Help quieting this Perrin exhaust setup w/o losing flow?
 

Lately my BRZ has been attracting too many cops. I don't want to ruin performance or retune, but I want to quiet it down a bit. I inherited the current setup from the original owner. The only stock piece I got was the OEM front pipe (resonators, cat), however I can obtain a stock exhaust/header fairly easily.

Without going thru trial and error could anybody suggest the best way to not ruin the flow but quiet it down? A different catback and leave the header/overpipe/testpipe? Just put the OEM front pipe in?

Thanks!

JDL UEL catted header
Perrin overpipe
Motiv test pipe
Perrin 2.5" resonated catback

Yes, put the OEM front pipe in or an aftermarket hi flow catted front pipe. The cat in the front pipe will quiet it down quite a bit.

Has anybody dyno tested a high flow setup, but retaining the stock cat pipe?

Probably.

@kch wasn't it at you that told me Bob@DriftOffice tells a lot of people to just keep the stock front pipe, it doesn't make that much of a difference?

I know nothing about it myself, but this is close to my "want list" setup so I would suggest matching up the catted JDL front pipe to the header. Throwing a cat in the middle should help.

I'd say just put back stock front pipe and center section. You'll not loose much, but you'll be more quiet.

How are you differentiating between "stock front pipe" and "center section". Aren't those the same thing?

JDL ultra quiet FP or HKS double res FP, both should tone it down a little without hurting flow. Cats in FP (or lack of) and what catback exhaust you have are the two main things that effect volume, aside from your right foot.

You could consider selling your catback and putting those funds to getting something like CSG MXP or Q300 they are pretty quiet with good flow.

If cabin noise is another concern get some sound deadening under the trunk liner and back seats.

Replace the UEL header with a 4:2:1 EL.

That test pipe is what’s making your car so loud lol. Get a JDL UQFP with cat+resonator or double resonator and you should be much more bearable. If you do get a cat+resonator, JDL do have a 500+hp GESI catalytic converter option that you can request through DM on Instagram. Any other setup besides a test pipe should do a really good job at quieting down your exhaust sound.

+1 on the high flow cat front pipe. You’d be surprised how much a cat quiets down a car lol. I would consider something like the JDL Ultra Quiet or the Motiv high flow front pipe. Maybe one with a single resonator too. I doubt you’d be sacrificing too much as far as performance goes. A couple horsepower is a fine price to keep the cops off your ass lol

Thanks guys. I put the stock cat pipe back on last night and it did help considerably. I’ll gkve it a few weeks and see if I need to now replace the catback exhaust, but so far it’s muchmore bearable!

If you're worried about not losing power, you'd be better off with the higher flowing front pipe and stock cat-back exhaust.


Another option is the ACE Laguna Seca spec cat-back, flows really well and is very quiet even with no cats.

Thanks for the feedback. Do you know of any dyno results where folks have tested these combos? The folks above you are saying the exact opposite :)