Engine Stock or aftermarket exhaust.

Stock or aftermarket exhaust.

so my friends 7th gen exhaust broke after he ran over something on the highway. So I get to fix it.. whoohoo. Now to be honest, I dont know much about exhausts at all. just know how they work. are there any after market exhauts out there that is just as quiet as stock? but gives a bit more performance or do i need to go with a stock exhausts again if i want quiet? I think i already know the answer but I just want to double check. hopefully this weekend i can go to the junk yard and find a stock exhaust. oh well. your answers will be appreciated.

Thanks.

If you want a quiet exhaust go for the chambered or oval design. And if your lucky find a JDM muffler with a JASMA badge. There are not many bolt-on mufflers for our cars, so you're best bet is to weld it onto the existing pipes.

JASMA badge:

www.JASMA.org
From what I know JASMA has a standard maximum dB level a muffler can produce. So whatever muffler that is JASMA certified is gonna be quiet almost like stock.


Here's an example of a freeflow type muffler



Here's an example of a Chambered type muffler



The pros of having a freeflow muffler is self-explanatory. Here's a diagram showing how chambered mufflers work:


Basically it tones down the noise by making it pass thru the chambers. It is gonna be little restrictive compated to a freeflow but way better than stock.

You can quiet an aftermarket exhaust with a resonator. I have a magnaflow one and that reduced the sound a lot.

does it become as quiet as stock? because most i've seen are usually a bit louder. plus the resonators look tacky. but those exhausts are usually cheaper too..

The stock exhaust already has a resonator in the mid-pipe. Did that get damaged too or are you replacing it?

replacing. it looks like the exhaust had rusted a little and then something hard hit it and cracked it. not sure though. anyway, i'm just exploring my options before i head to the junkyard this weekend.

aftermarket exhausts are a game. you never know what kind of sound you're going to get. you might like it, or hate it. with my 1989 sr5 AE92, i had 4 different exhausts pipes and 6 mufflers (due to tickets and 5-0 bullshit). there'd be times I'd get sick of the sound after a few 1000 miles. on top of that, I had headers. and gutted the cat. you have to be bold and try it out. if you don't like it, well, thanks for playing the exhaust game!!! go out buy and install a different setup.

also remember, now this is my opinion, if you want horsepower, don't even bother. depending on your setup, you might get miniscule gains, either low/mid/high rpms, but not noticeable cheek flapping g forces. back when I was 19 yo i thought you'd be burning rubber and peeling out after installing a catback. no!!! isntead i was getting sound pollution tickets

it also depends on what you want. you want performance? looks? both? there are risks for every kind. having only looks (exhaust) can get you busted in Los Angeles. having that round 4 inch tip can make a few cops bust your balls.

The magnaflow muffler imo is a great choice. Its a straight through design with no baffles or obstructions aka. the freeflow design like DOT. said.

Cut away pic

straight through design.

The resonators don't look tacky because its under your car. You can't see it unless you get under and look really carefully. Magnaflows naturally don't produce that popping rice sound that those Civics make. Its a deep resonating tone. Tube/can mufflers tend to create that ricey popping noise which I hate with a passion. Unless it's what you like, I suggest sticking to the traditional muffler design. Resonators reduce the ricey poppiness even more and reduce the decibels of your exhaust noise quite a bit. It may not sound like stock, but it won't get you a noise ticket. I myself have the magnaflow muffler and resonator and everyone who's been in my car complements me on the subtle exhaust tone which is deep. After I have had my custom catback welded to replace the stock piping diameter, I noticed a slight deepening of the tone, but not much difference. So you should expect to have something close to what I have. But all in all, this is just my 2 cents. Just want to throw this idea out there. Good luck!

generally a 4 into 1 header is considered a race header. you will probably want one of these if you rev your car a lot doing any kind of racing or going to the track. the 4-2-1 will give you the best street performance.

I have a jasma/trust muffler that is from a 300zx for sale if you are interested.

wow, this post changed quite a bit. now its like exhaust 101.

as for my original info, i'm gonna hopefully get to the junkyard on saturday and pick myself a exhaust. if i cant, i may have to come back and post again asking which exhaust would be a good buy. cheaper than oem but good.

I forgot to add. Also consider the inlet diameter and the outlet diameter to match your engine. Don't just get the biggest diameter muffler, you need some back pressure.

Yeah, I agree. For piping diameter, if you don't have forced induction, its not ideal to have too wide of a diameter. You will actually lose power since it's not as easy to push all that exhaust through a huge pipe. Like in physics, smaller diameter = faster flow; larger diameter = slower flow.

