Will hi-flow BBK cats lets me pass emissions?

jaymac

New Member
Feb 18, 2004
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Northern Mass
My buddy has a BBK shorty X pipe w/ hi-flow cats laying around w/ less than 1000 miles. I have shorty headers, but want the cats anyway.
If I cut and welded those hi-flo cats onto my O/R H pipe, would that let me pass emissions? I don' t know if I'll be able to find a "hook-up" here in MA this year to make my O/R pipe pass again. plus, here in MA, staties have mirrors they can slide under your car if they want to :fuss:
I'm also not worried about loss in power as I lost a little low-end torque at cruising speeds w/ the O/R set-up and my torque converter.
Also, will it work for emissions even if/ though I don't have an air tube for the smog pump/secondary air system?
Thanks alot,
J
 
Even a car with all stock exhaust, including cats, can fail emmisions. It has alot to do with how the car is running in general and how your tune is.

If you car runs like a pig, you may need to do more than just weld those cats on.

Where in MA are you?
 
I'm in haverhill.
The car runs good. All sensors are new, tune is good ( I could probably lean it out more for testing :D)
I'm not worried about any conditions other than the cats, just wondering if they'll have an effect even w/o the air tubes and smog pump
 
Also, I haven't checked if those cats use the air tubes (a picture from Summit shows them using an air tube). If I just run a piece of high themp emissions hose from the tube on the cats stratight to the smog pump, will that be enough to make it function, or do I need the whole piece that splits off and goes to BOTH hoses from the smog pump? Where do both of those hoses go, anyways...?
 
The air pump helps with catalyzation. But having cats vs no cats definately cleans up the air - just not as much as it would with that extra air.

I am not smart enough to answer more precisely. :D
Good luck bud.
 
Recently my car passed with the stock 4 cat pipe and no smog pump. The emission numbers were 1/3 to 1/2 of what the maximum allowed is. I say if you have a stock pipe, throw it for inspection. Then your good until you can get the part you really want.
 
jaymac said:
so I "could" tehoretically pass w/ hi-flo cats and no smog pump?
Will I plug up the cats fi they're made w/ an air tube and I don't run one?

I would guess yes.

Best advice I can think of is... Ask the manufacturers of the cats what they recommend.

If you are dead set on not running an air pump (you would have good reason not to), then keep looking til you find the right cats for your application. Sorry I can't offer any references, I have yet to address this issue myself.
 
jaymac said:
so I "could" tehoretically pass w/ hi-flo cats and no smog pump?
Will I plug up the cats fi they're made w/ an air tube and I don't run one?


You would fail the "visual" part of the test right away. If somebody passed with out a smog pump they had to have somebody overlook the missing pump. I don't know where you live but that would never happen in California unless the smog guy was your buddy.
 
J, not that I would ever condone it ;) , but I dont see the diverter valve and the pipes to the heads being that important. That is only used for a little bit during warm up to get stuff hot faster.

For long term DD'ing, having a pipe run to the cats is more important. That is how older stuff was too (air injected cats on cars before EFI). This would be a bit better than nothing at all IMHO.
Just keep the check valve on the line from the smog pump (to catch backfires and save the pump).

Just my vantage point bud.
Good luck.
 
I personally failed emissions here in AZ without cats. So I threw on a BBK catted x-pipe with pipe plugged and passed with flying colors even without a smog pump. I actually blew less than my brother's Geo. :D Plus I used a acetone/alcohol combo in the gas.... :banana: