The February '01 issue of Hot Rod magazine talks about emissions and performance on pg 50. I know that this is one magazine's thoughts, but I figure since they are in the CA area, they must know something about performance with cats. They say that the cats do form a few inches H2O of backpressure, but if the internals of it are not melted or plugged, then they shouldn't really cause much performance loss. My opinion would be to try a cat-back system first, that way if you do decide to change them/remove them in the future, you are still up one with a better flowing exhaust system.


88 F-150 4X4 w/5.0 EFI 5 spd
86 Ranger 2WD w/2.3L EFI 5 spd to be 351W 4bbl C4

 

Regardless of all the ways to alter or remove Catalytic Converters , The fact remains it is illegal & if caught , you will face some stiff penalties . The converters are there for a reason .

 

OK, I'll jump in. First, any of the newer cats are less restrictive than the old cats. Second, many of the cats will advertise if it has a CARB # and in CA, I would make sure I had one. Also, CA used to have an arbitration board that you could take your unique request to and work out a situation like dual pipes with dual cats. A lot of times you would pay a one time penalty and they would allow you to work it out.

Dave,

When did CA start doing rolling stops? They didn't used to do that. I mean, think about it a little. How do they know a car was manufactured for CA smog instead of moved in when you came from out of state? They have different smog equipment and a lot of variables to look for from year to year and even model to model. And...if your emissions are low (if you have a carbed engine with a distributor, you can tune to low emissions), how do they determine whether or not your cat has been gutted?

I still believe the best solution for reducing smog is to insure that your car is well tuned and not burning oil. If we would address the problem from that perspective, we would all be better off and get better gas mileage to boot. Instead, idiot proof devices are installed to compensate for those that do not keep their cars tuned. Now, I realize that's all relative and there are some good issues with recirculative gases, but the biggest piece of waste that I've seen for smog equipment is the air pump.

Just my 2 cents...

'82 F150 2WD w/351W (orig 300 I6)
Slik

 

OK First on the rolling check points, I dont know when they started, I was made aware of them by CHP when they started calling us to impound cars of people driving without a license from these smog check points. They stick a sniffer on the exhaust and can tell if it is within spects or not.

As for wheather they will know about the cat being gutted, it will show on the % of CO2 reading. In califorina like I said before they do a very indepth check on a dyno. It measures CO2, HC, O2, and NO. they measure both, one at 15 mph and one at 25 mph, on a dyno, if either fails the car fails.

OK, now if you understand basic smog, and automotive, you will know that a gas motor running at its best that it will ever run only burns 68% of the fuel going through it, the rest comes out the tail pipe as polution. The cats job is to burn the unburned fuel that goes through the engine. The cat alone is the biggest air polution reducer. Because of Southern California's mountains around L.A. the polution caused by autos can not leave and hangs around the basin, which is why L.A. has one of the highest smog problems around the nation. Thus causing South Coast Air Quality to enforce current laws.

So please if you are going to give advise, please make sure it is legal and works.

I have been doing this for many years, and this is my living, so I do know what I say.

Dave

http://a2ztowing.homestead.com/a2ztowing.html

 

I know of the checks in california as it has happened to my friends, but they dont use a sniffer, they use a decibal meter and have the owner rev the engine and hold it at 1k, 2k, and 3k to get readings

1995 F-150XL SC/SB
http://members.sounddomain.com/blind
5-Star Rated F-150 (Big Stereo)

 

As for wheather they will know about the cat being gutted, it will show on the % of CO2 reading. In califorina like I said before they do a very indepth check on a dyno. It measures CO2, HC, O2, and NO.

A minor point here Dave....

BAR 97 exhaust gas analyzers (such as those used in CA and many other states) are 5 gas analyzers. They measure HC, CO, CO2, O2 and NOx.

 

[font size="1" color="#FF0000"]LAST EDITED ON 06-Mar-01 AT 06:23 AM (EST)[/font][p]Hey paulg, you wouldn't happen to have the P/N's for the cat. and Y-pipe handy would ya? My cat's ar 70% clogged so I really need to change them out...just havne't been able to find any performance cat's that will bolt up to the stock exhaust manifolds.

