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LT-1 engine mod vs emissions
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Instructor
Joined: Jun 2006
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From: Plano Texas
LT-1 engine mod vs emissions
One day I'd like to have some mods done to my LT-1 engine now residing in my 1994 Vette. I've been told by a friend that modified engines won't pass emission tests. I live in Greenville, TX where emission tests are not done YET. Oh, when I get my new plates I will put both on my car.
Race Director
Joined: Jan 2002
Posts: 12,261
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From: O'Fallon Missouri
My 94 is extensively modded and will still pass emissions testing. The car has ported heads, 224/230 605/622 camshaft, long tube headers, high flow cats, 52mm TB, e. water pump, and several other small mods, and will still pass Missouri's emissions testing.
It's all in the tune.
-Mike
It's all in the tune.
-Mike
Thread Starter
Instructor
Joined: Jun 2006
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From: Plano Texas
Originally Posted by STL94LT1
My 94 is extensively modded and will still pass emissions testing. The car has ported heads, 224/230 605/622 camshaft, long tube headers, high flow cats, 52mm TB, e. water pump, and several other small mods, and will still pass Missouri's emissions testing.
It's all in the tune.
-Mike
It's all in the tune.
-Mike
Thread Starter
Instructor
Joined: Jun 2006
Posts: 143
Likes: 0
From: Plano Texas
Originally Posted by STL94LT1
My 94 is extensively modded and will still pass emissions testing. The car has ported heads, 224/230 605/622 camshaft, long tube headers, high flow cats, 52mm TB, e. water pump, and several other small mods, and will still pass Missouri's emissions testing.
It's all in the tune.
-Mike
It's all in the tune.
-Mike
What did your mods do for your car? HP? Torque? Speed? ET? Gas mileage?
Race Director
Joined: Jan 2002
Posts: 12,261
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From: O'Fallon Missouri
Right now it's making 370+rwhp/345rwtq, has ran 12.3x @115-116mph with the old camshaft-has 20 more rwhp now. So, should run a little faster. Best of all it still gets 26-28 mph on the highway. Oh, the car also has 4.10 gears.
Thread Starter
Instructor
Joined: Jun 2006
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From: Plano Texas
Originally Posted by STL94LT1
Right now it's making 370+rwhp/345rwtq, has ran 12.3x @115-116mph with the old camshaft-has 20 more rwhp now. So, should run a little faster. Best of all it still gets 26-28 mph on the highway. Oh, the car also has 4.10 gears.
Melting Slicks
Joined: May 2002
Posts: 2,670
Likes: 4
From: Severna Park MD
Originally Posted by BlueMonster94
One day I'd like to have some mods done to my LT-1 engine now residing in my 1994 Vette. I've been told by a friend that modified engines won't pass emission tests. I live in Greenville, TX where emission tests are not done YET. Oh, when I get my new plates I will put both on my car.
The 94 PCM can adjust to a relatively big hydraulic cam and pass emissions as long as you have good cats on the car.
The 92-93 cars are speed density and require tuning for any major changes. Your 94 will be good to go as long as you stay within reasonable limits on mods.
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From: Plano Texas
Originally Posted by FELNGR8
I have the 218/228 LT4 Hotcam kit, headers, and custoim exhaust with Random Tech cats. It passed emissions with no tune changes as soon as I had the cats on the car. I only needed a tune after putting on a larger throttle body, and then it was for drivability.
The 94 PCM can adjust to a relatively big hydraulic cam and pass emissions as long as you have good cats on the car.
The 92-93 cars are speed density and require tuning for any major changes. Your 94 will be good to go as long as you stay within reasonable limits on mods.
The 94 PCM can adjust to a relatively big hydraulic cam and pass emissions as long as you have good cats on the car.
The 92-93 cars are speed density and require tuning for any major changes. Your 94 will be good to go as long as you stay within reasonable limits on mods.
