Shock adjustment help needed, launch video

Here's a video of my coupe launching. I have double adjustable afco shocks on all four corners. It is a manual transmission. Bias ply DOT slicks. Based on the video, what can I do with the shocks?

https://www.instagram.com/reel/C2tOMNaObib/

If the vid is posted on You Tube, there is an option to slow the video down to 1/4 speed. I couldn't seem to find that option on the above clip.

Send this video to Jeff McConnel who rides with Doc McEntire. He knows his stuff.

Joel, from what i can see, i think the rear axle is extending extremely fast, hitting the end of the shock travel, rebounding and repeating all in about 5 to seven feet.
If you can stiffen extension, i would be tempted to go extremely stiff, maybe starting as tight as possible. Also i would drop the launch rpm if you can some. If your suspension has a high and short instant center, that might be part of the problem.

Like stated if you put the video on You Tube it can be slowed down and stopped at spots for a more in depth look. I agree on tightening the rear. Both rebound and compression. The front has very little travel but tighten up the rebound there as well. Once the bounce is corrected it needs some wheel speed. Not being a stick guy my thought is raising the rpm at the start will allow that adjustment..
Doug

I'll try and get the video on to YouTube. Super busy in the throws of sick week. Maybe tonight will be able to get it up there.

Tightewn the extension to start on the rear....What is the rest of the rear suspension?

Id consider freeing up the extension on the Front as well suggestion previously made on the rear...Let it get a little pitch momentum.

Should be able to play this at .25x speed

I’m def not a chassis guy, but it seems to me that fundamentally it’s going to be hard to keep the suspension loaded properly when it sounds like there is an “almost” bog after you leave.
In my mind I’m thinking there is some relaxing of the suspension when that happens.

The car has a 4 link rear.

I run my rear shocks on the Road Runner, at full stiff on both Extension, and rebound. The more RPM, and harder I hit the tire, the faster it goes.

Now that I can watch in slow motion. The rear looks to have no seperation (even squats a tad) but still appears to dead hook until it bounces. Also no wheel speed. My first thoughts woukd be it needs more rpm and less tire pressure to gain wheel speed. But the underlying problem may be a bog leading to the above issues. Not sure I'd worry much about the front until the rear is fixed.
Doug

Thanks for all the input. So if it has no separation would tightening the extension help it or hurt it? As far as the bog, there's nothing I can do about that for tomorrow's race. So I'll just have to live with that.

I would say yes as it may reduce the bounce back after the hit. It may like a looser comp setting to aloow it to squat. That might give it some wheel speed. It's possible the 4 link is way off as well.
Doug

Try stiffening all four up as stiff as you can them and the see what that does and go from their
It may only need the rear only stiffer, tighter, but I would do both and then if that helps start softening the fronts a little bit at a time until you like it one way or the other

Very little suspension change front or rear in that video, everything looks way too stiff but then again I'm a Caltrac guy. How much travel does it have front and rear ? are you topping stuff out or reaching the limits of the suspension ? I know it sucks to have to use a race meeting for test and tune but I'd go looser on ext front and rear and see how the car reacts.

One thing to consider is these tracks are super tight from what I have seen this week. I think that is one reason Lutz in his pro mod has had a hard time getting down and is 2nd overall to a Coyote Powered mustang on a drag radial(6.29!) Some of the stick cars are running radials now as well.

Joel you might need to loosen the clutch up some to get the bog out, the wheel speed might be hard to come by with the tight tracks. A torque converter would also be a good solution and it would get that pesky stick out of the way

This is why no one will remember your name Claude...

I would agree stiffen the extension. Not suspension but what weight flywheel do you have? Many years ago 1980's I raced an Anglia with a four link, four speed, and it weighed 2,200 lbs with me in it. Ran low 10's high 9's Had a 30 lb flywheel in it, put a 15 lb wheel in it and it was so much easier to launch and drive. Light car does not need all the torque multiplication of a heavy flywheel.

Savage reply. LOL.

Be curious to know where the 4 link is set up is at.

The "bog" I am sure is caused by the dead hook issues. Pulling the engine down. More RPM, less clutch etc will likely help with both.

If he gets the reference, I'll buy him ice cream at Drag Week.

He should get it.

Well you can save your ice cream money. I'll have to go get it from Bailey's ice cream truck if it happens to run long enough to make there.

I got breakfast sandwiches, hot dogs, ice cream and water from the truck when it was on Sick Summer and Joe Barry was driving it…. before they ripped the gas tank out of it later in the week.

I think the rear axle failed on sick week last year, Joe got the gas tank, and the trans went out on Sick Week this year. Solid unit.

For my past at Valdosta today, I took advice from this thread and loosened up the extension on the front shocks two clicks, tightened up the extension on the rear shocks three clicks, loosened up the clutch. Our group was last to run today and about 1:00 I was just two cars from the burnout box. I started the car and had zero oil pressure. It ended up to be a broken off oil pump drive shaft. So I need to tow it back to Minnesota and my racing is over until springtime. Then I'll get serious about getting this thing dialed in. Thanks for all your help everybody!

Dang Joel- I was all in waiting to hear what happened on the pass. That sux!! I respect all your hard work to get there.

Don't we hate Murphy
Next year

I second the motion. If we back the launch RPM off to say 3k I can take some compression out of the rear shocks to get better weight transfer on a marginal surface. If you launch ot as god intended, at 4500-6000, it needs all of the shock it can get out back and as said it crushes the rear tires as launch RPM is increased.