Aero... racing boys.
#16
Rennlist Member
I have seen some great articles on home aero testing in autospeed.com They have a series devoted to it using a magnahelic guage or manometer to measure pressure differential at locations along the body....And the wool tufts/camera get some attention as well..good stuff in my book
#18
Rennlist Member
The sensors are linear and measure travel. On a high speed straight you should be able to tell if the rear is being loaded for a wing and for a splitter you should be able to tell what he front end is doing. Put the sensors on before any mods to get a base line, and then as you add the mods you can tell if it is helping or hindering with grip levels or whether you need to change spring rates, etc.
#19
Race Director
Thread Starter
My thoughts around grip levels and braking etc was to use ABS sensors hooked up to a Motec Dash...
Where do you get these suspension travel sensors from?
Where do you get these suspension travel sensors from?
#20
Rennlist Member
They are just slide sensors. They attach to the body and to a traveling part of the suspension.
Here is motec's sensor. Bottom of the page.
Http://www.motec/sensor/position
Here is an example
Here is motec's sensor. Bottom of the page.
Http://www.motec/sensor/position
Here is an example
#21
Pro
I think anything we might do is guesswork, however, looking at factory race cars will give you a starting point. Is your priority aero for downforce (I'm assuming so). In that case you want to run the car as low as possible, seal the front and sides (splitter / side skirts) and run a diffuser to channel the low pressure zone from behind the car underneath the car. Then if you can add a wing that sees clean air and some dive planes (not sure what angle to put these at) you've got a pretty good start - actually measuring the effectiveness of these additions would be pretty difficult and comparing between different designs would be at least as tough - but I think there are gains to be had by starting with basic principles.
#22
Yup, autospeed...
You can start here on part 3 of this series and click back to part 1. Also use the search on "aero" in this DIY area and find quite a bit more...
http://autospeed.com/cms/title_Under...2/article.html
You can start here on part 3 of this series and click back to part 1. Also use the search on "aero" in this DIY area and find quite a bit more...
http://autospeed.com/cms/title_Under...2/article.html
#23
Rennlist Member
They are just slide sensors. They attach to the body and to a traveling part of the suspension.
Here is motec's sensor. Bottom of the page.
Http://www.motec/sensor/position
Here is an example
Here is motec's sensor. Bottom of the page.
Http://www.motec/sensor/position
Here is an example
#25
Racer
I have a real life example on DIY Aero. I own an Lotus Seven S4 which I eventually will modify to go on the track. I have asked some of the experienced Seven drivers if fitting wings has any effect. The common answere is that it has an effect about 1-2 seconds per lap on a 1.5 miles circut. This is with a propper set up racecar whit an expert driver.
Her is one example:
This car does a 1.5mile circut 1-2 sec faster with front and rear wing. Grip is way better in high speed corners. The drag effect is not feelt on the straights. On some tracks the wings have less to none effect.
The driver is an expert driver, and winner of the Swedish racing series Modsport.
It shows that you can add wings and get an effect.
For those interested, here is an in car video from one of the races:
http://www.youtube.com/watch/?v=zv-mCxx1V90&hd=1
Her is one example:
This car does a 1.5mile circut 1-2 sec faster with front and rear wing. Grip is way better in high speed corners. The drag effect is not feelt on the straights. On some tracks the wings have less to none effect.
The driver is an expert driver, and winner of the Swedish racing series Modsport.
It shows that you can add wings and get an effect.
For those interested, here is an in car video from one of the races:
http://www.youtube.com/watch/?v=zv-mCxx1V90&hd=1
#26
Rennlist Member
I have a real life example on DIY Aero. I own an Lotus Seven S4 which I eventually will modify to go on the track. I have asked some of the experienced Seven drivers if fitting wings has any effect. The common answere is that it has an effect about 1-2 seconds per lap on a 1.5 miles circut. This is with a propper set up racecar whit an expert driver.
