Running catless, rasp and smell
 

With some newer less expensive headers coming to market (most catless), who here is running full catless?

I've only really been able to find 1 video on YouTube of a Borla UEL catless set-up.

I'm just curious because the exhaust I have is relatively tame and I have a catless front pipe. If I go to a catless header (which are half the price of UL catted, will simply using an O2 spacer keep me CEL free or will I be forced into using EcuTek (I have unichip atm)?

Also how is the highway drone? Rasp? Smell?

FT86 speed factory has a few videos on youtube of full catless setups id link but youtube is blocked at work :P

If the drone or rasp is to much you could get the namless frontpipe with a cat and helmontz resonator. Id imagine that would cut down quite a bit on both.

not FRS/BRZ but when i had RSX-S, i ran full catless header to exhaust. i used spacer/o2 eliminator to keep CEL off. I don't know about drone but there is little smell that might give you headache during stop on traffic light.

I'm running full catless on mine. I have a Milltek resonated catback, Milltek resonated front pipe, Milltek overpipe, and Borla UEL header. No rasp or drone, it's fairly quiet when cruising on the highway but gets loud when you punch it - just the way I like it :D I used an angled o2 sensor spacer from ebay, and after 1,600km (1,000 miles) no CEL so far.

Regarding the smell.. Without both cats, It does stink :bellyroll:

I have a bunch of clips of my exhaust setup in this thread:

http://www.ft86club.com/forums/showthread.php?t=39901

Thanks for the responses everyone! I guess I could go catless with a spacer and if I can't handle the smell or rasp I'd just replace the front pipe with a resonated and/or catted one.

I'm sure that the US – this stronghold of human rights protection – should introduce a federal law allowing drivers, who are stuck in a traffic jam next to a scumbag on a full catless car, to brutally and mercilessly extinguish by all available means both the turd and his stinking ride at the spot.

“That’s all I have to say about the war in Vietnam” :)

No one really cares that they are releasing very lethal gas into the air without a cat eh? figures.

Nitrogen gas...shit is dangerous

Joking, right?

I ran catless once in my life, and regretted it.


On our cars you're probably only going to save a hundred bucks and free up a miniscule amount of peak torque. But the trade-off is that your car will stink in a very unhealthy way. Whenever you come to a stop you're going to smell "gas" and what come along with that untreated exhaust fuel is carbon monoxide, hydrocarbons and nitrous oxide particulates. Each of the three are individually a great little poison to kill yourself with. Quite a cocktail together.


Then there's the other issues like how smelly it is, how the smell will get into your clothes, how raspy your exhaust will sound, and how really bad for the environment it is.


It's a really terrible compromise for a little bit of extra power. It's like saying "hey, we can make you .05 quicker in the quarter mile if you agree to have this dude sit in your passenger seat and chain smoke cigarettes with his window rolled up."

My turbo manifold has no cat, I run the full Milltek exhaust system non-resonated. It's quiet, doesn't smell and haven't had a CEL from running catless before FI. This smell is non-existent to me, or maybe I'm just too manly to notice. :/

Nitrogen oxides. I left out the oxides, but combustion without a cat will mean nitrogen oxides being produced which can be very lethal and also a way stronger green house gas that CO2

Not at all.

This has been covered before.

1. You get almost no power by running catless vs high flow.
2. You spew a LOT of particulate and terrible gasses into the atmosphere.
3. In the US it's illegal and carries up to a $25,000 fine depending on the state.


http://www.importtuner.com/features/...l/viewall.html

Import tuner did dyno tests on a 1999 Si (1.6L B16) and the short version is thit:

I/H/E, OEM cat: 147 hp
I/H/E, Magnaflow Ceramic Cat: 150 hp
I/H/E, Magnaflow Metallic Cat: 151 hp
I/H/E, Test Pipe : 152 hp.

So, MAYBE, you are making 2-3hp at the very most. It's not worth spewing raw emissions into the atmosphere for an unnoticeable gain.

My other car has been catless and daily driven for 7 years and not once have I had any exhaust smell come into the cabin. Even with my open dump that exits right under the car. You literally have to be standing right behind the car while its running to smell anything.

^^^ Dont forget that the turbo itself acts as a muffler. Turbo cars are generally a lot quieter than N/A cars with a straight exhaust.

It's true, but my car has always been quiet for what it is lol.