Theknifemaker

I did a search on the Warning Exhaust system overheat light and came up with 4 possible causes.
1. bad air pump
2. running to lean or rich
3. clogged cat
4. bad wiring
81 with 147K
So I figured, what the hell, lets go red line for a while and see if I could unclog the cat. I just got the car and it was sitting up for 2 yrs and a friend had bought it and drove it with a varnished carb (bad accl pump) and 2 jets didnt deliver gas. He also drove it like a granny. I bought it from him, changed oil, put a brand new nikki original carb (new old stock) new NKG br8eq-14s plugs, vacuum lines etc, fuel filter.
Well after doing this I got the warning exhaust system overheat. Thats when I ran the car and red lined it. Now the light hasnt come on for 10 to 12 miles of driving. So, a couple of questions.
Could I have unclogged the cat?
Will removing the rats nest increase HP (if so, about how much)?
If you remove the rats nest, do you remove cat also?
If I remove the cat, will I have to re-tune carb?
Last, what do I use to replace the cat, knowing I dont have much money to throw at this car but have welders and a ton of tools.

mazdaverx713b

iTrader: (91)

Could I have unclogged the cat?-no it would have clogged your muffler. bad idea to even think of unclogging a cat while on your car. take it off and knock the stuffing out of it.
Will removing the rats nest increase HP (if so, about how much)?-not much at all. if you dont have an e-check where you live and want to free up a couple of ponies, go right ahead.
If you remove the rats nest, do you remove cat also?-not in every situation. if you remove the air pump, you best remove the cat before it clogs up and does very bad things.
If I remove the cat, will I have to re-tune carb?-no.
Last, what do I use to replace the cat, knowing I dont have much money to throw at this car but have welders and a ton of tools.- make a slip fit straight pipe. seems logical to slip a pipe over the two ends of the cut pipe where the converter used to be and weld it in. i guess it depends on which of the three converters you are replacing

Directfreak

iTrader: (2)

Here's another way to blow your cat.

mazdaverx713b

iTrader: (91)

lol, priceless!

Theknifemaker

By replacing the cat with a straight pipe will it be a lot louder? Does it need to be stainless? Thanks for the tips. Direct freak, hell of a way to blow a cat, lol.

mazdaverx713b

iTrader: (91)

doesnt need to be stainless. it will be a little louder but not too much if you weld the pipe thoroughly.