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60 ft issues #3075896
09/09/22 08:29 PM
09/09/22 08:29 PM
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carnut68 Offline OP
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What could cause my slow 60 ft times? Mid 1.50's Here's my set up. 68 Barracuda fastback about 3400 w/me. 446 w/indy EZ standard port M1/ Proform 950. 590 cam. ATI 5200 convertor, torqueflite. 430 gears w/spool. Superstock springs clamped on front half 1 clamp on back and Calvert 9 way shocks. CE 3 way on front w/5 in travel. Hoosier Quick time Pro's 27x10.50 15. 17lbs air. Car doesn't spin, leaves straight. Engine is snappy. What am I missing?


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Re: 60 ft issues [Re: carnut68] #3075902
09/09/22 08:42 PM
09/09/22 08:42 PM
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[quote=carnut68 What am I missing? [/quote] the reason it is slowing ,down correct whistling
AKA, have you thought about the air density altitude change effects on your car? scope
If you have it tune lean for summer heat and humidity it will get a lot leaner in better air twocents
Does it miss or nose over anywhere during the run?
Another thing to consider is how many runs on the slicks, are they balling up and going away? work
How much 60 Ft ET are you losing? How about the 330 and 660 ET?


Mr.Cab Racing and winning with Mopars since 1964. (Old F--t, Huh)
Re: 60 ft issues [Re: Cab_Burge] #3075905
09/09/22 08:46 PM
09/09/22 08:46 PM
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any video of said car leaving from the back and sides? Birdtracker

Re: 60 ft issues [Re: Cab_Burge] #3075912
09/09/22 08:55 PM
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Originally Posted by Cab_Burge
[quote=carnut68 What am I missing?
the reason it is slowing ,down correct whistling
AKA, have you thought about the air density altitude change effects on your car? scope
If you have it tune lean for summer heat and humidity it will get a lot leaner in better air twocents
Does it miss or nose over anywhere during the run?
Another thing to consider is how many runs on the slicks, are they balling up and going away? work
How much 60 Ft ET are you losing? How about the 330 and 660 ET? [/quote] Cab, my 60's have never been good. Tires might have 25 passes. No videos, yet. There are some pic's on Mason Dixons website. If I go tomorrow hopefully I can get a good video. The car feels good. It doesn't do anything stupid.


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Re: 60 ft issues [Re: carnut68] #3075922
09/09/22 09:32 PM
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Re: 60 ft issues [Re: carnut68] #3075943
09/09/22 11:17 PM
09/09/22 11:17 PM
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What was the best mph? And avg mph? Any idea on HP? Dyno numbers?


1.50 60Ft. , 10.75@ 127MPH Hauling 3900 LBS.
Re: 60 ft issues [Re: Chargerfan68] #3075979
09/10/22 06:52 AM
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Are the times consistent?
What are you goals or expectations?
Have the times been better in the past?

Re: 60 ft issues [Re: Chargerfan68] #3075982
09/10/22 06:53 AM
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Originally Posted by Chargerfan68
What was the best mph? And avg mph? Any idea on HP? Dyno numbers?
Best MPH 126.1. Best ET 10.82@ Cecil County. Avg 122@ Mason Dixon. WAG on HP 550. No Dyno.


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Re: 60 ft issues [Re: carnut68] #3075983
09/10/22 07:02 AM
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The video needs to be closer and slow motion. I went through a similar thing but my car was losing 60 and I couldn’t get it back . If you search me you will find the thread . In short I ended up getting cal tracs and double adjustable shocks all the way around . In the long run Ingot it back to 1.40 . This year had the converter freshened no other changes and it’s 1.35 and .10 faster overall .

Video will help greatly.

Re: 60 ft issues [Re: Wirenut] #3075988
09/10/22 07:25 AM
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Originally Posted by Wirenut
The video needs to be closer and slow motion. I went through a similar thing but my car was losing 60 and I couldn’t get it back . If you search me you will find the thread . In short I ended up getting cal tracs and double adjustable shocks all the way around . In the long run Ingot it back to 1.40 . This year had the converter freshened no other changes and it’s 1.35 and .10 faster overall .

Video will help greatly.
If I go today I'll try to get a better video. The thing should 60 in the 1.40s. If I was having traction problems I would consider Cal tracs and better shocks. As for my convertor It only has about 25 passes on it, and have considered it possibly being the issue.

Last edited by carnut68; 09/10/22 07:29 AM.

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Re: 60 ft issues [Re: carnut68] #3075993
09/10/22 08:07 AM
09/10/22 08:07 AM
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Realize that 60ft without spin or excess chassis movement is a pure function of power. Weather, converter, engine set up. Engine can be broken down into carb, cam, intake, heads, ignition just to start. Suspension and traction at this stage are not the issue.
Doug

Re: 60 ft issues [Re: dvw] #3075995
09/10/22 08:17 AM
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Originally Posted by dvw
Realize that 60ft without spin or excess chassis movement is a pure function of power. Weather, converter, engine set up. Engine can be broken down into carb, cam, intake, heads, ignition just to start. Suspension and traction at this stage are not the issue.
Doug
That's a good perspective. Knowing how well your car works I'll take that as good advice. So I think what your saying is I'm lacking some power. Possibly in the tune?


