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A great Reason to install Ladder Bars

I sent a slow motion video to Cal Trac Tech Department yesterday. I told them my 60' was 1.39 to 1.40 for my 3780lb car. They told me the launch was just fine. The rear suspension is "unloading" about 3 to 3 1/2 inches (with my Cal Trac Setup that I have) and they said that's OK. It is NOT unloading to the point where the rear tires are starting to "bounce". They confirmed that it was probably right on the edge.
When I took the 120lbs out of the rear of the car (with the same Full Soft setting) on the rear shocks the chassis unloaded quite severely and the rear tires bounced.
They said to set the shocks "stiffer" (like DVW and Malex have been saying) and try that setup with the 120lbs out of the rear of the car. They, too, said it might control the chassis unloading.
Cal Trac Tech said he didn't think Double Adjustables were necessary because the chassis stayed "up" for the first 150' or so, so the compression setting of a double adjustable wasn't necessary.
I am going to try the stiffer setting (with the 120lbs out of the Rear) on March 3rd during the 1 day test and tune prior to the NHRA March Meet that weekend. I am pre-entered for that race.
Just an observation...QA1, Viking, Strange, Vari-Shock all make SINGLE adjustable shocks and they have an aluminum body....Cal Trac shocks are 9 Way SINGLE ADJUSTABLE SHOCKS, just white painted steel body...Correct ??
Just to confirm: If and when I buy new shocks they will only be Strange double adjustables.
 
Mike Gaines said:
I sent a slow motion video to Cal Trac Tech Department yesterday. I told them my 60' was 1.39 to 1.40 for my 3780lb car. They told me the launch was just fine. The rear suspension is "unloading" about 3 to 3 1/2 inches (with my Cal Trac Setup that I have) and they said that's OK. It is NOT unloading to the point where the rear tires are starting to "bounce". They confirmed that it was probably right on the edge.
When I took the 120lbs out of the rear of the car (with the same Full Soft setting) on the rear shocks the chassis unloaded quite severely and the rear tires bounced.
They said to set the shocks "stiffer" (like DVW and Malex have been saying) and try that setup with the 120lbs out of the rear of the car. They, too, said it might control the chassis unloading.
Cal Trac Tech said he didn't think Double Adjustables were necessary because the chassis stayed "up" for the first 150' or so, so the compression setting of a double adjustable wasn't necessary.
I am going to try the stiffer setting (with the 120lbs out of the Rear) on March 3rd during the 1 day test and tune prior to the NHRA March Meet that weekend. I am pre-entered for that race.
Just an observation...QA1, Viking, Strange, Vari-Shock all make SINGLE adjustable shocks and they have an aluminum body....Cal Trac shocks are 9 Way SINGLE ADJUSTABLE SHOCKS, just white painted steel body...Correct ??
Just to confirm: If and when I buy new shocks they will only be Strange double adjustables.
Click to expand...
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You sure kicked the can a long ways to get to this plan Mike! But you got there. Good luck.
 
Looks like he's runnin' Caltrac shocks too . . .


IMG_3039_JPG.jpg
 
Its not separation that necessarily is an issue. It's the speed at which the housing separates from the body. When the housing separates it's loading the tire. The more power you have, the more load is applied to the tire. Eventually no matter how slowly that load is applied the tire will be "over worked". Then the pivot point of the rear suspension needs to be lowered and or lengthened. All the shock does is control the speed of the movement. The load is controlled by the geometry of the front pivot location. If that location is above the cars actual center of gravity, the rear will separate. If it's below it will squat. This is why you will see very high power cars on slicks squat (pro mod). Their power level is applying more load than the tire can deal with. Now to through another wrench into the works we have radials (and somewhat similar stiff wall slicks). These tires don't flex the side wall as much. They can take more load. Take a look at the worlds fastest 275 radial car. Talk about separation, wow.
Doug

https://www.dragzine.com/news/lil-secret-swanstrom-goes-stunning-3-73-on-275-drag-radials/
 
Thanks for the compliment, Mike. If Malex's 60s improve that's a good thing. If you follow suit and your's improve, that's a good thing too. My point is that maybe there's a little more to gain in your set-up before tossing it and spending more $$$$$. I am as guilty as the next guy for wanting something newer in my cars; As they say, my car is always one more part away from being finished and my shop is always one more tool from being complete...lol.
My best to you in your efforts. I'll be watching...
 
coloradodave said:
Thanks for the compliment, Mike. If Malex's 60s improve that's a good thing. If you follow suit and your's improve, that's a good thing too. My point is that maybe there's a little more to gain in your set-up before tossing it and spending more $$$$$. I am as guilty as the next guy for wanting something newer in my cars; As they say, my car is always one more part away from being finished and my shop is always one more tool from being complete...lol.
My best to you in your efforts. I'll be watching...
Click to expand...
Well, I am going to exhaust my current setup (Cal Trac bars, Cal Trac Mono-Leafs, Cal Trac 9 way single adj shocks on the rear and Cal Trac 90/10 shocks on the front) BEFORE I do anything about Ladder Bars and Strange Double Adjustables.
If I can improve my PB of 10.158 down to, let's say, 10.05 or so, then I aint going to do nothing because 10 flat is my goal, without going under.
But...I do continue to believe that the Ladder Bar setup will improve my reaction times when I run classes that use the Pro Tree.
 
