Switchabe Thermostatic and cold air intake
01-15-2017, 02:03 PM
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Car: 89 Firebird
Engine: L98
Transmission: T-56
Axle/Gears: 3.73
Switchabe Thermostatic and cold air intake
To make tuning the carb easier and more consistent I need to eliminate as many variables as possible. Well the only one I can really do anything about is temperature.
That is one of the best to eliminate especially where I can have -4°F to 70°F in the same week.
Last year it got so cold that I hooked up the heat riser to the intake flapper and solenoid on a switch. That gave me hot air to keep the engine running when I started it. Then cold air for driving around. That helped but the cold air intake was too cold so I pulled CAI pipe and ran hot exhaust manifold air or some what warm and inconsistent under hood air.
So last year I found an all mechanical thermostatic air intake and put it on the hot air flapper. It massively improved cold weather starting and all around low speed drivability.
Problem is the only thermostatic valve I could find is for a pos Russian car that is a 1.6L and my suburban has a 454. The only reason Russia still makes this part is because they were building cars with carburetors up until about 10 years ago and it gets -30 in Siberia every year so you kind of need them.
So with this part I put the cold air pipe back on and had a switchable cold air and thermostatic intake.
The only problem was while going down the highway with the thermostatic valve engaged is if I pushed the gas down more than about 1/4 or 1/3 of the way the the intake restriction suction would cause the air fuel ratio to plumit from the fuel getting sucked out of the carburetor. Yes I have an air fuel meter.
To fix this problem I am building a dual snorkel intake with 2 flappers and 2 of those iron curtain brand thermostatic valves. Then I am going to add either a vacuum switch or micro switch to automatically open the cold air intakes as I push the gas down.
That will give me plenty of warm air and all the cold air my 454 now turned 489 could ever need.
That is one of the best to eliminate especially where I can have -4°F to 70°F in the same week.
Last year it got so cold that I hooked up the heat riser to the intake flapper and solenoid on a switch. That gave me hot air to keep the engine running when I started it. Then cold air for driving around. That helped but the cold air intake was too cold so I pulled CAI pipe and ran hot exhaust manifold air or some what warm and inconsistent under hood air.
So last year I found an all mechanical thermostatic air intake and put it on the hot air flapper. It massively improved cold weather starting and all around low speed drivability.
Problem is the only thermostatic valve I could find is for a pos Russian car that is a 1.6L and my suburban has a 454. The only reason Russia still makes this part is because they were building cars with carburetors up until about 10 years ago and it gets -30 in Siberia every year so you kind of need them.
So with this part I put the cold air pipe back on and had a switchable cold air and thermostatic intake.
The only problem was while going down the highway with the thermostatic valve engaged is if I pushed the gas down more than about 1/4 or 1/3 of the way the the intake restriction suction would cause the air fuel ratio to plumit from the fuel getting sucked out of the carburetor. Yes I have an air fuel meter.
To fix this problem I am building a dual snorkel intake with 2 flappers and 2 of those iron curtain brand thermostatic valves. Then I am going to add either a vacuum switch or micro switch to automatically open the cold air intakes as I push the gas down.
That will give me plenty of warm air and all the cold air my 454 now turned 489 could ever need.
01-21-2017, 01:29 AM
#2
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Join Date: Feb 2004
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Car: 89 Firebird
Engine: L98
Transmission: T-56
Axle/Gears: 3.73
Re: Switchabe Thermostatic and cold air intake
This is what it looks like.
The shinny tube connects to the exhaust manifold shroud and to the mechanical thermostatic controller. The large main intake goes to fresh cold air along with the other inlet to the thermostatic valve.
The shinny tube connects to the exhaust manifold shroud and to the mechanical thermostatic controller. The large main intake goes to fresh cold air along with the other inlet to the thermostatic valve.