1981 Performance/Emissions
Thread Starter
Cruising
Joined: Aug 2006
Posts: 12
Likes: 0
From: Midland Texas
1981 Performance/Emissions
I am in the beginning stages of restoring my new 81 bone stock Vette. This is my first encounter with a Corvette (A/T) and I'm excited. I will be pulling the motor in October for rebuild and I have been hearing that I am about to run into huge problems trying to obtain my goal of 275-300 hp and remain within Texas Emissions standards. I guess its conflicts with CCC and such. To make a long story short.....Is it going to be possible to hit 275-300hp and still be able to pass emission tests? Any suggestions?
Any input greatly appreciated.
Any input greatly appreciated.
Instructor
Joined: Jan 2002
Posts: 155
Likes: 0
From: Houston Texas
Good news! As of January 1, your 1981 Corvette (like mine) is 25 years old and no longer needs to meet any Texas emissions standards.
(At least, it does NOT need to be hooked up to the Machine and measured at Inspection time.)
(At least, it does NOT need to be hooked up to the Machine and measured at Inspection time.)
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
If what schwee says is true, it's rather simple to convert to a non-computerized setup.
I went to a non-computerized q-jet (I suggest finding a 4MV which start with a 7 in their number instead of a 1). M4M carbs are rated for higher cfm but tuning parts for them are hard to find. A 4MV will bolt right up and once tuned properly will run excellent. You'll also need a non-computerized distributor. I suggest a standard HEI which you can find on ebay for $85 or you can get a well built one from Summit for $120 - $300, depending on what flavor you want. There's no point to using anything besides an HEI unless you plan on winding it up past 7000 RPM. 300hp is easy with that.
I went to a non-computerized q-jet (I suggest finding a 4MV which start with a 7 in their number instead of a 1). M4M carbs are rated for higher cfm but tuning parts for them are hard to find. A 4MV will bolt right up and once tuned properly will run excellent. You'll also need a non-computerized distributor. I suggest a standard HEI which you can find on ebay for $85 or you can get a well built one from Summit for $120 - $300, depending on what flavor you want. There's no point to using anything besides an HEI unless you plan on winding it up past 7000 RPM. 300hp is easy with that.
Thread Starter
Cruising
Joined: Aug 2006
Posts: 12
Likes: 0
From: Midland Texas
Thank you for the input, wasnt wanting to register as an "antique" due to driving restrictions, but I now see it can be registered as a classic which doesnt have the driving restrictions. Computers gettin yanked in October. Thanks again for pointing this out!
Melting Slicks
Joined: Mar 2006
Posts: 3,342
Likes: 7
From: Connecticut
Originally Posted by Bangkok Dean
How can you put 1981 Corvette & Performance on the same line
Originally Posted by Kalway
I suggest finding a 4MV which start with a 7 in their number instead of a 1
Someone told my bench was too cluttered...
Instructor
Joined: Jan 2002
Posts: 155
Likes: 0
From: Houston Texas
Originally Posted by Visine
Thank you for the input, wasnt wanting to register as an "antique" due to driving restrictions, but I now see it can be registered as a classic which doesnt have the driving restrictions. Computers gettin yanked in October. Thanks again for pointing this out!
Some inspectors might get excited about missing emissions stuff, but if it's clean, you should have no problem.
After I removed the pump and brackets, I cleaned up all the hoses and stuff. For the air pump lines coming out of the top of the exhaust manifolds, I fab'd a steel line, bent cleanly, connecting the two manifolds and running under the air cleaner. Looks good - non functional.
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Drifting
Joined: Feb 2005
Posts: 1,738
Likes: 2
From: San diego ca
Originally Posted by Schwee
There's no special registration involved. Any car over 25 years old is exempt from emissions testing in Texas.
Some inspectors might get excited about missing emissions stuff, but if it's clean, you should have no problem.
After I removed the pump and brackets, I cleaned up all the hoses and stuff. For the air pump lines coming out of the top of the exhaust manifolds, I fab'd a steel line, bent cleanly, connecting the two manifolds and running under the air cleaner. Looks good - non functional.
Some inspectors might get excited about missing emissions stuff, but if it's clean, you should have no problem.
After I removed the pump and brackets, I cleaned up all the hoses and stuff. For the air pump lines coming out of the top of the exhaust manifolds, I fab'd a steel line, bent cleanly, connecting the two manifolds and running under the air cleaner. Looks good - non functional.
Melting Slicks
Joined: Mar 2006
Posts: 2,465
Likes: 0
From: Orange Park Fl
Originally Posted by Bangkok Dean
How can you put 1981 Corvette & Performance on the same line
Le Mans Master
Joined: Jan 2006
Posts: 9,192
Likes: 27
From: Boca Raton Florida
All ya got to do is read a bit, the CCC is pretty simple. Basically all it does is maintain Air/fuel ratio at idle/moderate throttle. At WOT it runs "Open Loop" and allows the Secondary needles/Jets to do their thing. The carb itself will flow ~650cfm, good for well over 300hp. The CCC will allow higher flowing intake, heads and exhaust and simply adjust F/A according to what the O2 sensor says. The CCC also controls EGR function, and tranny lockup based on other stuff, but those items shouldn't cause any performance probs.
Safety Car
Joined: Dec 2004
Posts: 4,071
Likes: 0
From: San Diego CA
Originally Posted by a1sensei
My '81 walks away from all but the most stout street rods and I still get 18+ mpg. The kicker is, I still use the computer, E4ME carb and computer controlled distributor. I did all the engine/ exhaust mods to get 350-400 HP and was concerned that the carb would run lean, but I'm at 14.7:1 normal driving, 13:1 at WOT. I still scratch my head every time I hear someone tell an '81 owner to ditch the CCC system. God bless, Sensei
The thing I hate the most about the CCC system is the ignition timing can't be changed.
The initial timing being the exception.
