Is this possible?

 

Wouldn't it throw a CEL light? Or even worst, a O2 sensor going bad?

 

With MTH Ecu mod they can fix CEL light.

 

I've been playing with the idea of not using a cat for quite some time now...not with my mini but with my pickup. I live in NY and we now only use OBD II testing for our emissions tests. Which makes it quite convenient to ditch the cat and just make sure the CEL doesn't illuminate. From what I have read over the past year or so I have never found any conclusive evidence that ditching the cat makes more power. I've actually seen dyno charts where not having a cat decreased the backpressure so much that the car actually lost hp and tq. Now we all know that dyno's are so shady but I believe it. You have to have some backpressure because engines are designed for work with it...we all jsut dont need as much as manufacturers give us. Maybe you might want to reconsider not running a cat and stick with a high flow unit that comes with the MTH header. Just my $.02
Steve

 

Randy Webb is trying to make 3" exhaust to get rid of the backpressure. So, in a forced induction car you can make more power by removing the cat.

 

Hmm that's really interesting. I never even considered the fact that forced induction would change the exhaust flow. But it makes sense. In my other case (my pickup) i'm talkign about a non-aspirated engine so thanks man for throwing that other angle on that. I appreciate it.

Steve

 

i'm just wondering how much more HP do you intend on getting without a CAT? 1 HP maybe? is it worth damaging the enviroment for that much horse power? besides the stinky smells from un-burnt gas (our cars run rich), carbon monoxide, nitrogen oxides', etc you get from running CAT-less; it is ILLEGAL to run cars and trucks cat-less on public streets and freeways without a catalytic converter.... (the track is different animal)\.. if i were running my car on the track all the time i would opt for catless header because the heat created in such events causes cat failure or melted cats...

just a thought.. remember, there are BIG fines for running without a cat.. also, if you are in a major accident your insurance could decline your claim because you car had a modified emission system. (no cat)

good luck!

 

Oh dude I hope you weren't directing that at me...I kind of just jumped into this thread in the middle of it. I was actually steering him away from running without a cat. I was just making a point that I was always under the impression that eliminating a cat can produce more power which I think quite a few people think the same way. But after talking with many many people about it, I've come to realize (in most cases) in can actually hurt the performance. Anyways I'll let this thread get back to the original guy who started this. BTW I would take a MTH header anyday and just be happy that I have one under the hood. The hell with dismantling it and altering the way it was meant to perform. I am very impressed at what MTH offers and wish a company like them was available for my Toyota pickup. Its in some desperate need of power and MTH is just so easy. Just a few more of my $.02. Thanks
Steve

 

i'm sorry about that. mis read the thread...:impatient i still stand by the idea that cats are good and cat-less is bad..

 

no prob man...no hard feelings here

 

high flow cats will not effect hp enough to get rid of it, things are much better than 10 years ago, the key is cheap cats do not last for long, a good cat is pretty expensive, this is one reason the mth header is rather pricey. the bmw engineers have been fighting power loss through cats for many years, they have had very stringent regulations for more years than us in the states, the other thing is our gas has allways been cheap until just recently, this allowed u.s. car manufacters to make hp with larger motors,5.7 v8's for example will produce more hp easily compared to 2.0 liter engines, let alone 1.6 engines. take the time to calculate hp to cc's and it is rather impressive the hp these little engines are making. the only case a cat needs to be removed is when running leaded race fuel, lead will kill a cat quickly.

cheers