Drag racer needing a little help on aero.

[donpearsall]

That thing moves out for such a big heavy car. You can really hear the turbo and blow off valve whistling. Good driving too.
Don

[jl222]

 
  Wow...good job, how many cars in the field?

  As a Bville racer wishing I could go 145 in the 1/8 mile I've been thinking about using different shocks in front that would support 1600 lbs front weight but give more weight transfer in low and secont gear but still
keep the front down at high speed. Any ideas?


                      JL222

[1212FBGS]

i kicked around a couple of ideas.... 1 idea used soft rebound dampening in the front springs that allowed lift and trasnsfer then limited and locked the front down with bell cranks, straps and bimba air rams at speed... another idea used soft compression to squat in the rear then airbags to restore ride heigth at speed....
kent

[krusty]

The air ram change idea sounds like something that will work. The NHRA Pro Stock guys use a Koni module to control shock valving changes in the first few seconds (60 ft?).  http://www.koni-na.com/pdf/KONI_Motorsports_2008.pdf   (start at page 18).  I don't think you'd need the Koni module.  A simple system could use a triggered output from an MSD box or add-on module (launch), and a quality adjustable time delay relay triggering an electric to pneumatic (E-P) relay which allows a small pneumatic cylinder(s) to move the shock  adjuster(s). Air source is from pneu. shifter bottle.  vic

[mtkawboy]

Whats that Big Dog have in it for motor ? Thats a stout piece !

[kiwi belly tank]

That's a stout ol "A" Chad, my E bodies are smiling. The bellybutton cars must be p'd.
  Sid.

[kiwi]

Great looking car. But I don't think any aero mods to the body are going to help you over an 1/8 mile.

[SPARKY]

the resistance curve climbs fairly fast 

[kiwi belly tank]

Soap box cars & guys on bicycles benefit from aerodynamic aids.
Seen any square fish lately??
  Sid.

[kiwi]

It is just that he will have so much hp and mass and the distance is so short that aero improvements will have a very minimal effect.
On my Hayabusa drag bike I have run with and with out fairings and the difference in mph is easily less than 2mph and that is over a 1/4 mile.

[kiwi belly tank]

Take your aero gain, calculate that by his size difference & that gives you some idea of what he's working with. If he put his package in a slippery late model of the same weight, he'd need to put a bigger gear in the top end. But then he'd just look like the rest of the field, "field cars".
Even your 2mph equates to a hunk of realestate on the top end.
  Sid.

[hotrod]

There used to be a guy here in Colorado in the 1970's with a 1953 Studebaker powered by a 426 Chrysler engine, the cars name was Taboo.
He was running 11.34 at this altitude, and was a hoot to watch, because on the top end his aero advantage would allow him to run people down. It looked like he was suddenly accelerating the last 330' but it was really the other car started to slow down a lot more than he did as their speeds got over 100 mph.

Aero helps drag cars but mostly over the last few hundred feet. If your a lower drag body, you will continue to accelerate when cars with poorer aerodynamics start to slow down with the same power level due to their higher drag as the approach the traps.

Larry

[cold85]

Thanks again guys I still have not tried any aero ideas yet. We knew the car was not pulling in high so after the last race we tore into the motor and trans and found some major carnage in the trans. I think we had two problems one ignition which we fixed but changed trans pumps which caused another problem but the symptoms were simular to the ignition and that sent us for a loop.
So now I am putting everything in before the next race so I can hopefully make full power passes this weekend. If all goes well I will be starting on the aero changes. Does any one have a good pic of a simular chin spoiler/dam i need to build?

[hotrod]

You can use most anything that sticks down and diverts airflow around the car and away from the front suspension hardware.

Here is a chin spoiler of the type commonly used in the 1970's, they are also called "air dams"



http://image.popularhotrodding.com/f/8821355/0601phr_09_z+1970_dodge_dart+.jpg

http://image.moparmusclemagazine.com/f/8545166/p164550_large+1970_Dodge_Dart_Swinger+Front_Drivers_Side_View.jpg


You can build a servicable one very easily with some aluminum angle, or light weight steel angle, a piece of 6" polyethylene strip or heavy duty garden stripping and a pop rivet gun. If a crude test chin spoiler helps then design an more permanent design. The intent of the air dam /chin spoiler is to make it easier for the air to go around the side of the car or over the top than to go under the front of the car and past all the hardware hanging down in the wind. Make it so the bottom edge is slightly lower than the lowest major obstruction under the car ( usually oil pan, transmission cross member and transmission pan, and lower A arms).

More modern designs are full wrap around near vertical pieces that go all the way from the outside edge of the front wheels across the front, typically about 3-4 inches below the bottom of the front sheet metal. Many of them have a small protruding front lip that makes it much harder for the air to get below the air dam, and in the import community are often called "front splitters". The openings are intended for brake cooling on track cars.

http://www.flyinmiata.com/index.php?deptid=4544&parentid=0&stocknumber=29-77550



Larry

[Reverend Hedgash]

My understanding of SPlitters is they come out horizontally from the car and not only help prevent air going under the car they help a bit with front downforce as the air coming down from the dam pushes down on it prior to going around the back.

This force has to come from somewhere though and that will be your engine so as usual in aero you need to make the decision whther it is worth the power loss for the downward force benefit.

rH+