When does the cat become a restriction?
 

So I have a Blouch powered MSM with most of the FM big enchilada junk. I have noticed now that the top down weather is here that when I step into it, the exhaust completely loses its tone and only produces a loud "whoosh". I have the FM 2.5" downpipe with cat and the FM MSM exhaust.

At what point does the 2.5" ceramic core cat become a restriction in earnest?

FWIW I am running ~15 lbs of boost with ~13º timing in the midrange rising to ~15º at redline.

at the moment it's installed.

lol the question is how much of a restriction, not if its a restriction.

probably not too much on your setup, but obviously a full 3" catless would yield moar power

that loud WHOOSH is awesome-sauce though, I pretty much try to achieve that on all my cars. absolutely amazing sound

It's not a good whoosh. It is a big turbo built motor 25 psi with stock 2" exhaust whoosh.

The sounds that car makes is pretty much it's best quality, honestly. It doesn't just sound like a "woosh" behind you, i promise. One of the smoothest sounding exhausts i've ever heard.

That said, i did kick around the idea of moving to the BeGi SGDP and doing the wastegate port work while i was in there. Should yield a decent bump in power (You know, just to make SURE you vent that block) and get you some more sound.

I am more concerned with a possible major restriction of power and flow than the sound. I am also running 3-4 more psi boost and several degrees more timing than when you had the car Ben. :giggle:

the bottom line is, how much money is that 20hp and possibly a couple hundred rpm worth of spool worth to you? if its worth it, go full 3" catless. If not, don't. I

We had it at 14-15psi at FM the first time. ;)


I'd say at this point... if you're going to do it, do it right. Whole new exhaust. BeGi SGDP, 3" Enthuza.

I've had a 2.5 catless downpipe and a metallic magnaflow cat sitting on the shelf since before I picked up the car from you. I just need the right motivation to weld the cat in and install it.

You're doing it wrong. Leave the cat out. :bowrofl:

You don't have to tell me about motivation. You think i've finished the 3" setup on the red car yet? Haaaaiiiilllllll naw.

Boost creep, bent rods

Port your wastegate. It'll be fine. You act like you're not just going to turn up the boost enough to bend shit anyways. :brain:

Meh

Get EBC going, tune curve to account for boost creepz?

Bro, no DC over 100% Bro...

you sound like you want to run ALLOFIT

on behalf of this forum, let me just say: YES, do it.

I would never put the turbokitten in my exhaust, so why would I put any other cat?

Keith

Because the IHI exhaust housing cannot deal with it and boost creep occurs. The easy fix is to run a cat of some type. The deal is that my downpipe has the ceramic substrate core which is not of the performance type.

the easy fix is to not run a failsauce turbo :party:

In for BORG WARNER S366 stock MSM block madness.