Jim Mills
Member
So the gen 1 sat for a week and when I started it up I noticed it was running a little rough. I drove it for a few and concluded one of the rear cats was started to get plugged up. I never made any mods to the exhaust and wanted to see what other members hear have done. Keep in mind my 01 has 172k on her now and extra funds are going to be put in the 07. I saw alot of debate over performance, legality and O2 issues and made me curious how the ST would act and if it would trip a code or not by removing the rears.
So I removed them last weekend & replaced with a straight pipe with welded in a bung for the O2. heres my conclusion: I immediately noticed a difference in idle & tone. I have driven it approx 215 miles this week and Im slighlty above 1/2 tank. I dont know the exact results but I believe I may have gotten a slight boost in the mileage (mostly highway) and in spite of popular opinion I have no check engine light on either. I didnt really notice any difference in power but it is a little more responsive. I swear the rpm's seem a little lower at 65mph. Could be its a just a little quieter. Only reason I was curious is because I have always believed the rear O2's were nothing more than emmissions garbage with no real function. I have seen many plugged cats and yet a rear will rarely thow a code. The only purpose of a rear is to signal the computer if its reading starts matching the front, indicating the converter is not functioning properly. In my ST's case I still have the pre cats on so I dont suspect the rear will ever throw a code. Just thought I'd share for those who were curious. If you want a real gain you would need to remove the pre cats. Dont know yet if I'll get that ambitious, but if I do it will be duals with a high flow cat & resonators in each line. someday maybe....
So I removed them last weekend & replaced with a straight pipe with welded in a bung for the O2. heres my conclusion: I immediately noticed a difference in idle & tone. I have driven it approx 215 miles this week and Im slighlty above 1/2 tank. I dont know the exact results but I believe I may have gotten a slight boost in the mileage (mostly highway) and in spite of popular opinion I have no check engine light on either. I didnt really notice any difference in power but it is a little more responsive. I swear the rpm's seem a little lower at 65mph. Could be its a just a little quieter. Only reason I was curious is because I have always believed the rear O2's were nothing more than emmissions garbage with no real function. I have seen many plugged cats and yet a rear will rarely thow a code. The only purpose of a rear is to signal the computer if its reading starts matching the front, indicating the converter is not functioning properly. In my ST's case I still have the pre cats on so I dont suspect the rear will ever throw a code. Just thought I'd share for those who were curious. If you want a real gain you would need to remove the pre cats. Dont know yet if I'll get that ambitious, but if I do it will be duals with a high flow cat & resonators in each line. someday maybe....
