U-bend Delete, No Cat..

[monte2k]

Hey Guys/Girls (theres gotta be some on here?)

So i have a 2000 Monte (3.4, LA1)... I've been told conflicting info on the U-bend Delete and removing the cat completely for those engines...

Will this help me or harm me? Some people have said that it will increase flow (might, might notice the difference) while otheres have said that the loss in back presure will do more harm then good?

Any advice here?

Thanks, much appreciated!

[3400-95-Modified]

The good ole backpressure debate won't hold much water... put it this way, the U-bend delete should help since any bend in a exhaust system is restrictive and smoothing out the pipe flow is a good thing... however the Cat removal is completely unnecessary if you ask me... Its only proven to add very minimal gains if any at all... Just keep the cat on and keep the air clean, the "power" gained is not worth the harm done out the pipe... IIRC some say its 2-3whp if that...

[robertisaar]

anybody happen to have a picture of the U-Bend? i've heard about it for about 3 years, yet have never seen 1 photo...

[3400-95-Modified]

Replacement

[robertisaar]

Hey GM:

:FACEPALM:

who the hell had that idea? and i'm assuming i'm looking right after the cat due to the O2 sensor. seriously, it probably cost more to make that u-pipe than a proper one, and for what benefit?

and does this affect only OBD2 cars, if so which ones? i've heard of the L67 guys doing it all the time, but i didn't know it was on the 60s too...

[monte2k]

Aright Wicked thanks man

Can i buy that part somewhere or should i just get some one who is decent with a welder to make one up?

[IsaacHayes]

It's to keep the after cat O2 sensor from hitting stuff in the road. With it straight up it's protected. yes OBD2 cars. Most of the 97+ W bodies have this, maybe the 99+ N bodies as well?

[Superdave]

i don't remember my '04 GAGT having it but i'll look today...

[IsaacHayes]

It may only be W bodies.

You can get them at various places online. Partsforyourcar.com might have it. ZPPerformance.com, intense probably has them etc.

Also the cat's on some of the Impalas/Monte like 2000-2003? or somewhere around there had problems with clogged cats. GM would replace them if the car was under certain amount of miles. My friend had it happen and was just out of the replacement period. So he had a new cat from a local shop and it fixed his no power issues.

Something about some insulation inside them breaking off and clogging the opening. Might want to throw on a high flow cat if you want more power and don't want to worry about that.

I suggest a magnaflow/carsound cat (can be found cheap new on ebay).

I went with a metallic core spun stainless one, and it's a lot shorter and bigger cells than stock.

[geldartb]

def not on the 99+ Nbodies. they angle the sensor upward towards the drivers side of the car.

the exhaust tunnel is wide enough and the sensor is far enough forward.

[monte2k]

well my plan is to gut the CAT and just run a straight pipe through it, weld it shut

[geldartb]

i hope you got some way to turn off the rear O2 sensor code cause if you dont it will trip the ses light.

either a tuner software or an o2 sim. why gut the cat it yields no performance increase.

[robertisaar]

it makes it louder??? its also one less thing that could break...

[monte2k]

i know its going to throw a code, i saw an emulator on zzp....

Will i even notice a difference with the u bend delete out of the way?

Any other cheap mods? the car seems a lil slow the respond with i slam the throttle... any idea what might be main cause of that?

[robertisaar]

you'll get a slight reduction in backpressure... that being said, a retarded powerful car would benefit more than one thats mostly stock