Cat or No cat?

Osmosis

Osmosis

New member
I purchaesd an RPM dual BB 60/1 turbo last year. When I put the turbo on, I also removed my cat, added a 2800 stall and alky on the ty for the turbo. The new turbo has a lot more umph to it, but it has a lag area in the part throttle during lower rpm's. I got a wild hair up my butt and put my 3 inch cat back on the truck to see if it would help reduce that lag during certain rpm's. My Ty seems to run way better with the cat on and it seemed to reduce a lot of the lag I was experiencing with the straight pipe. By the way, it's a high flow 3 inch cat. I can tell a tiny loss of power in the upper rpms with the cat on, but lets face it, our rig's don't rev that high unless we mod it with vortech heads/cam etc.

I'm curious of others experiences with an upgraded turbo and no cat's vs high flow 3 inch cats.:tup:

I guess my question is the cat giving me back pressure that I have needed to reduce my lag I had?
I'm sure the cat keeps reduces my hp down @ higher rpms, but our trucks only go up to 4800rpm stock.

My mods include;

AFPR @ 52psi, Code 59 running 20psi with alky, 2800 stall, RPM 60/1 dual BB turbo stage 3, 3 bar map, 97 octane, rear sway bar.
 
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Osmosis

Osmosis

New member
Re: Cat or No cat?

Yes, I know how to properly adjust the afpr. 52 with the vac line plugged. I get my best AF ratio with that fuel psi and my tune. Stock injectors, walbro 255lph pump, 3 bar map, 20 psi and alky. AF ratio is 10.7/1 @ WOT across the board. With out alky, my second chip is set @ 11.5/1 @ 49 psi fuel psi.
 
ghettosled

ghettosled

SYTY SUPERSTORE
Re: Cat or No cat?

boost should spool faster without a cat, however the increased backpressure with a cat responds different and gives you the feeling of more low end or instantaneous response.

I remember 10+ years ago experiencing the same thing with my Ty.
 
ghettosled

ghettosled

SYTY SUPERSTORE
Re: Cat or No cat?

boost should spool faster without a cat, however the increased backpressure with a cat responds different and gives you the feeling of more low end or instantaneous response.

I remember 10+ years ago experiencing the same thing with my Ty.
 
Osmosis

Osmosis

New member
Re: Cat or No cat?

Mike,

Thanks for the reply. My turbo, the one you sold me spools up the same with or without the cat. I hit 20 psi in a blink of an eye! Great turbo! It seems .....seems....... that I get much better throttle response with the cat on. I do notice a tiny bit of loss of power in the upper rpms, but hey, my ty is stock minus the turbo/converter and misc reliablity upgrades to put her in the 12s. Once I upgrade to vortech's and the conversion for the intake and larger cam, then, the cat is definatley gone! But for now, she seems to really run better with the cat on. I do have a high flow random tech. 3 inch cat, i'm sure that helps keep the flow going well with a little back pressure.
 
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