ok, here's the problem...the silencer in my muffler managed to fall out of the pos. So I'm faced with this decision, either have to pay for another silencer, or get a high flow cat. I know I need the backpressure, and my exhaust doesn't have a cat right now, and its a 2 1/4 custom piping all the way back to the muffler.
I dont have the money to buy a full cat-back stainless which is what I want. But I know how much back pressure the silencer gives, and I know my track times were decent with it, but... I figure a cat may give it a slight bit more backpressure than the silencer which may help a little, but I'm worrie it'll be either too much backpressure and hurt my times or won't quite the exhaust down enough, as of now its stupid loud and I hate to drive without the silencer. The muffler is a crappy arospeed, which I am not really happy with. I just bought it cuz i needed something cheap when we did my swap.
So does anyone have any suggestions, should I just get the silencer and know exactly what it'll sound and run, or take a chance on a high flow cat and later down the road I'll already have a high flow cat to get a full stainless cat-back.?
The motor is a JDM B16 SiR-II with only intake, ITR Intake manifold, and that exhaust....in case that would help any opinions.

 

yea, thanks for all the replies and opinons appreciate it,

 

Any amount of backpressure is bad. Think of exactly what it is... reverse flow. You want the exhaust to flow in one direction only.

Get a high flow CAT if you're performance oriented.

If the car is too loud for you now with the stock CAT & no silencer, it will be a bit louder with a high-flow CAT, so you'll want the silencer either way.

 

you need backpressure for naturally aspirated, forced induction you dont want any backpressure, and I dont have a cat at all right now. The amount of backpressure is the key

 

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Don't be an idiot...back pressure is bad...if you wanted backpressure why would you buy an aftermarket exhaust? Use your head, for and engine to preform as best as it can, it needs to suck in air as fast as possible and spit it back out in the same manner. The more air you can run through an engine the more horsepower you can create. That is why companies make free flowing intakes, intake manifolds, headers and exhaust, if you want a slow *** car, keep all the restrictive **** on it that came from the factory. Think about a 1.8litre engine has better flow characteristics that a 1.5litre...this is the obvious reason everyone wants a swap of some sort rather than the shitty engine that came in their car.

 

yeah don't confuse backpressure with exhaust gas velocity.
backpressure is bad. really think about it, you motor is trying to push those gasses out and BACKPRESSURE is holding it back.
exhaust gas velocity is what you need to make power down low.
someone posted an explanation on this somewhere in here so, i'll try to find it

this may have been said before but i'll say it once more, backpressure is an old hot rodders tale.

as for your question, i would get another resonator, no use in adding senseless back pressure

 

Where in the **** did all of this come from?

Tell you what guys.

For you guys running a near-stock or even all-motor set-up, go out and get a nice 3'' exhuast set-up with no cat and see how great the motor runs then.

It will run like ******* ****.

No cat and straight-through exhaust will also help the motor burn some oil too. That's always great!

I'd say get a good cat like CarSound or another if you know of any. It'll be quieter and the car will have more low-end to it too.

 

Run like **** how exactly? I'm not being an ***, I'm just curious as to how you would justify this statement.

How would an open exhaust cause a motor to burn oil?

 

now...now come on boys. All I can I tell you is with my old B18B set up I gained 11whp when I dynoed open header

 

well, however you guys want to word it, i need something, because since that silencer fell out, i have no mid range power what so ever... yea if i was driving around at 6-8200 rpm all day trying to rack up noise pollution tickets it would be ok..... but im not, i need it more quiet, and i want the kick i felt in the car when it was more restrictive... and im not a fuckn tard like 2liter obviously thinks, but i know how my car felt before and how it feels now... and how loud it was then vs now.... i know its give and take, but imagine how loud my freakn B16 is without a cat and only a muffler with one resonator that basically doesnt do much... so i have to do something before i get a ticket

 

and if i wanted a slow *** car i wouldnt be making plans for a 2.0 liter high compression B18b block with my B16 head..... or did a swap at all for that matter.
But there is a point, like B18C5 said, where you can have too big of an exhaust for daily driving like a 3" exhaust. If I didnt feel like my car was losing power(in the midrange) I wouldnt be worried, but for what my car is, I think I ran a respectable quarter mile time (14.57@ 95 on shitty street tires, I/E) and I would hate to jack up my times over some stupid exhaust mishap. Maybe if I ran it as is at the track with it being all loud and crap, and not getting much pull til after VTEC, who knows, maybe it would be faster, but I got the noise problem still....and lost midrange...

 

I have seen a car put on a test pipe with a big exhaust (2.5'') and soon after it began to burn oil. Blueish smoke was coming out of the exhaust, not black, and do you think it's merely a coincidence?

That's not the first car I've seen with a testpipe that burns oil.

I must be imagining things, or maybe it's all just a big mishap and every car that I've seen burning oil AFTER a testpipe and big exhaust installed just decided to burn oil for fun.

Why is it that I see "for turbo applications" on any 3'' exhaust for Hondas? All the best exhausts usually come in 2 1/4 or 2.5 inch piping, and some of the nicest all-motor cars run no bigger than 2.5'' exhausts - most run 2.25''.

Why is that?

Sure an open header might be nice at the strip or on the dyno, but run it like that all the time and I'm sure it would suck.

I'd still say get a CarSound cat if you can. Never once heard bad about them. I've got a friend who makes 190whp with one on his B18C1 with CTR cam and ITR pistons and mild headwork. This is with an Apex-i WS exhaust too.

 

I suggest some of you do some reading . . . . . .

http://www.team-integra.net/sections...p?ArticleID=47 This is one of several very good articles on exhaust theory & design on this site. You'll need to register to get in.

Another excellent source would be virtually any post written by SMSP on this board. You shouldn't have to look too hard.

But like 2literLsVtec & khoalie said, backpressure is a myth. Exhaust velocity is what's important. And there's no way to maintain high exhaust velocity with a silencer restricting the flow. If you want maximum flow as well as a reasonable exhaust volume, use a high-flow cat, as long a resonator as you can fit, & a twin-pass muffler (e.g. mugen, hytech, etc.)

 

well, mine must be having too much flow .... because its not pulling as hard as it was in lower rpm's.... i guess i was saying backpressure more or less as a generic term for it feels like i have too much flow... i searched for SMSP, didnt show up as a user and the integra site wasnt working right.... and i already have a super long resonator.... i just hate to put a cat on there after i went to so much trouble to get it removed, would another maybe smaller resonator help you think? And if I did end up buying the cat, is CATCO good? Or where can I price a CarSound Cat Tom? I admit the muffler sucks, I wish I had the money to just drop for a full Apexi Exhaust right now...but I've got to make this work til I get up some more money.

 

With regard to backpressure as a general statement- MOST spark ignited engines like a bit of backpressure to run well. How much backpressure needed will depend on what the engine is being asked to do and how it is built. Backpressure will generally help build torque in most applications. If you are at the drag strip constantly at ultrahigh RPMs, you do not want backpressure. If you are on the street, a little bit is good.

One of the other benefits of "some amount" of backpressure is to assist the pressure wave phasing to scavenge the exhaust from the cylinder when the exhaust valve is open.

hope this helps

 

yea, thanks, in different words thats about what I was trying to get at. Now I just have to take a shot in the dark about exactly how I want to fix my problem