i have a 92 firebird tbi with 173000 miles and i'm thinking of removing the emissions system. i don't have emissions test in michigan. can i remove it and what kind of change can i expect from the engine. any horse power inprovements. i know i need to plug the holes on the exhaust manifolds and lose the cat. but is there any other changes i need to make

 

Don't expect wild horsepower gains. You may actually reduce power by messing with the speed density system's brain (although that isn't very likely). Mostly you'll be reducing weight and clutter.

 

If you take out the smog pump and find a different belt you might gain a little power. I took it out to gain reliability.

 

You might feel a bit of a kick, if that. But The MAIN reason for taking that stuff out is to clean up the engine bay. Purley asthetics, and less stuff that can break.

 

I took all mine out and made it look a lot better, didn't really see any horse gains.....I can give you a number for the belt but I think there is a article here that says the length you need..... I'll get back with ya when I get out of work

 

You might not have emissions tests in Michigan, but removing or tampering with your vehicle's emissions systems is a federal offense punishable by a fine or jail time, if you get caught...

 

Yeah yeah......thats what they al say....hehe. But honestly I have read that a bunch of times and have never herd of anyone getting in trouble. Not even a fine. I have not been around as long as other guys (21), but here in MA the smog tests are very strict and I have only herd of failed inspections and even then 20 bucks in the testers pocket is almost allways the cure.

I know that is the route that I am gonna have to take to get my 500 HP 383 91 Z28 back on the raod with a legit sticker. There is no way in hell this monster is passing emissions.


I say do what you want, cops are too stupid to figure anything like, what emission controls your car came with, out. Hell most mechanics can't tell. Who exactly is gonna be doing the arresting? Not trying to be a *** but after rambling for a minute, I really became curiouse. I would like to know who to watch out for (supposedly),

 

I guarantee there is an anonymous tipline somewhere, I'm not saying its likely or even that they'll care, but it's always a possibility. My air tubes were cut and plugged very obviously and I passed MA inspection with a 20 year old cat.

I say get headers rather than plugging stock manifolds, its just a pain in the *** for no real gains.

 

I think cops might be able to give you a ticket for "faulty equipment" if you are missing an emissions device.

I got pulled over one time and the cop looked under my car by where the cat was to make sure it was there. Thankfully I still had it in then so no fine.

I think the "punishable federal offense" part is something the EPA puts in to screw auto shops. They go after the deep pockets, not individuals who couldnt pay a $1000 fine, let a lone a $20k fine.

Just follow the money trail.....

 

I can understand why you would want to remove the AIR but is there any reason why you want to remove the cat? You won't see any real performance gain by just deleting it and you may not like the sound of your LO3 without it. Just food for thought.

 

Less weight Those things aint light.

 

What's another 10 pounds on a 3200 pound car? I know it adds up and whatnot, but to stop pollution I'll limit my car just a bit.

 

When you remove the AIR system, you'd be wise to remove the cat as well, because the AIR system feeds the cat air to get it hot. VERY hot. Without the AIR system, it can't get hot enough to work properly, and will just clog up.

 

all the air system does is make the cat work before everything warms up. once the car is warm, the cat is warm enough. I fast passed IL emmisions with nothing but a cat.

Is this car daily driven? If i was driving my car every day i dont think i would take any of the emissions off. That equipment is there for a reason. I dont wana breath in those fumes! Its a TBI 305 anyways.... not a race car, it wont be any faster after removing that stuff.

 

Well what SMURFN' Z28 said about the car not gettting any faster is true. If you aren't swapping that motor, just leave the stuff.

Only reason I took all my stuff out is the fact that I am changing every last thing on the car. It will be daily driven, but only 3 seasons.

Air pump wieghts nothin', maybe 3 lbs.
After that the rest must all weight less than a couple pounds and then there is the restirction of the cats, but that is a whole other thread, hehe.

Anyways, I am done.

 

 

Not true.

 

Well, I guess I'm going to have to make an example out of you now, huh?


My 580 or so HP "monster" passed just fine. Infact, we ran it twice just to prove it wasn't a fluke, changing which pipe he put the sensor in, etc.

I suggest you learn a little more about cars before assuming something.

I take offense to that.

Can I say your too stupid to tune your car properly to pass emissions? How does it make you feel when someone calls you stupid?

-- Joe

 

Your most definately on to something!

Very very recently, we did an exhaust on my buddies T/a. (speed density car). I spent some time tuning it for the stock setup (with lots of datalogging) and fuel + spark was dead nuts on.

After the exhaust, first few runs with the laptop and the thing was CRAZY leaning out. I couldn't believe how much fuel I had to add with the new exhaust. Now keep in mind, we're talking headers, catback, carsound high-flow cat, etc. But still. Talk about a dramatic difference..

Speed density def takes more tinkering to get it right, but when you hit the sweet spot theres nothing like it


-- Joe

 

My car was bought with stock cat and the AIR system removed. I've put 10K on it. The cat STILL isn't clogged so I doubt that's even remotely true.

 

anesthes, with only cat removal, I'm not sure if that's enough of a change. With headers and full exhaust change-out, then definately you'll get into that situation.

As for cats clogging without A.I.R., urban myth. I ran my LG4 for 2 years w/o A.I.R., then put it back on when emissions test came up again, and it passed - I literally drove it from my garage after putting the A.I.R. back on, 3 miles to the test station, and it passed with flying colors.

A popular misconception is the A.I.R. is just there to get the cat warmed up. No, A.I.R. is routed to the exhaust manifolds during open loop operation because it is more effective there before the cat warms up. Once the system goes to closed loop, it has to be routed after the O2 sensor or it will give false readings there, and it is injected in the middle of the cat where it is most effective during those conditions (reducing CO, primarily, although it still helps combust unburnt hydrocarbons).

 

It is true... didnt you notice how theres a hose going from the AIR system down to your cat?

Theres a reason thats there...

 

no it isnt true it is there to give more complete burn of the gasses the go through the cat, it is manly there because it is a cheap what to help the cars through emissions. if it was needed than all cats sold would have an air tube.

 

The tube is there to keep the cat from getting clogged? WRONG! It's there to help burn pollutants which otherwise escape... they aren't trapped in your cat. I'd like to see one person that can prove the AIR pump removal ruined their cat becuase I've heard dozens of people that say it won't happen.

 

im gonna run a cat WITHOUT air and gaurantee i wont have a clogged cat, and i know this cus it wont be the 1st time ive done it

 

No, thats not what I said... that tube is there to get the cat hotter than it otherwise would get, which means it burns more of what goes through it.

 

i took all that crap off but my cat 5 years ago no power added but the cat is still fine