sgtdestruction

iTrader: (1)

Purchasing some new magnaflow high flow cats this weekend, but have a question about the O2 sensors. Should I keep the originals, or spring for new? V1 has only 40k miles on original cats/O2's.

Thoughts?

Vness

I kept one and replaced the other only because i could not get it off without destroying it. Have not had a problem

DMM

It doesn't matter, you're going to have to get the Cat efficiency DTC's turned off after you remove the OE Cat converters anyhow...or the check engine light will turn on.

Probably better off getting tuning pipes than having the converters that do not satisfy the emissions performance criteria anyhow.

sgtdestruction

iTrader: (1)

Unfortunately, my state requires emissions test, so I have to keep cats on. However, what do you mean by having converters that do not satisfy emissions criteria? Have you had experiences with the magnaflow high flow cats where they were not up to par for emissions tests?

Dmax/04V

Tenessee has emmisions testing?

sgtdestruction

iTrader: (1)

Suprisingly...yes...but an hour north in KY does not! Fail.

DMM

The aftermarket Cat converters will most likely NOT meet the performance criteria to satisfy the P0420/430 Catalyst efficiency DTC (diag trouble code). So, they would have to be set to "No Error Reported" via tuning software.

Does your state simply do a visual insp. and rely upon the OBD II software to verify correct operation as most jurisdictions? If your state uses a tail pipe sniffer, you're very likely to fail.

One of the reasons that aftermarket catalytic converters do not satisfy the performance criteria is that a catalytic converter is designed to "store" a specified amount of oxygen, which is directly related to size.

Dmax/04V

Next we'll have EU like safety inspections as well. Ridiculous I say.

sgtdestruction

iTrader: (1)

So it would probably be prudent to have the car tuned afterwards and have these codes set to no error.

Pretty sure they do tailpipe and possibly visual...as I have seen some cars get visual done, but always tailpipe.

So I am wondering if it would be worth it to just keep my stockers for the once a year check. 2-3 hours of work once a year never killed anyone...yet!

sgtdestruction

iTrader: (1)

This is really what I was looking for...so as long as I don't f them up in the uninstall, they should be fine to use.

sgtdestruction

iTrader: (1)

Thanks VNess and DMM...really appreciate the info. Helps me get one more step to where I am going.

isis

iTrader: (1)

Has anyone tried using the spark plug non foulers spacer to keep the codes off? It works on a lot of cars.

Blackpanther99

iTrader: (8)

Magnaflow high flow cats should be emissions legal. Alot of performance shops out there use Magnaflow's over stocks and have no problems.

54inches

iTrader: (4)

I have the SLP High Flow Cats on my V and they immediately threw codes, but would alternate sides and would turn off and then back on.

I had the rear cats tuned out by my tuner and have no issues now.

I left everything installed for visual inspection.

Dmax/04V

If you intend to swap the headers out for inspections I would invest in some arp header studs, will make your life ten times easier when you go to swap. Never have to worry about broken bolts in the heads.

54inches

iTrader: (4)

Sounds obvious, but do you have them on yours?

DACTARI

iTrader: (1)

Why not use clamps fore and aft to enable swapping in the stock cats and hi flow cats?

GT racer

I've heard that KOOKS ( the header folks) has a cat known as the GESI cat that robs zero horsepower, is totally emissions legal and doesn't throw any codes.

DACTARI

iTrader: (1)

Actually if you go that route you might as well go catless with a stretch of clamped pipe then swap in cats for inspection.

54inches

iTrader: (4)

I am not sure why go to all of the trouble, when you can have the car tuned and have the rear cats turned off and leave everything installed and not get haseled.

And modern day cats do not "rob" any power per say. Especially High Flow stuff.

Robbing power is of the older type cats.