Das GT

thaaaaanks......

though i havent called it the cadillac coverter yet

so the caddyvert cant burn a car up with more miles?...... kewl

98redstang

im so f*&kin confused with this burning bs.... i still stand with my theory and the guy is taking your brothers cars and scrapping them for cash. probably doing it to multiple people as well....

cliffyk

The catalytic converters "light off", I.e start doing their job of converting unburned hydrocarbons and carbon monoxide to CO2, at 400 to 600°F; they normally operate at 1200 to 1600°F--and can, if there's a lot of unburned fuel, reach 2000°F. This is why they have heat shields, sometimes insulated.

There are stories of people parking their cars in tall dry grass, and having the cat(s) ignite a fire--I have never directly observed this, nor I have never heard from a reliable source of this happening.

As to having/not-having cats it makes no practical difference in engine power as a properly sized converter presents very little restriction.

One last comment, back pressure is always bad--the less you have the more power you will make at any rpm. Here are a couple of white-paper documents that try to dispel the "backpressure myth".

Backpressure Myth

Backpressure Myth II

Rockwell28

As to having/not-having cats it makes no practical difference in engine power as a properly sized converter presents very little restriction.

One last comment, back pressure is always bad--the less you have the more power you will make at any rpm. Here are a couple of white-paper documents that try to dispel the "backpressure myth".

Backpressure Myth

Backpressure Myth II[/QUOTE]

After reading the articles I guess thats why with a wide open exhaust you feel like you lose power on the bottom end/take off bc it performs better in the upper rpm range with the less backpressure you have.

Rockwell28

but at the end of that 1st article it says that for street cars you want to keep the bottom end grunt the top end is better for race cars and track cars vs street cars

cliffyk

Yes--why is that a "but"?

cliffyk

Low back-pressure is a characteristic of a poorly sized exhaust system, I.e one improperly sized for desired operating speed range. As such it accompanies poor performance attributed to a particular exhaust system. It does not cause that poor performance, which is instead caused by the reduce flow velocity of an over sized exhaust.

It's the lower exhaust gas velocity, in the larger pipe at lower engine speeds, that robs the power as it does a worse job of pulling the gases behind it along for the ride, and assisting in clearing the cylinder and pulling in the fresh charge.

The key point to remember is that each pulse of exhaust gas has mass (weight) and is being "fired" out of the engine--it is expanding gas in a closed chamber with one way out, the "bullet" is the high pressure leading edge of the pulse.

boduke0220

There was a pretty decent difference when my buddy put an Off road H on his car ( 04 Mach 1) then took it off. this was all done in one day.

cliffyk

Did he go from the stock pipe to the after market? If so then there's the difference. There is also a significant placebo effect from the added noise...

Rockwell28

Was it a good or bad difference?