**update w/ video** Setting up DA shocks

Purchased and installed Viking crusaders front and rear.
abody .
SS springs
Foot brake
Auto
650 ish hp bb
Car runs 10.0s

The car started loosing 60’ 1.40ish typically and started sliding back to 1.45 or slower. Shocks were nearly 20 year old ce 3 ways.

I have been playing with the Vikings and not making much headway. TT last Saturday 8 runs and couldn’t get below 1.50. . Worked mostly on the rears with the fronts loose on rebound and about 5 clicks of compression. Started out being really a handful out of the hole and down track . By the end of the day I can say it felt better but still a weak 60’.

I started the day with the rears 5 clicks in compression and 12 rebound.

Tried adding rebound and lost time.

Tried adding compression and started to pick up then fell off again.

Am I doing the right thing working the rear first ?

Is there a ratio of compression vs rebound I should be following?

I welcome any experienced advice

current last visit below

only 2 runs before a flat tire.
got the front to sit lower . cant go much lower with tire /header rub.
added dampening to mostly rebound as suggested .
first run is right view vid. front = c8 r18 rear = c12 r16 as you will see bounces like mad
second run left view vid. front = c12 r20 rear=c14 r18 better but still not great . rebound is 1 click away from max in front a 3 from max in rear .

I think I need the stiffer valving kit from viking as i am almost out of rebound adjustment .

tire psi was 9

the 60 in the 2nd vid picked up .07

https://www.youtube.com/watch?v=w_YgF_2LWvY

https://www.youtube.com/watch?v=6aZXcd58u0g

radial or crossply ?

Tex

If the front rebound is too loose the front end will top out to quickly unloading the rear. Tighten the front up if they're full loose.
Doug

I would work on the front now, you have data from the rear to help you on both ends, my S/P car liked full stiff on the front shocks extension, going up
Let us know how yours does on both ends

Mt et drags non radial

Ok thank you both.

Unfortunately I don’t have anyone to video

Teach someone to video with a phone. It's amazing how good you can do. Especially in slow mo.
Doug

Thanks. My kids used to come but all work the weekends now.
I will have to figure something out

I'd bet the front is too loose. Tighten up the front shock rebound several clicks and try again.

I would probably call viking support since every shock and setup seems different.

My experience I wouldn't be afraid to try 3 clicks from full soft up front. It was HOT around here this weekend so if the track is HOT you need every ounce of travel you can find.

Unless its wheelstanding to out of control its not to loose.

On the rear HOT and greasy again means soften compression. When the track gets better you can add some clicks and stiffen.

On the rear the extension can be set somewhere in the middle to start > if the tire is getting crushed add > if spinning soften.

How stiff is the rear of the car? Can you push it down fairly easy?

(Not aimed at anyone here) - Its disappointing how many folks buy expensive shocks then set their cars up like hardtails and complain that the track is junk.

Your the second to say this so I will give it a try.

I think the rear of the car seems stiff. Meaning try and lean into it and bounce it and it doesn’t much.
It’s funny you ask because I was sitting in the staging lanes and a guy in a Torino kept walking up to his car and bouncing the rear and it seemed really easy like very soft . So I tried mine when I got back in the pits but not so much.

If it cant hit the tire hard enough travel can help. Loose on the other hand usually just unloads when it tops out. As long as it is rising, the front is adding transfer. Once the wheels are off the ground shocks and springs mean zero. If you don't have enough power to keep it up in the air, now your in trouble.
Doug

dvw is right. I put thicker bump stops on my dart and it ruined the car. I ended up running as thin as possible.

Some things to consider:

How low are the front torsion bars set? If possible you can lower the front to get more rotation.

Check your front suspension limiters / bump stops. Maybe they can be cut shorter to add some travel. A little bit can really help.

Tire pressure is another big factor. Check your gauge with another racer. I've seen then go off by 2 or 3 lbs randomly.

If its not crushing the tire then maybe lower it another 1/2 lbs.

