Rep Power: 0

2000 Civic SE d16y7
Injen Cold air intake
Megan Racing headers with universal aftermarket magnaflow high flow cat

Just bought a ebay catback exhaust with test pipe no cats
went to auto store to get replacement gaskets as the ebay ones where cheap
and bent in shipping
Auto shop guy said since its obd2 by removing my cat I lose all the back pressure
so my obd2 will go into limp home mode which will cause
terrible mpg since fuel to air ratio is now predetermined
rough idle
blown valves possible
and improperly heated o2 sensors

what are my options?
all help greatly appreciated

 
Rep Power: 189

Ummm no he does not know what he is talking about, it will remove a lot of the backpressure but not all of it he does not know what he is talking about, it will not go into limp mode, I have a apexi catback and a 4-2-1 header on my car now it runs just fine but you will run into a check engine light with the secondary 02 sensor on occasion, if you do then use 2 18mm sparkplug nonfoulers, dril the first one out with a 1/2" drill bit then attach both to the 02 sensor and then put that into the test pipe and good to go. See this link for the info; https://www.civicforums.com/forums/2...on-w-pics.html

 
Rep Power: 812

most cats on newer cars are almost like a straight pipe. very little backpressure and look at all the 400hp+ cars being sold that have cat converters. you only have a 100hp civic. i doubt you will even notice the difference with or without a cat except you will pollute alot more and possibly feel sick if you breathe in the exhaust too much. and the engine light will be on for no cat.

 
Rep Power: 217

Lol, isn't no BP just as bad as too much?
Don't be inhalin' them fumes. Lol.

 
Rep Power: 313

Yea there is a happy median you want to be at for maximum power. If you want to retain emissions standards but still have a high flow cat I have heard good thing about these:

http://www.dezod.com/pd_random_technology_hiflow.cfm

The price is pretty good too.

 
Rep Power: 217

Crap messed up my edit. Yeah. I just know that some of the people around here with these fart cannons know nothing about it. Lol.

 
Rep Power: 189

yeah i get a kick out of ppl who put a fart can on and call it an exhaust system. Backpressure can help torque and torque is the perceived hp you feel when you leave a light. For instance the older cavaliers z24s with the 3.1 v6 were torque monsters at 189 ft.lbs but sucked at hp 130ish hp, but to the average person they felt like a high hp car, why? simple torque. Hence why some hondas can be high hp but suck on the torque part. There is much research for you to do before start to get a good grip on what really works and what is bull*hit.

 
Rep Power: 812

if you want torque buy a hybrid lol. 200tq at 1rpm (yes 1).

 
Rep Power: 0

Thanks all for the replies

I got the exhaust on
and i went with the straight defouler
ran into some issues
straight defouler stuck 4 inches straight down from testpipe

so I had my friend drill out a angle for it
now its a completely sealed angled defouler and it only cost 5$
ebay exhaust sounds surprisingly good
no rasp at low rpms
no fart canon sound
and bolted in with no problems other than the above

after 70ish miles
the cel came on
reset
stayed off another 40
came back on
reset last night again
and refused to go off at all
still burning bright this morning

had it coded
and it definitely is the 2nd sensor
i am not sure why the defouler is not working
all i can think of is that the o2 sensor isnt heating up as much as it is supposed to so even though its roughly 4-6 inches away from the direct flow of exhaust its still reading to much??

1 other thing
I replaced the fuel filter, in hopes of better mpg
at the same time I did the exhaust
and new struts all around

the car now bogs/hesitates sometimes
it has the power
you can feel the power! ;-)
but almost like clock work if held steady at 20 or 40 (only those 2 so far..??)
when throttle is increased it hesitates, no revs, no fuel, no combustion
just a floppy pedal
once it goes though it goes
it also feels like sometimes when held at a steady speed it cant make its mind up wether to be in 3rd or 4th gear
like going down a hill I can feel it shift up to 4th
and just take off without any change in foot/gas pedal pressure
its kinda scary really if your not ready for it
(the car is not reving high when, before, or after, it does this sneak attack)

i have ran fuel injector cleaner almost bi-monthly
and when I can afford it I fill her up with plus gas and top off with marvel mystery oil

on the plus side
i just cleaned the k&N air filter with my new recharge kit
its that respect demanding bright red again yay!

 
Rep Power: 189

pull your plugs see if any are blackened or whiteish.

 
Rep Power: 200

direct flow of air would send the signal from the sensor to the ecu
but whenever changing exhaust its best to change 02 sensor since
i think brand new sensor are more sensitive to old sensor, since you use a defouler
i still dont understand that idea but anyway
your car bogs and the thing u change was fuel filter
check its connection and check if was put in right hope this help,
new exhaust shouldnt effect the bogging always back trace to what you do to the car and double check it if symptons begin to occur, and like above post said check the plugs

 
Rep Power: 200

oh where i live they check for emissions on obd2 cars
if caught without cat you get a black rejection sticker and if they see u drive around with that ur car gets impounded instantly, and we all want to breath in clean air come on now

 
Rep Power: 0

No emissions where I live, at least not for me. Neither her civic nor my 86 pontiac have cats. The bogging/loss in power has stopped, plugs checked and fine no burning or white, plugs and wires were put on brand new in February this year. Fuel lines checked and are fine. No leaks around the filter.

The loss in low end torque is definite.
Honestly though I think the exhaust is may be to free flowing or big for the little y7. Car has most power above 60mph. Hoping a mini me swap will help. Not opposed to a sohc turbo either, but the girlfriend is.