Is there such a thing as too little back pressure?

I plan on removing my secondary air injection, and when a friend of mine did the same his cats disintegrated. As in there were peices of honeycomb shooting out of his exhaust. Does anyone expect the converter destruction to have any noticable effect on performance? I assume there will be a reduction in back pressure.

 

thats a hot issue. many say yes cause it will burn up your valves or someting. others say no cause ppl run opn headers all the time. as long as there is someting there there wont be an issue. its more of an issue with the exhaust sucking in cold air, so as long as you have headers your fine. there is another tread about this somewere here.

 

wow a new way to gut a cat. lol. must have been bad on the muffler. yes u should gain some performance with a gutted cat. it allows more air flow. be better if i knew what car it was on but if u have a computer its best to have it tuned for the extra air flow.

 

The problem with no back pressure is that it's easy for the exhaust valves to suck in cool air in that split millisecond when they're still open and the piston begins it's return travel. That little bit of cold air can easily warp the valves and valve seats. As long as you have headers, you're fine as you have no place to suck cool air when the engine is at operating temperature. Now say that you ran with no headers or manifolds, just straight out the ports. The air around the ports is going to be drastically cooler than the temperature of the valves, meaning that it's constantly sucking cool air, which in theory could trash your valves rather quickly.

 

Hm sounds good. Yeah I didn't think about what my muffler would have to go through.

By the way its a 92 Z28 with a 305. Five speed . I'm gonna seafoam my baby tonight.

 

you can remove it with no problems...just go to the hardware store and find the correct size pluggs to fill in those holes in the manifold. they might be plumbing thread so you may have to go the the plumbing section but i thin i can remember using allen head caps on mine.

 

im with Jr. on this one..

So long as you have SOMETHING off the heads you will be ok. However, the car is in need of SOME backpressure. Those cars running open headers are putting out a good amount of power and are getting the pressure they need JUST from the headers. However, i dont see where the AIR system comes into play with this..

 

Just one thought for you Inspection, I know here in Pa where I live you have to have all factory smog equipment in place to pass even if it gets good numbers with the emissions test. Just a thought don't know what you use the car for street/strip wise. Same with removing the Cat . I know people who fab up a pipe to replace the cat but keep the Cat to throw back in once a year just for emissions.