What do you mean by how low are the torsion bars set? Measured from where?

Cutting off the stops someone welded on could be messy leaving it looking hacked.
I thought instead I would replace the stock lower bump stops that are about 1.50 with some shallower ones that would gain me about an inch then I would crank t bars down so it’s just touching.

I made an update to the original post.

Not sure if thats the common / sensible way to do it or should I have added as a reply ?

Rear suspension isn't moving, at all. Only thing happening is the tire bouncing up and down. Not spinning at the hit. Maybe rotating the tire one its out some.

Is it set high in the rear intentionally? Tire clearance issues? What springs are they? They look to be way wrong and way too heavy. What shock mounts? Stock? What is the installed at ride height C-C measurement on the shock vs. measurement fully extended? If the rear shock is a stock length deal on stock mounts, it has to be nearly topped out.,

Front is separating. Looks like it tops out and at that point is just bouncing the tire like a basketball.

Just chiming in.

Going way, way down in rear tire size would likely give you near a tenth between ratio, the tire adhering to the track too much down track, air over the car improvements with the car not being in a wedge, and weight transfer is easier if the car is more level.

Car needs to come way down in the back. If it has leafs, I'm assuming it's stock mounting with a mini-tub. That's the separation I would expect to see (maybe) at the hit with SS springs. Not at static ride height.

Thanks for the input . I truly appreciate the help .

They are ss springs (don’t know which ones) .

They are mounted inboard , via dc relocation kit. Front eye is as close to car as adjustment holes allow. Rear hanger is through frame fairly close to floor . Angle looks good .

Tires are 31.25

Just throwing this out there. I have had this car for a few years . Until last year it pretty consistently 60’ed 1.40 to 1.42 with an occasional 1.39 And an occasional 1.45. That was with 20 year old ce 3-way shocks .

Seems like I am having to go through a lot of change to only get back to where I started.

Looking at both vids it looks like it is topping out the shock travel making the rear porpoise up ad down
Did you compare the extended shock lengths on both sets of shocks? If not, if you can , do that now. If your new shocks are shorter at max extension than the old ones you may need to use shock extensions to help fix the extended length. If this is the case I might have a set of them, let me know if you need them or not
Try removing the lower shock retainers and slip them off the lower shock mount and see how much more down travel you have on them, then try jacking the back of the car up with the rear end hanging down with jack stands under the rear sub frames and see how much rear shock travel downwards you have that way also. Please let us know what you find on this
What does your rear spring shackle angel look like with the rear end hanging down all the way?
It ET better in the 60 before so you know it will do it again with the proper fixes

It happens. It's called "losing the rabbit".

Cab - I would bet a dollar that jacking that car up, putting jackstands under the chassis and leaving the rear hang, would not let it fall out any further than when it is on the ground. If there is so much arch that they are actually compressed, they need to be tossed.. Maybe need to be anyhow,

It appears to be bound up at full rebound. I agree with Cab see where the shock length is. Any reason for the tall tire? Too much gear? A 28" would lower the rear a ton. The bind needs to be fixed before the shocks can do anything. I'd like to see a pic of the rear shackle. Since its close up in the frame is it hitting the frame?
Doug

A smaller tire will bring the rear of the car closer to level, but won't do anything to get the rear up in the car higher if the springs are holding it out.

It does look like it's porpoising or bouncing out across the concrete. But if you look close, the tire is bouncing up and down. The suspension has no movement.

About 3” of travel from at rest to hanging the axel.

Shocks have about 2.75” of travel beyond mounting point with axel hanging .

*****sorry don’t know why pics came out sideways and upside down******

You need to have a lot more angle on the rear shackles so they don't rotate past center at max lift on the rear of the car
I would relocate the upper bushing hole forward two to three inches closer to the rear end to increase the shackle angle more, you can test where to put it by removing it and move the top part forward until you see what angle you like, it should be rotated forward while testing to see where you want it
I'm thinking more like a 45 to 60 degree angle instead of 25 to 40 degrees

Thanks Mr C

There is another hole forward of the current hole, but only on the passenger side . It’s like 1.25 more forward.

