Just purchased me an 89 iroc z... 305, 5 speed... A bunch of work done to the engine and the previous owner swears its pushing near 300. I call a bit of horse **** since as best as I can tell I'm still using stock headers (I need to confirm myself, friend is the one that was around there looking for me.). However I do know the car is fast as hell and that's for another thread.

Onto the exhaust! Previous owner mentions it has a flowmaster cat back system, 3" pipes. Welding job was terribly done so I'll need to redo that, but he mentions the cats are hollowed out (but then says it passes emissions on its own ? bs heh).

I'm digging the deeper sound of the flowmaster system but it's a bit too quiet. I do have a minor exhaust leak from where the previous owner banged one of the cats and if they're really hollowed out I might as well just removem anyway and run straight 3" pipes to the flowmaster system. (I know about emissions requirements etc.)

Now I'm not too knowledgeable on exhaust setups. My question is, with the flowmaster cat back system, if I remove those cats, will there be a performance decrease of any kind? I'd think not but would like to confirm. Also, if it is indeed stock headers I have no idea where to even begin researching which brand/model to use to give me decent sound / HP gain.

Thanks,
Bez

 

Nor am I, just want you to know reading/answering the rest of your quotes.

Yes. You did say, "decrease of any kind."

You need to confirm my every step so we agree/confirm, disagree/confirm I have no clue about what I am talking about if I work the physics at you. Bounce this off you like an atom spark bouncing off a side electrode, it should spark a thought of valid confirmation.

Complex but simple Cat Flow Characteristics:

1. Heat Expands.
2. Expanding heat moves faster.
3. Non-fired fuels are able to re-fire.
4. Cat continues the heat and speed flow.
5. Counters the enemy back-pressure for so long. << Bingo! Slow my air speed out to atmosphere is push me back in @ 14.7 Pea Yes Eye Confirm the complex is remove my cat is simple performance loss, NO?
6. Intake [fresh air] unit design is choose your weapons system called EGR/PAIR being timed when to shoot the air in.
7. Timed to close when it sent fresh air into the exhaust tract; was to simply add [fresh air] oxygen into the exhaust port.
8. Fuel re-fires are the un-spent is add oxygen.
9. Cat does the kitty litter to the fuel vapor of air and whatever what not spent is still un-spent is you can't get it ALL.
10. You breath 02 or water vapor is you cannot create or destroy what you burned is all of it, some of it, any of it.

Sound can be made using a muffler bearing. I can show you one in action. That is what I meant when I said I do not know about exhausts.
But there is a lot of research on the 350ci. You want the straightest pipe out of the exhaust port. Any curve will slow the air flow out the chamber. The speed of the heat is paramount, so you are wise to keep the cats hot-hot-hot is that exhaust. Your check engine light will come on if you stop a sensor from running correctly.
There are no resistors that can re-correct an analog signal. That is so fundamental, it is not funny. So if you think you can remove a cat and now the 02 reads a lot of gas not fired off, it will lean out the car and you are in limp mode more or less.

Pretty cool, no? Trick my shop manual will you. Walk year azz right to a code is CEL [check engine light] my dash.

 

THREAD DIGGER! And he's a moron! GREAT!

No removing cat doesn't decrease power... As for headers, just go ask in the 3rd gen section.

For the moron who posted...

1. Heat does not expand... Hot air does.
2. Hot air does indeed move faster.
3. 14.7 is not a pressure reading... It's an air/fuel ratio mixture.
4. Back pressure is a retarded concept people use as an excuse to put such and such exhaust on. What makes a difference is VELOCITY.
5. The rest of what you said makes no sense...
6. Straight pipes out of the exhaust port eh? Good luck.

