removing the cats

[gblue]

Aloha..we have no emmissions controls here in Hawaii...what happens when I remove the catalytic converters...I see an 02 sensor...any issues with that? Do I have an onboard computer with check engine light??
   
   Mahalo...Gregg Blue..1987 Mark iv

[C9OBY]

Aloha Gregg
   
   I took mine off and had no problems (aside from the car going a little faster!)
   
   The trick is to have them cut off after the 02 sensors.  On mine, the sensor is on the first bend of the pipe, hence the first practical cutting point (on a straight section) is already past the sensors.  This way, the sensors remain in place, enabling your EFI unit to continue working as normal.
   
   Good luck
   Bruce

[gblue]

thanks.
   I removed the cats from another car and the sensors somehow read a difference in oxygen content without the cats.....that sent my check engine light on permanantly.....I assume the sensors won't do it in this case because there is no check engine light...........if an 02 sensor goes bad how would I know?
   
   Gregg

[jbottini]

gblue, am I mistaken or isn't the check engine light at 7 oclock in the round indicator over the steering hub? Let me know how you make out, the cats are next on my list as well. Do you still have the big nut wrench for sale?JBottini

[nikbj68]

quote:Originally posted by gblue
   
....if an 02 sensor goes bad how would I know?
   Gregg
   

   When the O2 Sensor went on my daily driver, I noticed a large hole in my wallet! Fuel consumption went from 35mpg to 12!!!!
   [:0]
   I wouldn`t mind 12mpg in a 300bhp Cob, but not a 2.2l Honda Accord!

[jbottini]

Checked AK1113 yesterday and GBLUE....no check engine light. You should be ok, but you need a little back pressure to scavenge exhaust and make low end torque as I understand it.

[gblue]

aloha and thanks for all the info...think I'll take my car down to my friend at Midas and have them removed....and save them in my garage..........gregg

[Emmanueld]

Removing your Cats is not a cool thing to do, it is also illegal. With most modern engines the increase in power is negligible.
   
   Emmanuel

[Jan_AC_MKIV_1227]

come on, it is cool, it does allow engines to increase performance, the sound is awesome !!!

[cobham cobra]

A cat is not fitted to an engine to improve it's performance, therefore why retain it if you don't have to? The cats have been off of my '91 MkIV for the last 10,000 miles. The engine breathes a little better and there is a small improvement in performance. There is other stuff on the car, such as the air pump, that can be removed if your local car emission laws allow. The standard engine powers a pump to add fresh air into the exhaust in order to help meet emissions regulations. Of course no one mentions that the engine consumes a little more fuel to power the pump in the first place. I have also removed the small back boxes from the exhaust system, I now get about 24 mpg from the engine and it's not so asthmatic.

[Emmanueld]

Why would you want to become a gross polluter just for "a small improvement in performance" this is silly! Also, I hate to drive a car which stinks when you stop at a red light. So now your MKIV will have 185hp instead of 180! []

[ak1234]

Emmanueld ... your car has CATS So your a gross polluter like the rest of us
   
   Man you got all the answers ... 185 hp ... at which wheel ?? LOL
   
   Ron

[Jan_AC_MKIV_1227]

my air pump is gone as well and since my car has a Roush motor, I have a bit more than 185 HP,  more like 325, combined with the weight, the car moves just fine.
   
   Emmanuel, stay on the Frua board...

[cobham cobra]

Emmanuel, for a long time I have tried to avoid topics you are involved in because of your unpleasant and inappropriate interaction with other contributors, but I have two points to make.
   
   1) If you have such strong concerns about the environment, why do you take such pride in driving at least two cars with very large engines? Surely a hybrid car would be more appropriate?
   
   2) I value the input and discussions on the ACOC forum and was very pleased when you moved to the Frua section. I'm sure many of us are interested in the great work you are doing on your car, particularly your determination and attention to detail with the rebuild of your Frua. It is just unfortunate that your style of writing is so opinionated, intolerant and dismissive of any other person's opinion. Your argumentative style is more appropriate to a blog site than a community of like-minded enthusiasts.
   
   If I have offended anyone (other than Emmanuel) I apologize.
   John.

[Mark IV]

quote:Originally posted by Emmanueld
   
Why would you want to become a gross polluter just for "a small improvement in performance" this is silly! Also, I hate to drive a car which stinks when you stop at a red light. So now your MKIV will have 185hp instead of 180! []
   

   
   And you think cats remove odor? Cats are the cause
   of the "sulfer" odor when the ratio is not right.
   
   But I defer to your posistion as final arbiter of all things automotive! It seems you have all the answers and of course, you do not like MK IVs as they are "not ACs" and have "no performance", etc.
   
   Sorry I spoke, will you forgive me Father?