We took off the whole exhaust and cat tonight to go to the track tomorrow.

AND WWWWOOOOOWWWW!!!!!

That thing rips now and sounds like a Bad *** Car. NOt that it wasn't before. I love it but am frightened to get pulled over again.

 

you should move to GA
they don't seem to care how loud you car is

 

track as in track or as in drag strip?

 

I'd put it all back on, you're probably losing power. The stock ecu compensates for whole lot on this car.

 

Sounds faster though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by vapor &raquo;</TD></TR><TR><TD CLASS="quote">I'd put it all back on, you're probably losing power. The stock ecu compensates for whole lot on this car. </TD></TR></TABLE>


Or with no back pressure at least losing alot on the low end!

 

no back pressure for 1
for 2 if im not mistaken it will put the car into limp mode due to the fact of missing an o2 sensor (in the cat) and then cause the car to dump a lot more fuel. in return make you lose a lot of hp

 

lack of backpressure does not hurt low end torque numbers, this is a common misconception. You lose nothing and gain everything with low backpressure. There are 10 billion arguements on this subject, but I will explain to you guys a little bit. There are 2 things when dealing with exhaust, back pressure and delta pressure. Delta pressure is the difference in pressure across 2 different points, back pressure is obviously the resistance to airflow. This being said no backpressure and high delta pressure would be ideal. Having a high delta pressure would be creating pulses that form a vacuum behind it which actualls pulls the exhaust from the following combustion. This is piping diameter all ties in with where your powerband is. Obviously with 2 pipes, 1 being larger the same volume of air would have to travel at a higher velocity in the smaller pipe to move the same volume of air at the same rate. This is why large diameter piping makes power at high rpm, and small diameter piping makes power at low rpm. I hope that answers your questions. Oh, and you probably did gain power by removing your exhaust somewhat due to less backpresure, but you have not changed your delta pressure so your powerband would be left unchanged however what he said about limp mode is true, but alot of the time it actually takes the obd2 computer a while to realize that the second o2 is not functioning properly for some reason

 

You do not want backpressure. An engine makes power by low exhaust pressure, and high intake/combustion pressure. You want exhaust gas velocity, and open header isn't hte best way to acheive this. By adding about a 1-2 foot pipe off the end of your header, your scavening will be much improved and you'll make more power.

The exhaust pulses and low exhaust pressure cause a low pressure system behind the pulses, thus the intake charge travels after hte low pressure, making more power like the guy above mentioned.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PROFILES2000 &raquo;</TD></TR><TR><TD CLASS="quote">no back pressure for 1
for 2 if im not mistaken it will put the car into limp mode due to the fact of missing an o2 sensor (in the cat) and then cause the car to dump a lot more fuel. in return make you lose a lot of hp </TD></TR></TABLE>

ecu doesn't go into safe mode, you can run without a cat or secondary o2 sensor and the ignition and fuel maps remain the same except for a lousy MIL.

For the subject of backpressure and hp/loss gain. Everything said applies well with big block chevys, but if you remove an entire exhuast system and run open header on a stock s2000 engine and stock s2000 ecu, you will not gain power. You will only hurt your ears and the ears of others.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic596 &raquo;</TD></TR><TR><TD CLASS="quote">We took off the whole exhaust and cat tonight to go to the track tomorrow.

AND WWWWOOOOOWWWW!!!!!

That thing rips now and sounds like a Bad *** Car. NOt that it wasn't before. I love it but am frightened to get pulled over again.</TD></TR></TABLE>


ghetto racers on the prowl.....

 

If the exhaust isn't 'tuned' right, you could get pinging or detonation. I'd put it back on and get an aftermarket exhaust. Go to http://www.teamspugen.com They have nice exhausts for not a lot of money.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by civic596 &raquo;</TD></TR><TR><TD CLASS="quote">We took off the whole exhaust and cat tonight to go to the track tomorrow.

AND WWWWOOOOOWWWW!!!!!

That thing rips now and sounds like a Bad *** Car. NOt that it wasn't before. I love it but am frightened to get pulled over again.</TD></TR></TABLE>

haha again? am i to assume that you already got pulled over for excess noise due the removal of cat and exhaust.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S2KandSTi &raquo;</TD></TR><TR><TD CLASS="quote">If the exhaust isn't 'tuned' right, you could get pinging or detonation</TD></TR></TABLE>

please explain to me how an exhaust can cause pinging or detonation

seriously here guys no spreading old man tales on this board

i.e. the no backpressure makes for no torque crap

where the hell is my e-beer?

 

yeah what the hell does the exhaust system have to do with pinging or detonation? the exhaust system comes AFTER the combustion process, not before. you could argue that an intake system could cause detonation(too much air.........yeah right), but it at least makes some kind of sense b/c it DOES have to do with the combustion process.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by khoalie &raquo;</TD></TR><TR><TD CLASS="quote">

please explain to me how an exhaust can cause pinging or detonation

seriously here guys no spreading old man tales on this board

i.e. the no backpressure makes for no torque crap

where the hell is my e-beer?</TD></TR></TABLE>
This is not a tall tale. During the overlap period at the tail end of the exhaust stroke and the beginning of the intake stroke, both intake and exhaust valves are open. On all 4-stroke motors, this happens because the valvetrain cannot move as fast as the pistons, the valves come to a dead stop, then open again, right? This causes some of the intake pressure to leak out into the exhaust unburned, the reason we have catalytic converters, to burn that unburnt gas. Well, when you have too little exhaust backpressure, more intake air can leak into the exhaust causing less than normal pressure in the cylinder which can cause the ignition too go off too late, and you could push that ignition and gas out the exhaust valve and into the exhaust and cause a firing in the exhaust manifold which will cause a backfire close to the block and could push air back into the cylinder and cause excess backpressure and in the overlap period again, push too much pressure into the piston and slam the piston skirt into the cylinder wall aka knock. I need a picture or diagram to fully explain this. I didn't say it WILL happen, but it COULD.

 

back off

 

I know. Nothing happened. No pinging no back firing. Just nice sound. And we put it back on the next day. We are going to get the JIC full Ti exhaust.

 

Never got pulled over. Even drove side by side next to one on the freeway.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by S2KandSTi &raquo;</TD></TR><TR><TD CLASS="quote">
This is not a tall tale. During the overlap period at the tail end of the exhaust stroke and the beginning of the intake stroke, both intake and exhaust valves are open. On all 4-stroke motors, this happens because the valvetrain cannot move as fast as the pistons, the valves come to a dead stop, then open again, right? This causes some of the intake pressure to leak out into the exhaust unburned, the reason we have catalytic converters, to burn that unburnt gas. Well, when you have too little exhaust backpressure, more intake air can leak into the exhaust causing less than normal pressure in the cylinder which can cause the ignition too go off too late, and you could push that ignition and gas out the exhaust valve and into the exhaust and cause a firing in the exhaust manifold which will cause a backfire close to the block and could push air back into the cylinder and cause excess backpressure and in the overlap period again, push too much pressure into the piston and slam the piston skirt into the cylinder wall aka knock. I need a picture or diagram to fully explain this. I didn't say it WILL happen, but it COULD.</TD></TR></TABLE>

Please re-read what you are saying and tell me you're kidding.

 

Any VTEC motor sounds crazy with no exhaust or cat on. I ran my GS-R (B18C1) open-header once...sounds like *** but loud as hell.