[Bomis]

Hi!

Will it do any hp gains if i deleted the 2nd cats or is it just for the nice sound?

Im driving ar catted dp's.....

Thanks

Michael

[luca335i]

You might gain a few horses. On the stock exhaust I have no idea how much. It might be more beneficial to get a catback exhaust. The piping, and the weight are other restricting factors of the stock exhaust. On a catback you'll gain 8-10 whp and maybe more with a tune.

[ohaywood]

Originally Posted by luca335i

You might gain a few horses. On the stock exhaust I have no idea how much. It might be more beneficial to get a catback exhaust. The piping, and the weight are other restricting factors of the stock exhaust. On a catback you'll gain 8-10 whp and maybe more with a tune.

+1 I put a Gintani system on my car with no secondary cats and the biggest difference was probably in the weight. Try picking up that stock exhaust from the cats back and then pick up a straight tube from a cat-delete system and you'll be amazed at the difference.

[Zeph]

Originally Posted by luca335i

You might gain a few horses. On the stock exhaust I have no idea how much. It might be more beneficial to get a catback exhaust. The piping, and the weight are other restricting factors of the stock exhaust. On a catback you'll gain 8-10 whp and maybe more with a tune.

He wanted to delete the 2ndary cats, so he would need a DP-back system. Catback bolts up to the stock cats and doesn't replace them.

[edo]

I'm planning of getting rid of secondary cats. I have catless downpipes installed.

I did a lot of searching and decided to cut out secondary cats and weld in resonators. Why? Because I don't want it to be too loud and I definitely don't want any drone or rasp, which is quite usual with no cats and aftermarket catback.

Main "power killers" are the cats. Biggest gains are from catless downpipes, then secondary cat delete.
Stocl catback does't have that much restriction and you loose just several hp compared to an aftermarket catback.
Plus it's at least 10 times cheaper. Not that I care much about it, but still.

[Bomis]

Originally Posted by luca335i

You might gain a few horses. On the stock exhaust I have no idea how much. It might be more beneficial to get a catback exhaust. The piping, and the weight are other restricting factors of the stock exhaust. On a catback you'll gain 8-10 whp and maybe more with a tune.

I already have the bastuck exhaust.....if that helps anything...

[Bomis]

Originally Posted by Bomis

I already have the bastuck exhaust.....if that helps anything...

and everything else by the way except for ic...but i will have my helix ic in about a month!

[tke344]

Originally Posted by edo

I'm planning of getting rid of secondary cats. I have catless downpipes installed.

I did a lot of searching and decided to cut out secondary cats and weld in resonators. Why? Because I don't want it to be too loud and I definitely don't want any drone or rasp, which is quite usual with no cats and aftermarket catback.

Main "power killers" are the cats. Biggest gains are from catless downpipes, then secondary cat delete.
Stocl catback does't have that much restriction and you loose just several hp compared to an aftermarket catback.
Plus it's at least 10 times cheaper. Not that I care much about it, but still.

I made a thread about this a while back, seemed nobody had done it at the time. I'd love to know how the sound compares to catless dp's with stock secondaries.

[Craig@SupremePower]

i'd guess 8-10hp..

[Bomis]

wich is the best way to do it...just cut them of and weld new pipes in or what?

[Mote]

I'll chime in here. I removed my 2nd cats and have an Eisenmann exhaust. It is a loud setup but I did manage to put down 412whp on 100 oct.

Take it for what it's worth but I hear the 2nd cats really aren't that restrictive at all. You might gain few horses, if that.

[edo]

Originally Posted by Mote

but I hear the 2nd cats really aren't that restrictive at all. You might gain few horses, if that.

Shiv has claimed vice versa several times here.

[edo]

Originally Posted by Bomis

wich is the best way to do it...just cut them of and weld new pipes in or what?

I'm planning to weld in resonators - better sound, no drone.

[Bomis]

Originally Posted by edo

I'm planning to weld in resonators - better sound, no drone.

ok so can i reuse the oem resonator?

[edo]

Originally Posted by Bomis

ok so can i reuse the oem resonator?

Which one?

[Mote]

Originally Posted by edo

Shiv has claimed vice versa several times here.

And others have dyno'd with none to 1-2whp gains. It goes either way.. for some the sound and cost isn't worth it.

[edo]

Originally Posted by Mote

And others have dyno'd with none to 1-2whp gains. It goes either way.. for some the sound and cost isn't worth it.

I believe that gains are minimal if someone uses the same map/settings. But by removing secondary cats one removes restriction, which allows to use more aggressive maps/settings. Then the gains are bigger.

But these are just my assumptions as I don't have any data to prove.
However, almost everyone who has a turbo car (evo, sti, etc.) knows that you can't get much power with cats in the system. It's a bottleneck.

[per]

I am also considerring to remove the second cats on my stock exhaust, togehther with AR catless, has any one done this?? Soundclip? Any news?