Sidepipes with Cats?

matchframe · 09-14-03, 06:36 AM

Where I live, they just started requiring smog tests to pass inspection. I downloaded the requirements form the Texas Dept. of Public Safety and interpreted it to say that my '78 are not required to have Cats. I was having my other car inspected the other day and talked in length with the guys doing the inspection. I told them what I was doing with the Vette, and ask them if they would pass it if it had no Cats. They said no. They said they know of people who have Cats on their cars during inspection, then remove them immediately afterwards. That would be a major hassle with the Hooker style sidepipes to remove, and reinstall them once a year. I was telling them about the 25-year-old exemption, and how I interpreted the rules for inspection. They said if I could get a letter from DPS saying it was exempt, they would pass it.

My question is, if I cannot get exempt from having to run Cats, can I use something like the shorty style headers with the Cats at the collectors, them turn out to the '69 style sidepipes?

Will this pose a heat problem in the dash area?

Do they make shorty headers for Big Blocks?

My first choice is still the Hooker style pipes!

Thanks!

Bill

Bob_K · 09-14-03, 09:59 AM

Doug Thorley Headers makes a 50 state legal shorty header. Call them up and find out what the part number would be for your car. Then run run a front Y pipe (to be perfectly legal you can only one cat). Not sure if you can cut the y pipe shorter to make more room or not. Install the cat. After the cat, run the exhaust out to the sides. You'd have to add mufflers facing sideways between the the y pipe and exhaust to make it reasonable or you wouldn't be able to hear yourself think. You may be able to have the exhaust exit where sidepipes would. If it would fit like this, just add some sidepipe covers and I don't think anyone would be able to tell the difference.
I looked on my car yesterday to see if this would be possible but I think the exhaust would still come out too far back. Not sure though since I have true duals right now so I have no idea where the cat would end.
Let me know if you do the measurements and it would fit. My wife and I really want sidepipes on our 79, but this winter I'm returning to 50 state legal and don't think I can have them.

clar2001 · 09-14-03, 11:32 AM

sounds pretty involved, I want to run shorty headers on my stock exaust becouse duels won,t fit. I used to want the side pipes best look that way , but after hearing storiies about heat I don't think so .
Bill how about a stock set up for smoge & then but your side pipes on, In CA. its 29yrs to be exempt from smoge so I will never half to do mine agin.

DarkShark · 09-14-03, 03:02 PM

I played the smog game on the east coast for years. I have seen these things done, but I haven't done them. I would rather suck it up and play by the rules than dance around what was most closely resembling "legal".

You can "cobble" up an AIR system that uses tubes welded to the headers that LOOK like they owrk. Truth be known, there are no ports through the headers. They just appear to be working.

Next, all your emission lines are hooked up, but there are metal dowels plugging the lines on the inside. They look legitimate....

As for cats.....

I would get two large capacity converters installed wherever I could put them. One on each side of the exhaust for true duals.

For common sense purposes- you'd think that true duals with two cats is okay. Why? More cats than the factory used. Well, its not okay. The EPA and state mandates usually insist the "correct" number of cats is based upon the year in which the car was made. You'd think that EPA or the state would WANT you to use better more efficient equipment. No, they want you to use the same out dated equipment, merely to check the box that it is there. Just gotta love a beauracracy.

bossvette · 09-15-03, 01:18 PM

you may want to look into "Historical" or "Classic" plates and registration, some states have them for Classic cars there may be a mileage restriction but it is an alternative to "smog tests"

MaineShark · 09-16-03, 11:33 PM

As several people have noted, if the exhaust doesn't exactly match the original factory design, it probably won't pass the visual inspection. That means no side pipes, at all.

Of course, if you know someone, you mgiht not have to worry about it at all...

Joe

Tom73 · 09-16-03, 11:44 PM

Bill,
In Texas cars 25 years old and older do not have to be smog tested, so you should be exempt there. Part of the safety inspection is that they do a visual check to see that all the standard emission equipment is in place.

