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Discussion Starter · #1 · (Edited)
2017 WRX.
I am planning on installing the MAP intake and J-pipe, plus their OTS map and I have few questions I was hoping you could help me answer.
1. Is it OK to leave the stock cat back piping (mid pipe and axle back stock).? Would there be a problem by leaving the stock catback piping?
2. Is it ok to have the J-pipe to be 3” when the cat back stock is 2.5”? Of course I would put the adapter to make the connection, but I wonder if there would be a problem in the long term for having the stock cat back being smaller.
3. MAP provides their own OTS map, but I was wondering is someone have tried the COBB on that set up.
4. My understanding is the the J-pipe is the one that gives the most restriction and replacing that one along with the intake and the right tune will “unlock” a good amount of power, is that correct? Could this set up significantly reduce the durability of the engine?
Thanks for the help
 

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1. Yes, it is okay to leave the stock catback piping. Many people do it, I would recommend a catback in the future, more so for sound. This kinda answers #2 as well.

3. I had the MAP stage 1, now I'm pro tuned with intake, jpipe and a slew of other mods but I would recommend at least an e-Tune over the Cobb or MAP map, since the tune is custom to your car, no two are the same and you'll also maximize your gains with a custom tune.

4. JPipe and TGV are the most restrictive. Doing a TGV delete alone can help you see power gains equivalent to a custom tune and jpipe. Either way you'll want to get a custom tune at some point to maximize your gains and also safely run the modifications you've done.

I know MAP does their homework and the OTS they provide can be a little more aggressive that what Cobb provides. Durability depends on the maint you perform on the car and how you take care of it. The correct fluids, and also if you beat the crap out of it or whatnot. Fluids by means HTHS oil, gear / diff fluid, and even preventative measures such as an AOS, EGR delete, etc.

Sent from my SM-G950U using Tapatalk
 

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Cobb’s tunes will not support anything but Cobb’s parts. You can’t use their tunes.

The biggest issue you’ll have is going to be the mating of the 3” to 2.5” staying sealed. Grimspeed sells an adapter but I never could keep it from leaking there.

On the FA20f the restriction is to the intake side. You’ll get your best gains from tgv and egr deletes coupled with an intake.
 
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