Quote:
Originally Posted by aerohead
1) Is there any difference between the van and Suburban as far as engine bay air extracting through the front wheel-wells or not ?
2) And could the transmission cooler be affected by a change to the airdam?
3) And does transmission cooling rely to any degree at all on airflow physically sweeping through the transmission tunnel, and directly across the aluminum case as you drive?
4) You may have a full-synthetic lubrication package already, which can handle pretty extreme temperatures, but you'd want to know.  |
Both vehicles have nearly identical front overhangs with the much of the engine and the whole transmission well behind the wheel wells. The installed height of the air dam on the van is about the same as the Suburban/Tahoe ( about 9 inches above the pavement in the middle and 7 1/2 at the sides). They are both mounted at the front most point of the vehicle ( the bottom of the bumper). All radiator/ intercooler cooling air is coming from above the bumper on both vehicles, not like most cars that pull air from under the bumper. The Suburban has wheel well liners, while the van wheel wells are open at the front. I plan on closing these too when installing the belly pan and may run the liner down lower below the belly pan to deflect air away from the tires. However, I am concerned about brake cooling. However, I just checked the brakes and after 80,000 miles of mostly city driving, the pads aren't even half worn yet. The brakes are plenty big, the vehicle is rated at a GCWR of about 14,000 lbs.
I probably have significant room to play with in cooling....I am running a 180 HP 2.8l Diesel instead of a 400HP 6.0L Gas v-8. Currently, cooling is so plentiful that the vehicle won't even warm up often times in the winter. Fortunately the cargo area interior is insulated so it requires very little heating (and little cooling in the summer) to be comfortable.
I have noticed that the radiator has baffles nearly all the way around to direct air from the grill into the radiator instead of it just blowing everywhere. However, I did notice that there is a significant opening at the bottom baffle behind the air dam location. I wonder if this is a relief opening when traveling at highway speeds to reduce the airflow through the radiator. I suspect a bigger air dam would create a stronger pressure bubble at the front of the vehicle, but the backside of the bigger air dam would create stronger vacuum at this relief opening.
A front belly pan should do a much better job than just the open underside at directing air flow across the engine and transmission. You'll no longer have the vacuum right behind the air dam pulling cooling air down below the vehicle. The high velocity air at the rear edge of the pan should create a strong vacuum to pull air through the engine bay.
I wonder if creating a "blast fence" here would do any good when the underside of a van is a giant open cavity with the walls on both sides. I've also wondered about extending these "rocker panels" down to reduce air coming in from the sides per Semi trailer design.
The air dam is similiar in design to most newer SUVS's. It tapers down and back at first and then becomes at right angles to the ground. It appears most newer suv's are trying to divert the air around the jagged mechanicals with a back tapered air dam and directing the air smoothly under the vehicle.
This sounds alot like what Freebeard said
Time to head to find some full size SUV front wheel well liners and to pick up some ABS sheet. But a few other vehicle repairs first.