Sprint Car Difusser Help!
Sprint Car Difusser Help!
(OP)
Ok im new to this site and i believe it could help solve my problem. I race a sprint car. We have a front wing and a top wing(located above the driver). Those are our two main points of downforce. The area i have been thinking about is below the car. The bottom of the race car is NOT enclosed. only the front 1/4 of the car has a belly pan. therefor all the air after that is very dirty. I cannot find any rules on having a full length belly pan so i am going to make a stab at it. The only real place i have no idea what im doing is at the rear(difusser). How do i exactly go about designing the difusser? If you have a side view of the racecar the entire bottom (or belly pan line) is flat or parallel to the ground except the last foot at the rear has a bend upwards of about 3 inches. So when making a belly pan do i follow the curve upward or do i make it stay flat? once again this is the area for the difusser. Please help me.





RE: Sprint Car Difusser Help!
Andrew~BSME
RE: Sprint Car Difusser Help!
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Sprint Car Difusser Help!
RE: Sprint Car Difusser Help!
Sprint cars have asymmetric wings and asymmetric tyre size (stager) so why not design the belly pan and diffuser presuming airflow at a diagonal. I think perpendicular is to much as if the axis of the chassis is perpendicular to direction of travel, you are very close to going backward.
I would think 46 to 60 deg is typical attitude on the turns, but that is just my guess from occasionally watching a race.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Sprint Car Difusser Help!
With that being said, I have though about how to achieve a more "laminar" flow of air on a sprint car. As a visualize the air traveling over this car, I dont see how it would be possible to achieve better flow on an object as aerodynamically unclean as a Sprint Car. I believe the top part of aluminum on the wing is called a wicker bill? Which I know has been outlawed in some classes (ASCS). Does that mean it is not possible to achieve the results you are looking for? Absolutely not. Part of being a good engineer is knowing that you dont really know it all. So I must say that I don't have any more ideas for you. I dont think the improvements you are talking about making to your car would make a noticable improvement to your performance. Keep up that thinking though and eventually you'll hit on something.
Andrew~BSME
RE: Sprint Car Difusser Help!
How bizarre.
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Sprint Car Difusser Help!
RE: Sprint Car Difusser Help!
Cheers
Greg Locock
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips.
RE: Sprint Car Difusser Help!
A technical question was asked. No rules were mentioned. The OP asked specifically about diffusers. Have I missed anything.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Sprint Car Difusser Help!
RE: Sprint Car Difusser Help!
Effectively, you want to build a wing on the bottom that will be effective when the car is sliding.
So it would have minimum ground clearance along a line parallel to the car's axis, but displaced to the starboard side.
If you also tilted the motor to the left a bit, biasing the oilpan into the deeper area of the bellypan, you might be able to disguise the pan's actual intended purpose.
Mike Halloran
Pembroke Pines, FL, USA
RE: Sprint Car Difusser Help!
RE: Sprint Car Difusser Help!
If you do it subtly, you may be able to run a few races before it gets noticed, and maybe a couple more before it gets banned.
Mike Halloran
Pembroke Pines, FL, USA
RE: Sprint Car Difusser Help!
"Mike (NASCAR) Halloran" LOL !!!
A man after my own heart! I, too, am a "Smokey" fan.
Rod
RE: Sprint Car Difusser Help!
Mike Halloran
Pembroke Pines, FL, USA
RE: Sprint Car Difusser Help!
Many years ago, I was involved with a formula ford. We normally ran them in and then optimised them on a dyno. We decided to "run it in" on oil supplied by a sponsor, but we did not normally use the oil as it was not race quality.
We did one power run on the supplied oil. It gave 114 HP. Our best previous engine was 110. We changed oil, back to 110.
Needless to say we raced on the thin oil.
We had our engine examined after every race that season as it is very unusual in FF to be able to just pull out on the straight and drive past opposition, so it was presumed we must be cheating.
Regards
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Sprint Car Difusser Help!
RE: Sprint Car Difusser Help!
The bottom of the starboard side would look rounded/ tucked in, in the classical way.
The bottom of the port side would look cut off, sharp and square, at a level about midway up the stbd side's curve.
Sort of like this:
port side stbd side
| |
| |
| /
| /
--------__________ /
--------_______/
Section lkg fwd
Mike Halloran
Pembroke Pines, FL, USA