So I figured why my truck may run slow and cant pass on the highway. After research I learned that 3" piping might be too big of a diameter for the mods I have. My catback is a 3 inch which I believe may be ok. However when I changed to a 3 inch pipe where the resonator was and did a delete it may have thrown off the velocity. Tomorrow i plan on going to the exhaust shop and telling them to downgrade it to a 2.5 where the resonator pipe used to be. Apparently unless you have a turbo or heavily modded engine there is no need to run a 3 inch where the resonator is. Hopefully this solves the issue.

 

I find it difficult to believe that too big of an exhaust has robbed you of all power. You absolutely have something else going on.

 

Thats literally the only thing i changed. Everything is bone stock

 

Ecoboost or a 5.0?

I'm a bit jaded on sound having always messed with my exhaust system. Also a long time fan of road racing so am used to and enjoy many different engine types. Currently have a 2.7 Ecoboost and have owwned or worked with turbocharged engines since the 1970's. Turbo engine behave different as the turbo's halt any scavenging pulses and like as free flowing an exhaust as can be put on. I use a 4 inch cat back





No resonator just a large steel wool packed straight thru muffler. It is not as loud as you would figure. All in all though there is noy a lot a catback can do for power, it's mostly for sound, but I did get a quicker turbo spool and quicker response. KM

 

5.0

 

I have a Borla system with an aftermarket resonator. 3" the whole way back. Its not horrible, but I could definitely feel some loss of power on the low end as soon as I had it installed.

 

Yeah, i read a few posts about putting the oem size piping back on it where the resonator is and a few people said they had their power back. Only thing that 3 inch is good for is if you have some type of forced induction im assuming.

 

I'm honestly considering putting the stock exhaust back on. It sounds great, but on a long trip it can get annoying and I cant hear my daughter half the time because she's in the back.

 

I also find it hard to think a resi delete and a 3 inch pipe in it's place is lowering torque or HP. Those parts are well past the point of any scavenging to happen. Other things even if you did not alter them may be affecting the perceived loss of power. Is this loss a SOTP feeling? Do you have the ability to document any perceived loss?
Just an example but via my tuning module I monitor exhaust air flow and can make assumptions on power made from that.
3 inch inside diameter dual exhaust is very common on NA and small displacement engines (the 5.0 is considered such). The concept of "back preasure" has been quite thoroughly refuted. KM

 

I have the Corsa Sport on my 3.5 EB. I think it’s 3”. I like it. Zero drone, but plenty of sound when WOT.