Stockish retrograde.
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Joined: Oct 2008
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From: Gainesville, Your college town is weak.
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Stockish retrograde. I decided to write up about this since, in my quest for a compromising exhaust system I've run across several people in my same situation so this long *** thread is for you
So I've had my little Frankenstein Civic for 2 years now and it's been a perpetual project. Recently I decided that, because of all the time I'm spending in my car, the exhaust and intake HAD to be silenced. I spin 4 grand at 70mph everyday on my way to school and my tach is all over the place when Im driving around town for work. So +3 peak whp be damned, I was tired of the constant droning fro my 2.5" tanabe cat back. UF PD, GPD, and the ASO weren't huge fans of my set up either and frequently they paid a visit to my drivers side window. So I decided to build an intake and exhaust system that still flowed pretty well yet maintained a stock appearance and almost stock quietness.
After researching lots and lots of exhaust systems, and aside from the Tanabe touring system which in my humble opinion is an ORGASMIC piece of exhaust hardware, I came to the conclusion that I was going to have to go with something of a stock variety. I looked into OEM mufflers from several manufacturers outside of Honda/Acura, spent hours on youtube listening to what people were running and what certain stock systems sounded like. I ended up deciding on a 2008 Civic Si system because of it's sporty note and availability. I came this close to an ITR set up which would have been perfect, and if your reading this you may be in the same situation I was in. If you can get your hands on one, get one, its amazing, especially the DC5 systems with the valved muffler.
Anyways I picked up this axle back from a stock Si and when I got it out of the box I was surprised to see the size of the factory piping. It had to be at least 2.25" from the rear of the muffler out to the rest of the system and if the tip is removed, looks stealth as hell. I took it down to Midas and had them weld it on the existing 2.5" pipe that was already on my car. $40 later I had a stock exhaust that was not quite stock.
Now because my previous system was cat-less, there is quite a bit of buzzing above 4 grand especially when the car is cold, first thing in the morning. But cruising on the highway and accelerating up to 3k in the city is an auditory orgasm. Sounds fantastic, reminds me of my 944, untilt he buzzing starts. I ordered a resonated test pipe from Megan Racing and it will get here sometime next week to help with the buzz. If that doesn't help then it's a Magnaflow Spun Catalytic that will have to do the trick.
As far as any performance decrease with the factory set up, I haven't noticed any loss up top so if there is a decrease it isn't significant. Ive actually noticed increased bottom end response and mid-range pull. This could be relative however, based upon when engine set up your using. If your reading this and you have an NA SOHC D15, well, there really isn't anything you can bolt to that car that is going to give you any kind of REAL noticeable gains in power as you would if you ran say a cammed and stroked B18C5. I'm currently running a mild NA set up comprising of a B20 block, Civic Si tranny with 3.879 FD, P&P, Skunk2 Pro intake manifold with matched intake ports, a matched 70mm tb, BDL fuel rail, 7.5lb fidanza flywheel, 4-1 itr replica headers and an Exedy stage 2 carbon kevlar clutch. I am willing to sacrifice <5 peak hp to shut my car the **** up.
I will post pictures and audio when the system is finished, it needs that resonator put on and the rear axle piping needs to be refabricated since its bend and diameter doesn't allow the muffler to fully mount behind the rear bumper so it kinda hangs 2 inches lower than the rear bumper. Kinda like some mexicans do with their potato cannon eBay cans.
For my intake system, I am not ashamed to say that I was running a 3" PVC pipe from the TB to a conical K&N intended for a Chevy. It did the job, and putting a 2" intake tube on a 70mm tb made no sense to me. It sounded great, it didn't absorb heat like aluminum tubing does and it allowed me to place the filter far enough behind the headlight that I did not have to worry about inducting excessive amount of water into my engine.
So again, after some research I came down to a decision to reinstall a factory airbox system, rather than an open element system. When I learned in the Porsche realm with my 944 was that, at a certain RPM (in NA cars of course turbos are an exception) an open element filter will reduce peak HP over a chambered, or boxed, intake system. What I learned was true for the 944 was true for many cars, that at higher engine RPMs (8000 of them for example) the engine tries to inhale more air than the intake system can inhale, or there is just not enough air available for the intake system to bring in. Removing the factory box from a 944 results in a 7 WHP DECREASE ACROSS THE RPM RANGE ABOVE 2000 RPM because of this factor. The reason being because a chambered intake system, pressurizes incoming air leaving some in reserve for the intake system to inhale at higher engine RPMs, system like the Comptech IceBox which typically make more power than other systems on the market, use factory style boxes for this particular reason, Mugen also make CF pressurized air boxes as well. So it came down to which system to use? An integra air box system or a Civic air box system. Again, I got the Civic system because of its direct fit into my application although I am sure with some modification fabrication the Integra system will work equally as well and has the added bonus of using a cone filter rather than a panel.
