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240 Air flow/Pressure Metal splash pan

A

AJS

New member
Joined
Jul 26, 2004
Location
Australia
Anyone know what sort of airflow you get from the vents in the early metal splash pans fitted to a late 240?
Air dam in place.
 
AJS said:
Anyone know what sort of airflow you get from the vents in the early metal splash pans fitted to a late 240?
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Airdam Function - Many of the early 240's came without an airdam...Volvo warns that an airdam should be used only on cars with alloy wheels or '80 and newer steel wheels (these have larger holes for ventilation).

Splash Pan Function - it's primary function is as part of the cooling system. There to create a low pressure area below and behind the radiator.
 
Yes, any idea of the air flow through it though?
I can't recall what the late model pan was like.
The dam and splash pans are part of the same system so changing from one to another likely changes the pressure in that location.
 
AJS said:
Yes, any idea of the air flow through it though?
Click to expand...

One would need a Digital Manometer, with at least 1/100 inch (WC) accuracy to evaluate.

During highway driving is where this suction force exists. Vehicles with electric fans use belly pans for same effect. Belly pan serves four basic functions: 1. aerodynamics, 2. splash shield, 3. remove heat, and 4. suction pressure to pull radiator air thru at higher speeds.
 
IE you don't know.
Which is fine, hopefully someone who does know more than I do will chip in and save me some time.

We have a couple of guys who should know this if they see the thread.
 
AJS said:
Yes, any idea of the air flow through it though?
I can't recall what the late model pan was like.
The dam and splash pans are part of the same system so changing from one to another likely changes the pressure in that location.
Click to expand...


The late model pans have ZERO slots and cover the entire area from the cross-member forward, and the full width of the engine bay.

Hope this helps.

I have no idea how much quantifiable difference the old style pans slots would make, but there would be some increase in air pressure aft of the radiator as compared to late model pan. Some people run without the pans and claim no negative cooling consequences.

John
 
AJS said:
IE you don't know...Anyone know what sort of airflow you get from the vents....
Click to expand...

I do have a 1975 with OEM belly pan, along with the modified one used in later years.

I have no idea what your focus is, but here's a long story short.

Streamlining vehicles, aerodynamics, was taken more seriously in past thirty some years; before then, vehicles were built upon design (looks) without serious consideration to aerodynamics.

Here is a thread that touched upon this topic: The Official Drag Coefficient of Your Brick

When considering the new vs old design, the laminar flow would suck on the old design.

As noted before, aerodynamic considerations would not come into play until higher speeds are reached. And, the old design would increase the force of drag by a small pinch.

Air is going to flow thru radiator one way (suction draft) or another (fan), and I doubt for most all drivers, the fuel economy difference won't amount to a hill of beans.
 
aimless said:
The late model pans have ZERO slots and cover the entire area from the cross-member forward, and the full width of the engine bay.

Hope this helps.

I have no idea how much quantifiable difference the old style pans slots would make, but there would be some increase in air pressure aft of the radiator as compared to late model pan. Some people run without the pans and claim no negative cooling consequences.

John
Click to expand...

I found decreased cooling with the early metal pan.
Not a concern for me at this stage.

My interest was knowing just how much air goes through the early pan into the bay.
I doubt it's much based on how much cleaner the lower bay is with it fitted during poor weather VS not having it.
I was hoping for a quick answer. I can measure pressure and airflow but I don't have time to do it for a few weeks.
 
AJS said:
interest was knowing just how much air goes through the early pan into the bay..
Click to expand...

Belly pan was redesigned...today's belly pan fits any 240, 260 model 75-93.


If those slits were needed, the engineers would have insisted. Needless to say, the version-1 belly pans would cost more to make.

Considering how small those vertical slits are, along with that wire-mesh, that would have been turbulent air flowing thru them. I would suspect version-II would provide better flow thru radiator at highway speeds.

I had an electric fan on my previous 1984, and it never had a heating issue with version-II, on hot summer days at highway speeds.
 
84B23F said:
...

If those slits were needed, the engineers would have insisted. Needless to say, the version-1 belly pans would cost more to make.
It could have been cost cutting, it could have been changes to the cooling system, it could have been the airdam changes, it could have been a push to increase efficiency or any number of things which caused the change. An engineer does not get to "insist" on anything in production. They find solutions to issues which are caused by cost but they certainly don't get to dictate what should be done.

Considering how small those vertical slits are, along with that wire-mesh, that would have been turbulent air flowing thru them. I would suspect version-II would provide better flow thru radiator at highway speeds.
No wire mesh on mine. The newer one would have of course increased airflow though the radiator. Didn't the airdam come in at the same time as other aero changes? All the air flow into the bay is turbulent.

I had an electric fan on my previous 1984, and it never had a heating issue with version-II, on hot summer days at highway speeds.
Click to expand...
I went to an Efan to increase cooling over the mech fan.
 
