Drag Racing Discussions > Front Engine Dragsters
Down force and zoomies
wideopen231:
Noticed on another thread where Jon was talking about down force from zoomies. I know for fuel guys its big and with our little injected motors not so much, but still there. Being the always inquizitive type I got to wondering how much down force? Best angle and if there's enough thrust force to make any et difference,talking .0__ or .00__.It all helps and sometimes t takes cpl thing to equal noticeable difference. Heck if not for fun of tuning more out of it than next guy there would be no need for timing systems.
Anyone ever done ABA testing with zoomies or just tried different size and or angle. I can see where smaller tube having more velocity make make difference also.
Roger:
From Alan Ellis after switching from headers to zoomies on his Pro Stock 500" engine in his AA/A last year:
"The down thrust from the new zoomie style headers proved to be a tremendous advantage to the launch of the car. It allows us to apply more power early in the run which equates to quicker ET's."
gregm784:
"Able to apply more power" or had to make more power without header scavenging in effect?
Interesting topic for sure.
glofria:
Zoomies will have an affect in steering a (short wheelbase) car. it will not have an affect on a longer wheelbase car.
I believe that the optimal angle would be 45 degrees to the ground as an even trade off on down forces vs. thrust. As with the recent issues with nitro funny cars lifting the front end down track with too much thrust, down force is important. But not to the point of sacrificing performance and strain on the engine.
FYI, I am not am engineer, but I do understand certain concepts. So if my information is incomplete...
glofria:
Okay, I just read the other thread and i think Jon was referring to the back of the car washing out vs. steering. Canards will create down force (drag) on the back tires and that will keep the car straight down track. Had a conversation with Walt Stevens of the High Speed Motorsports N/TF team a few years ago about the canards they designed. It has definitely improved their performance.
For your reading pleasure:
https://www.nas.nasa.gov/About/Education/Racecar/physics.html
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