But here is good news, the inspection standard says:

If installed as original equipment by the manufacturer, the catalytic converter will be considered a part of the exhaust emission system on all 1984 and later model vehicles.

http://www.txdps.state.tx.us/vi/insp...ejectsubmit=Go

tom...

matchframe · 09-17-03, 06:13 AM

Thanks Tom,

The way I read it, I should be OK. When I talked to these inspectors, they were kind of on the fence since I did not bring any documentation such as this web page you provided the link for, and the rules they follow were not this detailed. They said based on that , they would not pass it.

I think I will print out this web page, and see what they say. If they are still saying the same, I wll try some other places.

I really want the hooker header sidpipes!

I appreciate the link Tom!

Bill

09-17-03, 04:12 PM

Just had my '78 in for inspection in McKinney TX. I read, and reread, the new DMVs 'rules'. I went into the inspection ready to fail the smog test (true dual exhaust, no cats)... when I arrived, the Jiffy Lube punched my VIN into their computer, and to my surprise told me I did not need the smog test. Then they proceeded to write me up for my directional light not working. Exterior blinker light worked fine, the interior indicator did not. Boy... being THAT picky made me wonder how half of the pieces of crap I see on the road actually pass these tests.

bossvette · 09-17-03, 04:22 PM

a big "tip" usually helps

matchframe · 09-17-03, 06:19 PM

Fishman,

Is Mckinney, in the Harris/Galveston/Brazoria etc. county smog test area?

BTW, I have my Speed/Tach out of my '78 Vette right now, and looked to see how the directional signal bulb is replaced. It is just a twist-in bulb, real easy to replace. Only thing, is I cannot tell how hard it is to reach while in the dash. Hope this helps!

Welcome to CAC!

Bill

Bossvette,

Good Idea!

Bill

Tom73 · 09-17-03, 07:02 PM

Quote:

Originally posted by matchframe
Is Mckinney, in the Harris/Galveston/Brazoria etc. county smog test area?

Time to study the Texas map. McKinney is just north of Dallas.

matchframe · 09-17-03, 08:41 PM

Thanks Tom,

I knew McKinney sounded familiar, I used to drive through it when I would drive to school 20 years ago.

Bill

09-18-03, 10:24 AM

Hey Bill...

McKinney is in Collin County... we just became part of the 'smog' test last year. I received very conflicting messages from the DMV and the Inspection garages. Even the guy at the Jiffy Lube was surprised when the computer spit back a message that my car was exempt. I was ready to pay the $100 required by the state to attempt to bring my old car up to par for the test. I was simply going to have my mechanic do a regularly scheduled tune-up and give that receipt to the state and then get my exempt status for the test.

I have 2 kids and not much time to do even a small amount of work on the car... until I get more time I have been taking the car to Corvette Corner in Rowlett for almost everything. The owner, Rich, is a pleasure to work with... I have had work done by his shop for 4 years without one complaint. If there is an 'issue' with the work, he takes care of it without an argument. I would highly suggest him to anyone in the Dallas area needing an extra hand (or a full restoration).

Until later... Brian

matchframe · 10-03-03, 04:31 PM

I just got back from the local inspection station. I talked with one of the inspectors, and told them what I was doing with the Vette. They said that in Texas, cats are only required on 1984 and newer vehicles. That's the way I had interpreted it earlier, but when I had my first conversation with them several weeks ago, they said it would be required since it came from the factory that way. Today, they confirmed for me what I had already thought, but I wanted to hear it from them before I bought the pipes. Interestingly, they said that the 78 would still be required to be smog tested. I responded that I thought if it was 25 years old, it would be exempt. They said true, when it turns 25. I had to point out that they should check the math, 1978 WAS 25 years ago. So I am still exempt from smog testing too.

So, it is Hooker Sidepipes for me!