Emissions and Noise-First Cat. Removal ?
 

Need some info about what to expect if I remove the first cat. conv.--the one close to the turbo. How much will the noise and emissions increase?

mine has been out for a few years and i pass emissions ( i think 3 times now or roughly 5 yrs)
i never noticed any noise, just FCO.
I don't have any actual numbers of how much emissions increase.

FCO? New one for me. The small size of the cat. makes me think it doesn't flow well, but I haven't looked inside.


I did take a die grinder to the elbow and enlarged the most restrictive areas. Took me ~15 min--easier than porting a small-block Chevy port.

when you go from stock to modified at some point you'll start hitting Fuel Cut Off FCO. we're talking turbo supra.
once you let the car start to breathe the computer will realize that there is way more air flowing than normal and you'll throw a error "code 34"and at the same time you will shit your pants
because the EFI will cut off fuel for just a fraction of a second . now picture this ...

you are punching it hard and the car feels real nice and it's pulling good , you're smiling big .. then all the sudden WHAM ! it's like you hit a car but there's none in sight
if you're not expecting it you will shit your pants .

you will quickly learn either
A:
not to punch it so much

or

B:
figure out you need to spend more money to get rid of that shit

I don't want to raise the HP that much. The horror of losing another HG is the big factor. I'm still getting the car back together-it's been over a month. I'm amazed that anyone can do this job in less than a week.


~10 psi is enough--at least for a few years.

dude you're gonna hit FCO at some point
and i know exactly what you mean .. that engine has earned your respect.

FCO happens around 1 bar

OK, I'm not going to boost that high. 10-11 psi is enough for me.

Tomorrow night is the dreaded turbo oil line attachment to the block. I put a bunch of antiseize on all the studs on the turbo and greased the others.

I noticed that both flanges on the oil line had warped a little from the tightening of the studs. I flattened them using sandpaper and a flat steel plate. Only took a few minutes. I wonder how many oil leaks have been caused by the under-turbo flange losing its flatness/sealing.

Wish me luck.

yeah those bolts are a MF to get at ...and btw 10-12 lbs will give you FCO --enjoy!

I see that Toy. moved the 1st cat. closer to the turbo in 1989 or 1990. My 1988 Turbo has it located back a few feet. I guess they wanted it in a hotter location.