Le Mans Master
Joined: Dec 2004
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I checked your car out. Very nice and I saw it's an automatic. The first performance mods I did to mine were 3.73 rear gears and a convertor.
No effect on emissions and with just those two mods alone and a set of real rear tires I went high 12's. Find out what gears your car has in it now. If it's got the 2.59 rears as many did you won't believe the difference the gears and convertor will make. Check under the lid of your center console for the rpo code for your rear axel. GM1 is the code for the 2.59's
No effect on emissions and with just those two mods alone and a set of real rear tires I went high 12's. Find out what gears your car has in it now. If it's got the 2.59 rears as many did you won't believe the difference the gears and convertor will make. Check under the lid of your center console for the rpo code for your rear axel. GM1 is the code for the 2.59's
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From: Plano Texas
Originally Posted by JD'S WHITE 93
I checked your car out. Very nice and I saw it's an automatic. The first performance mods I did to mine were 3.73 rear gears and a convertor.
No effect on emissions and with just those two mods alone and a set of real rear tires I went high 12's. Find out what gears your car has in it now. If it's got the 2.59 rears as many did you won't believe the difference the gears and convertor will make. Check under the lid of your center console for the rpo code for your rear axel. GM1 is the code for the 2.59's
No effect on emissions and with just those two mods alone and a set of real rear tires I went high 12's. Find out what gears your car has in it now. If it's got the 2.59 rears as many did you won't believe the difference the gears and convertor will make. Check under the lid of your center console for the rpo code for your rear axel. GM1 is the code for the 2.59's
As I recall, my car has a performance rear end, whatever that is. I saw something about that option on my window sticker.
Melting Slicks
Joined: Jul 2004
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From: Chicago Illinois
Originally Posted by STL94LT1
Right now it's making 370+rwhp/345rwtq, has ran 12.3x @115-116mph with the old camshaft-has 20 more rwhp now. So, should run a little faster. Best of all it still gets 26-28 mph on the highway. Oh, the car also has 4.10 gears.
Le Mans Master
Joined: Jul 2004
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From: NH
St. Jude Donor '14
Originally Posted by STL94LT1
With the M6 and 4.10's, the car is still only turning 1800 rpms at 70mph. I just filled up, will check the gas mileage when I refill.
I get 25-26 for long drives.
Le Mans Master
Joined: Dec 2004
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Originally Posted by BlueMonster94
I don't have the car where I can get to it. Truth be told it is in the local Ford garage having a tune up and other stuff being done to it. Where I live, you don't go to the Chevy place unless you have no other choice. I used to own a Taurus SHO (gulp) and this Ford house did a good job with some big time maintenance work. I trust them over a greasy garage or the Chevy house. Back to topic! As I recall, my car has a performance rear end, whatever that is. I saw something about that option on my window sticker.
As I recall, my car has a performance rear end, whatever that is. I saw something about that option on my window sticker.
Thread Starter
Instructor
Joined: Jun 2006
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From: Plano Texas
Originally Posted by JD'S WHITE 93
You should then have a 3.07 rear. Swap it for a 3.73 and you'll be very happy.
To tell ya the truth, I'm quite happy with the car now with the exception of those bugs that the Ford house in Greenville is removing from the car. Before any work has been done to my car, it was getting 25.5 mpg highway on a trip from Greenville to Tulsa. BTW, I do NOT rely on the onboard MPG data. I still figure my MPG the old fashion way, total miles divided by total gallons pumped after the trip. My next question would be how would the 3.73 rear end impact performance and MPG?
Le Mans Master
Joined: Dec 2004
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Originally Posted by BlueMonster94
To tell ya the truth, I'm quite happy with the car now with the exception of those bugs that the Ford house in Greenville is removing from the car. Before any work has been done to my car, it was getting 25.5 mpg highway on a trip from Greenville to Tulsa. BTW, I do NOT rely on the onboard MPG data. I still figure my MPG the old fashion way, total miles divided by total gallons pumped after the trip. My next question would be how would the 3.73 rear end impact performance and MPG?
