I know this is a chevy but i figured yall could probably help me out.

I am going with true duals on my 5.7 vortec (2 cats, 2 mufflers, no crossover just real true duals)

Question...

What do i do about the O2 sensors after the cats? Would you just buy 2" in/out cats and not mess with the little cat piping. Or can i get 2.5" in/out cats and the exhaust shop can weld O2 bungs in the 2.5" pipe?


thanks.

 

enjoy your no low end evergy with no crossover.

Why do you need to mess with your O2 sensors in doing this?

Your OEM size should be 2.75 so go with cats the size of your true duals.

 

eh, i wouldnt do cats on a 5.7 350!

 

ill have to agree.. ur better off with a crossover

 

edited.


and about the no crossover i really dont think theyre is any loss yall. these vortec 350s can handle it and i love the sound of real true duals

some food for thought....

http://sbftech.com/index.php/topic,2....html#msg24598
[quote author=Jay Allen link=topic=2493.msg24598#msg24598 date=1164832709]
First off.......Its a 302/302. It isn't a 306.

I did rebuild the shortblock. I fixed what I thought needed to be fixed. The GT-40 heads have an aftermarket valve job and have been converted to stud mount. I have played with various springs, locks and retainers. It has been a SR and it has been a HR. I have used just about any and every HR lifter just to see. It had 1 5/8 BBK headers with 2.5" exhaust with louder than hell Flow-Masters on it. I tried an X pipe. I tried an H pipe. I ran it with straight pipe. The straight pipe was the quickest, and loudest. When it ran 11.19, it weighed 3160 with me in it. I was able to manage a 1.47 sixty foot. This was with 4.56 gears and a 26 X 10 M/T slick. It ran 7.09 at 97.7 to the 1/8. I had too much gear and not enough clutch in it. It was fast to the 1/8 and it should have been quicker out back.

It made 305 RWHP and 317 RWTQ.

 

ahh nevermind ill just get the 2.5" cats. they have to expand it to 2.5" at some point because the muffler inlets are 2.5"

i guess they will just weld some new 02 bungs and if they dont i just buy some o2 simulators. i dont want my cel light on.

 

i'm not trying to start anything but he said nothing about how much quicker and you would more than likely have to run each setup on a different day so the humidity, temp, etc would make a difference. its been dyno proven that an x pipe makes the most power out of the 3 setups. plus he said he had flowmasters and such and doesnt say what he had together like x with the flow, h and the flow, and no crossover and straight.

 

id rather just cut the damn cats out...does anyone know of an inspection station in va that will pass it

stupid virginia laws

 

Were are all talking real world daily driving here, not 1/4 mile...

A crossover will lower your power band for the better in your truck, and you will be able to feel the difference...

 

ok i have a 06 5.4 what about no crossover with 2 6x9 magnaflow mufflers would it really be bad on power?im bettin it would sound really nice and loud! and chevyman cut everything off i love my truck but she will never sound like a chevy lol