[avalonandl]

Originally Posted by 17camaroSS

Mine gained 24 on the same dyno. Back to back

Was that with NO change in engine tune parameters?

[jaybee924]

Originally Posted by Joshinator99

Until they see no O2 sensors after them...

That's not accurate the system will have 4 o2's just rear tuned out. He He

[oldman]

Originally Posted by Redlinez

For those of us keeping cats, the catted longtubes are a decent gain.

I also think the gain is very wide so it just is not say 18 HP peak with 2" and cats. It is an average of say 12 HP across the entire rev range. So the added power under the curve is significant more than say a CAI.

[Joshinator99]

Originally Posted by jaybee924

That's not accurate the system will have 4 o2's just rear tuned out. He He

When they look at the secondary cats and see no O2 sensors after them, any competent inspector would know something is up. This is assuming the primary cats are gone as the previous poster suggested.

[jaybee924]

Originally Posted by Joshinator99

When they look at the secondary cats and see no O2 sensors after them, any competent inspector would know something is up. This is assuming the primary cats are gone as the previous poster suggested.

The o2's are before the secondary cats. I would be keeping the secondary cats. On Ca performance pipes, one pipe has 2 and the other has one but on that side before the secondary cat the stock system side has the second o2 hole. I'm talking about the CA performance cat deletes. Now you maybe thinking of the New Era Performance cat deletes. I know what I'm doing with the CA performance cat deletes. You can research if still in doubt.

[Joshinator99]

Originally Posted by jaybee924

The o2's are before the secondary cats. I would be keeping the secondary cats. On Ca performance pipes, one pipe has 2 and the other has one but on that side before the secondary cat the stock system side has the second o2 hole. I'm talking about the CA performance cat deletes. Now you maybe thinking of the New Era Performance cat deletes. I know what I'm doing with the CA performance cat deletes. You can research if still in doubt.

Correct... and you will have NO O2 sensors AFTER the secondary cats. Which is a dead giveaway to anyone with a clue. Will you get away with it anyway? Probably.

[Redlinez]

Originally Posted by oldman

I also think the gain is very wide so it just is not say 18 HP peak with 2" and cats. It is an average of say 12 HP across the entire rev range. So the added power under the curve is significant more than say a CAI.

As many like to say, it's a cumulative effort as well. I didn't do one mod at a time and redyno every time. Ideally, that would be cool, but don't have the time or extra money. I had Pray port my 95mm, stock IM, install E85 sensor, catted TS longtubes and tune all in one visit. The change was pretty awesome. Some would say "only 50rwhp??". That like you said isn't the only important factor like many get hung up on. Same way some shops are famous for peak RWHP, but not "fast or quick" cars. I would feel a huge difference from 3000 rpms up.

[oldman]

Originally Posted by Redlinez

As many like to say, it's a cumulative effort as well. I didn't do one mod at a time and redyno every time. Ideally, that would be cool, but don't have the time or extra money. I had Pray port my 95mm, stock IM, install E85 sensor, catted TS longtubes and tune all in one visit. The change was pretty awesome. Some would say "only 50rwhp??". That like you said isn't the only important factor like many get hung up on. Same way some shops are famous for peak RWHP, but not "fast or quick" cars. I would feel a huge difference from 3000 rpms up.

[s346k]

the gains are from the tune. i've seen first hand what adding headers with no tune does.

[enzia35]

And what does no tune headers do?

[s346k]

Originally Posted by enzia35

And what does no tune headers do?

nothing. my car, when stock, was door to door with the other 1LE. at the track my car was quicker and faster than an a8 car with headers and no tune.

edit: both cars also had a cai setup on them, as well.

[Redlinez]

I gained about 3 peak with the rotofab last week on my 2020 SS. No tune and it ran richer. Waiting for a tune when I have the money for ported 95 and IM and/or E85.

[Redline_2ss]

Originally Posted by s346k

nothing. my car, when stock, was door to door with the other 1LE. at the track my car was quicker and faster than an a8 car with headers and no tune.

edit: both cars also had a cai setup on them, as well.

See this confuses me more🙃 people saying 35 whp in other threads and then there's people saying no gains here. And other people saying 20+whp I guess I'll just find out when I put em on

[Booher]

They are saying headers with no tune has no gains. You need to tune the car to benefit from putting headers on, and it isnt 35hp on an ss. Ive heard 10-15 from headers and 5 hp for each cat delete. I don't have proof as I have high flow cats and did multiple parts at once as its the most cost efficient.