secondary cat removal = more HP?
 

Just curious if anyone ran a straight pipe in place of the secondary cats on a LFX and saw any power gains. Is it much louder or are there any downside to doing this? such as CEL or lost of TQ etc.... Thanks!

Is there a reason you don't want to just get solo high-flow downpipes instead?

I think you'd benefit a lot from getting that new pipe + high-flows with resonators. If you just straight pipe the secondary, it might get a little droney.

I did at one point. It isn't much louder but while you do get "some" more volume, the primary cats are bigger and more prominent by extension. Real power is in high flow cats or catless downpipes. (After having them both in my hands I'm still not positive the stock cat pipes are 2.5" compared to catless downpipes but I assume they're the same)

I'm cheap :bonk: :smiling1:. but seriously I can get a straight pipe with flanges to bolt back the cats back to stock for super cheap. I thought before I get the 80mm tb port job on my manifold and get it tuned for E85 id would be interested in seeing if it was worth deleting those cats. If I hate the sound I'd just bolt up the cats again. They are only like 6 inches long I wouldn't think they could make the car that much quieter :noidea:. But if it freed up HP that anyone else has seen on a dyno i'd be game to try it.

As mentioned above, your front cats are still going to restrict.

I honestly think the downpipe replacement is your best bet for the most power.

They are practically the headers of the LFX world, it is unfortunate they are a little expensive.

Yea not worried about it getting a little louder, more worried about not gaining any HP from doing it. I know ARH are under $600 for high flow cats, and the Solos are around $800 I believe. Just trying to get a little more HP before the dyno in a few weeks. I guess I could leave that as my final upgrade If I decide to keep the car much longer. Outside of the SLP crank pulley, I've bolted on everything you can get for these V6s :smoking:.

Yea seems like that would be the only restriction i'd have left in the whole engine. Sucks they arent cheaper but maybe i'll just be happy with 305-308RHWP after i get it corn powered :noidea:. Or if I keep it longer i could go with Cams, DP and a new clutch. really max out the V6 power.

What sort of gains are made with hi flow cats or catless? I’ve been debating this as my next step, but haven’t found any info.

The more cats you remove the more you will notice it. Secondary cats removed with only primary stock cats may have an improvement, high flows or catless would give an improvement you could definitely feel, each with a greater improvement than the option before. At most on a completely stock vehicle it could be a max of 15whp. But everything matters if you're chasing peak numbers.

DSX you running any cats?

Negative. Catless downpipes. But I also have the Magnaflow resonated x.

yea, i'm not running any resonator so thats why i cant run catless. Highflows maybe, but i'll see where my dyno numbers are at once i get the E85 tune.