Exhaust question
 

So I just brought a 2018 BRZ and I want to do a catback thats going to be fairly loud but not suck after headers. Im waiting on the headers till after warranty so Ive been looking at HKS spec L, Perrin, and invidia r400. I plan on doing a EL header (probably JDL catted cuz NJ but I can always take that pipe out with them) and a resonated mid pipe or catted mid pipe (if I do uncatted EL header) Im leaning the most towards HKS. I like loud but its my daily so I don't want drone to the point where I can't have a conversation. I also know of DEZOD but its a little more than I want to spend. I also think the r400 sits a little low. What do you guys think? Any tips or suggestions for me?

NJ here. Just keep the stock Headers and stock parts for inspection. After that just swap back.
Also go Perrin and PLM. That is what I run

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But headers need tune and if something goes wrong the dealer will see that. My problem with perrin is its so quiet pre-headers, and I like some sound

Hello DannyRZ, congratulations on your purchase and welcome to our forum ...:clap:

Since you don't want to put on an aftermarket header until after your warranty expires, but you want some sound now, you may consider a split mod approach.

Replace the muffler with a simple axle back for now, then further modify the exhaust system later on when you install a header. Something like this may work for phase 1.

https://shop.namelessperformance.com...r-s-2013-2016/


Enjoy your new machine … :thumbsup:


humfrz

Get a cheaper catback and sell when you're ready for headers. In the grand scheme, several years is a while to sit on a catback. Get something you enjoy now and change post-header. With stock headers if you get a catless front pipe and a nice catback, both are easy to swap for inspection and it'll still be mellow.

Thank you! I love it. I was thinking about doing that I just hate buying stuff twice haha. Thats why I thought the HKS was a good choice cuz it seems to sound good by itself. Ill probably to a mid pipe too before headers. Its just headers and the tune that Im gonna sit on.

I know thats why I wanted a decent sounding one that I can pair with a mid pipe for now. I think its bull that headers can void stuff, but Im worried if they see the computer was flashed they will refuse a warranty if anything goes wrong.

That's why I saved money and bought used. The warranty, to me, is useless. I'd rather get something that has already lasted through the warranty and had its hiccups addressed. Too late now for you, but consider this in the future! Or YOLO and put the headers on!!! I'm usually in the YOLO corner and I haven't been burned yet.

Some dealerships are reasonable and will excuse a reflash tune, but headers I am sure there's no tolerance for

hahaha truuu. The guy who sold me the car I have in writing that as long as I don't mess with the computers or the header I'm good, I can do exhaust and intake blah blah. The dork that did the financing was like "a catback might void the warranty for messing with the engine flow" and I was about to laugh in his face.

Well, if you got a catback with 1"ID piping, he could have a case! Thankfully, I think only John Deere, Husqvarna, and Honda use that size exhaust.

You know, you could go full standalone and swap it out when you go to the dealership :). MOTEC/VEMS/AEM

haha imagine. Maybe I should do a perrin 3in haha. i have no plans for F/I though

FI or not, 3" will sound good. For whatever reason, people are conservative with exhaust on this platform. Bonus is that a Perrin will re-sell much better if you decide in 2 years that you want something else!

Well maybe cuz with an N/A motor a 3in seems like too much in terms of lost back pressure where as with FI it makes mores sense

Back pressure is basically a myth. It's exhaust gas velocity that is much more important. Modern high performance engines flow very well and a three inch exhaust for a naturally aspirated engine isn't out of the question anymore.


It would be interesting to see back to back comparisons of a well designed header (like the ACE) with both 3inch and 2.5inch single exit exhausts. I'm willing to bet you'd see a very small bump in power, especially at the top end.