CalTracs setup - Chassis separation or limit it?

I know when Calvert first came out with CalTracs years ago, he was recommending stiff multi-leaf springs with minimal arch and stiff shocks to keep the chassis separation to a minimum ("Wasted motion").

However, most of the pics I see these days of leaf-spring Stock Eliminator cars that are using CalTracs or Assassin Bars w/ similar ETs as my car show quite a bit of separation... almost as much as you'd see from the old SS springs or slapper bars setups.

I'm all ears here, folks.

Not sure if this is what you are looking for. I am not super fast, 1.41-1.45 60.ft. This pass was 1.43 10.35

https://youtu.be/rYA-Ipb1GWE

That looks Great to me !!!!!

Cal Track by nature of it's instant center location will always separate. The trick is controlling the speed of that separation with shock rebound.
Doug

Short front segment compared to GM cars. Always going to hit the tire hard. You need a good shock to control it all...

Dont you have a post that you want a "cheap" shock ?

Smh..lmfao !

Tony - Not sure what "smh" means, but I'll take a guess it means you think I'm an idjit.

EDIT: I already have "cheap" shocks. What I asked in the other post is recommendations for a reasonable and -- yes, affordable -- upgrade from what I have now.

Your times are very close to mine, so it's a good comparison. Are those CalTrac (Rancho) 9-way adjustables?

Did you notice your slicks try to unload shortly after the hit? See if you can slo-mo starting about the :58 mark. At least that's what I think I'm seeing.

I saw the same thing

Shaking My Head.

Not at all, just giving you a hard time.....lol
If I thought someone was an idiot, I wouldn't reply

My sons duster has cal tracks with their split mono. He's got Afco double adj in the rear. They have to be quite stiff to control the hit, and he's been 1.45 10.99 . Honestly I think he needs more shock at this point. Look at this way , it's cheaper in the long run to buy santuff a or big gun Afros once, than buying Viking ,strange, or reg afcos.

Maybe Shiloh (White Dart) will chime in. His car works great and hauls the mail.

My Roadrunner runs 10.90's (Heavy POS) hits the tires hard (4-speed) and I control everything with the shocks.

I had my sliders where yours are.If you watch the slider it maxes out at the hit almost inloading the tire.I moved the slider so that it is 80/20.
I want a go-pro for Christmas!!!!!
Also,I went Viking with the stiffer valving for the rear.

I think the shocks needed tightened up, I had them probably 3-4 clicks from full tight. A couple of runs later I tightened them up and improved 60ft. Made 3 10.19 passes in a row after tightening them up.

The key is to keep the tire planted.. controlling the rate of separation is Paramount.. you don't want to drive the tire into the ground

Look at how rise in the rear of a drag car gets less and less the faster the car gets.
As acceleration decreases in a slower car, controled seperation keeps the tire loaded enough for good traction. Once you get enough weight and g force planting those tires to get the front off the ground, you don't need any. It takes virtually no seperation and about eight inches of forward travel in my dart to get there. My carhas the power to keep the tires planted very early. A high 10 sec car not as much. Every car and situation will vary.

I agree with Greg, there are big differences between a 2800lb 8sec car that scales well and a nose heavy 3800lb 12 sec car.

In my case, it's a low-to-mid 10-sec 3800# nose-heavy car.

Brad that comment was not pointed at you.

If I was buying shocks for your car I would buy probably buy double adjustable AFCOs.

My best 60ft has been a 1.33. It is always in the low 1.30's and I am using Rancho 9 ways on the back. I am using home made caltracs with stock leaf springs and shackles. I am running Drag Radial tires.

I didn't take it as an insult; I just wanted to add some context on what I am (or, should be) running.

Found this article that I think is applicable to my original question: https://www.racepagesdigital.com/extensi...feet-at-a-time/

Wish my Challenger weighed 2950#s, instead of 3750+...

Why not go full tilt and buy Santhuff shocks?? Actually I am in the same boat looking at shocks for a slightly heavier and faster car and I think the AFCO's seem to be the best bang for the buck right now

very interesting how are these guys going 1.0 sixty-foot . On a tiny 275 or small tire. And never lift a front tire off the track.. we have a hi 11-second. Street Dart.. has way better shocks than it needs hooks in a car wash with an 8 inch slick.. and never does a wheelie.. the fact of the matter is we race on prep surfaces.. I used to be one of the guys that struggled with the whole shock situation someone once said spend absolutely as much money as you can on shocks you will be way better off guess what they were right. There is no need to kill the tire it doesn't matter how slow or heavy your car is get some good shocks and be done with it

Mellow 1.36 60' launch off the brake: https://m.youtube.com/watch?v=YSNmSkJh_XE

Menscer shocks on all four corners. No drama!

