Eurojet

Good evening , I have a question about Downpipes or whatever you want to call them on a NA car
Armytrix sell a Race high flow down pipe and I think there are a few more that do also
Would i see any benefit (worth while HP gains )on removing the stocks and replacing them with something like this.

Thank you

Accidental L8 apex

They're called long tube headers and yes, these engines really benefit from them. The noise level goes up, but it's glorious. 😁

Eurojet

These are not long tube headers these are the ones I'm talking about , I had a set of long tube headers ended up selling them

https://www.armytrixusa.com/armytrix...151461512.html

HLG600

"Down pipes" are usually thought of on turbocharged cars, but in this case those are just the sections of the exhaust that come after the exhaust manifolds / headers.

Factory cats are not a huge bottleneck here. The factory log-style exhaust manifolds, however, are.

For me, there are better things to spend the $1K (plus install) on.

deadlyvt

You'll pick up 20 ish whp. But don't spend a crazy amount on those.. they are just pipes any exhaust shop could do. Lth are the better bet though no sense changing just doing the decat imo

BalanBro

They do offer a catted version (200 cpi core) as well. I like the idea of that, especially if it could pass the OBD2 catalyst efficiency check. Unfortunately, they are a bit pricy (~$2K) and I haven't heard from anyone if they are effective enough to pass plug in emissions testing.

At least they look to be reasonably DIY friendly though.

GarlicBread

Do any aftermarket setups actually pass currently?

Sort of a position im in at the moment between just doing a full decatted/terrible emissions vs trying to play the game with Johnny Law until historic plates are available.

Plenty of catted LT's etc but I'm curious if you HAVE to have the resonator in order to pass emissions.

Joshinator99

Definitely do not need the resonators to pass emissions (California might be the exception!) in most states as it has no impact on emissions, only noise volume.

menaceAMG

I have long tubes straight back to mufflers with no cats or resonator. It's tuned, it passes emissions..... A tuner can help you. Unless you live in a state that physically looks like CA I believe.

Oh and prior to the long tubes, I removed the one set of cats and the resonator, that doesn't affect obd emissions test at all.

eightysixtuned

"downpipes" for our cars reuse the factory shorty headers which are the biggest restriction. if you want noise this is a good solution but is you want power true long tubes with collectors under the car are the only way.