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.

Exactly! Easy! Fart while running guys - you won't feel the smell of your shit at all!! Someone behind you? - Cool bros don't care about such stuff, right?

it stinks when you're sitting at a red light, but that's about it.

Actually no I don't care. I have no problem with crop dusting people :bellyroll:

Stock diesel pick up trucks smell worse than any modern day car running no cat

What about the babies that are in the back of mom or dads car inhaling all the harmful uncatted gases cars are farting out? The law made it illegal for a reason, just like heroin. I'm remembering a South Park quote, "Save the children!". At least run an overpipe/front pipe cat. We have 2 so why not keep at least one.

Try Moscow traffic - follow it 2 feet behind the exaust tip at 3mph average for 2 hours ;)

I live in frigid Minnesota where we have enough trees to suck up all the icky air. If I could speed up this so-called "global warming" I'd do it.

First green house gases from cars.. Are a tiny fraction so it doesn't matter. Second global warming due to man is a scam and it's not warming anymore.
Third the concentrations needed to kill or harm anyone from running cat less are considerably higher than anything you can measure a foot from your exhaust.


NOx CO and CO2 into the atmosphere is all a temporary problem so unless you live in Cali or some other closed in valley it won't harm anyone.

It does stink although rarely if ever for the driver. Any classic car is the same. Most of all bikes on the road are the same as well.

The only reasons not to run without cats is possible fines, rasp and possibly smell.

Reasons to do it : cost, power if your talking about the headers, weight.

1 diesel truck with a DPF delete blowing black smoke = 100 catless tuner cars

the prius does more harm to the world during the manufacturing process than our car could hope to do with a catless header. and i dont know about the states, but prius drivers all speed like maniacs on the highway here and totally kill their gas mileage.

Well its not exactly a scam, and its now called global climate change, and yes it is exacerbated by human presence. They just released a study about it recently and it doesn't look good, not to mention the study itself was 'optomistic' because of information withheld. Yeah auto emissions isn't the biggest offender, and it won't bother you or me today, but its my kids who will have to deal with the socioeconomic impact of climate change in 20 years. So please do me a personal favor and not f-up my kids' future environment, they have enough crap to inherit as it is.


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if your gona spew all that, you had better ride a bicycle to any destination under 20 miles away, or your a lazy hypocrite. and on top of that, it should be a used bicycle because creating a new one takes energy that runs on fossil fuels. but chances are you dont. if you add up all the engineering and manufacturing that goes in to a car, then bring in the insane amount of damage oil rigs and refineries do, just to get a car to move its insane. then the average person uses all that to move the lazy sack of shit that is the modern human a few miles across town.

thats not really an option, once you replace the header and get the aftermarket header rasp, the front pipe is not going to do much for you at all to tame rasp, unless you go back to the stock one, in which case why even bother swapping the header. Been there, done that, purchased a Q300.

How many cats does our car have? And how many can we get away with on a stock tune to not have a CEL? I would get a tune but I don't want my cel on when I go in for warranty work.

Our cars have two cats, one attached to the exhaust manifold and one in the front pipe.

The one in the front pipe can be removed without a CEL as there is no down stream sensor to monitor it. If you replace your headers with a catless version, you will get a CEL with a stock tune. I have heard the defoulers work OK for getting around that.

Right now I am on a stock tune with headers and get a CEL almost once a day. (50 mile commute.) I just clear it with torque app.

lol chances are I do actually - I walk to the train station more than I drive my FR-S.... and commute via electric train to NYC... which uses electricity from a nuclear power plant :) I guess the point I was trying to make is - the mentality needs to start going the other direction. I'm not spewing anything, no need to be so defensive. Kumbaya :thumbsup:

Haha touche.

Running full catless is douchey and pointless on anything but a track only racecar.

Ask anyone who lived in LA in the 60s and 70s if cats are a good thing.

Cheers
Nathan

"Releasing a study" doesn't quantify and amount of proven fact.

if you're truly worried about your kids find a new planet... Geneticly modified foods, big pharma medicines, chemicals in everything... its not "global climate change" i'd worry about...

Just try finding a peanut butter with the ingredient "peanuts."

If you don't already realize its next to impossible to find and if you do its Genetically modified peanuts ground for the PB.

So inclosing, screw your concerns because big government and nuclear technology is doing and will do more harm than any catless car

Uh. OK. Peanut butter. Fear (or is it faer) peanut butter. Dont see how that relates to individuals choosing to break the law and pollute the air, but thanks for your wisdom!

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My lawn mower is catless.... So is my weedeater and any bike you find for sale.


Also they changed "global warming" to climate change because they had lost the debate. Now anything abnormal is our fault.

Look at the "fix" taxes and regulations which will never solve any problem. It's about control.


No point except price to not run one cat though. It won't help performance. No need to have two either though.

God you guys are making my head hurt...


Reasons to run catless:
- You're cheap
- You're running leaded gas


High flow cat vs a straight pipe is within the statistical noise of a dyno.


Also, it's not about global warming or anything like that, NOX is a serious health risk to your local community. I dunno about you, but I like breathing.


Not to mention you guys are comparing it at idle vs actually driving the car (idle is lean, WOT is rich, hope that person behind you doesn't have their windows down on their eyes are going to be burning).


Comparing it to a diesel is a bit dumb too. Diesel exhaust LOOKS polluting, but it's mostly soot and doesn't have the same health issues.

I have had plenty of full catless cars. Never noticed any smell from them. Anyone ride motorcycles? The vast majority if them have no cats...

The new diesel trucks actually exhaust cleaner air than the air its ingesting here in new jersey