I purchased an EM1 Civic air box, much like the factory one my EX came with that I now regret selling and made some measurements. The tubing on the B16A engine is larger than that on the EX. Duh. The CTR and ITR tubing are larger than that still. However, peeps want almost a stack for the tubing alone so I, and my fascination with using pluming products on cars, decided to just buy the air box and that I would fabricate a tube for it. I bought the box and got a filter mounted it, went to Lowe's bought some 3" duct flex tubing for 4 dollars, some t-brackets and voila. To the bottom of the intake box I ran some flex tubing behind the bumper like the DC2 ITR, ran some flex tubing from the intake box to the TB and discovered that they were almost identical in size. Good to know.
The car sounds great in consideration of when it needs. The exhaust is still buzzy but again, i think the resonator will help with that immensley. I can hear my radio now and I dont feel like i'm driving a propeller powered autombile anymore since the BRRRRRRRRRR sound is gone. I will post pictures videos audio etc, as progress is made
So I've had my little Frankenstein Civic for 2 years now and it's been a perpetual project. Recently I decided that, because of all the time I'm spending in my car, the exhaust and intake HAD to be silenced. I spin 4 grand at 70mph everyday on my way to school and my tach is all over the place when Im driving around town for work. So +3 peak whp be damned, I was tired of the constant droning fro my 2.5" tanabe cat back. UF PD, GPD, and the ASO weren't huge fans of my set up either and frequently they paid a visit to my drivers side window. So I decided to build an intake and exhaust system that still flowed pretty well yet maintained a stock appearance and almost stock quietness.
After researching lots and lots of exhaust systems, and aside from the Tanabe touring system which in my humble opinion is an ORGASMIC piece of exhaust hardware, I came to the conclusion that I was going to have to go with something of a stock variety. I looked into OEM mufflers from several manufacturers outside of Honda/Acura, spent hours on youtube listening to what people were running and what certain stock systems sounded like. I ended up deciding on a 2008 Civic Si system because of it's sporty note and availability. I came this close to an ITR set up which would have been perfect, and if your reading this you may be in the same situation I was in. If you can get your hands on one, get one, its amazing, especially the DC5 systems with the valved muffler.
Anyways I picked up this axle back from a stock Si and when I got it out of the box I was surprised to see the size of the factory piping. It had to be at least 2.25" from the rear of the muffler out to the rest of the system and if the tip is removed, looks stealth as hell. I took it down to Midas and had them weld it on the existing 2.5" pipe that was already on my car. $40 later I had a stock exhaust that was not quite stock.
Now because my previous system was cat-less, there is quite a bit of buzzing above 4 grand especially when the car is cold, first thing in the morning. But cruising on the highway and accelerating up to 3k in the city is an auditory orgasm. Sounds fantastic, reminds me of my 944, untilt he buzzing starts. I ordered a resonated test pipe from Megan Racing and it will get here sometime next week to help with the buzz. If that doesn't help then it's a Magnaflow Spun Catalytic that will have to do the trick.
As far as any performance decrease with the factory set up, I haven't noticed any loss up top so if there is a decrease it isn't significant. Ive actually noticed increased bottom end response and mid-range pull. This could be relative however, based upon when engine set up your using. If your reading this and you have an NA SOHC D15, well, there really isn't anything you can bolt to that car that is going to give you any kind of REAL noticeable gains in power as you would if you ran say a cammed and stroked B18C5. I'm currently running a mild NA set up comprising of a B20 block, Civic Si tranny with 3.879 FD, P&P, Skunk2 Pro intake manifold with matched intake ports, a matched 70mm tb, BDL fuel rail, 7.5lb fidanza flywheel, 4-1 itr replica headers and an Exedy stage 2 carbon kevlar clutch. I am willing to sacrifice <5 peak hp to shut my car the **** up.
I will post pictures and audio when the system is finished, it needs that resonator put on and the rear axle piping needs to be refabricated since its bend and diameter doesn't allow the muffler to fully mount behind the rear bumper so it kinda hangs 2 inches lower than the rear bumper. Kinda like some mexicans do with their potato cannon eBay cans.
For my intake system, I am not ashamed to say that I was running a 3" PVC pipe from the TB to a conical K&N intended for a Chevy. It did the job, and putting a 2" intake tube on a 70mm tb made no sense to me. It sounded great, it didn't absorb heat like aluminum tubing does and it allowed me to place the filter far enough behind the headlight that I did not have to worry about inducting excessive amount of water into my engine.
So again, after some research I came down to a decision to reinstall a factory airbox system, rather than an open element system. When I learned in the Porsche realm with my 944 was that, at a certain RPM (in NA cars of course turbos are an exception) an open element filter will reduce peak HP over a chambered, or boxed, intake system. What I learned was true for the 944 was true for many cars, that at higher engine RPMs (8000 of them for example) the engine tries to inhale more air than the intake system can inhale, or there is just not enough air available for the intake system to bring in. Removing the factory box from a 944 results in a 7 WHP DECREASE ACROSS THE RPM RANGE ABOVE 2000 RPM because of this factor. The reason being because a chambered intake system, pressurizes incoming air leaving some in reserve for the intake system to inhale at higher engine RPMs, system like the Comptech IceBox which typically make more power than other systems on the market, use factory style boxes for this particular reason, Mugen also make CF pressurized air boxes as well. So it came down to which system to use? An integra air box system or a Civic air box system. Again, I got the Civic system because of its direct fit into my application although I am sure with some modification fabrication the Integra system will work equally as well and has the added bonus of using a cone filter rather than a panel.
