think thats right..
Also if you had read the link I posted:
and OP I found the part in there that references my point of going from wider to narrower.
Also if you had read the link I posted:
Pipe diameter does have an effect on flow rates as well, but again it is not the major factor in most cases. 2.5" may flow enough for up to 300-350 h.p. without being a restriction. 3" is usually capable of flowing 500-600 h.p. before becoming a restriction. This is assuming that you have designed the rest of the system up to par. There are also full 3.5" systems and those that start out at 4" and taper down. Unless you are making over 500-600 h.p. anything over 3" is a case of diminishing returns and in most cases has no advantage. There is more to gain going from 2.5" up to 3" than there is going from 3" to 3.5". A 3" system will not loose torque compared to a 2.5" system if designed properly. In fact if designed properly 3" may be capable of making better low end torque than 2.5". Again, since the way to make the most torque with a turbo exhaust is to get the turbo to spool-up as quickly as possible, it should be the main goal of the entire exhaust system and good flow after the turbo is one way to achieve it. We use 3" as we want our system to flow enough to be capable of coping with a customer's changing goals. Properly designed we can offer it to the big power crowd while still appeasing the low end torque club.
Tapering the diameter does not make more power, torque, or bring on boost faster. However having smaller pipe towards the end has less effect that having smaller piping at the beginning. In other words a system that has 3" pipe for the majority, and necks down to 2.5" at the end will flow enough for more power than a complete 2.5" system. The further downstream you neck down the exhaust the better……..if you decide to neck it down.
06-04-2009, 08:37 PM
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Its approximatly 1 and 3/4". The reason thats its 50% bigger is because of the area of the pipe and simple math.
(3.14 x 1.8 ^ 2 ) / 4 = 2.5" (I measured mine before I installed the new one hoping to reuse the exhaust tip, I know it was 1.8 something)
(3.14 x 2.25 ^ 2) / 4 = 3.9"
2.5 x 50% = 1.25
2.5 +1.25 = 3.75" which is almost 3.9"
Darn, you beat me to it.
Last edited by YSUsteven; 06-04-2009 at 08:37 PM. Reason: Automerged Doublepost
06-04-2009, 08:46 PM
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06-04-2009, 08:59 PM
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Stock = 1.75"diameter, Area = 2.405"sq
Aftermarket= 2.25"diameter, Area = 3.976"sq
3.976/2.405=1.6532 or 65.32% larger.
Oh wait.....you must be an engineer.....you were doing things weird and the seemingly hard way for no obvious reason, and still got the wrong answer......... OH SNAP, did I say that? LMFAO, j/k. Some of my best friends are engineers......well no, no they arent, but hey at least you finished, I decided I liked being greasy more than I did sitting in class. Maybe Ill go get my MSE when I retire.
06-04-2009, 09:47 PM
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I will ask in a different way.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
06-04-2009, 09:49 PM
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Youre an engineer? then wtf is up with your mafungo formula and calculations????
Stock = 1.75"diameter, Area = 2.405"sq
Aftermarket= 2.25"diameter, Area = 3.976"sq
3.976/2.405=1.6532 or 65.32% larger.
Oh wait.....you must be an engineer.....you were doing things weird and the seemingly hard way for no obvious reason, and still got the wrong answer......... OH SNAP, did I say that? LMFAO, j/k. Some of my best friends are engineers......well no, no they arent, but hey at least you finished, I decided I liked being greasy more than I did sitting in class. Maybe Ill go get my MSE when I retire.
Stock = 1.75"diameter, Area = 2.405"sq
Aftermarket= 2.25"diameter, Area = 3.976"sq
3.976/2.405=1.6532 or 65.32% larger.
Oh wait.....you must be an engineer.....you were doing things weird and the seemingly hard way for no obvious reason, and still got the wrong answer......... OH SNAP, did I say that? LMFAO, j/k. Some of my best friends are engineers......well no, no they arent, but hey at least you finished, I decided I liked being greasy more than I did sitting in class. Maybe Ill go get my MSE when I retire.
