TLEV or LEV-I cat, does it matter?

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Aug 23, 2004
Bay Area, CA
Hey guys,

I posted a while back that my girlfriend's 2001 Mustang needed cats and that her father had fixed it. Looks like he hadn't gotten around to it and we're going up to the house to pick it up in the next few weeks so I'd like to get it fixed at that time. Thankfully I have a spare car for her to use while hers is "down". But I digress...

Looking at Magnaflow's CA-legal cats, it lists two types that will work for her car: a TLEV model and a LEV1/LEV model. I looked in the engine bay for the emission sticker but couldn't locate it (removed/ink burned off?) so I'm not sure which one to buy although the TLEV says "OE Spec".

Thanks for any advice!
It's required for emission testing.

They're both listed as CA legal and none are really more expensive than the other.

I'm just unsure if putting a LEV or TLEV on when the other was installed will have any impact, either on emission testing or performance. That's what I'm trying to figure out.
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You need to be concerned that the cat you have matches the family engine code that's on the emissions sticker.

the cats sold in CA are laser engraved with the family engine codes on it. If the numbers on the cat don't match the engine code on the sticker, it's an auto fail.

Even though it doesn't matter, it's yet another way for california to get cars off the road.
Originally Posted By: Olas
i dont want to sound funny but if you have correct fuelling & ignition you dont need a cat, theyre only a ba.d aid for bad design

Cali inspection not only REQUIRES them, they will be uber-Gestapo about checking to see if they actually are stamped with the correct C.A.R.B. numbers, or else one FAILS, regardless of how 'clean' what ever is coming out of the tailpipe may be.
Sometimes the engine sticker will say "Emission family" followed by a huge string of letters and numbers. If you called Magnaflow, they might be able to decipher those codes and tell you which cat to use.
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