Throttle stop time ?

powerstrokeace · 09-11-2011, 07:11 PM

Guy's I have 2 dragsters and I'm trying to get these on the 8.90 index. How ever I'm really not sure what the best thing /time setting to start with.
1) both cars are more than 1 second under the index.
2) How do you set the throttle stop RPM in the pits. (dedenbear cc3 and scc1 controllers in each car)
3) how soon do you have the throttle shut down
4)When do you shift? (one shifts on RPM and the other on time)

Anything else you might be of help would be great

Ace

Bill Baer · 09-12-2011, 10:43 AM

ACE

I have a hard tail dragster that can run more that a second under I have an inline co2 cylinder with a pinch valve to slow the opening and I currently turn it on .15 and off in the 1.50 range I shift on time 1.0 second out so it comes off the stop in high gear.
To set your "on the stop RPM" disconnect the air line(s) and load it against brake (on jack stands of course) if you have an electric stop put a jumper wire on to turn it on to test on the brake. ( Mine is set at ~4500)
Shifting by RPM works too but it usually comes up pretty quick after the stop comes off.
I try to get one lap too fast and one too slow and calculate the ratio from there.
The crew chief pro software will get and keep you close but you can't put bad runs in it and expect it to be accurate pay attention to your 60' times if they are not consistent your data will be bad and so will your and or the software's predictions.
Just my way of doing it there are a lot of ways to skin this cat!

Hope this helps.

Chris Williams · 09-14-2011, 10:42 AM

2) With the dedenbear boxes, just change it from linkage to base plate, or vice-versa and (up on a stand of course) floor it with the button down and you'll be able to set the rpm. Important note to self: remember to set it back. We've forgotten and it's been a disaster.

3) For us, with a hardtail you want to go on the stop as fast as you can (to let the car settle asap). In our hardtail, we went on the stop at .000. It took a small fraction to come down, but that worked very well for us. FWIW, in our suspended car, we go on at .020.

4) We found shifting on time is much more consistent than on RPM. We shift at 1.00sec so that we're in the low power RPM range which prevents the car from overpowering the stop, and creeping up off the dead stall RPM. It is very consistent.

Hope this helps.

09-11-2011, 07:11 PM	#1
powerstrokeace Junior Member Join Date: Apr 2011 Posts: 15 Likes: 0 Liked 0 Times in 0 Posts	Throttle stop time ? Guy's I have 2 dragsters and I'm trying to get these on the 8.90 index. How ever I'm really not sure what the best thing /time setting to start with. 1) both cars are more than 1 second under the index. 2) How do you set the throttle stop RPM in the pits. (dedenbear cc3 and scc1 controllers in each car) 3) how soon do you have the throttle shut down 4)When do you shift? (one shifts on RPM and the other on time) Anything else you might be of help would be great Ace Last edited by powerstrokeace; 09-18-2011 at 11:09 PM.

09-12-2011, 10:43 AM	#2
Bill Baer Senior Member Join Date: Jul 2007 Location: Nothern IL Posts: 596 Likes: 1 Liked 1 Time in 1 Post	Re: Throttle stop time ? ACE I have a hard tail dragster that can run more that a second under I have an inline co2 cylinder with a pinch valve to slow the opening and I currently turn it on .15 and off in the 1.50 range I shift on time 1.0 second out so it comes off the stop in high gear. To set your "on the stop RPM" disconnect the air line(s) and load it against brake (on jack stands of course) if you have an electric stop put a jumper wire on to turn it on to test on the brake. ( Mine is set at ~4500) Shifting by RPM works too but it usually comes up pretty quick after the stop comes off. I try to get one lap too fast and one too slow and calculate the ratio from there. The crew chief pro software will get and keep you close but you can't put bad runs in it and expect it to be accurate pay attention to your 60' times if they are not consistent your data will be bad and so will your and or the software's predictions. Just my way of doing it there are a lot of ways to skin this cat! Hope this helps. __________________ Bill Baer 3391 SC, 339B SC, QR Last edited by Bill Baer; 09-12-2011 at 11:05 AM.

09-14-2011, 10:42 AM	#3
Chris Williams Member Join Date: Mar 2009 Location: Woodinville, WA Posts: 401 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop time ? 2) With the dedenbear boxes, just change it from linkage to base plate, or vice-versa and (up on a stand of course) floor it with the button down and you'll be able to set the rpm. Important note to self: remember to set it back. We've forgotten and it's been a disaster. 3) For us, with a hardtail you want to go on the stop as fast as you can (to let the car settle asap). In our hardtail, we went on the stop at .000. It took a small fraction to come down, but that worked very well for us. FWIW, in our suspended car, we go on at .020. 4) We found shifting on time is much more consistent than on RPM. We shift at 1.00sec so that we're in the low power RPM range which prevents the car from overpowering the stop, and creeping up off the dead stall RPM. It is very consistent. Hope this helps. __________________ Chris Williams 6304 SC, TD, ET