Cats removal

[BLKbandit98]

How hard it it taking out the cats on a LS1? Its the passanger side, so its a bolt on peice (i think). Any tools/hardware required? How mechanically inclined must you be? How long will it take?

[Vertiviper]

How hard it it taking out the cats on a LS1? Its the passanger side, so its a bolt on peice (i think). Any tools/hardware required? How mechanically inclined must you be? How long will it take?

Sawsall and some pipe to weld in place really.

[96Firebirdformula]

Well on my lt1 if you take out cats it will throw a code unless get simulator might be same way on ls1

[BLKbandit98]

it looks like its bolted on the passanger side.

[BLKbandit98]

i was gonna ask a shop to do it, but they said $200+ tax

[firemedic0135]

Unless it is clogged you may not want to try it.
I pulled mine the other day and it turned into a 8 hour project.
First I snapped one of the collector flange bolts at the manifold and worked to get it out for about 4 hours until finally giving in and drilling a new hole to place a bolt to secure the flange.
Then when I was tightening the other side I snapped another one off and now have an exhaust leak that is throwing codes and my #2 bank is running at max trying to compensate since it thinks I am lean.
Well now I am waiting on headers and blowing black smoke all over town.
If you have to do it then you will need a 9/16 deep socket and a long extention and a breaker bar or a impact.The 9/16 is a bit small but fits really well with a little tap from a hammer.
spray pb blaster on the studs above and below and let it soak for awhile.
Then get to cranking. if you start to loosen a nut and it gets tight after it has loosened then spray some more lube and work it back on and off or a few turns to free it.
You absolutly cannot rush it or you will snap them things right off and then you will be in the same boat as I am.
I did it to try and see if it would make a diff at the track to try and end the debate and ...well it was just a pain in the ass and I wouldnt reccomend it.
BTW I just gutted mine with an air hammer and didnt replace with pipe as I wanted to keep the apperance of cats.
Hell with em I am getting LT'S

[JL8Jeff]

The nuts that hold the cat-pipe to the manifolds are 15mm but usually are rusted pretty bad. Spray down the studs with PB Blaster for several days ahead of time and hit them with a wire brush to remove the rust. If you don't have an impact gun, you will most likely break a stud. I just did headers and broke one of the driver's side studs but got the other 5 off. Are you looking to replace the cat or just take it out? I wouldn't mess with it unless you have the time to fix broken studs.

[firemedic0135]

The nuts that hold the cat-pipe to the manifolds are 15mm but usually are rusted pretty bad. Spray down the studs with PB Blaster for several days ahead of time and hit them with a wire brush to remove the rust. If you don't have an impact gun, you will most likely break a stud. I just did headers and broke one of the driver's side studs but got the other 5 off. Are you looking to replace the cat or just take it out? I wouldn't mess with it unless you have the time to fix broken studs.

They are 15mm but we only had an impact in 9/16 which is just a fraction small but fits those rusty nuts really well and wont strip off.

BTW did you have any trouble removing your header bolts?

[Firebirdjones]

I was pulling mine off and on replacing them with a gutted pair in about 15 minutes flat. It's very easy to do.

I guess the stud breaking problem is a matter of whether or not you live in a rusty climate. Mine were fine, but the car has never seen salt and rarely gets wet.

When you put it back together use some antiseeze on the threads,,,,works wonders for next time.

[ApexVIII]

Well on my lt1 if you take out cats it will throw a code unless get simulator might be same way on ls1

yea soma on LS1

[JL8Jeff]

They are 15mm but we only had an impact in 9/16 which is just a fraction small but fits those rusty nuts really well and wont strip off.

BTW did you have any trouble removing your header bolts?

The header bolts were fun too. It looks like the factory used some form of loc-tite or glue to hold the bolts in. I had to give most of them a real quick yank on the ratchet. I removed all of the wires and a couple of coils to help avoid smashing my hands too bad. I'm only 5'6" and weigh around 140 so I couldn't get too much leverage with the car up on ramps. I had the old exhaust out in about 3 hours. I couldn't get the EGR bolts loose on the manifold so I bent up the lines and fished the whole manifold down and out with the EGR stuff trailing behind. I wasted a lot of time there alone.

[Firebirdjones]

The header bolts were fun too. It looks like the factory used some form of loc-tite or glue to hold the bolts in. I had to give most of them a real quick yank on the ratchet. I removed all of the wires and a couple of coils to help avoid smashing my hands too bad. I'm only 5'6" and weigh around 140 so I couldn't get too much leverage with the car up on ramps. I had the old exhaust out in about 3 hours. I couldn't get the EGR bolts loose on the manifold so I bent up the lines and fished the whole manifold down and out with the EGR stuff trailing behind. I wasted a lot of time there alone.

Ya I noticed that too when I recently installed my headers. I can't believe GM actually put loctite on bolts that thread into aluminum.
I was never a big fan of that,,,since aluminum is so soft you really risk damaging or pulling out some threads. I never use the stuff on aluminum. I always use antiseeze on aluminum parts to keep the threads somewhat lubricated for long life,,,,expecially on something that may come on and off a few times.