Any car going 1.0 60 ft has virtually all the weight on the rear tires, would you agree with that? It doesn't matter what the visual is, weight transfer is enough to get the job done. I can make my dart run the same 60 ft with the front skimming the track; right up till track prep and my tires go away. Then a wheelstand can get the job done a little better. Most of us don't have our cars sorted out to the Nth degree nor do we have the best tires and equipment. So we bandaid the situation to get the job done the best we can.

60ft is just a portion of the ET. A car that runs high 10's won't 60ft like a car that runs high 8's. It takes power with proper application to get the quickest 60ft. You can have plenty of traction and still have slower than expected 60ft. Ask yourself. Are you 60ft chasing, ET chasing, or bracket racing? All 3 are different set-up's. Then of course there is the variable of surface prep. Again a difference, not just in the tune but the car itself. Don't think your going to go to the local airport no prep with a heads up ET chaser on the same set-up. All this boils down to what you want to accomplish. Some guys will do fine with low buck 9 ways. Stepping up the power means stepping up the support system that goes with it. That means a shock with more adjustment and more than likely stiffer valving. For most of us here a decent double pair will accomplish your goals. Get a usable set (4) shocks with the proper range of adjustment. Now the rest of the car needs to match. correct range of front travel, no bind in the rear, correct instant center location, nose weight, converter, SLR, proper carb cal if foot braking. Then, test,test,test. It's not just bolting on magic shocks.
Doug

I appreciate your knowledge.. just goes to show I have lots yet to still learn.. the car that you've mentioned a couple times who's leaf spring and bar are you using is it a caltracs or assassin or homemade and what size tire are you running . Also curious on the shock as well..

I don't get your sarcasm or attempt to scrap with me over this. All i intended to point out is every situation is different. All i have an interest in is getting what info to the OP i can that may help his setup. Over and out.

. First of all I wasn't being sarcastic I was being honest. By your response I wish I would have been sarcastic. I learn by trial-and-error mostly by making the same mistake over and over again. And Real World Experience using leaf springs.. I see many fast cars that never pull the front wheel off the ground I asked a question you answered
I assume the answer you gave was correct
.no reason to get upset. Still curious on your rear suspension.. your 60-foot times are impressive.

Everyone's feedback on this subject is appreciated. Nobody's nose should be getting bent outta shape as far as I can tell.

No argument there. I'm expecting the new combination is going to take some time to get sorted out.

My bad. On pain meds
I have 30 inch ladderbars (way too short) 33x15x15 stiffwall goodyears,130 lb springs (too stiff?), Afco big gun shocks.Torqueflite with 4.56 gears for a SLR of 11.17, which is considered hi for my ET in the Door Slammers chassis book. 46.7 percent weight on the back with a total of 3065 at the line. I would love to change this car over to a fourlink, so i wouldn't have to compensate so much with a very stiff shock setting.
I usually promote overspending on shocks, but didn't here because Brad has another thread on it. I think there is a lot yet to figure out on my car, after looking at data logger info. Also I am very impressed with the power you are making with the sb.

Guys I am new to Caltracs. But I'm the video, it looks like there's 6 or 7 inches of body lift separation. Do you want that much on that car? If you were running a stick car would u still want a lot of separation. I remember SS springs recommending no separation w a stick car and only a couple inches of lift at the rear tire w automatic.
Is it different when u add the bars?

Plenty of lift. If you want less, keep an eye on consistancy from good prep to poor track prep and pick your poison. I think the main thing is being able to control the rate of lift as much as how much lift you allow.

I watched a number of videos since this post and was really surprised by how the X275 cars, for example, were doing just what you described above. Some of them are lifting the front wheels, but just barely, and carry them down track a ways before they come back down really smoothly.

That's in complete contrast to what you'll see from a lot of fast Stock Eliminator cars that still pull the fronts waaaaay up before they drop back down to earth. I wonder if that approach to tuning for radials (275/60 or 9 x 30) would translate well, if the Stocker guys tried it. Or maybe a Stocker's weight distribution and other chassis limitations still require a good bit of pitch rotation to get off the line consistently.

your comparing apples to oranges, a stocker has no where near the power that an X275 or Ultra car has. the average Ultra car has 13-1500 hp or more. Stockers use all they can, the radial cars are all about power management and smooth application of it as soon as possible. X cars are 60' in the 1.0's Ultra cars are in the 1.teen range.
Also, a lot of Ultra and X cars move the instant center back an up. this hits the tire hard but doesn't lift the front, otherwise theyd be on the bumper all the time

Understood. But I wasn't sure how much of this was because a radial tire works better w/ the chassis tuned differently than a bias-ply, or because of all those other variables like HP, etc.

