will removing cats on a 99 throw any codes

[ASKYOURWIFE]

Hi guys...Im currently bone stock and putting down 410/465..

im about to order a smooth tube and go catless and then dyno hoping for 425 rwhp and 480 rwt...Can i just have my muffler shop remove the cats and add straight piped or will the 99 throw codes and give me problems?

Thanks for any help. Im planning on doing this in the next few days.

 

[Russ M]

Yes.

You will need O2 sims.

 

[Sam 01 RT10]

You can also have the PCM reprogrammed for a bit more HP, and it will ignore the signal from the rear 02 sensors, so you won't need sims.
My 01 with no cats or mufflers, tubes/filters, and a tune made 435rwhp.

 

[ASKYOURWIFE]

Were can i get 02 sims and how much are they and how easy are they to install as well as the price to install???

 

[mntngts99]

I have a 99, with a Roe, No cats and no codes.

 

[jwbond]

I put down 443/488 w/ headers, intake, and 3" exhaust...cats are still on. I wonder where'd id be with them off.


How loud is the car w/o the cats? Can you compare it to something common I can relate to?

 

[ASKYOURWIFE]

were can i get the 02 sims?

 

[99 R/T 10]

I am the same as mntngts99. 99 with a Roe S/C, no cats and no codes. You shouldn't need them. Give it a try and see what happens

 

[Russ M]

You guys have Vec 2's with your Roe units, which is probably the reason you do not through any codes.

 

[mntngts99]

You guys have Vec 2's with your Roe units, which is probably the reason you do not through any codes.

1999 is a questionable year for simms, from what I've found most do not need them.

 

[Russ M]

You guys have Vec 2's with your Roe units, which is probably the reason you do not through any codes.

1999 is a questionable year for simms, from what I've found most do not need them.

My 99 threw a code 20 mins after removing the cats. I reset it, and another one came up at the next start up and so on.

 

[ASKYOURWIFE]

Well I just went to my friendly muffler shop to remove the cats..But the guy refused to touch the side sills...

Is it hard to remove them or is it pretty much just unbolting the bottom...

any links to pics or a walk through???

thanks. BTW..We located were the sims would go and that seams easy enough. But how about some pricing on the sims?????

 

[ASKYOURWIFE]

Will the ROE simms for $130 do the trick????I just replace them with the existing ones and Im not gonna pull any codes?????

Thanks

 

[Russ M]

ASKYOURWIFE,

The ROE sims should work just fine, but you should really consider having the computer tuned so you pick up even more power for the $500.00 that DC charges. Even if you gain only another 5 rwhp(and you will gain more) the power curve will be much stronger after the tune, and you will not need the O2 sims either.

Installing the sims takes 20mins without a lift.

Removing the side sills is very easy, do it your self in the garage and drive the car to the muffler shop without them its the way I did it to make sure they didnt scratch them.

There are screwes up top 3 I believe, to remove them pop the plastic covers with something flat and be carefull not to scratch the paint. Then there are 2 more screwes on top when you raise the hood, these are very easy to access. Finaly there are a bunch of screws on the bottom take them out. After that the sill should just slide right off, if it does not then you missed something.

PS. When the muffler shop removes the cats make sure they dont damage the insulation(mine did).

PSS. After your done come on here and tell us how much more pleasant the car is to drive without the furnice at your feet, and sills that do not remove skin if you touch them after a 20 min drive.

 

[ASKYOURWIFE]

Ordered the roe simms and roe smooth tubes...Will be doing the cats shortly..

ill post a dyno to see how much i improved over my stock 410/465...

Thanks

 

[Sam 01 RT10]

Russ/Askyourwife- I found a paint scraper works great for popping off the black plastic caps on the side sills without scratching anything.

 

[ASKYOURWIFE]

Thanks a lot....

 

[Hoosier Daddy]

Russ/Askyourwife- I found a paint scraper works great for popping off the black plastic caps on the side sills without scratching anything.

Or two credit cards