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Re: 60 ft issues [Re: carnut68] #3076031
09/10/22 12:07 PM
09/10/22 12:07 PM
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My friend Mike sent me a short video of your car from Friday night a week ago. I don't have anywhere to post it, though. My thoughts:
- the whole car sits up rather high, typical of what I think of with bracket cars on Super Stock springs; not seeing much pitch rotation
- your front dampers may have 5" of travel, but I don't think you've got 5" of extension travel from the static ride height, unless you are using shock extensions and have trimmed down the upper control arm bumpers
- CE shocks don't move very freely; a set of Calvert's "loose as a goose" 90/10s might be a better option that won't break the bank

Questions:
- you mentioned it's a 5200 ATI; at what RPM are you leaving?
- where is your ignition set for initial & total timing?
- have you tried any different accelerator pump cams from what the Proform carb came with?
- have you measured the available front suspension travel from the static ride height?
- have you tested how the car responds from leaving off or slightly above idle vs stalling up against the converter?

wave


2021 Challenger 6.4L Scat Pack 1320 (2022)
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
wheels, tires, air filter: 1.714, 11.833 at 115.80 (DA 310 ft)

1973 Challenger 452 ci street/strip (2008)
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
Re: 60 ft issues [Re: carnut68] #3076055
09/10/22 01:46 PM
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I assume you have a transbrake. What rpm are you launching at? You say no tire spin. That may be one of your problems. Dead hooked on a slick leaves you “stuck” with your hard ratios. Induce some spin to get your engine in a higher rpm range. Effectively this will change the ratio the engine “feels”.
My opinion would be to raise launch rpm and stiffen the shocks. Maybe change the caltrac bar angle to induce some spin.


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Re: 60 ft issues [Re: TRENDZ] #3076090
09/10/22 04:41 PM
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If it is spinning it ain't moving forward as fast as it can shruggy
Watch some of the ultraslow motion vids on Top Fuel, Funny cars and Pro Stock cars, they don't spin when leaving the starting line scope
They wrinkle the sidewalls as they go forward without spinning scope


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Re: 60 ft issues [Re: TRENDZ] #3076165
09/10/22 09:48 PM
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I’d do a cranking compression test on a few cylinders(with the carb at WOT).... primarily to gauge the relationship between the compression ratio and the camshaft.
What are you running for valve lash?

Have you done a low speed, high gear, flash stall test?
Are you getting an honest 5200 out of it?

Frankly, I’d consider 5200 to be on the lower end of what I’d want for that combo.


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Dealer for Comp Cams/Indy Heads
Re: 60 ft issues [Re: carnut68] #3076177
09/10/22 10:34 PM
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To answer a few questions.
The flash stall is 5200.
Valve lash is .020 cold.
Initial timing was 27idle 35 total. Tried 37 total today,it picked up.
Tried leaving off idle ...leaves harder.
Up on convertor [footbrake] 2500 and 3500 no big difference. Leaves softer.
Put a known good carb on today and it picked up everywhere, but 60 ft.
Went to Keystone for tnt. Typically it's slower there than Mason Dixon [elevation] but I was 3/10ths quicker today. I had the best 60 ft 1.51 leaving off idle, 17lbs air. The car really responded to 37 degrees total timing and the carb swap. Picked up 4 mph from the first run. 119 to 123.7. A friend who was there said there's about 8 in separation on the rear suspension.
We did a compression check shortly after the engine was put together all the cylinders were around 205.


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Re: 60 ft issues [Re: carnut68] #3076178
09/10/22 10:40 PM
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I’d try opening up the lash .004-.005 and see if that impacted the 60’ time

For perspective on the stall speed....... the Normal T/A 8” Race converter for a 440 bracket race engine would flash about 5600.
That configuration was derived long before there were Indy heads.......... so it was lotsa stall....... with small heads.
Typically, the trend would be to increase the stall speed as the heads got bigger.

My take on the 8” of rear separation is........ it takes(wastes?) energy to wind the springs up that much.
If the car didn’t lift so much........ maybe it would use that energy to move forward instead.


68 Satellite, 383 with stock 906’s, 3550lbs, 11.18@123
Dealer for Comp Cams/Indy Heads
Re: 60 ft issues [Re: fast68plymouth] #3076184
09/10/22 11:07 PM
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Originally Posted by fast68plymouth
I’d try opening up the lash .004-.005 and see if that impacted the 60’ time

For perspective on the stall speed....... the Normal T/A 8” Race converter for a 440 bracket race engine would flash about 5600.
That configuration was derived long before there were Indy heads.......... so it was lotsa stall....... with small heads.
Typically, the trend would be to increase the stall speed as the heads got bigger.

My take on the 8” of rear separation is........ it takes(wastes?) energy to wind the springs up that much.
If the car didn’t lift so much........ maybe it would use that energy to move forward instead.
Now to figure how to close that separation. Clamps? Shocks? Cal Tracs?


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Re: 60 ft issues [Re: carnut68] #3076187
09/10/22 11:19 PM
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Two screen shots from a fuzzy video showing staged and right after the green. Noticeable front extension, but it doesn't look like 8" of rear separation to me... maybe 3-4"?

Screenshot_20220910-191357_Video Player.jpgScreenshot_20220910-191539_Video Player.jpg
Last edited by Brad_Haak; 09/10/22 11:26 PM.

2021 Challenger 6.4L Scat Pack 1320 (2022)
100% stock: 1.680, 11.894 at 113.75 (DA 175 ft)
wheels, tires, air filter: 1.714, 11.833 at 115.80 (DA 310 ft)

1973 Challenger 452 ci street/strip (2008)
pump gas, DOT radials: 1.454, 10.523 at 126.44 (DA 514 ft)
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