.. correct me if I'm wrong but aren't most stalkers running a radial now.. I think the original reason for the Post was just to show that cars can hook and go fast without pulling the front wheels off the ground.. we hit our car with everything that we can on the starting line. . it has been quite the adventure getting the car to work without all the rotation.. I myself have asked many questions on this forum regarding.. rotations.. I have found the most important thing is controlling the rear end of the car.. if it separates too quickly it will Top out and unload the tire.. if it's too slow it will never hook.. has kind of been a science project of mine on my car..

An enlightening moment for me was years ago watching Billy Gliddens car at Route 66 skate off the line Fronts skimming the track. The rest of the field was pulling the fronts and getting thier collective butts handed to them.

Yep. Pic below is the 2017 Stock Finals at Indy showing two 10-sec 340-powered cars pulling 'em up, a lot of chassis separation, and planting their 9" radials.

(It also happens to be the background image on my work PC )

? stalker? if that's directed towards me, I think not

5.10 @ 140 on a 275, no wheelstand. I think im qualified to comment, and yea your correct about controlling the rear. Smash the tire and hold it there. If I give Brad a hard time....he knows where im coming from.


reading is fundamental....you meant "stocker" not "stalker"....I guess I should read more..LMAO ! ! !

Yep.

I’d say...... about this much seems to work pretty good:

I'd recommend you run the best double adjustable shock you can afford and the same for the front. I run Menscer Big Gun Afcos and Cal Tracs with M/T Pro 275s. I try to keep the rear separation to a minimum at launch.

Yep just a little will do ya!

I don't have the video a friend took years ago, or any pics from when people were telling me it was pulling the fronts 4-6". What I do know is the Ranchos were on #4 of 5 (one click from stiffest), and I raised the tire pressure after 440Jim pointed out that I was squishing the sidewalls too much. The rebound setting on the front dampers should have been tightened up some to see if I could keep the front suspension from topping out so hard on the launch without hurting the 60-ft, too.

The goal is to get to 100% Anti-Squat. This means trying to keep the rear wheel neutral during the launch. If you have a light big power car you need to control the front end lift with wheelie bars. Pro Stock, Pro Mod ect...

Every guy that runs in the NHRA Stock class has there car figured out to the umth degree. The rest of us are trying to learn as we go to get our combos figured out to be the quickest we can be.

My experience has shown me that I'm still very far away from knowing everything.

A couple of guys on here have impressed me though the years and I don't take there advice lightly.

White Dart (Shiloh)

Al Alguire

W5Dart66 (Brett)

Best of luck guys and keep us in the loop on how to improve.

Could you post a side shot at rest so we can see the amount of rise please?

Same for you,picture at rest
I'm still chasing the carbs,car leaves straight 85% of the time so I have not tried different settings and preload.
Does more preload help if the it's going straight off the line?

How do achieve 100% anti-squat if the instant center is above the anti-squat line? A Cal-Track instant center is pretty short, most likely putting above the anti-squat line. You can slow it down with stiff rebound, but the physics says it'll still separate. Am I missing something?
Doug

I said the goal is 100% Anti-Squat
I didn't say it should be done with CalTracs
You not missing anything, you have to control the separation with whatever you can, shocks, weight, front end travel, ect...

Watch the World fastest leaf spring Mopar, it's a Dart that runs real hard and the I don't think it lifts the front tires off the ground.

I'm saying if you work on it you are looking for 100% Anti-Squat.

Man thanks for the kind words those are some big names that you Tangled me up with
. I have learned a lot from both Brett and AL Myself.
. As ET improves the
Suspension requirements change. I think the best thing is get the cars out there and get some video up so we can all take a look. And all learn from one another

Video's show Digby's Dart separating a good 4" or more at the rear. Mark Menscer made mention recently that instant center settings are getting shorter and higher to load the tire harder. As for the front being controlled with slow rise, I agree 100%. Depending on available tire hit the car may or may not need front travel. 2 opposite ends of the car. Most cars I've been involved with that don't work have rebound too loose on either front, rear, or both ends.
Doug