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Slowing down by taking timing out #2538213
08/18/18 07:35 PM
08/18/18 07:35 PM
Joined: Oct 2007
Posts: 472
Minnesota, USA
humpty Offline OP
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humpty  Offline OP
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Minnesota, USA
Does anyone pull timing to run index classes? If so, how much can you slow down? Car runs 10.1 - 10.2’s and need to slow to 10.5. I can pull up to 9.9 degrees with the ignition if need be. I don’t want to mess with a mechanical stop as I’m running 2 classes, one is heads up all out, the other is index.

Thanks.

Re: Slowing down by taking timing out [Re: humpty] #2538219
08/18/18 07:46 PM
08/18/18 07:46 PM
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Posts: 19,304
Las Vegas
Al_Alguire Offline
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We have done it in S/ST to SLOW the MPH down and we do it with the Dragster to keep it legal for my son who is not licensed to go faster that 7.50. In the dragster we pull 10-12 degrees out to keep it over 7.50 here in Vegas. In my old Cuda I ran it at 22 total to keep the MPH down a bit mostly for track positioning. It still went 160 that way.


"I am not ashamed to confess I am ignorant of what I do not know."

"It's never wrong to do the right thing"
Re: Slowing down by taking timing out [Re: humpty] #2538220
08/18/18 07:47 PM
08/18/18 07:47 PM
Joined: Oct 2011
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bean town ....Ca
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WHITEDART Offline
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Originally Posted By humpty
Does anyone pull timing to run index classes? If so, how much can you slow down? Car runs 10.1 - 10.2’s and need to slow to 10.5. I can pull up to 9.9 degrees with the ignition if need be. I don’t want to mess with a mechanical stop as I’m running 2 classes, one is heads up all out, the other is index.

Thanks.
you could always re adjust the throttle cable.. I would think trying to kill three or four tenths with timing would be hard on the bearings.. you could add weight also staging deep can scrub as much as 10th

Last edited by WHITEDART; 08/18/18 07:48 PM.

In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
Re: Slowing down by taking timing out [Re: humpty] #2538248
08/18/18 09:33 PM
08/18/18 09:33 PM
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MI, usa
dvw Offline
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Timing doesn't kill much. Close the throttle to get it close. We use a fine thread 3/8" bolt as a stop and count the number of hex flats we rotate it. Then use weight. To the point now where we're setting it to .00X on 9.25 ET. Watch the track and the weather. You can be deadly if the 60ft doesn't move.
Doug

Re: Slowing down by taking timing out [Re: humpty] #2538274
08/18/18 10:30 PM
08/18/18 10:30 PM
Joined: Apr 2007
Posts: 289
Lowes
steve660 Offline
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Have you tried lowering shift points?

Easier than messing with timing.


PSO headed 632 from MM. Cracked cylinder, loose valve seats, low oil pressure, low cylinder pressure.
..... Now its a door stop....
Re: Slowing down by taking timing out [Re: humpty] #2538316
08/19/18 12:01 AM
08/19/18 12:01 AM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
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If you retard it enough the engine won't have enough power to idle.


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Re: Slowing down by taking timing out [Re: humpty] #2538338
08/19/18 12:29 AM
08/19/18 12:29 AM
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Posts: 20,645
So Near, Yet So Far
topside Offline
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I would think shifting at lower RPM, or reducing throttle opening, or adding weight would be easier; those have all worked for me when I wasn't trying to slow the car down!

Re: Slowing down by taking timing out [Re: humpty] #2538343
08/19/18 12:33 AM
08/19/18 12:33 AM
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northwest USA
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NANKET Offline
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It's tough if you are doing 2 classes on the same day, weight is your friend. Short shifting with a manual valve body can make you car very inconsistent.

Deep staging is good to slow it down but then your reaction time is way off. Do you have a trans brake/delay box or foot braking?

Re: Slowing down by taking timing out [Re: humpty] #2538401
08/19/18 01:45 AM
08/19/18 01:45 AM
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Bend,OR USA
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We mess around with a lot of things back a long time ago to slow down a 10.60 car the run S/ST(10.90 index) we ended up getting the largest ET reduction by over revving the motor from 6400 RPM to 7000 RPM shifts in 1st and 2nd gear scope
We tried taking timing out down to 28 degrees in two degree increments, we tried short shifting at 6000. 5500, and 5000 RPM and even shifting directly from 1st to 3rd shruggy
We didn't add weight though, didn't have anywhere legal to store it shruggy
Lots of ways to slow them cars down up Find out what you like and which works best for you up


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: Slowing down by taking timing out [Re: humpty] #2538417
08/19/18 02:30 AM
08/19/18 02:30 AM
Joined: Oct 2007
Posts: 472
Minnesota, USA
humpty Offline OP
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humpty  Offline OP
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Minnesota, USA
Thanks everyone. I tried launching in 2nd but it slows too much. Looks like I will try to fabricate a mechanical stop that I can remove and set back quickly as some of the rounds end up being nearly back to back. Next year I may focus on setting the car up for 10.0 and run both classes shooting for the same ET. Thanks to Whitedart I have heads that should make it an easy 10.0 combo.


