De-cat exhaust system

[Capagotks]

Originally Posted by eTiMaGo

bike engines are nice, but they need to be revved up to crazy speeds to make much useful power. That's not too much of a problem on a bike as weight is very low, but a car is far heavier, wouldn't make things very sluggish at lower RPMs?

Although, I suppose, with this kind of swap, you wouldn't want to drive at low RPMs ever!

Hey did you get my last PM about the yarisworld sticker and my paypal address?

Anyway, a turbo would help along with racing filters and the like, and maybe the transmission could be modified to adjust the ratio and reduce the top speed/increase acceleration. And I would remove the yaris transmission and get a mechanical LSD and use a custom transmission (or add in an idler gear to have a 6 speed forward and reverse, 250km backwards would be awesome.... )

[Capagotks]

Originally Posted by Vanderkitten

I decatted and race-piped the Yaris last week... top end is GREAT... low end is brutally underserved. It did improve over 3-4 engine cycles, and it's in preparation for some un-normal aspiration, but now I am pondering Supercharger over Turbo!

in your situation i would go with a supercharger to help the low end. do they make one for the 1NZFE (or whatever engine you have?) Im designing a system for My D&T (Design and technology) major project at school, it involves removing the cat but without affecting the low end power. i'll put up some plans here when I get it working (still in the design stage)

[regime]

the yaris has a 1.5 thats needs back presure to make the little bit of torque it has....

if you havn't done alot of engine work, i wouldnt open up the exhaust too much...

[CASTREX]

Originally Posted by Vanderkitten

I decatted and race-piped the Yaris last week... top end is GREAT... low end is brutally underserved. It did improve over 3-4 engine cycles, and it's in preparation for some un-normal aspiration, but now I am pondering Supercharger over Turbo!

Hey Vanderkitten, I really will like to see some pics of your exhaust set up! when ever you have some time.
I will most probably decat my Yar as well. Is the race pipe custom made??

To what diam did you open your pipes? The Yar is 1 3/4" cat back (I think)... So I was thinking first to delete the cat but kept a resonator and then open the entire pipe just a little bit up to 2" back to the muffler (I have Dynomax Turbo exhaust waiting just to keep things quite)

I hope such exhaust set up won't have a terrible effect on the low end tq.

[Spades]

wow....not only is de-catting illigal in most places...on new cars it f--ks up the computer unless you get a piggyback to trick the o2 sensor or reflash the computer. besides, with the amount of high flow cats on the market for race applications, WTF would you wanna de-cat a car with 105 horsepower???

I mean really guys...when you are pushing 400+ horsepower and a 4" diameter high flow cat isnt pushing enough air through, then lets worry about it, chances are at that point the car wont be street legal anyway...untill then, do yourselves a favor and save some cash and (dare i sound like a pot smoking hippie) stop dumping your "octane boosted" weapon r intake mostly stock econoboxs emissions into the atmosphere...

EDIT: get rid of the damn resonator first, not only is the stupid thing restrictive it tones your exhaust down...if you have to straightpipe something get rid of that pile of scrapmetal.

[chongopants]

So i take it, it would be a bad idea to simply remove everything before the cat? Where is the second O2 Sensor exactly? I haven't looked real hard at the exhaust yet. But I would like to let it breath, and I honestly dont care about emissions or sound. Just pure performance. Anyone have any ideas that wont damage my engine let me know.

Thanks

[BailOut]

Originally Posted by chongopants

I honestly dont care about emissions

Spoken like a true Texan.

[chongopants]

Yup, still dont care... its a yaris, my 81 f-150 with no smog sytem and 300hp puts a LITTLE bit more out than the yaris, oh and so does my honda lawnmower... so meh, keep your thumbs down....

[chongopants]

oh and my yaris bets better mpg than yours so ... unless you have a $10,000 electric conversion, I am getting mid 50s in mpg in town...

[severous01]

first off...it's illegal

second...you will get almost no gain out of the cat removal, you'd be better off with a catback

third, the cat is there to remove NOx, CO1, hydrocarbons, and converts it all into CO2 and water. if you wanna be an ass and contribute to pollutants in the atmosphere go ahead. i hope someone finds you and puts u in jail and fines you the full 250k.

i'll tell you this, and you can take it for what you want. i've done extensive research and on newer and older cars, i've worked in shops and custom shops, and i've tried it several ways and with several different cats and styles. the very best thing you can get is a cat from random technologies. it's a full pass, hollow cat. i dont know how it works but it does, even at WOT. second would be a magnaflow cat as they're cheap as 20 bux on ebay for a 2.25". third and last option, if you're a backyard mechanic with a torch and some extra pipe laying around and you're a cheapass....you can gut or delete the cat alltogether. and be an idiot.

i have a 383ci camaro, full length headers, borla catback, and 2 magnaflow 3" cats. i make more power with the cats than without. and it cost me a total of 40 bux plus 10 to weld the 'adapters' from the stock units on. i tried open headers, exhaust, with and without cats...and with todays fuels and addatives it's better to leave the cats on.

here's the link to random tech if you're really wanting to delete the cat...but you're more worried about saving money than the environment so i doubt you'll be using it:
http://www.randomtechnology.com/products.html

[chongopants]

yup.

thanks.

[ddongbap]

Originally Posted by BailOut

Spoken like a true Texan.

I don't either. And I'm from California.

[YarisPR]

Does the yaris come with 2 cats and a resonator?

[06silveryaris]

Originally Posted by Capagotks

speaking of rotaries, do you think onw would fit in a yaris, mounted sideways, and even if the front bumper had to be extended?

Some guy in my town had put one in a 99 tercel and kept it front wheel drive. They made a plate for the tranny to use the toyota one. I know they had issues with the intake side of the engine. It was carburated, but now the car is full track car and made rear wheel drive and of course still rotary powered. BTW don't remember if it was 12a or 13b

[06silveryaris]

Originally Posted by YarisPR

Does the yaris come with 2 cats and a resonator?

Yes

[fmicle]

Originally Posted by BailOut

Spoken like a true Texan.

+1

And then they bitch about the Chinese building one new coal power plant every week

[fmicle]

Originally Posted by ddongbap

I don't either. And I'm from California.

I wonder if this attitude would change if you guys had to breathe that crap yourselves... But hey, I guess it's alright if some poor kid somewhere will develop some respiratory disease because of the smog, as long as it's not your kid...

[BailOut]

Originally Posted by fmicle

I wonder if this attitude would change if you guys had to breathe that crap yourselves... But hey, I guess it's alright if some poor kid somewhere will develop some respiratory disease because of the smog, as long as it's not your kid...

... or if they had lived through the destructive acid rain events of the 1970's, which were mostly solved by making catalytic converters compulsory.

Those that do not learn from history are doomed to repeat it.