How much power would a catless UP pipe add?

[DoubleM_95]

I have a mainly stock 2003 WRX with the exception of an HKS Catback, HKS BOV, and an AEM intake. Im wondering how much power a Catless Up pipe would add. Thanks

[Calvinball]

My understanding is that it won't really be adding power, but you will get a little quicker spool on the turbo. Most importantly though, those earlier models want a catless uppipe because there is a possibility of the cat itself breaking up and therefore shooting bits into the turbo, thus ruining it.

I'm sure someone who isn't a silly 3rd gen owner will come in and clarify more.

[DoubleM_95]

Alright thanks. Because i want to eventually do a 20g turbo upgrade. And i hear with that you have to do some other mods as well (catless Up, 3inch exhaust, injectors, etc)

[Calvinball]

Alright thanks. Because i want to eventually do a 20g turbo upgrade. And i hear with that you have to do some other mods as well (catless Up, 3inch exhaust, injectors, etc)

Definitely. And here is where I fully and respectfully bow out of the advice giving, as there are others on the board far more qualified to discuss all that. I do know that you definitely don't want the stock uppipe on there if you are going to be modifying like that.

[Ruh Roh]

for a 20g or any turbo upgrade the stock uppipe will need to be replaced. Why a 20g? what whp are u aiming for? also are you running a tune? if not put the stock airfilter back on and take the bov off as well. you can reuse them in your build but now isnt the time unless tuned for the intake

[SD_GR]

You could sell the intake and BOV to finance an up pipe and the required gaskets, studs (it's an older car), and bandages. Also buy a resistor; search "resistor CEL fix" for info.

See how you like the car, and then consider getting only what's necessary for you to like the car a bit more each time. A 20G involves a lot of time and expense for an aging car.

Just IMO.

[MainFrame]

From the butt dyno, I would say catless uppipe provided a considerable gain in torque, with just a minimal horsepower gain.

[DoubleM_95]

for a 20g or any turbo upgrade the stock uppipe will need to be replaced. Why a 20g? what whp are u aiming for? also are you running a tune? if not put the stock airfilter back on and take the bov off as well. you can reuse them in your build but now isnt the time unless tuned for the intake

My goal is around 260-300 whp for now.

[sxcrxy]

My goal is around 260-300 whp for now.

1stly get rid of your bov if you want sound get at lease a 50/50 bov to keep your ecu happy

secondly you have a intake + bov and not mention anything about a tune? you want power its all in the tune and running these item without a tune is like a time bomb ticking

i hit 300whp on a td05 big 16g, @ 22psi a vf34 will probs get you into the 280whp range and not have anywhere near as much lag as you will with a 20g oh and if your going to run a 20g you could probly get more than 300whp but how much can your stock internals take? how is your compression levels? i say you should read some more threads on turbos and mods but yes you will see good gains with a better up pipe