Throttle stop help

BLIND MULE · 07-13-2009, 07:42 PM

First time stop user here. 3100lbs ,496bbc , 1.80 glide. Has electric Dedenbear under carb stop. Truck runs 6.15 with 1.37 60ft in the eighth have never even run it in the quarter yet. Was wondering about where to start and stop the stop and where to shift at and what RPM for a rough idea.

Chris Williams · 07-13-2009, 08:40 PM

Shift on time, not on RPM. Trust me, been there, done that, got the scars. Try something like 1.5 seconds out. You're looking for a time that makes the car run really stable on the stop -- the RPMs on the stop don't vary. Once you find a time that works, never touch it again. Makes for too many variables.

Lots of ideas on what the best "dead stall" (RPM when on the stop) is. I think you should pick a number that gets you to a time on the stop of between 1.5 and 2.5 seconds. If you're on it less than that, it'll be hard to find enough variability for all conditions. If you're on it longer than three seconds, you'll find it hard to be consistent. I think higher RPMs are better, but that's just a preference to not drop the engine way out of its power band. Here again, once you find a dead stall, stick with it. In fact, check it at the beginning of each weekend to be sure it's set the same.

As for what start/stop, there are a lot of opinions on this, but I'm a start at 0.00 guy. Then take a stab at an end time, work from there. First time, it's a total crap shoot (esp. with the dead stall discussion above). Once you have a run, swing the time wildly (like add/subtract a second) and run again. That'll give you a ratio, and you're good to go from there.

HTH,
Chris

BLIND MULE · 07-13-2009, 09:26 PM

Yeah I ordered a Pro Cube with the three timers so i could shift on time. Thanks for the advice.

Ron Finney · 07-14-2009, 09:39 AM

What class are you going to try and run? S/G or S/ST?

BLIND MULE · 07-14-2009, 12:51 PM

S/ST guess i kinda shoulda added that . lol

Ron Finney · 07-14-2009, 01:16 PM

For RPM on the stop the consensus from most are approx. 4100rpm...seems to be where most of us are. I would go on the stop somewhere around .1 to .3 seconds....with slower cars .2 to .3 works great. Dragsters/roadsters like .1 From there like Chris said you need to make a full run to see what your car actually does to know how much to slow it down. My guess is that you are going to run about 9.75 so you need to kill about 1.15 seconds. You'll just have to throw some time at it and see how it responds....you will probably be around 2 to 1 on ratio. So I'm guessing that you will put about 2 seconds in the stop.

While it is trial and error, it usually comes around pretty quickly...you will get a ratio within a few runs.

Welcome to the Super Classes!!

Ron & Meridee
33 S/C

Boogeyman Bill · 07-20-2009, 01:59 PM

Quote:

Originally Posted by BLIND MULE

First time stop user here. 3100lbs ,496bbc , 1.80 glide. Has electric Dedenbear under carb stop. Truck runs 6.15 with 1.37 60ft in the eighth have never even run it in the quarter yet. Was wondering about where to start and stop the stop and where to shift at and what RPM for a rough idea.

Aren't you guys going to discuss the Weather Station he needs. I made that mistake when I first started running on the TS 2 years ago. I had the TS but didn't know to buy a Weather Station. Man, what a learning curve that was...

Of course once I got the weather station I had to get a generator etc. I'm finally set up and things are becoming clearer now. Last weekend I finally got around to using my beeper.

Chris Williams · 07-20-2009, 04:18 PM

Quote:

Originally Posted by Boogeyman Bill

Aren't you guys going to discuss the Weather Station he needs. I made that mistake when I first started running on the TS 2 years ago. I had the TS but didn't know to buy a Weather Station. Man, what a learning curve that was...

Of course once I got the weather station I had to get a generator etc. I'm finally set up and things are becoming clearer now. Last weekend I finally got around to using my beeper.

Although I have a full setup from Family Software and highly recommend it, I know lots of folks who win with just a portable unit like the Performaire or even the Krestrel.

Boogeyman Bill · 07-20-2009, 04:43 PM

Quote:

Originally Posted by Chris Williams

Although I have a full setup from Family Software and highly recommend it, I know lots of folks who win with just a portable unit like the Performaire or even the Krestrel.

