Catalytic Converter Question

[markanthony]

I would not recommend removing all the cats and straight pipein it. You loose low end and over all the performance SUCKS. I went from factory set up getting 14 mph IN TOWN to 9 mph IN TOWN, tranny was constantly shifting out of over drive. Just take out the 4 of them and install 2. one on each side.

Think about this. The OEM (factory) cat's have that different inside material (non honeycomb) that is not easy to push threw. The new off the shelf and on, are a honey comb inside deal that one could see threw it.

Think of a drinking straw. fill it with, say, sand, then try to blow air threw it.. This would a OEM factory cat...
Now take the same straw, (without the sand) and fill it with, say, filter material, and blow threw it. This would be new cats... Honeycomb.
When you buy a new cat. Look threw it. You can see out the other end of it. It's straight threw... Would this not be thought as "high flow" Look at your old stockers and see what you can see threw them.

On mine. I went with some cheep ($100) cats and installed two. One on each side. I have not had any codes, problems, lack of power, loss in milage. Actually. I am now back to 13 to 15 mph IN TOWN. I have not been on the freeway long distance as of yet...

 

[GAINMOB]

idk...i want to do the rear cat delete...dont want to through codes though...are you the one that started the FB page?

 

[2000eb]

this is how mine was explained cats are priced/ categorized however you want to put it by the precious metals in them the frone cats with a 90 degreeisg bend have three precious metals and the rears have two precious metals. magnaflow does not make one with three precious metals so my shop uses catco for those two which are a hi flow cat and magnaflow for the rear two. thats my actual setup. im lookin at removing my magnaflows and do a rear cat delete since my 02 sensors are in the middle. i did notice a power increase as well as noise increase. but i did feel that with how much i have already opened up my exhaust ans lessening my back pressure i have lost a little nottom end but have gained top end mostly notice it when pulling a trailer.

 

[GAINMOB]

so where do the sensors need to be to throw CEL? i want to know so i know if i can do my 04 5.4 EB...

 

[2000eb]

freeway kinda confused by what your saying but i think i understand what your trying to ask. look under your truck at the cats and you will see the o2 sensor going into the pipe most lokely between the two sets of cats on each side. if you look at lets just say the driver side and you see the o2 plug in in between th two cats then you can remove the cat

 

[2000eb]

o and as for the whole little story about as no such thing as a hi flow muffler explain why on my brothers dodge with stock exhaust we pulled off the cat welded in a hi flow magnaflow and the truck rumbled like he actually had a fancy exhaust o and it still passed emissions for the last three years now so even if its not really hi flow cat call it a sounds badass cat that still lasts and keeps you emissions friendly.

 

[GAINMOB]

thx 2000...i'll be checking

 

[2000eb]

ok bad news i have th o2 sensor behind both my cats... i could have swore it was in between the cats so my question is did they re locate my sensors? that sucks i was just lookin under there cause i was checking to see how long they where so i could put pieces of straight pipe in place of the rear cats. but shure as shit i have a sensor then two cats then sensor on each side. i think the different sensor locations may have something to do with carb. because so many expys where built to be able to be sold in cali and so many where not mine has the cali carb bs and was sold in illinois.

 

[Racenut]

ok bad news i have th o2 sensor behind both my cats... i could have swore it was in between the cats so my question is did they re locate my sensors? that sucks i was just lookin under there cause i was checking to see how long they where so i could put pieces of straight pipe in place of the rear cats. but shure as shit i have a sensor then two cats then sensor on each side. i think the different sensor locations may have something to do with carb. because so many expys where built to be able to be sold in cali and so many where not mine has the cali carb bs and was sold in illinois.

That is the same set up that mine has and I have done the rear cat delete. Almost a year now and still NO CEL the only thing that the rear sensor does is make sure that the reading is different from the front.

So as long as you have at least one cat on each bank ( 1 Driver side and 1 Passanger side ) and it is located between the 2 sensors you will be fine.

 

[panda24619]

i HATE the cali CARB bs! but i have to deal with it until i move to zona or some where else.

 

[2000eb]

thx racenut

 

[markanthony]

idk...i want to do the rear cat delete...dont want to through codes though...are you the one that started the FB page?

Yep.. Thats me...

 

[markanthony]

On mine. I have (per bank) one 02 before the cat(s) and one after the cat(s), with two (factory setup) cats.

I tracked down the head ford mechanic at my local dealer that I do trust and have used for year and years and years..... We looked up on the computer their and read that on the 1998 - 2000. the front 45 angle cat had 3 different materials in it. It was made with cheep material to save a buck. It also stated that this cat was just mainly a PRE-BURNING cat. It is not intended to be the main burning cat. The second ( straight ) cat is the main cat and does 60% to 90% of the work. So if one was to remove one of the two cats (per bank) then it would be best to remove the first cat... The issue with this is that this 45 angle cat also has a really odd bend to it and makes it hard to replace with just " store bought " materials. Now. Due to the construction of this said cat. The bend angle on the bottom creates a " road block " for the exhaust to hit. So in other words. The exhaust comes out of the heads, into the manafolds, into the cat and hits the bend. You loose flow inefficiency.

So, with this knowledge. I took out the 45 angle cat and installed a almost 90, then my cat, and out the rest of the exhaust.

I also learned ( while at the dealer reading the computer ) the the 02's, cause the light to come on after a cat replacement cause of the burnt fuel ratio is WAY different then before. 02's are a low volt/pulse machine. They read/convert this gas ratio to current. While running down the road. The 02 will ( in all intense purposes ) remember this reading. If it changes, it throws codes.

So I would also suggest to replace the 02's ( all 4 ) or dip the ends the " smells " the exhaust in some paint thinner / lacor thinner for a short bit to clean out the smeller parts....

If any of that makes any sense.

Just the ramblings of what I found in information and my understandings.

 

[mindgame]

On mine. I have (per bank) one 02 before the cat(s) and one after the cat(s), with two (factory setup) cats.

I tracked down the head ford mechanic at my local dealer that I do trust and have used for year and years and years.....

Thanks for the excellent info!!

 

[Big Red Monster]

On mine. I have (per bank) one 02 before the cat(s) and one after the cat(s), with two (factory setup) cats.


I also learned ( while at the dealer reading the computer ) the the 02's, cause the light to come on after a cat replacement cause of the burnt fuel ratio is WAY different then before. 02's are a low volt/pulse machine. They read/convert this gas ratio to current. While running down the road. The 02 will ( in all intense purposes ) remember this reading. If it changes, it throws codes.

So I would also suggest to replace the 02's ( all 4 ) or dip the ends the " smells " the exhaust in some paint thinner / lacor thinner for a short bit to clean out the smeller parts....

If any of that makes any sense.

Just the ramblings of what I found in information and my understandings.

what if you just disconnect the battery for a few mins wont the sensors re learn the new mixture?

 

[99-4wd]

those anyone have a picture of this set up? 2 of 4 cats removed?

 

[K5rnt]

Here is my 97 f150 I have the exact same setup on my wife's 99 Expy no CEL in almost a year on both.

Notice the O2 in front of the cat and another way back by the y pipe.

 

[99-4wd]

cool pics, thx K5rnt!

 

[99-4wd]

can i do the rear cat delete if the 2nd o2 is in the actual cat?? i think on my truck the rear sensor is actually in the cat

 

[99-4wd]

hey MARKANTHONY, do u have a pic of ur set up??