Pros/Cons of removing a converter

[4u2envy_accord]

I drive a 1994 honda accord ex 4 door 5 speed and i was just wondering what the pros and cons of cutting of ur cat. are. I already have a performance muffler yet i want a louder tone. Will it hurt my car in anyway? Any help is much needed thanks!

[JD@af]

It won't hurt your car in anyway, but if you get pulled over, a cop is not going to be very nice to you with a removed cat. Gutting your cat is another option, so it at least looks like you have a cat. Quick run down:

PROS

Less restriction = more power
Less restriction = more noise (which you want, right?)

CONS

Less restriction = very difficult to pass smog test
Less restriction = more noise (difficult to ever keep a low profile while driving)

I recommend neither gutting nor removing a cat for a street car.

[DVSNCYNIKL]

I would also stray away from gutting your cat and just buy a full cat back exhaust. It's better and won't be as troublesome as gutting.

[drift]

here we go... a true list:

Pros:
- louder for a nicer, ricier effect
- reduces restriction within exhaust pipe


Cons:
- sometimes too loud
- reduces too much restriction for a naturally aspirated motor with a 2.25" aftermarket exhaust. in most cases, with a larger exhaust, the cat actually enhances performance by adding just enough restriction to raise exhaust pressure for more efficient evacuation of exhaust gases. in many cases, like with any "too large" exhaust setup, you lose low-end response due to low exhaust pressure... the exhaust gases cannot escape the pipe quickly enough and reversion becomes a problem. only at high rpm will the problem go away, as the motor is then flowing enough gases to prevent reversion. basically presents little to no gain in power, or too much loss of lowend response to justify the high end returns.
- very pollutive
- illegal
- can trigger check engine lights on OBD II cars as the second O2 sensor reads a dirty a/f mix... which can be solved with the use of an O2 sensor simulator.

[DemonicAccord]

then it begs the question re: the NA w/ 2.25" exhaust, would a high flow cat provide enough restriction at low RPM to be worthwhile investment?

[drift]

Originally posted by DemonicAccord
then it begs the question re: the NA w/ 2.25" exhaust, would a high flow cat provide enough restriction at low RPM to be worthwhile investment?

believe it or not, most stock cats from 1990 on are "high flow" by their design. they arent nearly as restrictive as the older cats.

as for the random cat, no it probably wouldnt create enough restriction for a naturally aspirated motor combined with 2.25" exhaust piping... until the higher end of the rpm band, where exhaust velocity will overcome the tendency for reversion.

[DemonicAccord]

but in a forced config, say 7psi form a DRAG kit, it (it being a Random product) would be useful

[EliteAccordPH]

Add some headers and keep your stock cat. Your current exhaust will be louder and you'll have performance gain yet be legal. Then if you want louder then get a high flow cat. Keep your piping at 2.25" any more like me 2.5" will make you lose low end.

[aLtErEgO]

What about a High Flow Converter?

[drift]

Originally posted by aLtErEgO
What about a High Flow Converter?

read ALL the posts before posting. this has already been discussed about 3 posts up.

[5 speed]

you must realize the following:

less restriction = less back pressure = less torque = less power

If anyone has ever had the experience of driving an older car prior and post muffler requiring replacement you will know that when amuffler leaks the car is sluggish and doesent drive as well

same is applicable for a catalytic, plus your screwing up yo life and others as the main purpose is to reuse and burn pollutants

[jdmakkordman]

you can add a high flow cat which costs a grip or i like Elites idea and just add headers AND an intake...youll get a little more power and your decibal levels will go up

[drift]

Originally posted by 5 speed
you must realize the following:

less restriction = less back pressure = less torque = less power

that is a bunch of bullshit.

backpressure is always bad. you want a well tuned diameter for your application to increase exhaust velocity. too small diameter or a blockage will cause a restriction and increase back pressure. too big of a pipe will reduce exhaust velocity and cause reversion.

larger pipe = reduced exhaust velocity = reversion of exhaust charge = loss of power due to inefficient combustion.

once the exhaust pulse has passed the cat, it becomes harder for it to reverse, therefore removing the cat on a 2.25" exhaust on a Honda may reduce performance by allowing reversion.

get it right or dont post. you'll confuse the unknowing.

[brads94accord]

well ifyou say you only have a performance muffler, you need to get new piping from the cat back and some 4-2-1 headers. oh guys, i ve got a question, rather than wasting bandwidth, i went to the muffler shop that is doing my piping and he said he can't do cat back piping since the flex section has to stay. he said he might be able to remove it if there is a flex section farther up on the exhuast system. is there?if not then how much power would i loose doing 2.25 pipe from the flex section back instead of the cat back since its about 16-20 inches of pipe?

[5 speed]

hey drift

yo mama got back pressure if ya know what a mean son !