We are all fans and will hope Famosa is good to you in March and you click off a 10.00....
 
Good luck Mike. I think you'll find you can make an improvement. Don't give up on the 1st try.
Doug
 
dvw said:
Good luck Mike. I think you'll find you can make an improvement. Don't give up on the 1st try.
Doug
Click to expand...
Doug and Dave,
I will have at least 5 passes at the March Meet before Eliminations on Saturday Morning (They run the 1st round on Saturday because there will be around 200 to 225 cars in the Bracket Class so they can "thin" down the number to 100 or so for Sunday). You have to win on Saturday to race in THE SHOW on Sunday. There will be 30,000 spectators on Sat and close to 50,000 on Sun.
My 1st pass will be my more "regular" setup with 120lbs of ballast back into the trunk, 16lbs or air and a 3600 chip in my transbrake. I know the Adjusted Altitude will be in the 500' to 1000' range at that time of the year. That hit should be in the 10.15 to 10.17 range...so that will confirm my base line. Then from there I will set the shocks stiffer and start taking ballast out of the car and see how it goes. For Eliminations I can always go back to my baseline setup and dial in at my 1st hit ET of 10.15 to 10.17. I will keep track of the Adjusted Altitude (Air Density) during my test runs so I can adjust my first round of eliminations run to accommodate any difference in anticipated ET due to Air Differences.
 
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Shock and spring lenght are very important. The rear segment lenght, centering pin to shackle mount, has to be long enough so that the shackle will have a distinctive rake to the rear when the cars full weight is on the rear suspension. If the shackle is straight or forward it limits the suspension travel/body separation acting as a stop.

Just because a shock manufacture says it's shock will "fit" your application doesn't mean it is ideal for YOUR car. If the fully extended lenght is to short it will limit body separation as does an incorrect shackle angle. With the jack stands under the frame and the suspension "hanging" the fully extended shock should be at least several inches longer than the shock mounting points.

I use AFCO single adjustable gas charged coil overs...minus the coils. They extend on their own and are a b**ch to compress at their highest setting to get to the mount point. The shocks are putting downward pressure on the rear tires at all times.They also have swivel joints at both top and bottom mount points...no binding when the suspension is doing its thing. They can be rebuilt/revalved. Dual acting shocks are not necessary on leaf spring cars.
 
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4spphil said:
Shock and spring lenght are very important. The rear segment lenght, centering pin to shackle mount, has to be long enough so that the shackle will have a distinctive rake to the rear when the cars full weight is on the rear suspension. If the shackle is straight or forward it limits the suspension travel/body separation acting as a stop.

Just because a shock manufacture says it's shock will "fit" your application doesn't mean it is ideal for YOUR car. If the fully extended lenght is to short it will limit body separation as does an incorrect shackle angle. With the jack stands under the frame and the suspension "hanging" the fully extended shock should be at least several inches longer than the shock mounting points.

I use AFCO single adjustable gas charged coil overs...minus the coils. They extend on their own and are a b**ch to compress at their highest setting to get to the mount point. They also have swivel joints at both top and bottom mount points...no binding when the suspension is doing its thing. They can be rebuilt/revalved. Dual acting shocks are not necessary on leaf spring cars.
Click to expand...
I checked my cars shackle angle and shock length and it passes the test you describe above.
Help me understand why double adjustable shocks are not necessary with leaf spring cars..
Thanks.
Plus: Do your AFCO Single Adjustable Coil Over shocks work the same as Non-Coil over Single Adjustable Shocks ? I guess they do ?
 
Hi Mike. The shock on a leaf spring car carries very little weight. On a ladder bar/ 4 link suspension the shock carries much more weight along with its coil spring. It has to dampen/control inward and outward movement to keep the coil spring under control.

On a leaf spring car it is only necessary to control how/when it settles down. The leaf spring relaxes as driveline pressure decreases.

I would think a non coil over would work the same as a coil over provided they are internally designed the same. Coil overs have provisions for the coil spring but other than that I would just be speculating. Randy Mans at Fast Shocks in Minnesota would be the guy to better explain it all. I do not have his number but he does have a web page.

A double acting shock on the front is a definite plus regardless of rear suspension type.
 
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4spphil said:
Hi Mike. The shock on a leaf spring car carries very little weight. On a ladder bar/ 4 link suspension the shock carries much more weight along with its coil spring. It has to dampen/control inward and outward movement to keep the coil spring under control.

On a leaf spring car it is only necessary to control how/when it settles down. The leaf spring relaxes as driveline pressure decreases.

I would think a non coil over would work the same as a coil over provided they are internally designed the same. Coil overs have provisions for the coil spring but other than that I would just be speculating. Randy Mans at Fast Shocks in Minnesota would be the guy to better explain it all. I do not have his number but he does have a web page.

A double acting shock on the front is a definite plus regardless of rear suspension type.
Click to expand...
Randy has a great reputation. I do not agree with your 1st two statements you made. The shock never carries any load, the spring does. Doesn't matter if it's a coil over, leaf, or torsion bar. A leaf spring car probably needs more control on rebound than it does in compression. You'll see that most single adjustable shocks control rebound only. My 2 cents.

Doug
Doug
 
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