Eliminating Catalytic Converter & going w/straight pipe
October-31st-2002, 07:40 PM
#1
Protege Newbie
Thread Starter
Join Date: Feb 2002
Posts: 24
Eliminating Catalytic Converter & going w/straight pipe
hey guys,
need yer help!
wanna take out my very "OLD" catalytic convert and switch to straight pipes... what things should i take into consideration?
since i don't have the equipment, i called a local muffler shop and they said they wouldn't do it cuz it'll mess up my computer chip. I was thinking in my head WELL can't you just do it anyway i'll pay you foo... the guy just wanted to get rid of me looks like.
What's the worst thing that could happen? gain in horse power? louder exhaust? My car's got over 140,000+ on it already and I am the third owner of it. I get enough exhaust sputting problems while accelerating, which i use redline to get rid of, but it seems that the catalytic convert or something is restricting the exhaust flow.
thanks!
need yer help!
wanna take out my very "OLD" catalytic convert and switch to straight pipes... what things should i take into consideration?
since i don't have the equipment, i called a local muffler shop and they said they wouldn't do it cuz it'll mess up my computer chip. I was thinking in my head WELL can't you just do it anyway i'll pay you foo... the guy just wanted to get rid of me looks like.
What's the worst thing that could happen? gain in horse power? louder exhaust? My car's got over 140,000+ on it already and I am the third owner of it. I get enough exhaust sputting problems while accelerating, which i use redline to get rid of, but it seems that the catalytic convert or something is restricting the exhaust flow.
thanks!
Last edited by tronic; October-31st-2002 at 07:48 PM.
November-1st-2002, 12:12 AM
#2
Registered User
Join Date: Nov 2001
Location: Somewhere near the yellow brick road...
Posts: 176
Consider getting a new engine if you keep straight pipes on it very long. Not a good idea! You will be seriously straining your engine with such a free flow set up. Turbo'd cars benefit from this, but N/A cars need the back pressure.
There are many others on this board with 200k+ miles on their stock cats...I have 160K+ on my stock cat, I think your sputtering problems are from other issues.
November-5th-2002, 05:16 PM
#5
Protege Enthusiast
Join Date: Apr 2002
Location: san antonio,texas
Posts: 95
whut?
i drive with a straight pipe. The only strain i could feel on my engine was before i installed my short ram intake and cone filter. The engine seemed to run less harder at highway speeds. aside from the backfires on downshifting i like my setup for a daily driver. BTW i have a 175,000 miles on my car.
November-6th-2002, 03:16 AM
#6
Registered User
Join Date: Jul 2002
Location: Davenport, IA
Posts: 120
Replacing your cat with straight pipe will not harm your engine. You can have straight pipe coming all the way from the manifold to the exhaust tip and it will create enough backpressure for your engine, even if you go with 2 1/4" piping. You'll gain slight hp towards the end of your powerband. If you put on the RX-7 VAF, it will be noticable.
November-11th-2002, 01:00 PM
#9
Registered User
Join Date: Nov 2001
Location: Somewhere near the yellow brick road...
Posts: 176
Originally posted by RX7_2ner
Replacing your cat with straight pipe will not harm your engine. You can have straight pipe coming all the way from the manifold to the exhaust tip and it will create enough backpressure for your engine, even if you go with 2 1/4" piping. You'll gain slight hp towards the end of your powerband. If you put on the RX-7 VAF, it will be noticable.
Replacing your cat with straight pipe will not harm your engine. You can have straight pipe coming all the way from the manifold to the exhaust tip and it will create enough backpressure for your engine, even if you go with 2 1/4" piping. You'll gain slight hp towards the end of your powerband. If you put on the RX-7 VAF, it will be noticable.
Some cars have multiple O2 sensors such as my Z32 which has 4 all together, 1 in each manifold and 1 before each cat. In that sense it will mess with the ECM causing the car to run much richer...hence the sulfer smell.
In regards to straight pipe not harming the engine...I think everyone would agree that any mod which causes the engine to backfire is harmful.
This is my 2 cents, I'm speaking from experience...Been there done that, just don't want any other newbies to go through multiple exhaust systems like I did.Being load doesn't make you fast, unless you drive a Honda. I kept my cat on my car cause I'm a "Rice-ist"
November-12th-2002, 08:18 AM
#10
Registered User
Join Date: Jul 2002
Location: Normal, Illinois
Posts: 34
no cat. take it out. im running 2.25 all the way back and have been for about 6 months now with no issues yet. and as RX7_2ner said, there is only one O2 sensor and it's in the manifold, no sensors in or after the cat.
November-12th-2002, 10:31 AM
#11
Registered User
Join Date: Nov 2001
Location: Somewhere near the yellow brick road...
Posts: 176
Originally posted by 90&00 Protege
Granted, a 1st gen Protege doesn't have OBD II, so no O2 sensor after the catalytic converter, but, normally aspirated 4-cylinder motors will loose low-end torque if they don't have back-pressure, so you're best bet is to remove your plugged cat and install a high-flow one. Then you've got the best of both worlds...enough back pressure to still have low-end torque and enough free-flow for high-end power.
Granted, a 1st gen Protege doesn't have OBD II, so no O2 sensor after the catalytic converter, but, normally aspirated 4-cylinder motors will loose low-end torque if they don't have back-pressure, so you're best bet is to remove your plugged cat and install a high-flow one. Then you've got the best of both worlds...enough back pressure to still have low-end torque and enough free-flow for high-end power.
Holy Crap man...You and Protege Menace are post ******! 
I joined the forum a month after you and look how many post I've got 
Can I have some of yours?
(semmy-post whoring)
November-12th-2002, 04:48 PM
#13
Registered User
Join Date: Jul 2002
Location: Normal, Illinois
Posts: 34
Originally posted by 90&00 Protege
Granted, a 1st gen Protege doesn't have OBD II, so no O2 sensor after the catalytic converter, but, normally aspirated 4-cylinder motors will loose low-end torque if they don't have back-pressure, so you're best bet is to remove your plugged cat and install a high-flow one. Then you've got the best of both worlds...enough back pressure to still have low-end torque and enough free-flow for high-end power.
Granted, a 1st gen Protege doesn't have OBD II, so no O2 sensor after the catalytic converter, but, normally aspirated 4-cylinder motors will loose low-end torque if they don't have back-pressure, so you're best bet is to remove your plugged cat and install a high-flow one. Then you've got the best of both worlds...enough back pressure to still have low-end torque and enough free-flow for high-end power.
November-18th-2002, 12:10 AM
#14
Protege Newbie
Join Date: Nov 2002
Location: na
Posts: 42
glass pack
when I had my sohc head I used no cats and straight pipe w/echo changer.but for low end and high end I had to put a glass pack where the cats were it will work trust me this added at leats 10 ponies with a cone filter.
November-8th-2019, 02:52 AM
#15
Registered User
Join Date: Nov 2019
Posts: 1