And just because I'm an engineer doesn't mean that I don't get dirty on ocasion. It feels much better to accomplish something yourself instead of paying someone else to do it for you, as long as I know I can get it done myself with the tools I have.
06-04-2009, 09:56 PM
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I will ask in a different way.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
06-04-2009, 10:10 PM
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I will ask in a different way.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
If I left the downpipe, cat and piping to cat 2.25" then went 2.5" afterwards, would it be better than 2.25" all the way?
I was figuring that the exhaust would still have the 2.25" for the first 1/3 of the exhaust for low end and if I romp on it, the travel distance of the exhaust to hit 2.5" is shorter and might help my high end.
I could be totally wrong on this, but it sounded feasible.
If you want only top end power, go with 2.5" but if you prefer midrange power go with 2.25". A 2.5" will have a deeper sound than the 2.25" because of the reduced air velocity.
Also, our motors don't really make good power after 5,500 RPMs anyway due to our cams, and I prefer low end torque as I rarly rev mine over 5 grand anyway.
If you would have just though about it for a little bit and figured it out instead of saying that I was wrong, I would have never mention it in the other thread. To me you see two kinds of people, those that are idoits and don't know what they are talking about, and those that do know what they are talking about and you misinterpret what they are saying.
Also, don't take ideas out of context. Just because that link says that 2.5" is good to 300-350 HP, doesn't mean that a 2.25" would not be the best size here. Very few (if any) 2.2s are pushing 250 HP, and that article also specifically states for a turbo setup, which the OP has never mentioned in this thread. If he never plans on taking his engine north of 200 HP, there really is no point of going bigger than 2.25" anyway.
I also got a kick outa him wanting to punch you in the face about something you said on a fourm... Its not like its life and death here, just education.
Last edited by YSUsteven; 06-04-2009 at 10:10 PM. Reason: Automerged Doublepost
06-04-2009, 10:14 PM
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To me you see two kinds of people, those that are idoits and don't know what they are talking about, and those that do know what they are talking about and you misinterpret what they are saying.
I also got a kick outa him wanting to punch you in the face about something you said on a fourm... Its not like its life and death here, just education.
I also got a kick outa him wanting to punch you in the face about something you said on a fourm... Its not like its life and death here, just education.
Yeah me too, thats why I am on ImportsNC and SRTf0rums, it is so funny to see people getting that pissed off.
06-04-2009, 10:19 PM
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And of all the parts that your looking for, a new intake is not one of them??? While th K&N filter is a small improvement, you can still get more if you got a real intake. You want all the other parts to help the engine to breath better with the exception of a header and intake, why not them too?
06-04-2009, 10:25 PM
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The only reason that I could see some of these posters get that upset would be if these were race cars and if the slower car would get blown up after the race was over
My good sir... lol . .. . . .
Last edited by YSUsteven; 06-04-2009 at 10:25 PM. Reason: Automerged Doublepost
06-04-2009, 10:26 PM
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I have the ss/sc header and I dont have money, trying to get rid of the stuff in my for sale thread so I can pay off a speeding ticket. I have ss/sc mani, airbox mod, 2.5 catback(works great in high rpm and a bit in midrange) I want the K&N filter and DP to complete my engine mods for now, I am much more interested in turning so when I get my ticket and stuff settled I am going to prepare for TOTD
06-04-2009, 10:29 PM
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Dint see anywhere a mention of the SS/SC manifold, but you should really consider the intake with the other parts you listed, that is when money is available and the courts are off your back.
06-04-2009, 10:42 PM
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I probably will after I get done with my suspension, that will probably take a year or more to put together, I have several thousand I want to throw at it. I want BC coilovers, OTTP hardcore rear sway, TTR front sway, Bwoody endlinks, trunk brace, FE5 control arms, OTTP CAB's, OTTP rotated trans mounts and some other crap...