Re: Slowing down by taking timing out [Re: humpty] #2538486
08/19/18 11:50 AM
08/19/18 11:50 AM
Joined: Oct 2007
Posts: 4,205
New York
polyspheric Offline
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Obviously, weight works but it also will affect your chassis set-up


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Re: Slowing down by taking timing out [Re: humpty] #2538493
08/19/18 12:04 PM
08/19/18 12:04 PM
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bean town ....Ca
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WHITEDART Offline
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Originally Posted By humpty
Thanks everyone. I tried launching in 2nd but it slows too much. Looks like I will try to fabricate a mechanical stop that I can remove and set back quickly as some of the rounds end up being nearly back to back. Next year I may focus on setting the car up for 10.0 and run both classes shooting for the same ET. Thanks to Whitedart I have heads that should make it an easy 10.0 combo.

if you can run several classes with the same number on the window..you will have a major advantage..I bet 10s with the new stuff will come easy.


In the 8s N/A.with Brett miller W8's
5.07 at 133 at 2700lb
Re: Slowing down by taking timing out [Re: humpty] #2538574
08/19/18 03:32 PM
08/19/18 03:32 PM
Joined: Jul 2004
Posts: 19,317
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Thumperdart Offline
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Originally Posted By humpty
Does anyone pull timing to run index classes? If so, how much can you slow down? Car runs 10.1 - 10.2’s and need to slow to 10.5. I can pull up to 9.9 degrees with the ignition if need be. I don’t want to mess with a mechanical stop as I’m running 2 classes, one is heads up all out, the other is index.

Thanks.


Put EFI on it............... laugh2 Sorry couldn't resist OR go back to the carb you had before you got THUMPERIZED........... drumhit


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Slowing down by taking timing out [Re: Thumperdart] #2538577
08/19/18 03:46 PM
08/19/18 03:46 PM
Joined: Oct 2007
Posts: 472
Minnesota, USA
humpty Offline OP
mopar
humpty  Offline OP
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That’s right - this is all Thumpers fault! With the old carb I’d have to go up a class smile

Last edited by humpty; 08/19/18 03:53 PM.
Re: Slowing down by taking timing out [Re: humpty] #2538640
08/19/18 07:41 PM
08/19/18 07:41 PM
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Thumperdart Offline
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Originally Posted By humpty
That’s right - this is all Thumpers fault! With the old carb I’d have to go up a class smile


I use you and Ray Meyers and a couple examples of guys driving and hauling azz with Dommy's on the street and track and they think I'm bs-ing em...........too funny........ beer


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Slowing down by taking timing out [Re: humpty] #2538728
08/19/18 10:31 PM
08/19/18 10:31 PM
Joined: Oct 2007
Posts: 472
Minnesota, USA
humpty Offline OP
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humpty  Offline OP
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Well, now I have a couple options to test. My MSD Digital 6 Plus ignition has a step retard that’s activated by 12 volts so I wired a switch and now I can turn it on and off. When on it doesn’t retard until the rpm’s go well above idle so idle quality isn’t affected. I also built a mechanical stop that mounts to the carb base and stops the secondary shaft from opening all the way. I can install and remove it quickly without removing the air pan. I’m going to make a few passes and see how much it takes. If there’s too much stress on the cable I’ll add support under the pedal too. I have a spare throttle cable in case I’m way off on what “stressed” means...

Throttle.pngThrottle 2.png
Re: Slowing down by taking timing out [Re: humpty] #2538732
08/19/18 10:36 PM
08/19/18 10:36 PM
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Posts: 19,317
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Thumperdart Offline
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Very creative and like I sad, no clue on t-stop stuff........... thumbs


72 Dart 470 n/a BB stroker street car `THUMPER`...Check me out on FB Dominic Thumper for videos and lots of carb pics......760-900-3895.....
Re: Slowing down by taking timing out [Re: humpty] #2538742
08/19/18 10:58 PM
08/19/18 10:58 PM
Joined: Mar 2006
Posts: 9,791
MI, usa
dvw Offline
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Closing just the secondary's may not be enough. On mine I shut down primary's and secondary's on 2 carbs. It won't phase the cable. I've been using a mechanical stops since the early 90's. Never broken a stock cable.
Doug

Re: Slowing down by taking timing out [Re: dvw] #2538784
08/20/18 12:38 AM
08/20/18 12:38 AM
Joined: May 2010
Posts: 81
MO.
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CROWBAR Offline
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I think that set up will FLEX too much. Have someone look while you matt the pedal then push harder. Over time I think your bracket will bow.

Re: Slowing down by taking timing out [Re: humpty] #2538815
08/20/18 01:51 AM
08/20/18 01:51 AM
Joined: Oct 2007
Posts: 472
Minnesota, USA
humpty Offline OP
mopar
humpty  Offline OP
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Thanks Doug. I checked and the primaries and secondaries are connected so they both are limited by the stop. There is a slight delay between the primary and secondary engagement but after that it's solid.

Crowbar - thanks for the heads up. It's actually very solid. I've done several tests and so far it's all good. However - I'm headed to test and tune Friday and only the time slips will tell!

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