Her is one example:
This car does a 1.5mile circut 1-2 sec faster with front and rear wing. Grip is way better in high speed corners. The drag effect is not feelt on the straights. On some tracks the wings have less to none effect.
The driver is an expert driver, and winner of the Swedish racing series Modsport.
It shows that you can add wings and get an effect.
For those interested, here is an in car video from one of the races:
http://www.youtube.com/watch/?v=zv-mCxx1V90&hd=1
Her is one example:
This car does a 1.5mile circut 1-2 sec faster with front and rear wing. Grip is way better in high speed corners. The drag effect is not feelt on the straights. On some tracks the wings have less to none effect.
The driver is an expert driver, and winner of the Swedish racing series Modsport.
It shows that you can add wings and get an effect.
For those interested, here is an in car video from one of the races:
http://www.youtube.com/watch/?v=zv-mCxx1V90&hd=1
I don't think anyone is not saying aero is beneficial. What most of us are struggling with is how best to quantify the results for any given modification. Most of the larger outfits use wind tunnels which I would say is out of most of our capabilities. The other is work as a group and figure out what works best for a given platform. Most of us are data hogs who want to look at some time of data stream to determine what we did is working or was a glorious mistake.
#28
Rennlist Member
McDonalds Drivethrough....create downforce now!
#29
Rennlist Member
There was a thread in the NA forum a few months ago where a SP2 racer took his car to a wind tunnel for a few hours of testing. He was pretty limited to playing with tire pressures to raise and lower the car - but discovered that rake, as well as ground clearance, plays a big role in downforce (or minimizing the upforce).
However, looking at his data and my average cornering speed, we're talking about a very limited contribution to grip... I think there is more to be gained by reducing drag - like covering panel gaps, removing mirrors, covering side windows, etc. - and getting a little higher top speed on the straights.
To change subjects slightly, shock potentiometers can tell you a lot! I put them on my car at the end of the season and I'm still trying to figure out the data. It's interesting to note that, even with a full cage, my car exhibits 2 degrees of body twist while cornering (left or right) - imagine how much it would twist without a cage!
However, looking at his data and my average cornering speed, we're talking about a very limited contribution to grip... I think there is more to be gained by reducing drag - like covering panel gaps, removing mirrors, covering side windows, etc. - and getting a little higher top speed on the straights.
To change subjects slightly, shock potentiometers can tell you a lot! I put them on my car at the end of the season and I'm still trying to figure out the data. It's interesting to note that, even with a full cage, my car exhibits 2 degrees of body twist while cornering (left or right) - imagine how much it would twist without a cage!
Last edited by Van; 01-03-2013 at 08:13 PM. Reason: dumb thumbs
#30
Nordschleife Master
Wow, I was just thinking about this very topic this morning....
My question however is in regards to the 968 wing vs the standard rubber tail on the 944/951. Do these two variants offer the same rear down force? Is there any real data on these different rear wing/tail configurations?
My question however is in regards to the 968 wing vs the standard rubber tail on the 944/951. Do these two variants offer the same rear down force? Is there any real data on these different rear wing/tail configurations?
I view the 968 spoiler as more of a diffuser. It smooths the air flow, for less drag. Its purpose is not for downforce, though I'm sure it does create some.
F1 designers spend hundreds of hours in the wind tunnel, and change their designs nearly every race. Even the best engineers, with the best computers, in the world cannot create a "perfect" design. They still use glo-vis paint to test their parts. As said above, you can do the same with some yarn and someone with a camera in another car. That is how the Shelby Daytona's body was tweeked..and it won a few races.
With boundary layers, high and low pressures, drag, lift and downforce all needing to be accounted for, its extremely difficult to get right by "guessing". The 944 is pretty aerodynamic, even by today's standards. The most gains (IMHO) are made from under the car, and around the wheel wells (high pressure areas). Also, venting the air trapped under the hood should give a good gain. Added wings and downforce should be used to balance the car, more than sticking it to the road. Even the high powered cars just aren't doing the speed needed to maximize benefits of a ton of downforce...not to take the hit of the added drag anyway.