Hey guys just wondering a direction here. Car is pretty consistent just wondering the best coarse of action to get rid of this spin/hop.

Car is 6.30 door car hooking good of the get then Looses grip .25 after launch. Shock are compression is pretty loose 2 or 3 from full loose. Extension is about mid way.

This message has been edited. Last edited by: Bob Payton,

Maybe include some car specifics.
Cu in / HP
Weight with driver
Rear diff gear
Rear tire size / brand
Adjustable front shocks?
Obviously a Glide. What planetary gear?
4-link or Ladder bar?
Wheels up launch?

I like the stall rpm.

468 bbc, launch is 3800, 4 link, tires are mt 32x14s, 4.88 gear. 2750 with driver. Front struts are old as dirt not adjustable. Doesn't pick front end on launch. Rear adjustable shocks. 1.80 pg.

what is the light blue line

does it have a wheelie bar

I would highly recommend getting a good slow motion video of the car launching. What you are looking for is how much the tire is flattening and if it is bouncing up. Also how much the body is separating at the hit.
I have an idea what it needs but with out a good video it is just a guess. One possibility is too low of air pressure and rear shocks not right allowing tire to wrap up, flatten and then unwrap bouncing up (spin). May be as simple as more air or may require tire change. May be able to control it by changing four link settings. There is an issue and it is spinning now you need to find out why. Video.

How much air in rear tires?

Light blue line is 02. Tires are are 7 5psi and brand new. To me it looks like a shock change just not sure which way to go.

Rear tires need more air imho. Consider starting at 10 psi and work up in 1/2 increments to no more than 12 psi.

You should / might be able to feel the tire running over itself in the launch now.

I have video. It will just take a bit to download. Hmm didnt think 7.5 was that far off. I could try it .

Are these MT 3074 or 3074S ? The 3074S are stiffwall.

quote:

Originally posted by Bob Payton:
I have video. It will just take a bit to download. Hmm didnt think 7.5 was that far off. I could try it .

We've run the 3074 and 3074s both a 9lbs. 2850lbs Cutlass going 9.60s

30751 mt

quote:

Originally posted by Bob Payton:
. Front struts are old as dirt not adjustable. Doesn't pick front end on launch. 1.80 pg.

I think you may have answered your own question.....

quote:

Originally posted by Big Steve:

quote:

Originally posted by Bob Payton:
. Front struts are old as dirt not adjustable. Doesn't pick front end on launch. 1.80 pg.

I think you may have answered your own question.....

Its on the list to be changed but there are plenty of good cars that leave wheels down. I will mess with air pressure and see where that gets me.

At 103 circumference try 10 psi, make one run and look at your DA. This should show if tire pressure is possibly part of the problem.

Here’s a 2840# car with 32x14 stiffwall (Hoosier 103” RO) at 10.5 psi. Leaves wheels down (street struts) and runs 6.0 /6.2/ 6.4 depending on gear leaving in and ignition tune up. This run was 6.25

6.25 Run

quote:

Originally posted by Big Steve:

quote:

Originally posted by Bob Payton:
. Front struts are old as dirt not adjustable. Doesn't pick front end on launch. 1.80 pg.

I think you may have answered your own question.....

This^^
My car did the same thing, I loosened the front struts and it fixed it. Front suspension is often overlooked....

OK still trying to get the run from last weekend but this was a pass last year at the end of the year. Only thing different now is the slicks are brand new.

https://www.youtube.com/watch?v=ys5X88s5__Y

The car has struts on it not but I think they are some street setup non adjustable. I am working with Strange to try and identify them.

To me it looks like it hits really hard and can't keep it planted.. If what I was told a few years ago that the Extension is the "hit" and compression keeps it planted, you should try loosening the extension and then tightening the compression. I don't think it would be tire pressure, they look like they have the right amount of wrinkle.

I vote for new struts. Looks way to tight. doesn't stay tranfered.