Will this creat more travel ?

Also what effect would unclamping the rear spring segment have ?

Unclamping the rear will make it, the rear half, separate more, not good
Moving the upper hole forward to increase the rear shackle angle will allow the springs to move forward without going past 90 degrees, straight up and down on the shackles, and not pulling the back of the car down as it goes past 90 degrees
Now get to work fixing it
Your car looks a lot like my old pump gas Duster but higher in the rear end. I had ladder bars with coil overs installed on it
That car would hook up in a mud puddle in a rain storm AKA aside, it flat hooked

9 PSI seems low to me, my 31x10.5 w hoosiers, wouldn't 60ft under 13 psi.

Deaks, Hoosier is making a 31 !0.5W 15 slick? Didnt know they started making one, have to check that out.

I have run them as low as 8 .

The 60 has typically been better the lower the psi

Not gonna pretend I'm a 60' guru but if you slow the video down you have 5 almost 6 sidewall wrinkles. I've always been told 2-2.5 and any more the tire is wadding up and acting like a spring. If you watch, that's what I'm seeing, the tire wads up, and releases momentarily and initiates the bucking. Even as big as those are, I'd be going the other direction in PSI. I think you're trying to compensate some other issue by continuing to drop pressure.

Yes I tend to agree with you.

I will try and correct the rear shackle angle in hopes to create more travel or spring movement .

Switch to sliders. It won't be that much more labor.

Not a pro here either, but I think the rear is too high and the tire too soft. I have a 67 Barracuda and i like to keep the upper wheel well lip about 1" above the tire. I use Vikings doubles on the front at 1 or 2 clicks rebound and 12 compression. Calverts on back at 5, but next outing i will try 7 on rear because i get a ton of extension. At 1 click rebound i was pulling 1 foot wheelies, 2 clicks tamed it down alot to 5" wheelies. I use a tubular upper control arm as well. My drag radials hook like glue. One other thing, put some 12" extensions on your headers, you might find some power there. I think your porpoising my be the soft tire, because when you pull up i see the car bouncing from the soft tire.

I didnt see where you said the total weight as you leave the line.. any tire will run best with a certain
pressure for a given weight.. my car is light and I run 6.5 to 6.75 PSI and above that it spins.. you should
start with GOOD tires not some set thats been on it for 10 years.. you would be using that as your
zero point which could be wrong to start with.. tires dont last as long as people think.. on mine
the tire is pretty well shot at a 100 passes then the 60' starts falling off.. I could tell by the 60' numbers
the side walls would be shot.. that was with tubes to help stiffen the side walls.. to look at the tire it
looked fine and had plenty of life let in it.. I use to sell them off.. my 60' would range from 1.19 to 1.22
then I got a new set.. there is no reason for a big burn out.. that just burns up the tire.. just needs
to get a light bit of smoke to clean and warm them up.. so start fresh and dont waste your time
trying to tune the suspension which comes next

Have you tried more air pressure? In the photo with the shackles is the drivers side almost vertical? As already mentioned if you have to move the top shackle mounts in the frame I'd go ahead and install sliders, it'll be a much easier job.

Not a chassis tuner so take this with a dump truck load of salt. In the videos I see three things, one it appears just as the drivers front tire comes off the track the rear tire unloads. Two, there is almost no movement in the rear, separation or compression. Three, the rear tire needs more air. I'd add some air to the slicks, slow down the rebound in the front and loosen both the compression and rebound in the rear. In that order.

The above and $1.75 will buy you a cup of coffee in some places.

I have to agree w/ all of this.

Man! I was there that day. I will be at LVD sat and sun on 9/12-9/13. If you are going back, stop by and I will video the cars launch for you. This is my car.

Not sure why removing the rear leaf spring clamps and gaining more body separation would be a bad thing. Then let the shock do its job of controlling the axle.

