Dave Salazar from A2WT is...
Dave Salazar from A2WT is getting ready to run the first baseline, this will provide a way of looking back and seeing how much downforce we've gained or lost from our adjustments.
The next thing to do was to put the car at race attitude because, as I'm sure a lot of you readers have already concluded, a Dirt Late Model will never sit that flush when traveling near 100 miles an hour. The guys of Menscer Motorsports were ready and after a few adjustments the car was almost hiking the LF inside the wind tunnel.
The incredible thing was that even with the car at attitude, the downforce numbers actually increased. The biggest jump we saw was the increase in the side force numbers. After we ran the car at attitude, we then put it back to ride heights and started to work toward evening out the car's downforce numbers.
The goal would be to attain a front-to-rear downforce balance closer to 50-50 by trying to increase the downforce at the front of the car without affecting the rear too much. Plus, we need to remember the reason why the bodies are designed with so much rear downforce is because of the need for better bite off the corners. You need that much downforce to be able to help accelerate better.
Another interesting fact that we came across was how much horsepower we would need just to overcome the drag being produced. Remember from earlier, as the speed increases, so will the drag. We'll need roughly eight times the amount of horsepower to overcome that drag. What we found out was that to achieve a top speed of 135 mph, we would need roughly 400 horsepower. "This is a huge number for you guys," says Salazar. "Now we know that we don't need to be concerned with reducing the amount of drag." This is because no matter how much downforce we create we'll always have an abundance of horsepower to be able to overcome that drag."
This could be a factor for you crate Late Model guys though, if you're only pushing near 400 hp. Then, you might want to look at getting the body as low to the ground as possible and reducing the amount of drag.
Putting the car at attitude...
Putting the car at attitude shows the type of downforce we are creating when the left front wheel is almost off the ground.
Next we reduced the speed of the wind to 40 mph and were able to see how the air was traveling around the car by doing a smoke-wand test. We don't record any data during this test but we were able to see exactly how the air travels over the body. What we were able to determine and see was where the "dirty air" was being produced. We could see that the air traveling across the center of the hood wouldn't actually ever get to the spoiler, but the air flowing over the right and left sides of the spoiler is where all of the downforce was made.
Help increase the front downforce To help increase the amount of front downforce, the team tried a variety of different changes to the front end including different hoods, fenders, and more and we found a few gains. One of the most impressive gains was found by simply taking a 90-degree piece of aluminum and running it horizontally across the front fender (as shown in the picture on the previous page). This seemed to help the front downforce numbers. Don't get too carried away though on how tall the piece is, a 1-inch piece did just fine. If you go too much larger it will actually start to hurt the rear downforce numbers by deflecting too much air away from the roof and spoiler.
The other adjustment we tried which seemed to help was installing a carbon-fiber air-filter cover. This piece helped both the front and rear downforce numbers.
Rear Spoiler Now, the rear spoiler is where we found some really good information. A small rear spoiler change can affect how the car handles drastically. A good example of this is the gurney bracket that was attached to the rear spoiler. The flap is only a couple inches wide and it helps hold as much rear downforce as possible. What we did was take the gurney flap and turn it around backwards to where it faced the direction of the wind just to see if we lost downforce. We found that we lost 100 pounds of downforce at the rear of the car. Someone asked, "Is that a big change?" To which Dave responded, "Well if your driver can't feel 100 pounds of change, you need a new driver."
These bodies produce a ton...
These bodies produce a ton of downforce, but 70 percent of it is coming from the rear of the vehicle. In order to gain front downforce, the team added a 90-degree piece of aluminum across the hood. It made a big difference on the front downforce numbers.
This carbon-fiber air filter...
This carbon-fiber air filter duct not only increased our front downforce numbers but we saw an increase in the rear as well.
What we found out with the...
What we found out with the rear spoiler was a simple, minor change could cause huge changes in the rear downforce numbers. But what surprised us was the rear spoiler, if tilted too far up, would cause an increase in drag, but a decrease in rear downforce.