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Plumbing my A/C to cool my throttle body... ehm, instead of heating it.

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Plumbing my A/C to cool my throttle body... ehm, instead of heating it.

 
Old 04-14-2019, 11:39 PM
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Akadeutsch
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Default Plumbing my A/C to cool my throttle body... ehm, instead of heating it.

Im not driving my C4 in the cold. At least not this summer. So my thought is to use the super high tech and also hollow throttle body to hold super cold
refrigerant, instead of hot coolant. I could plumb cold refrigerant from the low side of the evaporator. That should be dry ice cold. I wonder if I could put threads on the two Male coolant fittings on the throttle body? I think there is enough room for more than enough threads there. Enough to handle a couple hundred psi anyways... Do you guys think the gaskets it the throttle body would have to be changed out and likely custom made? If so what martial are refridgersnt gaskets made of? PAG rated?
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Old 04-14-2019, 11:55 PM
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Not enough performance gain to be worth the effort!
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Old 04-15-2019, 12:47 AM
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383vett
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It's not like the air is passing through intercooler bricks like in a C6ZR1 or a C7Z before entering the engine. The air passing through the throttle body barely has any contact with it's 2" surface. As Mack said, very little gain, in fact negative gain when you factor in running the ac compressor.
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Old 04-15-2019, 08:59 AM
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Originally Posted by 383vett View Post
It's not like the air is passing through intercooler bricks like in a C6ZR1 or a C7Z before entering the engine. The air passing through the throttle body barely has any contact with it's 2" surface. As Mack said, very little gain, in fact negative gain when you factor in running the ac compressor.


It also could cause a sticky throttle. The purpose of the engine coolant (heat) was to prevent icing that might restrict throttle blade movement. Adding a "super cold" refrigerant instead of heat could cause the icing.

Last edited by QCVette; 04-15-2019 at 09:00 AM.
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Old 04-15-2019, 09:08 AM
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It is also not how refrigeration works. The exit side of the evaporator contains gas, not liquid and has already gone through its phase change and the associated latent heat after passing through the expansion valve. The amount of sensible heat it would pick up in the throttle body is miniscule. Regardless, at no point in the AC system would you approach "dry ice" conditions.
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Old 04-15-2019, 07:05 PM
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Indeed you would lose power running the AC compressor.

Better to do the TB coolant bypass and run a 160deg T-stat, IMO.
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Old 04-15-2019, 09:30 PM
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Originally Posted by Akadeutsch View Post
Im not driving my C4 in the cold. At least not this summer. So my thought is to use the super high tech and also hollow throttle body to hold super cold
refrigerant, instead of hot coolant. I could plumb cold refrigerant from the low side of the evaporator. That should be dry ice cold. I wonder if I could put threads on the two Male coolant fittings on the throttle body? I think there is enough room for more than enough threads there. Enough to handle a couple hundred psi anyways... Do you guys think the gaskets it the throttle body would have to be changed out and likely custom made? If so what martial are refridgersnt gaskets made of? PAG rated?
You will get zero gain from this and you might reduce the efficiency of your AC. Any hp gain you would theoretically get at the throttle body would be eaten up with a corresponding loss from extra load on the AC pump.

I also don't think the throttle body itself will seal several hundred PSI. The hoses might seal but the throttle body itself wont.
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Old 04-15-2019, 11:16 PM
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Originally Posted by auburn2 View Post
You will get zero gain from this and you might reduce the efficiency of your AC. Any hp gain you would theoretically get at the throttle body would be eaten up with a corresponding loss from extra load on the AC pump.

I also don't think the throttle body itself will seal several hundred PSI. The hoses might seal but the throttle body itself wont.
Where on earth are some of you guys dreaming up this ****? Normal operating suction pressure on an 80 degree day is around 45 PSI for r134A.
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Old 04-16-2019, 10:54 AM
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It's not practical on a Corvette. It would require a custom heat exchanger and intake. It would not fit under hood with out a 6 inch or more scoop. Trying to duct cold air from evaporator case or moving evaporator itself - there is no space.
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Old 04-16-2019, 12:06 PM
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Originally Posted by ihatebarkingdogs View Post
The system pressure in a non-operating system in an under hood environment on a summer day just after engine shut down (system = OFF) will rise to much higher than 45psi. More like 150- ish. The pressure will equalize throughout the system.

The water manifold is attached to the bottom of the throttle body with screws and a gasket. This gasket won't hold refrigerant at any pressure.
Let's not split hairs here. The OP meant for his "invention" to work in an operating environment. Subsequent comments assumed the same and that happens to be 45 psi suction.
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Old 04-16-2019, 12:15 PM
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As previously stated, you'd lose any performance advantage of a cool TB to the cost of running the A/C. Suggest you look into methanol injection instead. This will lower your intake temps by 40-50 degrees and will be a lot simpler to install.

If you want to do something DIY, you can always coat the inside of your intake with epoxy. We did this on our LT1 impalas and it was good for around 2 tenths in the quarter - about the same as putting a bag of ice on the intake.
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Old 04-16-2019, 06:39 PM
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Originally Posted by arbee View Post
Let's not split hairs here. The OP meant for his "invention" to work in an operating environment. Subsequent comments assumed the same and that happens to be 45 psi suction.
The highest pressure on the cold side will be when the car is not running and on a hot day it can be well over 150psi.