You make me lol

 

1. Cold air expands = But you get it technical point of it, did dent yer head a little.
2. Yeah, and now match my action/reaction is EQUAL stop the fresh air from moving out with the spent is if you can control the heat, you control one of many variables to stop overlap from pulling more gas out is zero if you were going after ideal conditions.
3. What is the air pressure on your skin? I rest my case is 1Atmo my world is a vacuum. Do I live in a velocity stack on the move is suck the air out of my lungs is why I survive in what pressure cooker you are inn about now is trip you up we are both in the same world is be on the same page, boy.
4. WOT makes the crank spin faster? Back pressure going in to fill a void or are you not fighting 14.7 being that pressure, boy, is VELOCITY! Pressure is amps is kill you with so much pressure is so much velocity is analog my speed 0 to 5000 amps.
5. 14.7 is a dead engine. Which is more heavier? 14.7 pounds of chit or 8 pounds of sheeze is, you some more on?
6. No front fenders ya sissy is go and rush your hood only is the latest gig.

I better make you laugh. It's just OTTO-speak king.

 

Oh boy...this is going to be fun. First off...can you speak English correctly? It would make this so much easier.

1. Technically any fluid (air included) will expand and contract depending on the size and shape of it's container according to diffusion. A cold fluid inside a container will expand just as much as one that is hot providing the container has a fixed volume (last time I checked exhaust systems do). Therefore I submit that a hot or cold fluid will only expand as much as the walls of it's container will let it until it exceeds the pressure the container is capable of retaining. Then you have an explosion. Then the fluid diffuses into the atmosphere...

2. Hot air can move slower than cold air, or vice versa. The hot air simply has a higher average kinetic energy than the cold air, allowing to exert more pressure for a fixed surface area of a container. Fluid flow is strictly based off of temperature differentials. Fluids will flow from a hot area to a cold area due to the change in densities. This means that the temperature of your fluid is irrelevant, but the difference in temperature is what matters.

3. The current air pressure on my skin is approximately 86 kPa which equates to 11.78 psi. Last time I checked I don't live in a vacuum, although I may live at higher altitude than some. As far as I know you're on the same world as me, but by the way you speak I can't be sure.

4. This one makes no sense. First of all, pressure is not "amps" (please do Mr. Ampere a favor and capitalize his unit next time). If you're attempting to make a fluid model that is analogous to a circuit and the flow of charges pressure equates to voltage and velocity equates to current. Kal is correct, backpressure is a silly concept. The basis for the concept is that during the valve overlap stage in the combustion cycle of a cylinder if you don't have enough "backpressure" you will blow the charge of fuel out of the exhaust valve and thus not make enough power. First of all this does not effect horsepower at all which is strictly based on how much exhaust volume you can carry away from the motor, but it will effect low end torque. At high RPM's there isn't enough time for the charge to be blown out and therefore it is retained. The issue with low end torque can easily be taken care of by a tuned header in which you utilize the pressure differentails that are oscillating in a sinusoidal fasion to help pull exhaust out of a combustion chamber on the negative pressure part of the cycle and it can help retain the charge as the exhaust gas is escaping on the high pressure side. This is why a tuned header with longer primaries will make more torque in the low RPM range because it's resonant frequency is lower due to the longer primary tubes.

5. This makes no sense at all. 14.7 is not a dead engine, it's a real number. 14.7+8j is a complex number, what's your point?

6. I'm not even going to dignify this with a response.

Now, can we stop spreading incorrect info and work on our English a little?

 

good lord paz.....
I will say this in your terms


is my is you yo is is? cuz is what is does is sometimes! is face to toe face is what is now is. fizzle dizzle.....



You make me want to kill myself with all the times you use the word "is" in a place it was never meant to be........ I have no idea what your saying...all ive gathered is that you have no idea how a catalytic converter works


to the OP. Im sorry for this. we are taking actions to deal with it but forum policy keeps us from just banning him for being annoying and uninformed. please just ignore him

 

OP, to answer your question more directly (sorry about that slight interruption), no you are not going to see a performance decrease with hollowed out or no cats at all with the flowmaster cat back.

 

OK, one more time:

14.7 = Dead Engine.
14.7 = WOT the engine
14.7 = Is the constant
14.7 = Is the vacuum
14.7 = For every action is an opposite and equal reaction.
14.7 = Pull or push a balloon, then let it go. Did it remain where you pushed or pulled, or did it revert back to that 'constant.'
14.7 = Tit IS WOT TIT IS!

FI is the sensor remains in that push is pull my 0 to 5.0v.


Pressure out the kidney and when empty = Fill in the blank.