headers: emission legal? hp?
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
headers: emission legal? hp?
Guys,
I've read here what long tube headers can do when you gut the cats, etc.
Here in MD, I know I must have cats. If I use stock cats, will the car
pass emissions? Keep in mind we are tested on a dyno.
Can I even use the stock cats or must I use bullet cats just to fit?
How much HP would I get if I do this with a ZZ9 or similar cam ?
How much HP if I do ported cyl. heads and headers?
Thanks, Thanks, Thanks everyone!!
I've read here what long tube headers can do when you gut the cats, etc.
Here in MD, I know I must have cats. If I use stock cats, will the car
pass emissions? Keep in mind we are tested on a dyno.
Can I even use the stock cats or must I use bullet cats just to fit?
How much HP would I get if I do this with a ZZ9 or similar cam ?
How much HP if I do ported cyl. heads and headers?
Thanks, Thanks, Thanks everyone!!
Safety Car
Joined: Feb 2000
Posts: 3,529
Likes: 1
From: Howell N.J. Home of Redgar
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Re: headers: emission legal? hp? (sothpaw2)
You should have no problems passing inspection as long as you keep stock cats without gutting them or if you went to Random Tech cats which is the way I went those stock cats are heavy and ugly !!! good luck :thumbs:
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
Re: headers: emission legal? hp? (sothpaw2)
Guys,
Can I even use the stock cats or must I use bullet cats just to fit?
Thanks, Thanks, Thanks everyone!!
Can I even use the stock cats or must I use bullet cats just to fit?
Thanks, Thanks, Thanks everyone!!
When they do the test they walk around the outside of the car looking underneath with a mirror. I don't think they know what they are looking for, but the supervisor and the state government manager would know what is up. If you failed for whatever reason (the day too hot?) what would they do? I don't want to be in the position of being the first example to find out. But I may be going through the hassle this summer even with my stock cats on the car because I have to go in August, probably on a hot day.
With Glendenning gone, I hope it won't get worse than it is now, not like California.
Team Owner
Joined: Sep 2001
Posts: 62,171
Likes: 1,735
From: Athens AL
C7 of the Year - Unmodified Finalist 2021
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Re: headers: emission legal? hp? (sothpaw2)
I think Random Tech makes a bullit cat to fit LT1 with headers, or you will have to have it welded in place. I doubt if the stock cat will fit without some cutting and welding. Hard to say whether you will DEFINITELY pass emissions, but you should as long as you keep the stock cam and have cats in place.
Headers are good for roughly 10-15hp on average. Ported heads should bring somewhere around 15-20hp.
I would use the LT4 hotcam, but with any performance cam and emissions testing, youll have to DEtune the engine to get it to pass emissions.
Headers are good for roughly 10-15hp on average. Ported heads should bring somewhere around 15-20hp.
I would use the LT4 hotcam, but with any performance cam and emissions testing, youll have to DEtune the engine to get it to pass emissions.
Thread Starter
Safety Car
Joined: Sep 2002
Posts: 4,030
Likes: 6
From: Maryland
Re: headers: emission legal? hp? (sothpaw2)
Yes, I have the LT1.
So is it reasonable, then, to get long tubes, use the old cats, and just
have a muffler shop cut and splice to make it fit?
And, what is cam specs should I watch out for? If I change the cam,
or whatever else I change, it's got to pass emissions. I don't want that
nightmare.
What would I do to "detune" it for emissions? You mean stock chip and
fuel pressure?
So is it reasonable, then, to get long tubes, use the old cats, and just
have a muffler shop cut and splice to make it fit?
And, what is cam specs should I watch out for? If I change the cam,
or whatever else I change, it's got to pass emissions. I don't want that
nightmare.
What would I do to "detune" it for emissions? You mean stock chip and
fuel pressure?
Melting Slicks
Joined: Apr 2001
Posts: 2,474
Likes: 1
From: Drive it Like You Hate it Cincinnati OH
Re: headers: emission legal? hp? (sothpaw2)
You do not have to DEtune to pass emissions!!! My 89 passed fine with zz9 cam 1.6 rockers and long tubes.. My LT4 passes fine with the hot cam.. As long as it is running roght, you'll be fine....
Drifting
Joined: Nov 2000
Posts: 1,276
Likes: 0
From: Ft. Worth Texas
St. Jude Donor '11
Re: headers: emission legal? hp? (sothpaw2)
Yes, I have the LT1.
So is it reasonable, then, to get long tubes, use the old cats, and just
have a muffler shop cut and splice to make it fit?
So is it reasonable, then, to get long tubes, use the old cats, and just
have a muffler shop cut and splice to make it fit?
jeff
Safety Car
Joined: Sep 2001
Posts: 4,095
Likes: 1
From: modland CT
Re: headers: emission legal? hp? (DINO)
You should have no problems passing inspection as long as you keep stock cats without gutting them or if you went to Random Tech cats which is the way I went those stock cats are heavy and ugly !!! good luck :thumbs:
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