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Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

 
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Old 01-14-2010, 08:18 PM
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Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

Looking at getting and exhuast for my new Honda Prelude 2000 model. didnt kno wether a 3" catback would make me loose to much power or wether i was best to get 2 and a 1/4 inch or 2.5" catback instead. But still want it sounding nice! please help?
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Old 01-14-2010, 08:21 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

Just get the Mugen exhaust

then it sounds good and you don't lose power
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Old 01-14-2010, 08:39 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

who told you 3inch is less power o_0?

secondly, you wouldnt want to go 3in because the gains isnt that worth it and going louder isnt always the smart thing t do =p
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Old 01-14-2010, 08:43 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

Lol a mate reconds 3" will loose me power, but i said nah it wouldnt i just wanted to make sure, with my V-tec would a 2 and a 1/4 be the way to go? and what do you mean by gains??
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Old 01-14-2010, 08:53 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

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Originally Posted by Mitch_H22 View Post
Lol a mate reconds 3" will loose me power, but i said nah it wouldnt i just wanted to make sure, with my V-tec would a 2 and a 1/4 be the way to go? and what do you mean by gains??
he means gains in performance (more horsepower)


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Old 01-14-2010, 09:08 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

Here is a link to a motorcycle site. It has a really nice graphic about why we want tuned exhaust. The short story is that you want to set up a shockwave in your exhust that sucks fuel/air mix into the chamber. A proper sized pipe will allow the exhaust gas to suck the mixture in as it leaves the combustion chamber. You need an engineer to do it right.

What I'm also saying is that 3in is probably TOO big for a stock NA engine. The engine will have to push the exhaust gas out rather than letting thermal dynamics do it for you. None of the Honda engineers put 3in pipes on their NA racing cars.

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Old 01-14-2010, 09:12 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

few things here---

1: a 3" cat back won't bolt up directly to your exhaust w/out an adapter flange that ups your piping size from 2 1/4 to 3" or you find piping that flares out to a larger 3" hole

2: 3" is a great size for exhaust for imports, any larger and you'll just be hurting yourself.

3: Your not going to see almost any power from any cat-back exhaust. Maybe 1hp. Believe me take my word for it. Cat back for NA mostly stock motors is most of all for look and sound. If your at stock height I'd say go w/ a twin loop muffler. They sound pretty quiet and they have an authentic race look to them. Mostly 2 1/2" tips to 3" tips. None of that 4" bullshiit fart can lookin exhausts.

and remember, there is no such thing as back pressure. Only exhaust velocity
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Old 01-14-2010, 09:37 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

You will not loose power imo. Here is one thread on preludepower. TUNED 3" Exhaust Vs Untuned 3" - Preludepower.com
There was another better thread but I cannot find it atm.
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Old 01-14-2010, 11:05 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

just go with a 2.5in cat back and call it a day. personnally i like greddy, and lookin at the Spectrum Elite Cat Back from them.
either that or a OBX twin loop with custom bent piping.
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Old 01-14-2010, 11:25 PM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

I dont have the time or energy to truely reiterate it here well tonight....

But, 3" is the way to go. Simply said, without having the ability to truely create a great scavenging effect by designing the exhaust and making the car match it you cant do any better than to go a bit larger... Considering you are not going to redesign your exhaust tunnel and be able to redesign the lengths of your exhaust, the best gains will be seen by going with a larger free flowing exhaust. As stated above, velocity is the problem and not back pressure (how silly). The larger the pipe, the lower the velocity. That sounds bad, until you factor in turbulence. At a certain speed, pipe angle, or even piping inperfection turbulence is created. Turbulence slows down the flow of a fluid, in this case exhaust gases. Slowing down the fluid becomes an issue quite quickly and creates back pressure. Granted, its rare it gets so bad you notice it. Either give it room to expand, or allow the fluid to travel slower in the first place and not encounter large amounts of turbulence. Simple fluid dynamics guys. Should I cover the thermodynamics involved in it too and complicate it?



Now, the truth about cat backs. Your not going to gain much from one, aside from a headache... Why people bitch about not gaining much from one is beyond me. If you expect a catback to add alot of power, you should examine the way a motor works first. But, that takes me into a page lesson teaching everyone alot more about fluid dynamics and thermo dynamics.

Who really wants me to tell them the limiting factor changes from one thing to another as we change components on our cars? In order to maximize a gain from a catback, you must modify the rest of the system to match it. Your going to need to optimize the ability to flow a fluid into and out of the combustion chamber in order to maximize your results. Thats where a quality IM, header, Intake, PnP, and cams come into play. The honest truth is, you will always have a limiting factor. The question is which one limits you the most currently?
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Old 01-15-2010, 11:50 AM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

I think 2.25 is farly reasonable, but then again it wouldnt hurt to go 2.5!!! either one is good honestly!!! Jus make sure if you choose 2.5 that your Flux capacitor is active!!!
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Old 01-15-2010, 11:52 AM
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Re: Will I lose much power with a 3" catback exhaust, or should i get Less diameter?

Quote:
Originally Posted by lilbluelude View Post
I dont have the time or energy to truely reiterate it here well tonight....

But, 3" is the way to go. Simply said, without having the ability to truely create a great scavenging effect by designing the exhaust and making the car match it you cant do any better than to go a bit larger... Considering you are not going to redesign your exhaust tunnel and be able to redesign the lengths of your exhaust, the best gains will be seen by going with a larger free flowing exhaust. As stated above, velocity is the problem and not back pressure (how silly). The larger the pipe, the lower the velocity. That sounds bad, until you factor in turbulence. At a certain speed, pipe angle, or even piping inperfection turbulence is created. Turbulence slows down the flow of a fluid, in this case exhaust gases. Slowing down the fluid becomes an issue quite quickly and creates back pressure. Granted, its rare it gets so bad you notice it. Either give it room to expand, or allow the fluid to travel slower in the first place and not encounter large amounts of turbulence. Simple fluid dynamics guys. Should I cover the thermodynamics involved in it too and complicate it?



Now, the truth about cat backs. Your not going to gain much from one, aside from a headache... Why people bitch about not gaining much from one is beyond me. If you expect a catback to add alot of power, you should examine the way a motor works first. But, that takes me into a page lesson teaching everyone alot more about fluid dynamics and thermo dynamics.

Who really wants me to tell them the limiting factor changes from one thing to another as we change components on our cars? In order to maximize a gain from a catback, you must modify the rest of the system to match it. Your going to need to optimize the ability to flow a fluid into and out of the combustion chamber in order to maximize your results. Thats where a quality IM, header, Intake, PnP, and cams come into play. The honest truth is, you will always have a limiting factor. The question is which one limits you the most currently?
Repped, thanks for that post man!
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