So the axle is not moving in relation to the car, but the car is bouncing. How will tightening the shock do anything? The shock controls axle movement which we don’t have. With the rear ride height, there isn’t much weight transfer. If we go full loose on extension for the shocks does it try to throw the axle out of the car? If not, then is the spring really controlling the axle not the shocks? My idea would be get a good tire pressure setting by having someone take a picture of the tire marks of the launch. Then you know basically what the tire wants. Then I would try to get the axle to move by loosening the extension of the shock all the way and loosen the compression a good bit. It will probably crush/bounce the tire at the hit, but you can start tightening the extension until it slows down. When it is still bouncing the tire just a bit at the hit. Start tightening compression to see if you can hold the axle down through the initial bounce. Just spit balling

That use to be the thing to do back before the shocks got much better.. the spring has a couple
jobs to do and thats to hold the car up and keep the axle in place.. shocks control the rest
(thats breaking down to its simplest form)

It’s worth the try . I won’t have time to make any major changes until winter , then maybe caltracs are in my plan .

Only thing is I am out of rebound adjustment in the front . I could have Viking overnight the heavier kit for the front .

Where should rear tire pressure be ? Tires are 31.25 12.5 w
Car is 3100 or so

I am going for the weekend as well, so if I don’t have a helper in tow I will take you up on it . Either way I will find you .

I assumed Cab meant the spring would separate . Maybe he will clarify .

Yes the spring does separate

And does this damage the spring? Or cause a dangerous condition ?

You need to have your shocks checked out. I had a bad Viking shock on the front of my car and sent them to Afterworks to be fixed and revalved.

I've never ran that tire but I'd start upping the pressure until it spins and back it down from there. Do the front shocks first though IMHO.

Yes the spring does separate
[/quote]

And does this damage the spring? Or cause a dangerous condition ? [/quote]

No it doesnt do anything to the spring.. too low of tire pressure is more dangerous when the
tire starts to squirm around on top end

Ok so we know there is no simple fix .

As has been mentioned, I think a set of rear sliders would make more sense than another set of holes in the frame to correct the shackle angle . There are already two holes on one side and three on the other (who knows why) , so if I go sliders I would like to clean up that area as it wasn’t done very well.

As I said there won’t be time for revamp of the rear suspension until winter .

There are only 2 months of track time left so I think I will play with tire pressure, shocks and maybe even remove the factory spring clamp and use an after market clamp in different positions to see if I can minimize the issue a bit .

Thanks to all , you guys always learn me something . If you have any thoughts on limping it along let me know .

If any of you will be at lvd this weekend, you know what the car looks like now , stop by and say hi .

Furry Stump I will be looking for you .

Absolutely! My name is Rhett and I’ll be the one beating my head on the side on my trailer!

Think of the rear leaf spring like this.. the front of it controls where the axle is and the rear part is just
the spring to hold the car up.. the shock controls the rate the rear end moves and how fast.. the angle
of the shocks is based on what the car is used for.. a race car the shocks are vertical and a street
car they are angled for doing corners.. on my street rod I put them vertical for drag racing with some
distance running(I built the car mainly for DW but I latter changed my mind) I didnt see the pic of
your car but if the back end is up in the air it just makes it harder to get traction so if you can try
to make the car level

Thanks much .

Just saw you are in ct.

Where abouts?

I’m in Colchester.

So I was watching the video of the last run on Saturday. So it hits the tire and then tries to throw the axle out of the car. At the hit it plants the tire moves forward about 6” then the body separates until it tops out the rear travel and unloads the tire making the tire spin. the tire then bounces with the rear suspension at max lift all the way through the 60’. I think you are pretty close to full stiffness on rebound. Either you continue going stiffer on rebound to slow the separation down or you could lower your percentage of rise number. Basically drawn a line from the center of the contact patch of the tire through the front spring eye. The farther forward that line is angle softens the of the tire slowing down they body separation. .

