I'm finally looking into a new exhaust system. Most of the ones I've found do not come with cats. Living in BC we do have emmision testing here. I'm wondering if I lose the cat will I still pass the emmision test? Anyone pass without there cat?

Thanks

Dave

dave2001, first you should find out if your area is diesel exempt from emissions. if it is you can dump the cat as long as you dont have visual inspections on emissions. if you do you can hollow out your cat very easily. if you are not diesel exempt you will need cat to pass emissions.(bummer)

I have a ho 6.5. Was told the downpipe is more freeflowing than on other 6.5s. Is this true? I looked as good as I can and I see very small dents. Have not changed any exhaust. I was also told the exhaust was bigger on the ho. Mine is two and 3/4 after the muffler.

dave2001, first you should find out if your area is diesel exempt from emissions. if it is you can dump the cat as long as you dont have visual inspections on emissions. if you do you can hollow out your cat very easily. if you are not diesel exempt you will need cat to pass emissions.(bummer)
Ya.. we test the diesel here, but only on the sniffer and dyno. There is no visual check anymore. You think without the cat my emmision would not pass?

Dave

96gm65, if you look hard enough it looks as if my kids were denting your pipe with a 2 pound ball peen hammer(what was gm thinking) try an aftermarket down and mandrel bent x-over. flowmaster has a good one and there are some sponsers on this site that have excellent oversized systems. breathing free is diesel friendly. dents=restriction.

dave2001, you might be able to pass with an additive that reduces emissions. i think there are many diesel friendly ones on the market. not sure if stanadyne additive reduces emissions. maybe someone else might know. i know it is good for your ip.

hey dave, you could make a quick connect cat and straight pipe system for your truck. you can put cat on to pass emissions and next day, presto ,cat disappears. kinda like smog magic.

Something I did for my "off road only" bypass is knocked out the studs of my old crushed down pipe flange & welded a short piece of straight pipe to it, and then used some stainless flex exhaust tube ala JC Whitney & stainless wraparound clamps to make jumper connection, easy on easy off when you get legal and reinstall your cat, when finished off roading. I shot some pics but at nite with flash files too large will add pics in daylight

Thanks bowti, I was planning on a new downpipe but didn't think it was needed unless I pull . Dave, sorry if I hijacked your post. Can a person get a larger cat. Or maybe one thats flows better. I read someplace where they used a Dodge cat.

You should be able to pass with out it if they aren't checking visually

Most racing supplier (summit,jegs) sell free flowing CAT's but the diesel runs a soot trap.

96gmc65, i dont know about emission laws around your area, but where i live diesels are exempt. that being the case i totally uncorked my ride.no cat no muffler sweeeeeeeeet sounds and a lot more power. if you can dump the cat then dump it. first they choke our engines with cats then they reduce the sulfur in the fuel so you go through ip's even faster,whats next? the smog police should crack down on the real polluters.

Both my 96 GMC and 96 Chevy have Kennedys exhaust found here :

http://www.kennedydiesel.com/categoryresults2.cfm?Category=2&SubCategory=66on
The soot trap is removed on my trucks. But he does give you directions if you want to maintain it in his system. The exhaust was easy to install and I noticed better performance/ MPG as well as lower EGT's. I highly recommend this exhaust to replace the poor downpipe and the restrictive stock exhaust. If you look under your Hood it should have a sticker that says emissions exempt since both of mine do. I do not know what states are starting the testing and when but you should be grandfathered in with a 96. Hope this helps

If you loose the cat I can pretty much guarantee you that you will fail emissions. I installed a nice 4’’ free flow exhaust from Pinnacle on my ’95 Burb, and I cannot get it to pass emissions. I took the test 3 times, and failed each time. After the second attempt I paid an emissions specialist to $250, to basically bang up my passenger side mirror. That is the first and last time I will ever pay a shop to work on my rig. Luckily my wife is quite the sweet talker, and she talked the emissions guy into getting a waiver. I have a two year grace period, before I have to go through this exercise again.

If you loose the cat I can pretty much guarantee you that you will fail emissions. I installed a nice 4’’ free flow exhaust from Pinnacle on my ’95 Burb, and I cannot get it to pass emissions. I took the test 3 times, and failed each time. After the second attempt I paid an emissions specialist to $250, to basically bang up my passenger side mirror. That is the first and last time I will ever pay a shop to work on my rig. Luckily my wife is quite the sweet talker, and she talked the emissions guy into getting a waiver. I have a two year grace period, before I have to go through this exercise again.
I'm wondering how badly you failed the test? Up here in BC our standards are not as strict as yours I believe.

Also could be way they ran the test, of course you are up against a stacked deck when you don't have one in place and your sticker says you are supposed to have one, which is I left option to re-Cat if need be, I wonder how you would have made out with a shelled Cat & a tube passing thru the body, not that I advocate that you try to decieve a representative of an official state agency.

It's amazing to me how F trucks get a pass & S trucks don't; neither makes any more smoke than the other, just Big Government exercising it's muscle because we have let them get too big, I'll stop now as I'll go into a rant better suited for the off topic forum. Anybody want start a rant over there to satisfy a need to vent?