Straight pipes and tuning?
 

So I'm looking into a new FRS and I noticed that in my state (California) that if you buy a new car you don't have to test for smog for 5-6 years you just have to pay..

This got me thinking that maybe I should run straight pipes and delete the cat for a few years and when time comes throw my stock gear back on..

My main question is...

If I go straight pipes and delete the cat will I have to tune my car? And will any shop in California even tune it? Won't it be considered "illegal" so shops will decline service?

http://blog.perrinperformance.com/wp...st-diagram.jpg

As the car has two cats, i gather youll be removing the cat from the front pipe and retain the header in the stock header?

If so, you wont need a tune, you only need a tune if you change the headers (regardless if catted or catless) as there is an O2 sensor in the headers after the cat, but there is not one after the cat in the front pipe.

In a nutshell, straight pipe from the overpipe back youll be all sweet, itll be real loud. I dont live in Cali so i cant say a shop will or will not decline you, but i would say theyll do the work for you, but you cop it on the chin if you get done for not running a cat. I hope i helped.

I was looking into both options.

I'm leaning more towards the full exhaust and new headers.
I'd like a little extra torque or hp, but I don't want a crazy loud exhaust.
Stock is too quiet though :P

And too loud like you said might get me in a bit o' trouble haha.

If you go aftermarket catted headers and a catback it'll give a nice sound. Plenty of videos on YouTube of different set ups. A personal favorite of mine is an Invidia q300 paired with any aftermarket header, then buy yourself an Open Flash Tablet to clear the check engine light and be done with it.

Unfortunately the twins don't have much gains hp or torque without getting a tune. A catback will maybe give you a couple of horsepower but not much at all.

If you don't want crazy loud, straight pipe with no cats from header back is definitely NOT the way to go lol. I have a catless UEL header with just a muffler delete and it is pretty loud.

Now to get the extra HP and torque, you will need to get a catless header of some sort and tune, which when paired to a full straight pipe would be painfully loud. You could get catted headers, but from what I can understand you don't gain quite as much when compared to catless. Also, there is only one catted aftermarket header that I can think of, and that is the FT86SpeedFactory one.

In my opinion, with a catless header you need at the very least a resonator somewhere in the exhaust or else it just sounds kinda shitty and will be unbearably loud, with tons of drone. A catless header paired to non-resonated, non-catted catback system sounds like a raspy mess.

Watch this video. He has a catless header, catless and non-resonted front pipe, and a tomei 60r, which I believe has one resonator. It sounds good, but my god is it loud. A full straight pipe would make your ears bleed hahaha.

[ame="https://www.youtube.com/watch?v=ocO6y-R3GHk"]Borla UEL headers, PLM over pipe, Tomei front pipe, Tomei 60R, OFT 1.58 stage 2 tune, FR-S BRZ GT86 - YouTube[/ame]




-J.B.

A tune is not needed. However you will need a tune if you want to get rid of the CEL.
As for sound, exhausts are not loud or quiet because the cats are taken out. They are loud or quiet because of lack of sound suppression (from smaller/ineffective or removed resonators in the exhaust)

-alex

hey thats @Anthony

I'm curious how long you'll get away with it before you get a ticket. There have been several posts here where residents of the People's Republik of Kalifornia have been pulled over and ticketed with completely legal exhaust setups because the cop just felt like it, and they had to go to a referee to get the exhaust inspected and the ticket dismissed. One guy had cops pull him over and ticket him after he had already gotten his setup ruled legal, and he was told he would have to keep going back to the referee each time it happened. These tickets were for both loudness and emissions, with cops demanding that people pop their hoods for inspection.

That was with a LEGAL exhaust. Yours will be illegal, so you won't have the option of getting it inspected. You sure you want to risk that while you live in a nanny state?

I think it depends on the person and how that person drives the car.

Little known fact: for the last ~9 months I've been driving with a combination of loud exhaust, quiet exhaust, cat, no cat, and everything else you can think of as far as header/front pipe/exhaust combo is concerned. Probably close to 30 different configs at this point.

No cop issues and my car, while modified, doesn't stick out like a sore thumb.

I've been modding cars in California for 20 years now. Gotten a ref ticket once, and that was because I ran a red light.

-alex