Costly Mistake? Please Help
Thread Starter
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Joined: Jan 2003
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Costly Mistake? Please Help Well since I've heard of people gutting their cats or replacing them with straight pipe, I thought it would be a good idea for slight performance and different sound.
I replaced my cats with the mufflex kit. When I started the car right after the install, there was smoke and it was running rich (obviously due to the computer being confused and there were no longer any cats). On the drive home the smoke went away and the SES light never came on.
Now here is my concern. Do I have enough back pressure to prevent any damage from occuring? i.e. swallowing a valve or f*ckin anything up internally?
I also plan on dyno tuning to fix A/F ratio. The reason I replaced the cats to begin with was because they were rattling like rocks. Do I need to go back and tear out all my work and just buy new cats? Can this be fixed by dyno tuning to advance the timing? What should I do? Thanks for the help.
I replaced my cats with the mufflex kit. When I started the car right after the install, there was smoke and it was running rich (obviously due to the computer being confused and there were no longer any cats). On the drive home the smoke went away and the SES light never came on.
Now here is my concern. Do I have enough back pressure to prevent any damage from occuring? i.e. swallowing a valve or f*ckin anything up internally?
I also plan on dyno tuning to fix A/F ratio. The reason I replaced the cats to begin with was because they were rattling like rocks. Do I need to go back and tear out all my work and just buy new cats? Can this be fixed by dyno tuning to advance the timing? What should I do? Thanks for the help.
Originally Posted by Rice Burner
Well since I've heard of people gutting their cats or replacing them with straight pipe, I thought it would be a good idea for slight performance and different sound.
I replaced my cats with the mufflex kit. When I started the car right after the install, there was smoke and it was running rich (obviously due to the computer being confused and there were no longer any cats). On the drive home the smoke went away and the SES light never came on.
Now here is my concern. Do I have enough back pressure to prevent any damage from occuring? i.e. swallowing a valve or f*ckin anything up internally?
I also plan on dyno tuning to fix A/F ratio. The reason I replaced the cats to begin with was because they were rattling like rocks. Do I need to go back and tear out all my work and just buy new cats? Can this be fixed by dyno tuning to advance the timing? What should I do? Thanks for the help.
I replaced my cats with the mufflex kit. When I started the car right after the install, there was smoke and it was running rich (obviously due to the computer being confused and there were no longer any cats). On the drive home the smoke went away and the SES light never came on.
Now here is my concern. Do I have enough back pressure to prevent any damage from occuring? i.e. swallowing a valve or f*ckin anything up internally?
I also plan on dyno tuning to fix A/F ratio. The reason I replaced the cats to begin with was because they were rattling like rocks. Do I need to go back and tear out all my work and just buy new cats? Can this be fixed by dyno tuning to advance the timing? What should I do? Thanks for the help.
Originally Posted by Rice Burner
Thanks a lot. How should I drive the car before I get it tuned? I haven't taken it past 2500 rpms yet because I am worried I will mess up the valves as mentioned earlier? Thanks again.
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if u have sims dont worry nothing will mess up i have no cats and gmmg and my friend has no cats and loudmouth, both those cat backs flow real good and our cars are running great. id rather be rich than lean but just takin the cats off wont be bad. i did the same and just took off the cats with the same pipes, yeah the air fuel was off a little bit just cause the cyl can fire a lot better now wiht fresh air and gas. just get it all tuned right and like said before, enjoy 
what cat back do u have?
what cat back do u have? Thread Starter
TECH Regular
Joined: Jan 2003
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when you gutted your cats did you put O2 sims in the rear??
if u have sims dont worry nothing will mess up i have no cats and gmmg and my friend has no cats and loudmouth, both those cat backs flow real good and our cars are running great. id rather be rich than lean but just takin the cats off wont be bad. i did the same and just took off the cats with the same pipes, yeah the air fuel was off a little bit just cause the cyl can fire a lot better now wiht fresh air and gas. just get it all tuned right and like said before, enjoy what cat back do u have?
Thread Starter
TECH Regular
Joined: Jan 2003
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With just a off road y pipe you dont need to have it tuned but you have to get O2 sims? Do you have them?
tuning will be good either way. but i got the same pipe u have right before i got headers i know what your talkin about. i used my predator to monitor things but nothing was so far off to be concerned. u can bring those rpms up if you want
Joined: Nov 2001
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From: Schiller Park, ILL Member: #317
Originally Posted by Rice Burner
Thanks a lot. How should I drive the car before I get it tuned? I haven't taken it past 2500 rpms yet because I am worried I will mess up the valves as mentioned earlier? Thanks again.
Tuning is not even close to 'required' for cat removal. O2 sims will take care of the SES light that you'll eventually get without the cats (or tuning can take care of it too if you go that route).....
