: Cat Restriction??? Custom Down Pipe being fabbed.



2013CTSV
05-13-13, 04:24 PM
Hey guys,

Simple question, how restrictive are the cats in these things? I plan on having my buddy fab me up a flange to flange down pipe and utilize most of the stock exhaust except the rear canister, I will be cutting that out and running straight pipes right to the tips. Let me know of your experiences please & any recommendations I will gladly consider.

Regards,

Brendan

Chrispy
05-14-13, 02:17 PM
My only recommendation would be to buy earplugs if you are removing the muffler(s) along with the cats :)

2013CTSV
05-14-13, 03:27 PM
My only recommendation would be to buy earplugs if you are removing the muffler(s) along with the cats :)

Lol its gonna scream huh? I kinda expect that, I love the sound. Im going to keep the resonators in the middle of the exhaust in hopes of keeping it a little cleaner and not drone so much, we shall see. Do you or anyone for that matter have dynos of before and after or sound clips? I did some searching on here but didnt find anything, maybe I missed a post or something?

Moparman4444
05-14-13, 04:08 PM
You may want to consider adding a Holtz pipe. If I remember the term correctly, its a pipe about 16# long stubbed on your exhaust pipers where drown goes to die.

tlsmikey
05-14-13, 06:02 PM
I believe that Billy Boat makes a down pipe to eliminate the cats near the factory manifolds, however from what i've been told the sound is terrible. Not loud as much as just really poor, raspy sounding.

Da V-Man
05-14-13, 08:06 PM
Im going to keep the resonators in the middle of the exhaust in hopes of keeping it a little cleaner and not drone so much, we shall see.
Those aren't resonators - they're also cats. If you remove the muffler, it's gonna drone.

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You may want to consider adding a Holtz pipe. If I remember the term correctly, its a pipe about 16# long stubbed on your exhaust pipers where drown goes to die.
The correct term is Helmholtz resonator. The proper length is not necessarily 16" - it's dependent on the frequency that you want to cancel. The exhaust gasses passing by the inlet to the Helmholtz pipe causes the air in the pipe to vibrate out of phase with the exhaust gasses. This out-of-phase vibration is then introduced into the exhaust stream where it cancels out the same frequency in the stream.

2013CTSV
05-14-13, 09:34 PM
hmmm, maybe I will buy some mufflers than. I dont like the huge canister and it prob weights a good 50lb so that can go haha. Im still weighting options and have been looking up youtube videos of people combos. I've seen quite a few I like but also like doing my own thing because its much cheaper and the same quality sounds can be achieved with proper mufflers/resonators. I shall keep digging, anyone who has experienced doing a custom setup please let me know or show me to your thread!!!

PremierJosh
05-14-13, 10:03 PM
We have done quite a few different exhaust setups on v2's. My favorites are longtubes with offload X back to stock axle back and custom built x moved to the front with cats removed back to stock axle back. At very least do Borla XR-1's in place of your mufflers. You can also do cutouts if you want it crazy loud, but even over 700whp they gain very little.

Chrispy
05-15-13, 09:51 AM
Lol its gonna scream huh? I kinda expect that, I love the sound. Im going to keep the resonators in the middle of the exhaust in hopes of keeping it a little cleaner and not drone so much, we shall see. Do you or anyone for that matter have dynos of before and after or sound clips? I did some searching on here but didnt find anything, maybe I missed a post or something?

In my opinion if you get rid of the cats do a proper x pipe setup into the stock mufflers. It'll sound great at WOT and not drone...Best of both worlds.

If you do headers might as well do a pulley and tune at the same time...regardless going into stock mufflers will not hurt power and will sound fantastic.

HUGN*RDS
05-15-13, 11:39 AM
I thought the second bank of cat's were not monitored by our O2 sensors for a reason..


If anyone is interested I have a set of exhaust (piping) for sale; I removed from my car all except the corsa mufflers and my modified stock manifolds.

What I have to sell are the kooks 3" x-pipe (w/high-flow cat), the long stright pipes (that run along side driveshaft) and the rear piping section that connects the straight pipes to the mufflers. Someone could use this setup to connect to the stock mufflers (I was going to, plans changed). I used the same stock manifold flanges to connect the x-pipe, but it would need to be modified as I modified my stock exhaust manifold when I deleted the 1st set of cats. I basically altered how the flanges faced the rear of the car (the stock manifold flanges) and it worked perfect. I was very happy with the exhaust until I changed my plans. It's all stainless and I have pics for anyone interested. Shipping is $70.

Atv
05-25-13, 01:39 PM
How badly does it stink catless?

baabootoo
05-28-13, 12:20 AM
It shouldn't stink at all since the cats, and residue, causes the stink.