Chris, I've got the Alta Lab II unit. The unit is much smarter than I am

( But I'm beginning to understand more each time out.
Bill

Ron Finney · 07-20-2009, 09:00 PM

Good Advice you need the weather....but not totally convinced you can't do it with a hand held. Maybe 'cause that's what I use (cheap). But then again, I am the only guy in Super Comp that still shifts his car by hand (stubborn). Definitely doesn't hurt to get the best data you can... If bucks aren't an issue go with the good stuff suggested, 'cause even the handhelds have a learning curve.

Ron & Meridee

33 S/C
'09 Jeg's Allstar

07-13-2009, 07:42 PM	#1
BLIND MULE Member Join Date: Dec 2002 Location: Alabama Posts: 318 Likes: 0 Liked 0 Times in 0 Posts	Throttle stop help First time stop user here. 3100lbs ,496bbc , 1.80 glide. Has electric Dedenbear under carb stop. Truck runs 6.15 with 1.37 60ft in the eighth have never even run it in the quarter yet. Was wondering about where to start and stop the stop and where to shift at and what RPM for a rough idea.

07-13-2009, 08:40 PM	#2
Chris Williams Member Join Date: Mar 2009 Location: Woodinville, WA Posts: 401 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help Shift on time, not on RPM. Trust me, been there, done that, got the scars. Try something like 1.5 seconds out. You're looking for a time that makes the car run really stable on the stop -- the RPMs on the stop don't vary. Once you find a time that works, never touch it again. Makes for too many variables. Lots of ideas on what the best "dead stall" (RPM when on the stop) is. I think you should pick a number that gets you to a time on the stop of between 1.5 and 2.5 seconds. If you're on it less than that, it'll be hard to find enough variability for all conditions. If you're on it longer than three seconds, you'll find it hard to be consistent. I think higher RPMs are better, but that's just a preference to not drop the engine way out of its power band. Here again, once you find a dead stall, stick with it. In fact, check it at the beginning of each weekend to be sure it's set the same. As for what start/stop, there are a lot of opinions on this, but I'm a start at 0.00 guy. Then take a stab at an end time, work from there. First time, it's a total crap shoot (esp. with the dead stall discussion above). Once you have a run, swing the time wildly (like add/subtract a second) and run again. That'll give you a ratio, and you're good to go from there. HTH, Chris __________________ Chris Williams 6304 SC, TD, ET

07-13-2009, 09:26 PM	#3
BLIND MULE Member Join Date: Dec 2002 Location: Alabama Posts: 318 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help Yeah I ordered a Pro Cube with the three timers so i could shift on time. Thanks for the advice.

07-14-2009, 09:39 AM	#4
Ron Finney Member Join Date: Jul 2008 Location: Greenwood, IN Posts: 168 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help What class are you going to try and run? S/G or S/ST? __________________ Ron Finney 396V S/C

07-14-2009, 12:51 PM	#5
BLIND MULE Member Join Date: Dec 2002 Location: Alabama Posts: 318 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help S/ST guess i kinda shoulda added that . lol

07-14-2009, 01:16 PM	#6
Ron Finney Member Join Date: Jul 2008 Location: Greenwood, IN Posts: 168 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help For RPM on the stop the consensus from most are approx. 4100rpm...seems to be where most of us are. I would go on the stop somewhere around .1 to .3 seconds....with slower cars .2 to .3 works great. Dragsters/roadsters like .1 From there like Chris said you need to make a full run to see what your car actually does to know how much to slow it down. My guess is that you are going to run about 9.75 so you need to kill about 1.15 seconds. You'll just have to throw some time at it and see how it responds....you will probably be around 2 to 1 on ratio. So I'm guessing that you will put about 2 seconds in the stop. While it is trial and error, it usually comes around pretty quickly...you will get a ratio within a few runs. Welcome to the Super Classes!! Ron & Meridee 33 S/C __________________ Ron Finney 396V S/C

07-20-2009, 09:00 PM	#10
Ron Finney Member Join Date: Jul 2008 Location: Greenwood, IN Posts: 168 Likes: 0 Liked 0 Times in 0 Posts	Re: Throttle stop help Good Advice you need the weather....but not totally convinced you can't do it with a hand held. Maybe 'cause that's what I use (cheap). But then again, I am the only guy in Super Comp that still shifts his car by hand (stubborn). Definitely doesn't hurt to get the best data you can... If bucks aren't an issue go with the good stuff suggested, 'cause even the handhelds have a learning curve. Ron & Meridee 33 S/C '09 Jeg's Allstar __________________ Ron Finney 396V S/C Last edited by Ron Finney; 07-20-2009 at 09:03 PM.