Can anyone tell me the pros and cons of replacing my factory cats with high flow cats? Im currently running a Flowmaster 40 series on my 4.0 Explorer but still looking for more power. Are High flows the way to go? Thanks.

 

If you HAVE to run cats the high-flow ones are the way to go. Less restriction=more power/gas milage.

 

How will this effect the sound? And are they still emmissions legal?

 

Somewhat louder. Mine passed the IM 240 emission test here in CT. They look under the vehicle with a mirror to inspect. Not a big power gain unless the originals are plugging but it is noticeable.
Mark

 

The high-flow should pass an inspection just fine. I put one on mine, but still have 1 stock cat. It's a 3" in and 3" out from summit, 80 bucks. Catco brand. Good cat, no problems but I didnt see much for a power improvement even though I know it flows better. 5-10hp is hard to feel so i'm sure it's just my judgement. The 1st cat is probably alil plugged anyway. There are no cons that I can see.


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95' F-150 XLT 4x4, 302, 5 spd, MSD 6A, Flowmaster Exhaust, Sunroof, Clear corners w/ Diamond headlights, CD player with 2 10" subs and some 32" BFG Muds .

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Justin - One Happy FTE Member