Emmisions with Headers

Post by **Anand** » Mon Sep 30, 2002 2:59 pm

I was wonderring if I would pass emmisions in CA if I were to get Hotshot Headers with Apexi dual N1? I already have intake by the way...so I would be running I/H/E deal for now...

Post by **R240NA** » Mon Sep 30, 2002 2:59 pm

On an S14, you'll lose the catalytic converter when installing the header, so no it won't pass. S13, you'll stil keep the converter since it's further back.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

How would you go about passing emissions then...maybe temporarily rigging a cat further on down or something? (assuming it would pass with a cat and those headers)

Post by **bruinbear714** » Mon Sep 30, 2002 2:59 pm

black240, I emailed you about the n1duals... I have the hotshot header sitting in my garage if you want to see how it's set up. Since I'm thinking about getting the n1 duals also, I'd like to see how it's set up on the car since we're both heading in the same direction

I believe the n1 duals extends all the way up to the cat right below the oem header. If that's so, then it is impossible to weld a cat in there unless you hack the HS header. If it extends up to the dummy cat (the one sitting right below the driver), then you can replace that dummy one with a real cat and everyone's happy.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

That's right. if you already have full exhaust, then you'd have to hack it somewhere to throw that cat on.

Personally, I'm going the easier route. I had my local muffler shop make a custom 2.5" cat-back, and I threw an Apexi N1 muffler on the end. I only paid $70 for the custom piping and $100 for the muffler, as opposed to paying over almost $500 for the Apexi N1 exhaust.

and now i'm taking off my cat and bolting a test pipe on (hollow pipe) in place of tha cat. So when I need to take the emissions testing, all I need to do is just bolt the cat back on in place of the test pipe.

Of course, this is before i'm getting my headers.

YouTube · Post by **EZcheese15** » Mon Sep 30, 2002 2:59 pm

Just add a high flow cat to your exhaust system. If you are OBDII, then move your downstream O2 sensor to behind the cat. If your are OBDI then just add the cat.

It might cost you some money but you won't really loose any performance (despite what people think, a high flow cat is not gonna make a difference unless you are running some serious boost). That way you are legal and don't have to worry about getting tickets or failing emissions.

Post by **bruinbear714** » Mon Sep 30, 2002 2:59 pm

The problem is that the N1 duals go all the way up to the HS header, so there is no room to place a cat in between... unless the exhaust stops at the dummy cat, in which case you can replace that with an OEM one.

Post by **Anand** » Mon Sep 30, 2002 2:59 pm

The exhaust stops after the dummy cat....

Post by **b240** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:That's right. if you already have full exhaust, then you'd have to hack it somewhere to throw that cat on.

Personally, I'm going the easier route. I had my local muffler shop make a custom 2.5" cat-back, and I threw an Apexi N1 muffler on the end. I only paid $70 for the custom piping and $100 for the muffler, as opposed to paying over almost $500 for the Apexi N1 exhaust.

and now i'm taking off my cat and bolting a test pipe on (hollow pipe) in place of tha cat. So when I need to take the emissions testing, all I need to do is just bolt the cat back on in place of the test pipe.

Of course, this is before i'm getting my headers.

Do you have a turbo or just stock ka? i did that with my apexi n1 single and ka. it sounded like ****.

Post by **Anand** » Mon Sep 30, 2002 2:59 pm

I think you have the right Idea Bruinbear. you can replace the fake cat with a real one and still have the headers. BUt I don't know if it will still pass emmisions...???

Post by **b240** » Mon Sep 30, 2002 2:59 pm

Hey black240 when are we going to have a socal meet. Im going out to OC monday and tuesday.

Post by **b240** » Mon Sep 30, 2002 2:59 pm

Do you have aim? AIM me at xxxb20xxx

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

b240 wrote:Do you have a turbo or just stock ka? i did that with my apexi n1 single and ka. it sounded like ****.

I have the KA. If you have a KA, then getting the N1 is pointless. You don't need 3" piping on a N/A engine. It actually robs you of some performance by creating more back pressure. 2.5" is plenty.

