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Hey guys, I thought I would post a question here as I know can trust your opinions and feedback as the MX no doubt has similar characteristics.

I have a question relating to aftermarket exhaust options for the BRZ/86.

A (lucky) mate has just picked up an 86 and is shopping around for exhausts. I won't bore everyone with the "what should he get" question as he and I have discussed it at length. On my recommendation he has decided to go with a Hitech cat back system, with the view to possibly add the headers at a later date. He has asked me if I think its worth him getting hitech to add the high flow cat option.
I havent had any experience with good vs bad of high flow cats on NA motors. I was under the impression that for chasing peak figures on a dyno a high flow cat will benefit, but for street driveability would a high flow cat alter the back pressure that seems to be sooooo critical to NA engine performance? and therefore ruin the daily drivability?

Any/all opinions happily accepted, thanks in advance.

Backpressure is horrible.

You never ever ever want backpressure.

Go and google it, backpressure vs velocity.

Dann

NitroDann wrote:Backpressure is horrible.

You never ever ever want backpressure.

Go and google it, backpressure vs velocity.

Dann

i'm assuming that is a big YES vote for the high flow cat then?

Yeh, google the term and click the first link by memory its a honda forum.

Dann

Read up on HKS systems

http://www.ozft86.com.au/forums/threads ... #post-5692

Whilst I own a GTS86 I have no affiliation with this company[GT Auto Garage], but must mention that it is next door to MX5 Plus/Automotive Industries in Brisbane and they have been testing since the 86 was released. I'm looking at the HKS titanium once the car is run in - should be around 2017 at the rate I'm going!!

Hope this assists

A highflow won't make the car harder/worse to drive.

Mine's got a highflow and there was stuff all difference (OEM midpipe still)

With the RS*R on, it just made it a lot louder, and also made it pop and crackle (letting unburned fuel through)

With the OEM muffler you can't tell a difference.


NFI how many cells my cat is, it's not much, the holes in each cell are about the size of a maccas straw.
The OEM one's holes were about the size of a toothpick

NitroDann wrote:Yeh, google the term and click the first link by memory its a honda forum.

Dann

Great read, thanks Dann

perhaps we should re name this forum as a partnership with the other things- if you want advice on Toyotas maybe they have their own forum. Too much already. 86 owners I believe are being issued with stickers " My other car is an MX5" or "My other car is a real sports car" or "My hair does not get messed up in a Toybaru"

Lol, I think he just knows this community well enough to trust us for the right advice, and an exhaust is an exhaust.

I take that as a compliment

Dann

NitroDann wrote:Lol, I think he just knows this community well enough to trust us for the right advice, and an exhaust is an exhaust.

I take that as a compliment

Dann

This ^

just shows you -some of us look at the hole in the middle of the donut. Positive + - it had to be there I just missed it.