exhaust system

stocker 89

Registered User
I recently installed a new stock exhaust system from the head pipe back on my 89 SC . The reason for this was my cat on the driver side would rattle under WOT. The muffler shop told me the cats have clay packs in them that break down over time. Here is my question. Since my old system is still in good condition I was think about cutting into the old cats and gutting them then welding the casing back together and changing the resonator. Has anyone tried this before? Would it cause unwanted back pressure? Would it increase horse power? Would it affect my O2 sensors? Would I want run a strait pipe through the cats ? What is a good up grade for the two mufflers at the rear? This exhaust would only be used on the weekends. I would change back to my stock one for everyday driving. Thanks, DAN
 
You can gut them out and run them everyday for that fact (but your exhaust noise will be louder in the car). Unless you have emisions testing. I know in N.Y. as long as the cat is there it passes inspection. I have gutted out a few of the H pipes on a 5.0 before, no big deal. You will have better flow if you leave on the bigger resinator. I remember reading an article a few years back in MMFF that the gain for an "off road" cat setup is only a gain of about 2 hp. I don't think I would want to change my exhaust every Fri and Sun for 2 horses...Bill
 
Looks like I should just leave well enough alone. The top speed limit around here is 65. The fastest I have ever drove my SC is 125mph (guessing). To bad there is no super highway around here it might be worth doing. Thanks for your input.
 
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