TrailDawg
https://www.ford-trucks.com/dcforum/User_files/3aa4d35538ab4f5a.jpg
1993 F150 2WD
4.9L-Auto
Pro-Comp Stage-2 6" lift
Auburn Pro-Series Diff. w/4.56:1 gears
35x12.50x15 General Grabber MT's

 

Just a point...I'm not the one giving out illegal advice. But I do sympathize with those trying to run a decent vehicle and trying to balance all the smog stuff. I used to live in the LA basin so I am well aware of the problem they have, I'm still not convinced that they have the solution. The cats, I agree, are probably the biggest contributor to removing pollutants, but that is the first that I had heard of only a 68% efficiency ratio. Man, it makes me wonder what they put into the air at the dragstrip when the fuel burns your eyes from them running down a quarter of mile. It also does not make sense that the laws are so stringent that they do not allow you to improve your vehicle and remove even more pollutants with a dual cat setup. If it is done correctly, it will be a cleaner car. In parts of NC, the smog tests at idle are the federal standard which is a little bit less stringent than CA, but I believe my truck; without the air pump and with dual cats, would meet the sniffer test in CA. It would not pass the visual, which does not make sense to me. Why don't they just run the sniffer test and if your vehicle passes then great, if not, then the vehicle comes off the road until the appropriate smog equipment or tune up is in place to meet the specs.

'82 F150 2WD w/351W (orig 300 I6)
Slik

 

This CAT scenario has me wondering about another thing related to the same. On my 88 with a 4.9, the air pump discharges into a three way type of plastic valve, and from there it is diverted to either the 6 exhaust ports in the cylinder head or to the cat. On mine, apparently the check valve leaked in the line that goes to the cylinder head and it melted part of the valve that diverts the flow of air. I plugged the line at the exhaust to the head and the pump still diverts air to the cat. This would probably still pass an emmissions test but not a visual check. I checked with FOMOCO on the price of a new diverter valve and check valve and it all came close to $200.00!!! This all may have the O2 senser giving false information th the ECM but it does not seem to effect performance at all. Here in Virginia they have not yet started doing emmissions checks except in a few heavy populated areas and is only done when you get the annual inspection. Where I am you might get a visual under the hood check.

 

Traildawg!!!!!
I don't have the P/N for the single 3" in/out high flow cat that I have. I do know that if you call Summitracing they can give you the P/N for a high flow cat just like mine. I bought mine from Summitracing for $110. Smaller tubings are cheaper but I wanted the bigger pipe. Boy that sounds awful! Remember though you need one of Flowmaster's Y-Pipes to install the single hf cat and combine those dual outlet headers into one.

 

While you're at it check out DynoMax. They have some hi-flo cats for some pretty reasonable prices.

'82 F150 2WD w/351W (orig 300 I6)
Slik

 

But.......but........the whole reason I asked you for the P/N's was so I wouldn't have to dig out my Jeg's and Summit catalog's paulg :P

BTW, I used to work at Jeg's, and beleive me when I say you're better off ordering from Summit.

TrailDawg
1993 F150 2WD
4.9L-Auto
Pro-Comp Stage-2 6" lift
Auburn Pro-Series Diff. w/4.56:1 gears
35x12.50x15 General Grabber MT's

 

You know while your at it you out to replace the rubber shift plugs on your truck's M5OD. I did so on my 94' and it made a world of difference in how the transmission sounded and operated. I wrote an article as a guide on how to do this. If you want to check it out let me know and I'll email it to ya!

 

As for as conversion that would have cleaner exhaust, I am for it, but you have to understand that these laws that pertain to emmissions were written back in the 70s, and like most laws have not been updated much. The fact that the supercharged Tbird burns so clean that it does not need much, yet it still has all the junk on it. Go figure.

There are ways to make cars more efficient and burn cleaner, than the original set ups, but as long as uncle sam has his say it wont be that way. Dual exhaust and dual cats set up properly would burn cleaner exhaust, but the ways it is now, were in one of those catch 13s.

Seems everytime someone starts on emmissions or cats, it opens that damm can of worms.

I hope that the original post got some help out of all of this.

Dave

http://a2ztowing.homestead.com/a2ztowing.html