Um... Yeah, what I said.

I see three at summit:

WLK-15038-Dynomax-Stainless Steel, Universal, 2 1/2 in. Inlet/Outlet, 14 in. Length $53.88

CTO-6906-Catco-Stainless Steel, Universal, 2 1/2 in. Inlet/Outlet, 14 in. Length $55.69

CTO-6806-Catco-Stainless Steel, Universal, 2 1/2 in. Inlet/Outlet, 12 in. Length $60.99

How close to the headers should they be?

Are we talking roasty-toasty feet?

Are there any better solutions? (I have no AIR system and cannot run AIR headers)

 

Well theoretically they should be as far from the engine as possible to decrease the backpressure that the engine feels. EPA wants them as close as possible to react while the gasses are as hot as possible (in my understanding). Anything high-flow is going to be fine and not really hurt your power all that much. So for the two choices I mentioned, depends whether it's sniffer or just visual. However, a well tuned, efficient engine is the best way to have low emissions, bar none.

Simple heat shield strongly recommended for those without asbestos socks.

-Chris

 

I was thinking of doing the same thing over summer, and I think the stock position behind the crossmember is the best place. Might be a little warm, but with a shield, it should be ok.

 

two cats will not pass emissions test.so i have learned from this board.

 

Has to be stock--dual cats arn't legal either--leave'em off and save your money.

Is it tampering to install a dual exhaust system on a vehicle originally equipped with a single exhaust?

Yes. The general rule is that a motor vehicle emission control system (which includes the exhaust configuration) may not be changed from an EPA certified configuration without subjecting the repair shop to liability for violating the federal tampering prohibition. The exhaust system configuration, including the location of the converters, and exhaust pipe diameter and length, are items specified by the manufacturer because engines and some of the associated emissions systems are generally affected by the exhaust system backpressure, which subsequently affects vehicle emissions. The installation of a dual exhaust system with two converters would, therefore, be considered tampering.… It would not be considered tampering to install a dual exhaust system with two converters if the vehicle manufacturer certified an identical engine-chassis configuration for the vehicle model year or newer that includes such an exhaust configuration.

Good reading--->http://www.off-road.com/dodge/tech/Emissions_Legal.htm

 

Interesting reading for sure. The way I intrepret the articles any race car new enough to have had a catalytic converter is most likely considered illegal, even if it has a converter. The EPA requirements apply to the fuel delivery system (carb, manifold, heads, etc) as well as the exhaust. I have to wonder why the manufacturers of high performance components haven't been busted? The EPA police would be able to balance the National budget if they started showing up at NASCAR events and even cruise nights.

 

It all depends on the enforcement. My 83 truck now has true duals with dual Dynomax cats (and no mufflers). I have been through inspection twice with this setup and have had no issues.

 

I installed two Catco high flow cats on a true dual exhaust system when I modded my 77's motor. (heads cam intake carb headers) The stainless cats have built in heat shields, and passed Illinois (very strict) emissions with flying colors twice. No problems using two...no problems with heat.
Eddie

 

Are two cats legal if your system was originally equiped with one? The short answer is maybe. By federal standards, no it is not legal. By state or county standards it depends how the inspector is required to look. For example "all emissions equipment is to be intact" is very different from "all emissions equipment is to be intact in it's original location and tested that it is working".

I just went through this round last month and basically in my county a true dual with dual cats would pass. They are not required to look at the location or to see if it's been hollowed out. Just that the car has a cat.

I would strongly suggest finding out exactly what your county/state requirements are before spending money and time. Talk to a friendly mechanic. Search the DOT website.

Oh by the way I found out that for L48 vettes, the current emissions book is wrong. It states that all vette engines are suppose to have an AIR pump where the books in prior years that the AIR pumps are required on all vette engines except L48s, excluding Cali cars and high altitude cars (check the emissions sticker above the brake power booster.) I argued that they can't change the rules in the middle of the game. I also showed him my chassis manual which shows the optional engine setup for L48 engines without the AIR pump.

Good luck!

 

Most of the kids working at the inspection places don't have a clue as to what emissions equipment looks like on a '70's car anyway...

 

Thanks guys. I know the legality is sort of a gray area... okay, black area. I think I'll eventually have to comply with emissions at some level but the extent of which will be determined by how friendly or ignorant the local inspector is.

I've converted to EFI but have no EGR, AIR, EFE, or Cat so I'm going to have to ask around to see what inspectors would be willing to pass. Worst-case senario, get classic tags or move to Ohio.

I'm just trying to find combonations others have used so I have options on hand when I talk to the inspectors.

Here in PA they start inspecting for emissions starting with 1975. Isn't that my luck? Thing is, it's just visual. Doesn't matter that in current trim it's WAY cleaner than the stock setup, even brand new.

I'm going to start another thread in a minute about a 2-1-2 setup.

 

I suppose it depends on who's inspecting the car,but in Pa. they just passed the "visual requirement".I had 3" duals put on and the shop insisted on a converter to meet the Federal requirement.It had to be a single converter in the stock location(Mine is an 80)So I insisted with my "stock 500hp 406" on a 3" set of pipes,and supplied him with two Edelbrock RPM 3" in/out mufflers. He came up with some high flow 3" in/out converter and managed to weld everything up. It sounded great,and as far as I can tell,there's no sign of restriction. (6500 rpms...no problem)

 

I would love to see a picture of that. I assume you have headers and the converter is under the passenger seat. I currently have a 2.5 inch system with a hi-flo cat and stock manifolds. Thanks.

 

I have Hooker Comps and the cat is under the passenger side ,but for some reason I can't find pictures. I had some but they were fairly dark anyway.Midas Mufflers did the work,only because they were the only shop around with a 3" mandrel to bend the pipe.

 

I too, would love to see a photo of this.

 

SEE Admissions by EPA - What emission standards before 80
http://forums.corvetteforum.com/show...um_id=3&arch=1

BY EPA:
"Congress amends the Clean Air Act. At the request of automakers, the HC standard is delayed until 1980 and the CO standard until 1981. The NOx standard is delayed until 1981 and is relaxed to 1 gram per mile."

1981
"New cars meet the amended Clean Air Act standards for the first time. Sophisticated three-way catalysts with on-board computers and oxygen sensors appear in most new cars."
BY EPA
http://www.epa.gov/otaq/consumer/12-miles.pdf
(current EPA link)

You need to talk to hotrodders in your state. Find out what the standards are. Some original junker might pass a visual even w/o any of it working & a dual cat car that could pass a test might fail!
If you have to have a cat- duals rec. behind crossmember for performance. If you had to have a single cat- it might pass hooked up as a crossover.


In some places if the car is clean & doesn't sound like it has an exhaust leak, they typically don't even look under it.