Van Aero theory

[shackwrrr]

Aright been thinking about the design and theory of the front bumper/ grille on my van. My biggest concern is cooling and road handling. What I've noticed that people do is put an air dam on the bumper then leave the space between the bumper and core support open. Even the Chrysler TSB shows fitting a dam to the bumper then drilling holes in the "flap" between the bumper and the core support. To me this idea doesn't work, the air dam on the bumper creates a low pressure behind the bumper but in front of the core support. This would cause air to be taken away from the radiator/intercooler. My theory is to fit an air dam to the core support and either remove the lower portion of the plastic bumper or fit an aluminum bumper. This would create a low pressure area in the engine bay pulling air through the radiator and sucking the van to the ground. Also the radiator will not only feed from the grille, air can feed from under the bumper, in front of the air dam. This is how most newer cars work.

Any thoughts of this? I could make some pictures but I'm on my phone.

[turbovanman²]

Need pics, lol.

I know for a fact the lower air dams work as without it, my van wants to wander on the highway and runs hotter, with it, the front end is more planted and runs cooler.

[ShelGame]

The Daytona Shelby Z chin spoiler, for example, has a long/wide flat section behind the chin that goes all the way back to the core support. It does have a decent size hole in it, but not nearly as big as without the flat. I assumed it was for the same reason - to prevent recirculating 'hot' radiator air.

So, I think you can do it 2 ways: #1 - 2nd air dam at the core support as you mentioned, or #2 - A flat close out panel between the air dam and the core support. I tend to think that #2 would be less drag.

[A.J.]

Aright been thinking about the design and theory of the front bumper/ grille on my van. My biggest concern is cooling and road handling. What I've noticed that people do is put an air dam on the bumper then leave the space between the bumper and core support open. Even the Chrysler TSB shows fitting a dam to the bumper then drilling holes in the "flap" between the bumper and the core support. To me this idea doesn't work, the air dam on the bumper creates a low pressure behind the bumper but in front of the core support. This would cause air to be taken away from the radiator/intercooler. My theory is to fit an air dam to the core support and either remove the lower portion of the plastic bumper or fit an aluminum bumper. This would create a low pressure area in the engine bay pulling air through the radiator and sucking the van to the ground. Also the radiator will not only feed from the grille, air can feed from under the bumper, in front of the air dam. This is how most newer cars work.

Any thoughts of this? I could make some pictures but I'm on my phone.

You mean like this?







I think the air dam needs to below the radiator, not in front of it if you want to create a low pressure differential (vacuum) to pull air THROUGH the radiator.

What I've done and noticed:
1) I put a skid plate on my van. It ran hotter.
2) I removed the skid plate and I installed an air dam pictured above and my van ran cooler.
3) I installed an air dam on my Dad's '85 Chrysler T&C wagon and attached it in front of the core support below the bumper. I then got another one and installed it under the core support. I took it on a road test on a 110* day and on a certain section of highway that gets the engine temp to 230*. In front of the core support or under it it made no difference. The engine still reached 230* at the same section of highway.

Dad's T&C wagon, 1st install. Looks better but I didn't feel was practical.





Dad's T&C wagon, 2nd install. Looks not as good, seems more practical, make no difference in placement. My Dad says it does but I think he's just stroking my ego so I continue to modify his car for free.






A.J.

[shackwrrr]

Yes like that, but remove the flap between the bumper to allow bottom feeding. I have the metal bumper so it naturally bottom feeds already. I noticed a definite improvement in cooling with the aluminum bumper only, I also plan on adding a dam like yours AJ, exploder right?

[shackwrrr]

Shown in the first picture, high pressure is built in front of the air dam/bumper/grille and is forced through the grille opening. Behind the airdam a low pressure area is made in front of the core support and radiator, this pulls the air through the grille but bypasses the radiator.

In the second picture, high pressure is built up in front of the air dam again but now the high pressure pushes up into the area between the grille and radiator. Behind the air dam again is a low pressure area but the low pressure is now under the engine bay, this pulls that extra air from between the radiator and grille through the radiator theoretically cooling the car/van better.

Does the T&C still have an internal transmission cooler? If so this could be the reason that the temps still peak at 230* on hills. The cooler being in the outlet side of the radiator basically re heats all the coolant that just got cooled by the radiator. Most likely the transmission temps are normal but it just puts more stress on a radiator that is probably close to its limit in cooling ability.

Here is where I am saying to remove the "flap" from the plastic bumper, this would allow the high pressure area to push air in from underneath, flowing more into the radiator. If I remember though your intercooler is in this area so doing so may allow air to "cheat" past your intercooler to the radiator, good for engine cooling but not for air cooling. My intercooler is in the engine bay like the radiator so with mine this would help.

[GLHNSLHT2]

look at the 84-86 TurboZ, the nose is completely sealed off all the way back to the rad support where the airdam is. I don't know why in 87 they opened it up and then dropped the lower airdam and side skirts They would of looked sweet and worked awesome if they had under body ground f/x like the 84-86's did.

[A.J.]

Does the T&C still have an internal transmission cooler? If so this could be the reason that the temps still peak at 230* on hills. The cooler being in the outlet side of the radiator basically re heats all the coolant that just got cooled by the radiator. Most likely the transmission temps are normal but it just puts more stress on a radiator that is probably close to its limit in cooling ability.

The T&C has a TU T-II radiator, separate trans cooler, an air to oil oil cooler, and a FMIC that blocks everything.

look at the 84-86 TurboZ, the nose is completely sealed off all the way back to the rad support where the airdam is. I don't know why in 87 they opened it up and then dropped the lower airdam and side skirts They would of looked sweet and worked awesome if they had under body ground f/x like the 84-86's did.

I had an '89 Daytona ES and I built a shield that sealed off the front air dam/spoiler to the radiator. That thing funneled so much air through the radiator the fan only came on while sitting in traffic.

A.J.

[GLHNSLHT2]

yea I did the same thing on my 87 ShelbyZ. Same results.