Deleting the 2 front cats?

[Northpole]

I have been searching here for info on the 2 front cats.
I want to remove all 3 cats on my Mark VIII LSC 1995.
I read here many have removed the 3rd with good results, but what about the
2 cats in front? Is it okay to remove them?
What to do with the O2 sensors?

 

[Right on the Mark]

I thought you read my post about my exh build. Sig ,you should always mention what year your car is, it makes a difference.

 

[87TTOPGT420]

The passengers side can easily be removed drivers side can't it's part of the complete manifold

 

[Northpole]

I thought you read my post about my exh build. Sig ,you should always mention what year your car is, it makes a difference.

Yes sorry about that!! Great stuff, but we are still not sure what to do with the O2 sensors Are they necessary? Or should we weld these on the new pipe like they where on the cats? One trick is to weld the sensors a bit far from the pipe then they were on the cats, (so the space from the sensor will be larger then before). But we dont know how these sensors works, so is this enough?
Or are the front cats not so restrictive as the 3rd? Should I just remove the 3rd...?

 

[chris2523]

o2s are necessary.
1995 is obd1. meaning you can dump the cats without doing anything to the computer. the eec iv / obd1 does not monitor the cats. eec v / obd2 (96+) does.

 

[Northpole]

o2s are necessary.
1995 is obd1. meaning you can dump the cats without doing anything to the computer. the eec iv / obd1 does not monitor the cats. eec v / obd2 (96+) does.

Ok thanks.
So that leaves the O2 sensors left, would it be okay to mont/place them on similar place on the new tube (that replaces the front cat), as they were on the cats? That would not be a problem for us, we just need to know if this will be okay

 

[thaywood]

o2s are necessary.
1995 is obd1. meaning you can dump the cats without doing anything to the computer. the eec iv / obd1 does not monitor the cats. eec v / obd2 (96+) does.

Yep. So if you have a Gen2 and you want to gut or remove the two small cats, you'll have to use a MIL/CEL eliminator or an O2 sensor extender and hope it fools the computer into thinking the car still has cats. But, technically, you won't need to worry about it if you live in a non-emissions county where they don't do the OBD-II inspections. If you get an OBD-II instpection with a CEL, they won't pass it and they'll fine you if you don't fix it within a certain period of time. My sister had this happen with her '02 Jeep GC. O2's were bad and they told her $250 fine if it wasn't fixed within 30 days. Cost her $300 bucks to fix it That's why all my vehicles are registered in a non-OBD-II county I can have CEL's all over the place and give the man $13.10 and drive away

 

[Stangman]

Go buy some mustang MIL's. If you don't wanna buy em, there's sites out there that show you how tobuild them

 

[chris2523]

would it be okay to mont/place them on similar place on the new tube

yes.

 

[chris2523]

Go buy some mustang MIL's. If you don't wanna buy em, there's sites out there that show you how tobuild them

he doesn't need to on this car.

 

[Northpole]

yes.

Thanks!
We will work on the car tomorrow, remove all cats and 2 new Cherry Bomp in.
I am looking forward to try it, and not the least "get a new sound"

 

[zmt325]

you do realize one of the cats is part of the exhaust manifold?... just gut them, take a metal rod and crush all of the ceramic into pieces small enough to remove out the pipe.

 

[Coherent]

Unless you plan on adding headers or doing some major work all you can really do is gut the two upper cats and delete the third. I guess you could also remove one of the upper cats and only have to gut the one attached to the manifold.

 

[beerdog]

Get 2003/4 cobra exhaust manifolds. Then just run straight pipes eliminating the cats. Add an xpipe. Get a tune. Make sure to but the special gasket for the passengers side flange.

You can probably find a set of monisfolds for 50$ at one of the mustang/SVT forums.

Don't waste your time modifying the stock manifolds. Plus the cobra ones flow better.Not as good as Kooks, but better than stock.

According to my computer I am getting at least 15% better milage since eliminating the cats.

 

[warrioralumni08]

Not trying to thread jack, but if I remove my two front cats on my 94, the car wont run like :q:q:q:q since it's obd 1?

 

[SATURN5]

Cats don't have any effect on how the car runs, unless they are plugged....

 

[Stangman]

you do realize one of the cats is part of the exhaust manifold?... just gut them, take a metal rod and crush all of the ceramic into pieces small enough to remove out the pipe.

Problem with that is, you create an expansion chamber that is full of hot air. I did the same thing though. Im going to modify my drivers manifold one day...

 

[Don Pfau]

I thought I remember some folks had problems with the O2's after gutting there cats ??? And a whistling sound ?? But maybe they didn't do a though job ??

 

[chris2523]

Not trying to thread jack, but if I remove my two front cats on my 94, the car wont run like :q:q:q:q since it's obd 1?

you gotta read man!

93-95 is obd1. 96-98 is obd2.

o2s are necessary.
1995 is obd1. meaning you can dump the cats without doing anything to the computer. the eec iv / obd1 does not monitor the cats. eec v / obd2 (96+) does.

it also won't "run like :q:q:q:q" on a gen 2 either. but you will have a code saying the cats aren't working. o2 eliminators or a tune clear that right up.

 

[warrioralumni08]

you gotta read man!

93-95 is obd1. 96-98 is obd2.



it also won't "run like :q:q:q:q" on a gen 2 either. but you will have a code saying the cats aren't working. o2 eliminators or a tune clear that right up.

I can read! Lol, I just want to make sure because I don't want it to bog down or whatever, and run like crap. Will most likely be cutting them off and welding in some pipes, then an x and two mufflers, not sure though. =/

 

[Sapperfire]

Most of the guys that gut cats shove a pipe inside the cat...this eliminates the expansion chamber...and keeps it looking stock incase anyone gets nosey

 

[warrioralumni08]

Most of the guys that gut cats shove a pipe inside the cat...this eliminates the expansion chamber...and keeps it looking stock incase anyone gets nosey

One word...Oklahoma. =] My brothers live in Texas. I believe he gutted his cat, actually cut it apart, and welded it back together, but that didn't sit well with the police? Inspection? Hell, I can't remember, they found out though.

 

[slowmkviii]

Don't just gut them do like sapp said or imo
Just weld new pipes in after cutting off the cats

 

[Northpole]

Update:
We did remove all 3 cats, and mounted some nice Raptors mufflers, great sound and hopefully better fuel eco and perhaps a few hp? We put the O2 sensors back in the same place as before, just now on new pipe, no cats.
When driving from the garage everything was just fine, BUT after few miles, the "Check Engine" light came on
The engine is fine.
After 1 hour at home I did start the engine again, and no "Check Engine" light. I went for a short drive and after 3 minutes drive it came on again... I stopped the engine for few sec and started again, no light, then after 2-3 min drive it came again, etc...
- I have not yet found a error code for this, but will write it here when I have, but again it could be difficult to do as the error only occurs after driving for 3 min...
- Anyone here have an idea what this could be?

I did the same thing on my Audi TT few years ago, I remember we did move the O2 sensors few mm from the pipe until it "fooled" the computer. Can we do the same here, will it work?

Will this error message have any affect on the fuel consumption? I presume the engine will be fine even this light is on?

 

[slowmark95]

Subscribed.

Gutted my third cat a while ago (95 base), want to do the same with front two, but was worried about the check engine light coming on.