You guys are thinking about it the right way, but think of this. The best exhaust is a short exhaust. The best exhaust is an open exhaust (a motor will love to have fire shoot out of an open header). When you are talking about a muffler replacement a less restrictive muffler is beneficial on a stock setup.

The piping matters a huge amount on the entire exhaust system, but if you keep the stock piping, then your concern is taking restriction out of the exhaust flow, which is what a straight through or larger diameter muffler will do. Basically you are taking the cork off the rear of the exhaust. You get plenty of restriction with the stock crappy manifold, cat, resonator, and crunch bends.

ahh you filled in all the rest of the parts we missed. LOL Yep, totally agree. Unfortunately, running straight out of the head or header would be reallly loud and obnoxious. You could probably hear your car from half a mile away. LOL

Well the thread was about exhaust. I was just thinking about the muffler. Hehe.

So... To add more:

Also consider the header design. If you want gain power in the higher RPM band go with a 4-1 design headers. Like this:


If you want low-mid range RPM gain go for 4-2-1 design hearders:


And if you're gonna do you own piping, try to design it with minimal bends and curves.

wow, this thread is good, didnt expect anything come out like this.
Seems like I don't need to add anything since you guys covered everything already.

True... But you you're gonna love the 4-1 in the freeways. Hehe.


Hey DrunkSaru, which junkyard are you gonna go to? If I'm free, can I tag along? Let's talk about it tom.

dude, when i woke up this morning, i had really bad chest congestion and coughs. hopefuly this will clear up later in the day. but if i go on saturday, i'll let you know. Pick your parts in Van Nuys. i think admission was still $3 to get in. or 7? damn i cant remember now.

exhaust. well it depends on ur mood. lets c. do u really want the stock rusty exhaust or do u want 2 b a modder? everyone has there own taste of exhast. for example u can use the jdm ones which are stupid loud, american ones liek magna flow, or u can just slap on other exhaust from other cars. like i've seen people slap on a is300 exhaust or a wrx exhaust. those are pretty nice because of the shame and also quiet. as for import exhuast i'm pretty shure i can come with a silencer but thats just more ristriction 2 ur car. ^_^

One other note about aftermarket mufflers. Yes straight through types are the best due to less restriction. However, make sure it has a perforated core not a louvered core. A louvered core cheapy muffler can be more restrictive than a stock muffler. Perforated cores are the best performance since they flow like a straight piece of pipe.

ok, so you have the AE101-102. exhaust is somewhat short, but still somewhat long. you have two catalytic converters right now, one inside your stock header, one downstream, and a resonator (also called a first stage muffler). if you want performance, i wouldnt push more than 2.5 inch pipe since its not F/I. also, size of the pipe depends on the bends. if they are mandrel, stick with 2.5 inch, if they are crimped or forced then the pipe tends to buckle at the turns and a 2.75 inch pipe can quickly turn into a 2.5 inch corner. also, for your muffler you can get a restricting muffler and it can sound loud, it all depends on the pipes. and as for the muffler entrance/exit diameter, dont worry if you go bigger than the pipe because you already have backpressure back upstream and with a bigger inlet/outlet you cool the exhaust temps and make the exhaust more profficent. if you want performance and quiet go get a 2 inch mandrel bent (or 2.25 inch forcebent) pipe, keep your upstream cat, gut your downstream cat, get a new resonator and then get a straightflow muffler and a silencer. they screw right into the tip of the exhaust and reduce the exit size of the muffler which quiets it out.

Lots of good ideas and information in this thread. Myself, to enhance your performance think about 4-2-1 headers, Cold Air Intake, and a custom exhaust system with a resonator. Check out my system below. With the manual 5 speed tranny, cai, bored out headers, hyper-ground system, and custom exhaust system, I gained a significant amount of horsepower. The exhaust system is set up for the turbo kit coming this April.

http://trdforums.com/forum/showthread.php?t=16477

You mean to say "header", not "headers" unless you have more than 4 cylinders.
btw I also have a custom mandrel bent 2.5" Magnaflow catback exhaust w/ resonator. haha what a coincidence. The pictures look exactly like my setup. How much did you pay? Dr. Tweak was saying something about 950 in his post there. I only paid 350 for everything. Well, I knew the guy too so he hooked me up. hehe

It's a typo, yes, Header. I paid 950 for the job. I have no regrets, the vehicle is performancing great and can't wait for the new suspension system and turbo kit. No CEL and that was a concern.