Connecting a Ram air

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Jean-Pierre

Well-known member
Joined
Sep 12, 2018
Messages
46
Reaction score
21
Location
France
My Car
Ford Mustang Fastback 73 351C
Hi guys,
I own a 73 equipped with the 351C 2V. The car is also equipped with an Edelbrock intake and a 4v carburetor. I bought it like that.
Since it has the Naca hood, I just installed a Ram Air on it. I plugged it into the air outlet of the edelbrock which is on the back.
However, I find that it works poorly. It closes fine when I start the engine but then it accelerates a lot to get it to open. I throttle at 3500, 4000 rpm to make it work. Is this normal? I specify that the vehicle is stationary during the test.
Is the connection correct? Is something missing?
Translated from French by Google.
 
The ram air ducts are designed to work at low engine vacuum -- which occurs at wide open throttle under load -- which is not something that normally lasts very long.
Sounds like yours are working as designed.
 
The louvres are kept open with a spring. Once there is enough vacuum to counter the force of the spring it closes. Once the vacuum is near zero the louvres spring back to open. I ended up adding a vacuum switch so I keep them open all the time unless is raining. Since I have EFI, I can measure the inlet air temp and I can see a 10 degrees drop in a normal day. I don't see any change in manifold pressure when open so it acts more like a real cold air intake rather than RAM.
 
Thank you for your answer. Indeed, I am a bit worried about this summer.
Above 30° celsius (86 fahrenheit where you live), it tends to heat up if I stay stationary....
 
Thank you for your answer. Indeed, I am a bit worried about this summer.
Above 30° celsius (86 fahrenheit where you live), it tends to heat up if I stay stationary....

Heating while stationary or while in traffic is normally an airflow issue. You may have insufficient fan speed or an inadequate aftermarket fan
 
Heating while stationary or while in traffic is normally an airflow issue. You may have insufficient fan speed or an inadequate aftermarket fan
When we bought our 73 Mach 1 about 6 years ago I resolved the ***** light laden instrument panel with a Dakota VHX analog gauge unit (they are on both of our 73 Mustangs). One of the first things I noticed is how when driving the temp would hang just below 200 degrees F. But if i idled for more than a few moments or was driving in slow traffic (under 25MPH), the temp would climb quickly to 235 and for even longer such periods of idling or slow driving it would hit 240. But once I got moving over 25 the temp would quickly drop to just under 200 again.

It was clear to me it had an air flow problem through the radiator. So I began to look at the usual suspects. Although i was certain it was an air flow issue I took the time to do the basics with a cooling system pressure check to make sure I had no leaks, made sure the radiator cap help adequate pressure before venting, and looked inside the radiator to make sure the coolant was flowing freely when the thermostat was open.

Everything checked out. So I knew I would not be plagues with additional issues while resolving the air flow related problem. The radiator cooling fins were not clogged with insect parts or other debris, nor were they flattened down. What I did note was the radiator was larger than it would have been for a 302 non-A/C car. But the air shroud was the one for a smaller radiator and was not fitting the radiator properly.

I could have looked and purchased a properly fitting fan shroud, and called it a day. But, no, this was my opportunity to do something I had always wanted to do. Install an electric fan based cooling system with a fancy radiator.

In short, the dual electric fan solution worked perfectly and it let me do some other things to further improve the operability of the car. I sam away from my laptop and painfully keyed all this on my iPhone. Once home I will provide additional info. H til then suffice it to say that I am very pleased with how the project turned out.
 
When we bought our 73 Mach 1 about 6 years ago I resolved the ***** light laden instrument panel with a Dakota VHX analog gauge unit (they are on both of our 73 Mustangs). One of the first things I noticed is how when driving the temp would hang just below 200 degrees F. But if i idled for more than a few moments or was driving in slow traffic (under 25MPH), the temp would climb quickly to 235 and for even longer such periods of idling or slow driving it would hit 240. But once I got moving over 25 the temp would quickly drop to just under 200 again.

It was clear to me it had an air flow problem through the radiator. So I began to look at the usual suspects. Although i was certain it was an air flow issue I took the time to do the basics with a cooling system pressure check to make sure I had no leaks, made sure the radiator cap help adequate pressure before venting, and looked inside the radiator to make sure the coolant was flowing freely when the thermostat was open.

Everything checked out. So I knew I would not be plagues with additional issues while resolving the air flow related problem. The radiator cooling fins were not clogged with insect parts or other debris, nor were they flattened down. What I did note was the radiator was larger than it would have been for a 302 non-A/C car. But the air shroud was the one for a smaller radiator and was not fitting the radiator properly.

I could have looked and purchased a properly fitting fan shroud, and called it a day. But, no, this was my opportunity to do something I had always wanted to do. Install an electric fan based cooling system with a fancy radiator.

In short, the dual electric fan solution worked perfectly and it let me do some other things to further improve the operability of the car. I sam away from my laptop and painfully keyed all this on my iPhone. Once home I will provide additional info. H til then suffice it to say that I am very pleased with how the project turned out.
I agree, there is lots of room up front for a dual fan electric with a new rad. which one did you get?
 
Yes, my mechanic also recommended the double fan solution at the front. He did it on his and it hasn't heated up since. So I'm going to start with that before thinking about changing the radiator.
 

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A radiator which has some sedimentary obstruction in the tubes can often give the same symptoms as not enough airflow. It can get warmer at idle and low water speed, but cool down when the pump is spinning fast enough to push harder at circulating the coolant. After checking the basic things, thermostat opening, cap holding pressure, radiator holding pressure, etc, and before spending money on fans and , for God"s sakes, an expensive, non- radiator shop "rod-able" high priced aluminum radiator, Stick with the basics you learned in High School Auto Shop....remove your radiator ( easy on these cars ), and have a radiator shop clean and "rod" the radiator out. This is often the least expensive answer, and is even more important should you operate your car in warmer climates and/or have air conditioning, which will steal some airflow and add heat to your radiator. I can start my car and let it idle indefinitely without overheating. Either I'm lucky, or the stock components, in good operating condition, just work. I've had many cars in my life so far, Hot rods, muscle cars, stock passenger cars, antique cars, and rarely had overheating issues ( knock on wood ), however, when I did, once with my 1930 Model A Ford, and once with my 1970 Olds 442 w-30, both times, it was a trip to the radiator shop that tuned me right up, and the price was right. It was never my water pump or fan, or some other component. Having led you down this path here, I do realize that radiator shops have become fewer and farther between. Today, new cars use radiators with non-rebuildable aluminum cores and plastic tanks. Labor costs and some EPA mandates got involved, and cars aren't built with brass tanks and cores anymore, so yes, times have changed and these services aren't everywhere like they used to be, but check around. This service may be all you need.
 
I end up just keeping a screw in the car and disconnecting the hose if we're in a club run. I'm not sure if anyone else can confirm this but it sure does eat into the fuel consumption. And nooooo....it's not because I have my "foot in it" all the time, although it does happen more frequently than when I'm riding with the DW. I did notice at normal cruising speeds; it eats a bit more but also performs (throttle response with a 500CFM Holley 2V) and even sounds better.
 
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