>belly pan >> It could have been cost cutting, it could have

Volvo says: "...the key words associated with Volvo marketing have been durability, reliability, safety, and comfort. The 1984 Volvos are no exception to this rule. Volvo does not believe in change for the sake of change, consequently there are no startling revelations in the Volvo story for 1984. Instead, we see continued refinement of an already well thought out and carefully crafted product line."

>No wire mesh on mine.

Later today, I'll take a pic and post

Tidbits:

1. Approaching the '86 240 from the front, your eyes will surely be drawn first to the large rectangular European-style, semi-sealed beam headlamps. Not only do these lights provide excellent illumination, but they also contribute to better aerodynamics thanks to their canted front surface which leads the air smoothly up over the hood and out across the wraparound marker lamps. The grille, hood and front fenders are all lower, giving a slightly more wedge-shaped appearance and enhancing the car's ability to slice through the air. A spoiler beneath the bumper completes the aerodynamic package at the front.

>Didn't the airdam come

2. 1.1 Front Airdam (spoiler) - Many of the early 240?s came without an airdam......MORE HERE...
 
AJS said:
No wire mesh on mine.
Click to expand...

1975 244 US-Federal

Capture_zps8aef9fce.png
 
All the airflow theories are great, but bunk. Anything you add to restrict the air escaping out of the engine compartment will only serve to provide additional pressure drop and decrease flow. If you make the straw smaller, you have to blow harder to move the same amount of air as the larger straw.

The belly pans were to protect the front of the engine from getting snow packed up in there when driving through deeper snow. The warm engine will then partially melt the packed in snow and as it cools overnight will then freeze solid to the engine and around all the accessories in the front of the engine. You are then stuck with an engine that will not start as it is literally "frozen". Seen it happen several times to various cars back in South Dakota when I was working in a garage in high school. Early 80s Camaro/Firebirds seemed particularly susceptible. I also saw it happen to an 80s Jeep Eagle (one of the weird 4WD car things) after an afternoon of drift busting. He also packed it up around the wheels and it froze to the wheels. He was very late to work that day.

The pans also conveniently prevents splash up into the engine compartment when driving at speed through a large puddle (more common in the PNW).
 
Based on?
The pan change was part of the Aero changes was it not?

IF it restricts the airflow. If it reduces turbulence in that area flow out of the bay can be increased.
 
quillc said:
All the airflow theories are great, but bunk..... belly pans were to protect the front of the engine from getting snow packed up
Click to expand...

1986 Chevelot Caprice - I was "snow plowing" and whole engine compartment filled with snow, and even one belt came off. No belly pan there...

Eco-modelers - They claim better mpg with smoother surfaces underneath.

Air Flow Dynamics - I crack the driver's side window down at highway speeds, and cigarette smoke goes out the window...in fact, one can flip the ashes into air, and they get SUCKED out.

1967 Chevrolet Chevelle NASCAR


Smokey Yunick - The underside was an engineering marvel. The floor boards were lowered to create a belly pan, custom-made adjustable front control arms replaced stock units, and a revised front steer system was used to optimize the Ackerman angle and make room for the engines belly pan style oil pan.

used-1967-chevrolet-chevelle_nascar-smokeyyunick-9423-5117058-41-640.jpg
 
84B23F said:
1986 Chevelot Caprice - I was "snow plowing" and whole engine compartment filled with snow, and even one belt came off. No belly pan there...
Click to expand...
My point exactly. A belly pan helps prevent this.
84B23F said:
Eco-modelers - They claim better mpg with smoother surfaces underneath.
Click to expand...
Lots of people claim a lot of silly things. Simply adding a belly pan doesn't get you there. The air dam below the bumper is doing all of the work there. To see any significant benefit, you have to put a belly pan pretty much the length of the car. You are much better off closing up as much of the front openings as possible and removing things that generate drag (blank off most of the grille, make the front air dam as low as possible, remove the wipers and rear view mirrors and so on). Essentially you want to make the exterior of the car as smooth as possible and not allow any air through or under the car. If you look at cars running on the salt flats, they tape up everything to minimize drag.

84B23F said:
Air Flow Dynamics - I crack the driver's side window down at highway speeds, and cigarette smoke goes out the window...in fact, one can flip the ashes into air, and they get SUCKED out.
Click to expand...
Yes that is true. It is caused by a low pressure area behind the front windscreen as the air is forced up and over the car. 240s are particularly good at this due to the steep flat winshield angle. You get a nice low pressure dead spot beside the driver/passenger door. On newer cars, this is less true to better aerodynamics.
 
quillc said:
Lots of people claim a lot of silly things.
Click to expand...

Smokey Yunick, I think he was mostly tight lipped, in those days.

There's a reason for that modified oil pan, and air-flowing over it had a purpose, especially at NASCAR speeds.

>low pressure area

That's right, on my stock 1993-245, there is air flowing under that belly pan, and it assists in sucking out engine compartment's hot-air, which mostly comes via radiator. That's why e-fans work, a "natural" suction draft exists, at highway speeds.
 
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