Retarder Cat Question - MP3

Alejo_NIN

Member
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RadonElement.Com
Ok, so i acquired a MP3 with a built motor, no turbo.
It is running, to the best of my knowledge a 8.5:1 compression ratio.
car has the following.

Proetege5 ECU
upgraded fuel pump
make-shift SRI (while i acquire a stock air box)
stock exhaust
OBX headers
it is missing secondary O2 sensor, but i don;t really car for now
and the second cat is in place.

i started the engine, and it runs really rough (expected from no turbo, less compression)

but for some odd reason, it felt as if the cat was on FIRE, literally, the inside of the car started smoking as the tar insulation around the shifter started melting from the head. bunch of smoke started coming out and it was just really hot inside. it was pretty hot to the touch.

now, at first i thought that i was missing the aluminum shield for the exhaust, but after further investigation, it was still there...then it occurred to a friend of mine that having this engine with low compression would not allow for all the gas to burn....i did some research online and found some info that backs up his thoughts and adds to it "damage to Catalytic Converter" ...
would this cause the cats to overheat to this point?
 
Ok, so i acquired a MP3 with a built motor, no turbo.
It is running, to the best of my knowledge a 8.5:1 compression ratio.
car has the following.

Proetege5 ECU
upgraded fuel pump
make-shift SRI (while i acquire a stock air box)
stock exhaust
OBX headers
it is missing secondary O2 sensor, but i don;t really car for now
and the second cat is in place.

i started the engine, and it runs really rough (expected from no turbo, less compression)

but for some odd reason, it felt as if the cat was on FIRE, literally, the inside of the car started smoking as the tar insulation around the shifter started melting from the head. bunch of smoke started coming out and it was just really hot inside. it was pretty hot to the touch.

now, at first i thought that i was missing the aluminum shield for the exhaust, but after further investigation, it was still there...then it occurred to a friend of mine that having this engine with low compression would not allow for all the gas to burn....i did some research online and found some info that backs up his thoughts and adds to it "damage to Catalytic Converter" ...
would this cause the cats to overheat to this point?

Ya, that cat is probably clogged, so all that heat from the exhaust gases is building up and getting really hot. If it clogs up to the point where gases can't escape enough to relieve pressure, it will literally explode, lol.
 
Ya, that cat is probably clogged, so all that heat from the exhaust gases is building up and getting really hot. If it clogs up to the point where gases can't escape enough to relieve pressure, it will literally explode, lol.

the cat will not explode. if the cat becomes clogged enough, the engine will just shut down because it wont be able to get rid of the exhaust gasses. i know this from first hand experience. i had a grand am with a clogged cat, and the engine would start, but only run for about 15 seconds before it shut down. then, it wouldnt start again untill all of the back pressure relieved itself. (about 10-15 minutes later) the only way to get the car to run was to remove the pre-cat o2 sensor.
 
the cat will not explode. if the cat becomes clogged enough, the engine will just shut down because it wont be able to get rid of the exhaust gasses. i know this from first hand experience. i had a grand am with a clogged cat, and the engine would start, but only run for about 15 seconds before it shut down. then, it wouldnt start again untill all of the back pressure relieved itself. (about 10-15 minutes later) the only way to get the car to run was to remove the pre-cat o2 sensor.

Maybe "explode" wasn't the best/most accurate choice of words. But you can blow a hole out the side of a cat. I've seen cats with holes blown in them. (shrug)

My brother replaced his quad's exhaust last month bcuz he blew the cat in half, actually. lol

*Edit, here ya go. Check this out:

http://forum.miata.net/vb/showthread.php?t=46500
 
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I wanna see pics of this car.

And why not boosted if it has a built engine? Actually, how do you know the engine is built?
 
I wanna see pics of this car.

And why not boosted if it has a built engine? Actually, how do you know the engine is built?

i bought the car right before the guy was ready to junk it. it is a well known friend of mine and i have seen this car on boost. i also know the machanic and i am 100% sure it has built engine. it is 8.5:1 comrpession i believe arias pistons and pauter rods.

it is not turbo because he had started parting out the car and had sold the turbo/manifold and ecu.
i will be transferring this engine from this car into my car and giving the car to my wife.
i am still debating between transfering the whole engine or just changing the turbo setup.
 
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