# Cut off cats...More MPG's!



## AlanSr (Jan 4, 2008)

I cut my cats off about 2 weeks ago just for the sound (and it sounds awesome!). But what I didn't expect is my MPG's went from 16.3 to 17.6 with a mixture of HW and city. 
I haven't even retuned it yet with the diablo......

Reg'ed in Florida so I don't have emissionsarty:


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## Poncho Dan (Jun 30, 2009)

I always thought that would be the most noticeable effect from losing the catalytic converter in a given car... better MPGs. I wonder if the so-called high flow cats offer the same.

My dad went full "test pipe" in his 91 Ford Festiva and consistently got 48mpg highway afterwards.


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## Mike_V (Mar 10, 2006)

Is that a fact, and if so, why?


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## johni53 (Feb 10, 2010)

AlanSr said:


> I cut my cats off about 2 weeks ago just for the sound (and it sounds awesome!). But what I didn't expect is my MPG's went from 16.3 to 17.6 with a mixture of HW and city.
> I haven't even retuned it yet with the diablo......
> 
> Reg'ed in Florida so I don't have emissionsarty:


Too bad I'm in Texas, would be nice to get better mpg and a cool sound by removing something instead of buying something but we have emissions tests as part of our yearly vehicle inspection.


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## YellO5LS2 (Jan 9, 2011)

I removed the CAT on my 94 Z28. No issue with the O2 sensors since all are in front of the CAT. MPGs instantly went from 23 highway to round 24 +. Smells like a lawn mower though, so it's obvious when they're gone. 

I wanna do the same to the GTO but I'm worried cause I'm not a professional tuner and worry about messing up the ECM and throwing a code if i remove the CATS or get high flows


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