Leave the stock clamps on the back half of those springs for now and clamp the front half every where you can, one on each leaf, that you can make fit where it hooks to the main upper spring Once you get that done and relocate the rear shackles so it has more frontward travel before it goes pass center it may make your neck hurt from the improved acceleration

Rhett
Thanks for the nudge.
Here is a link to the vid for anyone interested . https://youtu.be/bFP9XAFZ5PI
Made the following changes which all mostly resulted in minor changes in both directions

I removed 2 leafs from each spring pack and got the car almost 2” lower in the rear.

Tried it with rear segments clamped and unclamped.

Tried tire pressure from 15 lbs (spun uncontrollably) down to 9 and back to 10 whee it did best and consistent 1.50 .

Spoke with someone at Viking . Said it hits too hard . Rhetts crew also mentioned this.

I can change that by moving front spring eye to a mounting hole further from the chassis , but that will raise the rear even more .

At this point I,m just playing with it for education.

I will reluctantly dump another $1000 into it for cal tracks and sliders over the winter.

The front segments are all clamped and have been .

I am reluctant to make any more holes in the frame , as I will likely install sliders .

Question:
If I did sliders now , would the locations work for a Caltrac mono leaf or would I have to redo ?

Watching the new video. In my opinion it separates way more than is needs to. It's defiantly out of rebound travel and topped out. Compare the latest video to your earlier post with the rear axle hanging. Are the new shocks shorter at full extension than the old shocks? Separation is dictated by front pivot location. In your case the front spring eye. Without lowering or lengthening that point you can not reduce separation. Lowering the car will lower this point to the ground. But this is not a total cure as the center of gravity is now lower as well. The front eye mount needs to come down, NOT UP. Your only other alternative is to tighten the rebound slowing the separation. At this point air pressure and shock adjustments are a crutch to try and correct a instant center location that is to high and shocks topped out in rebound.
Doug

First thing I would do with that car is swap springs and lower the ride height in the rear. Too much rake. I wouldnt be surprised if the shocks are topped out too like Doug is saying.

I had to re-arch my springs on my Barracuda and lower the spring eye up front to fix it.

Its a PITA but so is driving a car that wont work.

When you say separating more than it needs to ? Do you mean how far the body is moving away from the wheels ?

The shocks are longer than the old shocks , both front and rear.

Rear axel hanging The shocks are about 1.5 “ longer.

When you say front eye mount needs to come down. You mean move it to one of the holes closer to the ground, further from the body?
Right now it is in the highest hole closest to the body.
If I move it farther from the body it will raise the rear of the car more . Correct?

Also that vid is maxed out on rear rebound and compression adjustment

Front is maxed out rebound adjustment and about half way on compression

Thanks for the opinion

Question
#11 Yes, the distance between the tire and body. This separation presses the tire to the track. To much and too quick can overwhelm the tires ability to hook.
#2 Ok
#3 It is possible in some instances with leaf springs to still top out. The rear of the leaf bends, especially unclamped and can actually have greater travel than hanging static.
#4 Dropping the front of the spring will raise the car some. But it will reduce the tendency to separate because the instant center is lower.
#5 Being maxed out on rebound will not allow you to slow the separation any further without revalving. The fact that the compression is full tight may be contributing to the bounce after the initial hit. If its to stiff the tire cant come back into the body, thus it bounces.
#6 Stay here for the time being Get the back taken care of readdress the front after.

I think taking out some separation and loosening the rear compression would be a good 1st step.
Doug

Thanks Doug,
So just for the sake of experience and experimentation I am going to revalve the rear shocks firmer , lower the front of the rear spring and see what happens . I should be able to get back to the track one more time this year

IF you want to see what a good launching leaf spring car looks like, i can text you a vid. We were at lebanon with my buddy nova saturday. 1.3X 60 foots. Leaf springs with cal tracs. Rear shocks are almost full tight on ext. He also had springs higher into the body. At Cal Tracs recommendation he lowered the front spring one hole and it works very well.
My Cell number is 914 417 1312. shoot me a text and ill text you back the vid.