The 45 PSI you see is with the engine on and the AC running. When the AC is on the compressor will pull a vacuum on the cold side relative to the hot side and regulate it to about 50psig, while the hot side can be over 300psig on a hot day. When you turn the engine off the compressor stops and the hot and cold side will equalize over time.

Go measure the suction side when the car is hot and has been off for 20 minutes and is not running. That is when the pressure will be highest and that is when he has to worry about it leaking.

Last edited by auburn2; 04-16-2019 at 06:48 PM.
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Old 04-16-2019, 07:03 PM
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Originally Posted by Akadeutsch View Post
Im not driving my C4 in the cold. At least not this summer. So my thought is to use the super high tech and also hollow throttle body to hold super cold
refrigerant, instead of hot coolant. I could plumb cold refrigerant from the low side of the evaporator. That should be dry ice cold.
Just do the easy "Throttle Body Coolant Bypass" mod, and that's enough. It'll prevent hot coolant from running through that area under the T.B.
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Old 04-16-2019, 10:56 PM
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Originally Posted by auburn2 View Post
The highest pressure on the cold side will be when the car is not running and on a hot day it can be well over 150psi.

The 45 PSI you see is with the engine on and the AC running. When the AC is on the compressor will pull a vacuum on the cold side relative to the hot side and regulate it to about 50psig, while the hot side can be over 300psig on a hot day. When you turn the engine off the compressor stops and the hot and cold side will equalize over time.

Go measure the suction side when the car is hot and has been off for 20 minutes and is not running. That is when the pressure will be highest and that is when he has to worry about it leaking.
You are correct and I am not disputting that. What I AM questioning is the original erroneous statements. The saturation temperature at the midpoint of the evaporator is around 40 degrees. It only gets warmer after that as it superheats. Where exactly is this "dry ice cold" going to come from? At any rate, 150 psi is a far cry from the "hundreds of pounds" as was stated.
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Old 04-16-2019, 11:03 PM
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Originally Posted by RetroGuy View Post
Just do the easy "Throttle Body Coolant Bypass" mod, and that's enough. It'll prevent hot coolant from running through that area under the T.B.
Enough said, think there's even a kit for it.

I won't even comment on the stuff in this thread.
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Old 04-17-2019, 08:56 AM
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Originally Posted by pcolt94 View Post
Enough said, think there's even a kit for it.

I won't even comment on the stuff in this thread.
There may be a kit, but I did my bypass for almost free using the existing hoses and redirecting them. Only had to buy a couple small hose clamps.
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Old 04-17-2019, 10:54 AM
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Bypassing a throttle body on a C4 Corvette may be okay but I have had major carburetor icing after disconnecting the hot air flow through the intake manifolds on VW's. The Icing happened here in Virginia in the late summer and is a very real problem on VW's. To be able to drive the car I had to re-install the original heated intake manifold.

I replaced my throttle body when in fact all I needed was the lower body for the throttle body. The lower section has the coolant flowing through it and the screws and part of the body were very soft from corrosion due to old coolant. Where does one get a replacement for the lower part of the throttle body?

The idea of a Methanol injection system is a good one if you want to cool down the combustion a bit. I use the SNOW Performance Water/Methanol injection system on my 1968 C3 and it does wonders for hot running engines. First the methanol makes the gasoline have an equivalent octane of 115 and the water cools and slows the combustion process. I use it because of the High compression but the water makes a huge difference in operating temperatures. The best part is that you can use windshield washing fluid for the injection system. Windshield washer fluid is frequently 50-50 methanol and water. The trick with a methanol injection system is to be sure that it doesn't fill your cylinders with water and hydro-lock your engine. I have two injectors and they have a flow solenoid that stops all flow when I turn it off or shut the engine down. Using the methanol injection systems I frequently hear people talking about mixing their own methanol. SNOW says no more than 50-50. Methanol like many alcohols will burn clear and that is not good if it finds a source of flame. It does not give you the rush that Nitrous does when activated. My system uses the vacuum of the engine to control the flow and that works very nicely. I am finishing up the new -4 AN SS PTFE braided lines for the system to make it look better and be more secure.

I hope the project ends up where you intended it to!
Good Luck!
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Old 04-17-2019, 01:57 PM
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Originally Posted by ctmccloskey View Post
Bypassing a throttle body on a C4 Corvette may be okay but I have had major carburetor icing after disconnecting the hot air flow through the intake manifolds on VW's. The Icing happened here in Virginia in the late summer and is a very real problem on VW's. To be able to drive the car I had to re-install the original heated intake manifold.
Not really a valid comparison; the VW has fuel flowing through the TB. That fuel is in the process of evaporating, which cools the air. The 'Vette had no such characteristics...nor does it have a reputation for carb icing.

OP could run the AC suction line (which is cold all the way to the compressor) through the TB coolant channels, run the AC in the staging lanes, then shut it off as he stages. I run my AC in the staging lanes anyway, to keep my coolant temps low. So...it's not THAT far fetched an idea.

I agree that it wouldn't do much, w/the speed the air flows through the TB.

Last edited by Tom400CFI; 04-17-2019 at 01:59 PM.
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Old 04-18-2019, 10:15 AM
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how is paint going to knock 2/10 off the 1/4
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Old 04-18-2019, 10:35 AM
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Depends on what you paint it with. You paint it with epoxy, you're basically putting a layer of plastic on the inside of a metal intake. GM didn't switch to plastic intakes to save money.
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