Over the summer I ended up with a carven catback that was 3 in and 3 out. I lost low end torque. After research I learned that staying at 2.5 on the piping I would have not felt and difference. Now I see the borla catback which is 3 in and 2.25 out. Anyone with the borla catback have a low end torque loss or do the tires screech like it did before? I've learned that this is definitely not a sound only mod, but if you go too big on piping of a N/A truck you will notice a loss of torque. Hence why I'm thinking 3 in and 3 out hurt my performance and debating if 3 in and 2.25 out will make it back normal.

 

How did you check this? Please don't tell us by "feel."

You also are not stating what you are dfriving and what engine you 'lost' torque on.

 

5.0

Yeah, I definitely did. Before I had the exhaust put on, I could easily overtake a slow moving vehicle. After the exhaust was put on it takes forever to overtake a slow vehicle and it just makes noise and doesn't pull when I hit the gas pedal. No other mods.

 

Same boat with my 5.0 and Borla S Type. I could feel it immediately. I've often thought about going back to stock.

 

Well this pretty much answered my question. Specifically our trucks need to be 2.5 in and 2.5 out on the pipes. If we had any type of forced induction 3 in would be the way to go.

 

If this is true, I don't think it's due to your catback being 3" instead of 2.5".

I didn't have any issues overtaking with my 3" catback and OEM tires and don't have any issues overtaking with the same catback and 35s.

 

Interesting. Maybe my exhaust needs to be checked then. Because for a V8 truck it literally does nothing when I put smash my foot on the pedal it just makes noise and doesn't move. You have borla right? I read on their site they run 2.25 out and carven has 3 inches out.

 

A speed density system needs a retune any time you change engine airflow characteristics, otherwise you'll probably lose power.

 

My 2021 %.0 had a Borla Touring, couldn't tell a difference.

 

That doesn't sound right at all. I'm not disagreeing with losing some torque due to less back pressure but the 5.0 still winds out as it always has.

I have the Pypes Race Pro which is 3" all the way through.