YouTube · Post by **EZcheese15** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:I have the KA. If you have a KA, then getting the N1 is pointless. You don't need 3" piping on a N/A engine. It actually robs you of some performance by creating more back pressure. 2.5" is plenty.

*COUGH* back pressure *COUGH* myth *COUGH*

3"piping may be too big for the N/A KA, but its not because of anything to do with backpressure. It is because the larger diameter decreses the exhaust velocity.

If you don't believe me, try blowing through a straw. Now try blowing through a straw that is twice the diameter with the same force. The velocity of the air is half as much

The quicker the exhaust leaves the engine, the quicker it can take in more air. The whole goal is to get the exhaust out as quickly as possible. Too small and you will have too much back pressure. Too large and you don't have enough power to push it all out.

Post by **Anand** » Mon Sep 30, 2002 2:59 pm

b240 wrote:Hey black240 when are we going to have a socal meet. Im going out to OC monday and tuesday.

naw.. i don't have Aim but I can meet up with you on monday and/or wed nights only though. I work till 9:00pm. If you want to meet up call me up... 714-325-2841. my cell phone. I am going up north this weekend for a wedding but I will be back on sunday night.

Post by **bruinbear714** » Mon Sep 30, 2002 2:59 pm

Black240 wrote:I think you have the right Idea Bruinbear. you can replace the fake cat with a real one and still have the headers. BUt I don't know if it will still pass emmisions...???

I'm more concerned about the loudness. I'm hoping with an aftermarket cat, n1 dual with silencers, and hotshot headers will be quiet enough not to attract a cop a mile away. The area I live in is swamped with cops now thanks to those civic and integra boys with their coffee can exhausts.

As for emissions, if they don't pass me with that setup, then I'll just swap back the header and exhaust and run the car with two cats.

Besides, I will only have to do this every two years so it shouldn't be too much of a hassle, unless the bolts get rusted again.

Post by **b240** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:I have the KA. If you have a KA, then getting the N1 is pointless. You don't need 3" piping on a N/A engine. It actually robs you of some performance by creating more back pressure. 2.5" is plenty.

im planning on going sr or ca.

Post by **b240** » Mon Sep 30, 2002 2:59 pm

and i would also like to state: Balls on your chin.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

Quote »...Too large and you don't have enough power to push it all out.[/quote]So then what happens....

YouTube · Post by **EZcheese15** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:So then what happens....

So then the exhaust velocity decreases. Which means less exhaust exiting the car per second. Which means less air coming in the engine per second. Which means less power.

Post by **b240** » Mon Sep 30, 2002 2:59 pm

quote:--------------------------------------------------------------------------------...Too large and you don't have enough power to push it all out.

When i first saw this i thought you were refering to my "balls on your chin" statement. Nm though.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

EZcheese15 wrote:So then the exhaust velocity decreases. Which means less exhaust exiting the car per second. Which means less air coming in the engine per second. Which means less power.

See this is what doesn't make sense though. Since the diameter is larger, the velocity doesn't need to be as great in order for the same rate of volume of gas to be exiting the exhaust. So slower velocity doesn't neccsarily mean less power. So what is eating power then?

YouTube · Post by **EZcheese15** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:See this is what doesn't make sense though. Since the diameter is larger, the velocity doesn't need to be as great in order for the same rate of volume of gas to be exiting the exhaust. So slower velocity doesn't neccsarily mean less power. So what is eating power then?

If the exhaust velocity is high (which is want u want), then it creates a vacuum behind the exhaust, up near the exhaust valves, helping to pull exhaust out of the engine.

If the exhaust velocity is too low, it is true that the same amount of volume of exhaust is leaving the system (larger diamter + less velocity = same volume). However, because the exhaust velocity is low, there is no vacuum created behind the flowing exhaust to help pull the exhaust out of the combustion chamber.

Post by **240canuck** » Mon Sep 30, 2002 2:59 pm

i don't got much money right now for an exhaust but what would happen if i removed the resinator from my exhaust and just welded in some piping? would it be more free flowing??? would the sound change? I need a new exhaust soon anyway my muffler has skin desease and my piping is all rusty. But i just want a more aggressive sound for now. anyway I don't care about emmisions right now I got 2 years to get it legal again and my old exhaust is crap anyway so I want to cut it up. give me some thoughts.