I purchased an EM1 Civic air box, much like the factory one my EX came with that I now regret selling and made some measurements. The tubing on the B16A engine is larger than that on the EX. Duh. The CTR and ITR tubing are larger than that still. However, peeps want almost a stack for the tubing alone so I, and my fascination with using pluming products on cars, decided to just buy the air box and that I would fabricate a tube for it. I bought the box and got a filter mounted it, went to Lowe's bought some 3" duct flex tubing for 4 dollars, some t-brackets and voila. To the bottom of the intake box I ran some flex tubing behind the bumper like the DC2 ITR, ran some flex tubing from the intake box to the TB and discovered that they were almost identical in size. Good to know.
The car sounds great in consideration of when it needs. The exhaust is still buzzy but again, i think the resonator will help with that immensley. I can hear my radio now and I dont feel like i'm driving a propeller powered autombile anymore since the BRRRRRRRRRR sound is gone. I will post pictures videos audio etc, as progress is made
Thread Starter
^Warranty voider
Joined: Oct 2008
Posts: 821
Likes: 1
From: Gainesville, Your college town is weak.
Rep Power: 223 Re: Stockish retrograde.
sorry i was gone for so long. vacation and finals and all that. I liked the set up a whole lot for many reasons.
It didn't draw any kind of attention from law enforcement or other undesirable individuals.
It sounded clean and sporty almost exotic. The exhaust note reminded me a lot of the exhaust i had on my 944, very smooth and mellow.
With the modified stock air box i got a lot more bottom and middle response without sacrificing much top end. I mean keep in mind companies like AEM that claim 7hp increases mean at the crank usually so that means what? 1 whp peak? To me a quieter more practical ride is worth sacrifing 1 peak hp.
Some recommendations if this is what your seriously looking at doing:
Use 2" or 2.25" piping, keep the cat or at least a resonated test pipe, keep the resonator. 2" piping will work much better and will be much smoother than the 2.25". I initiially used a 2.5" pipe and it buzzed like hell at >4k rpm. If you can, get yourself an ITR muffler use an ITR header and 2.25" piping through the entire thing.
It didn't draw any kind of attention from law enforcement or other undesirable individuals.
It sounded clean and sporty almost exotic. The exhaust note reminded me a lot of the exhaust i had on my 944, very smooth and mellow.
With the modified stock air box i got a lot more bottom and middle response without sacrificing much top end. I mean keep in mind companies like AEM that claim 7hp increases mean at the crank usually so that means what? 1 whp peak? To me a quieter more practical ride is worth sacrifing 1 peak hp.
Some recommendations if this is what your seriously looking at doing:
Use 2" or 2.25" piping, keep the cat or at least a resonated test pipe, keep the resonator. 2" piping will work much better and will be much smoother than the 2.25". I initiially used a 2.5" pipe and it buzzed like hell at >4k rpm. If you can, get yourself an ITR muffler use an ITR header and 2.25" piping through the entire thing.
Thread Starter
^Warranty voider
Joined: Oct 2008
Posts: 821
Likes: 1
From: Gainesville, Your college town is weak.
Rep Power: 223 Re: Stockish retrograde.
wow ive been gone for about a month now. Ill post you pictures up tomorrow if your still interested. I'm still working out on how to bypass the resonator in the airbox. I endded up just putting a 2" coupler for pvc tubing in there, it restricts the airflow a little maybe but from what i asked my physics professor, when you put a small reduction in a tube it actually increases output pressure... so maybe its a good thing?
Thread Starter
^Warranty voider
Joined: Oct 2008
Posts: 821
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From: Gainesville, Your college town is weak.
Rep Power: 223 Re: Stockish retrograde.
Registered!!
Joined: Dec 2008
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Rep Power: 214 Re: Stockish retrograde.
Currently i have a stock muffler/everything on my '97 civic. I'm thinking of just getting a muffler for now, but i don't want a can. I want it to sound hella good too. What would you guys suggest?
Thread Starter
^Warranty voider
Joined: Oct 2008
Posts: 821
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From: Gainesville, Your college town is weak.
Rep Power: 223 Re: Stockish retrograde.
I've seen some people use 2" mid piping and an RSX type S muffler and it looks pretty slick. This is what mine looked like:
looks clean and sounds smooth. Right now I got a Magnaflow 2.5" C/C with a 3" tip on it. That looks clean and stock too, only problem is now I have a 2.5" mid pipe so its loud and buzzy. Those ebay twin loops sound good too if you use the right size piping....
my $.02
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