Primary cat delete, factory exhaust intact?

Hi guys. Been thinking of deleting the primary cats and replacing it with a custom straight pipe or the one that PowerCraft offers, while keeping the stock exhaust but getting the factory software upgrade.

 

Was wondering if the secondary cats in the factory muffler would suffice in terms of keeping the fuel smell low, as some decatted cars tend to have after removing the cats.

 

Curious about the sound it should produce, how it affects back pressure, loss or gain of HP/TQ, CELs, etc.

 

Need your opinions and experience please.

 

-James

Just an update,

 

Got the custom cat deletes done this afternoon and instead of getting the exhaust software update, just decided to plug up the valve for now.

 

I think it sounds amazing and I am happy with the results. It sounds similar to a typical de-valved exhaust, but it's a little bit louder and gets pretty raspy and higher pitched in the higher RPM range. During deceleration it pops and rumbles. When it idles it kind of reminds me of of a muscle car with the loping and burble, but more high strung especially with the valvetrain noise. Got one CEL so far, but it was gone after I started her up later on. Throttle response is good, but feels "light and airy" if that makes sense, being that it seems like it climbs up faster in the RPM. If I decide to go louder I my consider the tube only exhaust from Tubi.

the exhaust note is kinda high pitched too, but the drone is awful

the exhaust note is kinda high pitched too, but the drone is awful

Hi Roy,

 

That was a first concern for me, so what my fabricator did was taper off a small area about halfway through and basically bottlenecked it. Honestly the drone or lower end frequency while at idle sounds like a normal devalved exhaust, only slightly louder.

 

Although what I noticed during super hard accelerations in the tunnel it gets really high pitched after driving around for a few hours, like those old Murcies with aftermarket exhausts, and trust me that is not a complaint!!

Excellent stuff, please keep the thread updated with your thoughts over time and any issues.

 

How much work was it to get at the cats to remove them?

Excellent stuff, please keep the thread updated with your thoughts over time and any issues.

 

How much work was it to get at the cats to remove them?

Hi Topjay,

 

It was more time consuming then anything. I believe they mostly used a plasma cutter so a steady patient hand was needed. They dismantled the rear end the night before, and by the afternoon next day they had it patched up and ready to go.