Splitter vs. air dam

[Otto]

In terms of drag reduction for a car, is most bang for the buck with a splitter or an air dam?

How about a splitter that continues aftwards as a belly pan?

[kach22i]

Otto, I would pose this as three problems or examples - for the first part.

Existing air dam is X inches above ground line:
4"
8"
12"

For set "A" add another dam 1/2 the distance to ground plane.

For set "B" add only a horizontal splitter of 6" projection parallel to the ground plane.

The second question should wait until the first part is answered in my opinion.

I also assume that adding both a dam and splitter is best, but this was not your question, right?

[mcrews]

any splitter mod should also have a front underbelly mod. I think that is a given.

But the two items acheive very different results.
1. Splitter: designed to increase downward pressure on the front. Air is still going under the car
2. Air dam: designed to move the air(that would normally go under the car) around the car.

Splitters are normally seen when the car's bodywork is already within a couple of inches of the ground.
usually,A dam is added to lower the front plane of the vehicle. it is not designed to address the turbulance of the air going under the car.

[mcrews]

sorry, back to the question.
In my opinion, a splitter(w/o an extentions as a belly pan), by design, wont have an impact on drag reduction.

[hiro256]

from the aerodynamic testing of corvette c5 for showroom stock racing paper
using "laguna" style undertray which closes in the front bottom making the corvette a front breather and splitter test results
base 1629N drag FT lift -70N RR Lift -947N
add tray w/ 3.75 cm splitter 1714N drag FT lift -355N RR Lift -855N
and w/ 2.5cm Splitter 1714N drag FT lift -311N RR Lift-985N

[mcrews]

base....................................1629N drag FT.....lift -70N.......RR Lift -947N
add tray w/ 3.75 cm splitter.....1714N drag FT.....lift -355N......RR Lift -855N
add tray w/ 2.5cm Splitter.......1714N drag FT.....lift -311N...... RR Lift-985N