Do I need a different tune after doing new exhaust?

Halfton_z71 · Feb 22, 2026

Hey guys, I just installed a cat back exhaust with a flowmaster super 10 muffler. Will this throw off anything with the computer? Would a different tune be necessary? I know there’s no sensors after the o2 near the cat but would the lack of back pressure change anything? Thanks!

99Sierra2500 · Feb 22, 2026

Might not need it, though probably could benefit from one.

ORVietVet · Feb 22, 2026

No need for a tune unless you just have an itch to spend money. Use Black Bear performance, if you do. Also, contact them and they will advise if needed or you will notice the benefit if you do. If you do a tune, you may want to mess with other settings and wake up the engine.

Halfton_z71 · Feb 22, 2026

ORVietVet said:
No need for a tune unless you just have an itch to spend money. Use Black Bear performance, if you do. Also, contact them and they will advise if needed or you will notice the benefit if you do. If you do a tune, you may want to mess with other settings and wake up the engine.

Thanks! I'll have to look into that.

Marky Dissod · Feb 23, 2026

Halfton_z71 said:
... just installed a cat back exhaust ... Will this throw off anything with the computer? Would a different tune be necessary?
I know there’s no sensors after the o2 near the cat, but would the lack of back pressure change anything?

If the exhaust system improves SCAVENGING
('back pressure'? In 2026, people still say 'back pressure'?)
improves SCAVENGING at or under 3000RpM - if it improves part-throttle Volumetric Efficiency - then yes, a tune based off of realtime driving data would be advised.

Long story short, if MpGs get worse, then you'd better get a tune where you send driving info back to the tuner (avoid mere mail order or canned/plug-in tunes),
so that the tune can be refined specifically to recoup those MpGs.

If the exhaust system improves MpG all by itself, congrats.