RichS 1986928

Every two years I need to pass the smog test in Denver Colorado...

My car has no cats and no air pump.

I put the stock cats back on and 'barely' passed 2 years ago. It was so difficult
that this time I want to put an air pump in the system. My old airpump is
shot, so I just want a 12V airpump that I can remove after I pass the
test.

Does anyone have a recommendation of a small 12V airpump that I can
squeeze under the hood easily? Maybe someone has done this before???

thanks

danglerb

cali4sun

Jim M.

AFAIK the stock cats NEED the air pump for light off and complete combustion. Why not just put an X-pipe and aftermarket cats on and be done with it? Sorry I can't help with a 12V application.

zoltan944

for those with 'normal' emissions standards Dave has high flow cats that may work, but for those with more strict standards go with these:
http://cgi.ebay.com/ebaymotors/2-5-2...Q5fAccessories

Jim is right, the older cats with their technology need the air pump, newer cats do not need an airpump

RichS 1986928

I've got the Xpipe and plan to do a full dual exhaust system as soon as they are available again from
928motorsports.

I have no plans to put on cats right now. I'm already losing power from the altitude here and don't want
to lose any more.

Like I said it passed two years ago with the stock cats and no airpump.. but just barely and it took about
10 tries. Including 5 by some teenage chick who kept stalling it. I don't want to go through that again.
They don't let you drive your own car through the testing here.

Maybe no one here has done this before so I'll report back. I'm going to try something like this:

http://cgi.ebay.com/ebaymotors/ws/eB...K%3AMEWAX%3AIT

Lopez

Are you going to put the stock cats back on too? It almost sounds like you are going to run with the air pump and your x-pipe.

Ralph Newman

Rich,
Find out where the mobile units are. Currently one is located on the southbound Mississippi exit ramp of I-225. This is close to my work so whenever I see them there I drive whatever car is due for an inspection through it. I do that 2 or 3 different days and when I receive my registration it has waved the inspection (but not the $25.00 charge).

RichS 1986928

Yes, I'll be swapping the Xpipe for the stock cats to pass the test.

Ralph, that's not a bad idea however I'd like to see where the car is actually running, does that give
you readout or just a pass/fail? Right now I know it fails.

zoltan944

Rich,
You take the xpipe and cut for the cats and use the same clamps used on the Xpipe now for the cats. It is easier to swap cats for the straight pipe than it is to change out the whole xpipe and an additional smog pump.
In Las Vegas Dave's super high flow cats (dynoed to lose only 1-3 hp) were good enough to pass. It took me about 15min plus jacking time to change straight pipes to cats go get tested, drive like that for a while and another 15 min to change back (once the clamps have the shape it is quick with an impact gun on low setting).
Takes me about 1.5hr to 2hrs to change the pipe on the ground (after first time with all the rusted crappy hardware on there). If that seems faster to you along with hooking up a 12v air pump then I would get the cheapest 12v pump possible and just zip tie it in there and hook it up for easy removal.
You will be suprised how much the highest flowing cat there is makes a difference over no cat on a sniffer test

Don Carter

In TX, when a car hits 24 years of age, based on build date, no more smog tests... Are there similar rules in CO?

My 86 passed recently after years of failing with high NOX. I have cats, but had to put a new O2 sensor in to pass, and of course ran it in 2nd gear for the test. Now I'm all set because July of next year (we have to pass every year), the car will be old enough not to need a smog test, so I can proceed now with the X-Pipe and cat removal.

RichS 1986928

Zoltan, I'm not quite understanding you.

If I could put on Cats that would only lose 1-3 HP and pass the test with no airpump, I'd probably do
it. What Cat/Cats will do that?

Are you talking about pulling the high flow cats on and off too? If I have to cut the x-pipe how is that
possible?

RichS 1986928

Unfortunately no, I don't think there is a 24 year rule here in Colorado.

dprantl

One year I passed emissions just fine with stock cats and no air pump... This was before I installed the X-pipe w/ high-flow cats.

Dan
'91 928GT S/C 475hp/460lb.ft