What is this thing called?

Just bought a TD with a KB Hemi. This is my first dragster, and my first Hemi. Lots to learn. I am currently "getting to know" the car in the garage. My throttle pedal has an air actuated limiter on it. I know how it works, in theory, but I don't know what it's called.

Any help?

-Scouder

PS. Since you guys are the repository of all knowledge, I'm gonna have a million questions over the next few months. We got snow today, so I won't be making my first pass until spring. Until then I'll just have to sit in it and make fake engine noises.

 

It's an air throttle controller. Probably something like this: http://www.acddragparts.com/products-2.html Used to maintain traction by limiting the throttle position on staging and launch, and gradually increase it to full throttle over a measured amount of time using timers acutated by transbrake, gear selector, timing controller, or any number of things.

 

Scouder

In addition a lot of guys use them for a burnout limiter so your motor's not on a two step, ect. I've seen lots of guys who desparatly need them when they do a burnout.

 

Do these contraptions only control the throttle blade opening? Is there any feedback from anything?

When it is used like a 2 step...
Does the "2 step" RPM vary with the change in weather, (so HP developed).

 

Mine mounts right at the throttle pedal, and only allows the pedal to pull the cable a certain amount, even though the pedal goes all the way to the floor. Then I'm guessing (I haven't traced it all out yet), that the delay box releases the cable at the same time as the transbrake and lets 'er have wide open. It might have a feature to bring full-throttle on over a preset time, but I won't know till I get documentation from the manufacturer, etc...

-Scouder

 

Don't be embarrassed, i did the same thing last winter

Tim Steed

 

Does the staging RPM stay real consistent from run to run or do you have to check and adjust it for every run?

 

i had one of those one time on a blown fiat i took it off and throwed it over in the floor along with the delay box and the power glide with the transbrake i dont think it reacts fast enough to suit me but a lot of people run them on bracket cars and automatic cars with blowers

 

So you just used the brake and brought your stage rpm up by feel?

-Scouder

 

Alright here goes'.... if you run an auto trans and a trans brake an air throttle is the stuff. What you do is have the air throttle set so that as long as the transbrake is engauged ( not just while you have your finger on the button but until it actually releases when the box counts down) that it keeps the blades open just enough to raise the rpm's to your launch rpm ( ex. 4000 rpms ). Now set your two step to the same thing, this way the two step holds the rpm even if the air gets better and it tries to climb higher than your set rpm. The last thing you want to do is set there on the two step with the blades wide open, it will load up with fuel and also don't worry about trying to open the blades slow, just have them open as fast as possiable when the transbrake releases. You should be good to go. Also you can check all of this with the engine off while making cool dragracing sounds vrrrrooomm Hope this helps, I've run an air throttle for a couple of years with no problems, and every other fast blown TD car runs them as well.

 

i went to a clutch and lenco 3speed so much more fun

 

Any ideas on how to make one work legally on a clutch car?

 

don't think there is a way, sorry.

 

Jody I'm pretty sure TAD or TAFC rules say that the throttle opening must be activated by your foot but... I see no reason you couldn't make it work on an outlaw car with a clutch .
Just use a micro switch off the clutch pedal to activate it .
when you let the clutch go it would snap the throttle open.

 

Approximately how much would this rpm vary because of the change in air?

 

I have seen my stuff change a couple hundred rpm's with no two step. With only the throttle controller the longer you stay on it the more the rpm's creep up. Plus with a two step you won't have to reset it ( the throttle controller ) at the start of every race to comp. for changes in temp and air. You just set it one time for ...say... 4000 rpm's and the two step will hold it there perfectly. My computer show's 4000 every time at the launch no matter when or how long I stay on the two step, I do however wait till my side of the tree starts down to mat the throttle though. You have to race on a staggered tree to really get it, the heads up guy's on here think we are crazy for fooling with the shit to start with Maybe I am, nothing like dialing 6.13 and racing a car dailed 6.95

 

2 step

ok what's the deal in TMD and TAFC is a 2 step or any other device allowed to use or not, we had a conversation here in Europe ( we need to follow the NHRA rules ) with a team using a 2 step on a TAFC
when you read the rules you can and if you read a little further they say you can't
also can you run 2 magnetos from msd the 44?
I remember in an old rule book you can use 2 magnetos but not to exceed 44 amp but it's not in the new rule book?
if yes why is nobody using 2 mag 44's?
thanks danny

 

This is exactly what we're gonna do. We didn't want to leave on just the two step w/ the blades wide open. We don't need the extra boost and fuel. So we're gonna set our throttle controller to open the blades enough to make around 4700-4800 rpm. Then program the two step for 4500. That way at full throttle w/ the trans brake engage and the throttle controller activated, we'll be studdering at 4500 even though there's enough fuel/air going in for 47-4800.

We use to leave on just the throttle controller w/ no 2 step. It was pretty inconsistent and like said before, the longer you're on it the more the rpms creep up.

Josh