Post by **leper421** » Mon Sep 30, 2002 2:59 pm

Quote »But i just want a more aggressive sound for now.[/quote]

If you dont have an intake yet, removing the y-pipe to the airbox and cutting holes in the bottom of the airbox will give a nice sound, especially above 3k.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

EZcheese15 wrote:If the exhaust velocity is high (which is want u want), then it creates a vacuum behind the exhaust, up near the exhaust valves, helping to pull exhaust out of the engine.

If the exhaust velocity is too low, it is true that the same amount of volume of exhaust is leaving the system (larger diamter + less velocity = same volume). However, because the exhaust velocity is low, there is no vacuum created behind the flowing exhaust to help pull the exhaust out of the combustion chamber.

Thanks for the explination bro, but I'm still struggling with this concept of how this vacuum is produced with the smaller diameter piping. I am a menchanical engineer at Georgia Tech, so I need to dissect the mechanics of everything.

Quote »what would happen if i removed the resinator from my exhaust and just welded in some piping? would it be more free flowing??[/quote]The sound will be a tad louder. The resonator is like a secondary muffler, and it doesn't strip you of performance. If you're into sound, just get an intake system if you don't have one allready. Replacing your stock muffler with a straight pipe muffler will also give you a louder sound.

YouTube · Post by **EZcheese15** » Mon Sep 30, 2002 2:59 pm

perpetual gyro wrote:Thanks for the explination bro, but I'm still struggling with this concept of how this vacuum is produced with the smaller diameter piping. I am a menchanical engineer at Georgia Tech, so I need to dissect the mechanics of everything.

http://www.nissanperformancema...2.php

Here's an article written by Mike Kojima on it. Also, he wrote a more technical article on it in SCC one month but I can't seem to find which month that was. If you would like, email me privately and I can give you his email address and you can ask him yourself what month the article was in, or even ask him directly to explain it. He is an engineer too and can probably answer your question with nothing but formulas if you so desire

Post by **240canuck** » Mon Sep 30, 2002 2:59 pm

thanks gyro when i finally get my end exhaust i want it to sound real low and grumpy when idling but not sound like a fart when the RPM get up there. If you know what I mean.

I thought removal of the resinator would not muffler the natural exhaust tone of the engine as much. which would give it that more low tone almost (dare i say it) V8 sound. Anyway anyone know a good setup for that type of sound???

I don't autocross or anything like that. I just want a mean sounding machine that may see a quarter mile every few weeks.

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

thanks for the link bro..here's an exert:

"To produce the most amount of power, an exhaust should have the least amount of restriction to the exhaust flow. Restriction hampers the burned exhaust gasses from exiting your engine, causing some charge dilution with the incoming fresh fuel air mixture. If all the exhaust gas cannot escape from you cylinders, it dilutes the flammable intake mixture that is trying to come in. The diluted mixture does not burn as well as a pure mixture. This causes a loss of power. You don’t feel so energetic at a packed club with lots of cigarette smoke, sweaty bodies and hot stuffy air right? Neither does your motor. With greater restriction, backpressure is generated making the engine work harder to pump the exhaust out of the engines cylinders. This is another pumping loss like we talked about in our last Revenge of the Nerds article about intakes. The harder it is to get the exhaust out, the more power wasted to pump the stale exhaust gas out of a restrictive exhaust system.

Some stock mufflers have up to 18 psi of power robbing backpressure. A well-designed performance exhaust typically has about 2-6 psi of backpressure. For comparison sake, an un-muffled straight pipe on a real race car usually has 1-3 psi of backpressure."

Post by **perpetual gyro** » Mon Sep 30, 2002 2:59 pm

Some self-proclaimed motor gurus state that you should not run too large of an exhaust tube on your car because engines need a certain amount of backpressure to run correctly. Although the statement about not running too large of a tube is correct, the assumption about engines needing backpressure is not. Remember this, it is one of the most common performance misconceptions out there. Read on and you will be able to argue with and break off any self-proclaimed expert on the subject!

Emmisions with Headers

Emmisions with Headers

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