Adding cats?

Tired of paying so much? Sounds like you just need to find a different shop. It might take you a few tries but you will know when you find it when you get a lady to do the inspection without them having a lift or anything where they can look under it easily. If you get a lady they do not want to crawl under your car to check for cats and just drive it.. You can get it done just look for a shop maybe a bit further out of Houston area which is where I think you are. The only problem would be if yall have county specific laws which you would be screwed there. It also might have been cheaper to buy the whole H pipe with the high flow cats in it already as well. Good luck with it.

I installed hi flo cats on my son's car and it passed right away.

I was getting mine done by some mexican shop. The dudes didn't even speak english and were happy to inspect it. After 3 years of using them, they got shut down lol

DAMNIT!!

I don't think they even knew what a catalytic converter was. lol

rjs281 said:

some on another forum i posted on said my car still wont pass. i do have long tubes. anybody done theres with this setup?

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If you have a sniffer test to pass it could be dodgy.

The thing with catalytic converters is that they need heat to operate. LTs tend to isolate the catalytic converters from the heat of the exhaust ports. If the car is run gently (like a sniffer test) or left to idle for any length of time the cats can cool down enough to stop working and the emissions levels will go up.

Another problem with so-called "high-flow" cats is that they suck. If you've ever looked at the honeycomb for an OE cat you can see there are thousands of small passages for the exhaust to pass through. Their construction uses washcoats to increase surface area further. On the Mustang there are two cats per side (even 3 in earlier cars) to deal with different exhaust compounds and phases of driving.

High-flow cats open up the channels to reduce pressure drop but this reduces surface area and dwell-time leading to less efficient catalysis. The result is generally higher emissions.

So that's two strikes.

A potential third is that you're modded. If your fuel system is reasonably well tuned and the O2 sensors are working properly (and staying warm since they too need heat to operate properly) you might be okay there. The tests are done in closed loop so this may not be a problem.

The OE cats are really something else. I had my KB 2V sniffed recently (required every two years here) and the readings were basically cleaner than the day I got it 7 years ago. I had to put the OE pipe back on some time ago because I knew my MRT catted-H wouldn't stand a chance (it failed miserably a couple of years back...) However, I have OE manifolds which doesn't help you much.

I've got a VW GTI 1.8T with a "high flow" downpipe on it due for the same sniffer test and it's been a crap-shoot the last couple of years. I think it's probably going to fail this year. Lucky I held on to the OE downpipe...

Drive out of the Houston area. In San Antonio they don't sniff and your car doesn't have to go on the rollers for emissions. The inspection was also $12, instead of the >$50 it is in Houston. All it takes is driving 2 counties outside of Houston and you will get a similar deal. The price difference alone pays for your gas out there.

No break in needed for cats. Make sure your car is well warmed up and you should be good.

I'm glad you are running cats. I run cats too because I don't want my car to smell like poo.

Dark04GT said:

Drive out of the Houston area. In San Antonio they don't sniff and your car doesn't have to go on the rollers for emissions. The inspection was also $12, instead of the >$50 it is in Houston. All it takes is driving 2 counties outside of Houston and you will get a similar deal. The price difference alone pays for your gas out there.

No break in needed for cats. Make sure your car is well warmed up and you should be good.

I'm glad you are running cats. I run cats too because I don't want my car to smell like poo.

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I've been running offroad exhaust for the past 7 years or so and I enjoy the smell

In the Houston area (Harris County) you have to get an inspection IN Harris county. My car passed with a magnaflow catted x pipe with high flow cats. They may not be as efficient as OEM cats, but they make it so the exhaust doesnt smell like ass (like an o/r pipe), it passed inspection, and it's plenty loud. So I'm happy