EVO Aerodynamics Review
Jun 28, 2010, 09:18 PM
#31
How about lap times with and without? That would be the easiest way to do it. I have a DL-1 datalogger but I need someone local to give me a hand with the software and calibration.
Downforce is like horsepower. You can feel it in your butt dyno. You KNOW it's there whether you have had your car on a dyno or in a wind tunnel, or not. Just like increased HP should result in lower ET's on the dragstrip, increased grip should result in decreased lap times. . .
Downforce is like horsepower. You can feel it in your butt dyno. You KNOW it's there whether you have had your car on a dyno or in a wind tunnel, or not. Just like increased HP should result in lower ET's on the dragstrip, increased grip should result in decreased lap times. . .
Jun 29, 2010, 09:49 AM
#32
A simple splitter with flat bottom will make some decent downforce. A 3-d undertray like the Voltex undertray will make some decent downforce even without a splitter element. Adding the two together will maximize the gains.
It doesn't have to be Voltex. They make some good stuff, don't get me wrong, but they are not the only thing out there that works. A splitter can be made from plywood, aluminum sheet, etc. You could probably make a simple plywood splitter/undertray to mount up to a stock bumper for about $100 including mounting hardware. For a full 3-d splitter/undertray with venturi/ducts you could start with a generic APR splitter then cut, bend, and rebond it to form the tunnels.
It doesn't have to be Voltex. They make some good stuff, don't get me wrong, but they are not the only thing out there that works. A splitter can be made from plywood, aluminum sheet, etc. You could probably make a simple plywood splitter/undertray to mount up to a stock bumper for about $100 including mounting hardware. For a full 3-d splitter/undertray with venturi/ducts you could start with a generic APR splitter then cut, bend, and rebond it to form the tunnels.
Jun 29, 2010, 08:46 PM
#35
Just a question about added downforce. Has anyone ever tested the amount of force that actually gets applied to the car for the cost of the added accessories> When I raced street bikes you could simply wrap a ziptie around a shock and determine how much the suspension moved. It would be easy to do the same on a car. At speed, considering no suspension adjustments are made, you could test to see if more force is applied simply by how far your suspension moved. (E.G. driving down a somewhat flat straight road pre vortex and post vortex kit.) I know there's devices that can actually measure downforce applied, but I don't think any of us are aero engineers that would have it readily available for testing.
Just a thought. I would love to see data, but maybe I just need to drive a car on a track with a kit and see how it compares.
Just a thought. I would love to see data, but maybe I just need to drive a car on a track with a kit and see how it compares.
Thats the thing... I always hear how well the areo performs but I don't see much data backing it up .... other than laws of science that is....
It would be nice to see cornering speeds of the same car with and without areo. That or braking data that shows decreased stopping distances.
It would be nice to see cornering speeds of the same car with and without areo. That or braking data that shows decreased stopping distances.
Ya, with out dedicated data I will never know. But I can't wait to set it up and see how much different it feels. From the original owner, he was as fast at Infineon Raceway w/ splitter and 305whp, as with 350whp and no aero.
Last edited by Speedlimit; Sep 13, 2014 at 07:20 AM.
Jul 2, 2010, 07:34 PM
#39
wow lots of posts since I saw this last.
a word of warning about measuring suspension travel.
I tried string pots on the front and back of my car. The data I collected lead me to believe there were to many variables to make any conclusions. Spring stiffness, loading of the drivetrain...even tire pressure, since soft tires would depress "better" than coilovers.
In the end I figure a pressure sensor under the wing's mount would give the best indications. As for an undertray , hey for those with a budget, measure the distance to the ground with a sensitive device.
a word of warning about measuring suspension travel.
I tried string pots on the front and back of my car. The data I collected lead me to believe there were to many variables to make any conclusions. Spring stiffness, loading of the drivetrain...even tire pressure, since soft tires would depress "better" than coilovers.
In the end I figure a pressure sensor under the wing's mount would give the best indications. As for an undertray , hey for those with a budget, measure the distance to the ground with a sensitive device.
Jul 2, 2010, 08:06 PM
#40
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With a steady state force the compresseion on the spring will be indicative of teh force applied at that corner, so measuring suspension travel can yield teh downforce teh car is making. I don't know about string pots but the sharp optical (not lasers) sensor have some amount of variance with temperature and I am sure have a large percent error.
Jul 2, 2010, 08:42 PM
#41
Sure I could read corner loadings, braking, accelerations, but the daily drivel of the road took out the meaning from the chaff. I was looking for downforce at speed relative to low speed. Part of the problem may have been instrumentation or it may have been due to the springs/shocks settling from over night, and then taking on a new profile from aggravation. As in, from garage start out to garage return the reading would be different a tenth. If the max your seeing is three tenths, thirty to fifty percent of your findings are in question.
So I was never satisfied I was getting worthwhile data.
The method is a question, maybe sonar? bats do it.
So I was never satisfied I was getting worthwhile data.
The method is a question, maybe sonar? bats do it.
Jul 3, 2010, 04:34 AM
#42
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Yeah I can see your point. Knowing exactly where the calibrated numbers are for each condition does drive more errors. I saw some linear pots made by Celesco with as low as 0.04-0.1% linearity. Those could take the slop out of the measuring equipment.
Last edited by oneguy; Jul 3, 2010 at 04:20 PM.
Jul 3, 2010, 06:22 PM
#43
You guys do realize that for about $1500 you can put your car in a wind tunnel and test it. I think you can get about 3 hours of testing for that price. That should be plenty of time to check stock bodywork, front splitter, undertray, rear wing, ride height . . .
wheres the fun in that
