Need Advices to Setup Rear Suspension

-
360tripleblack7

360tripleblack7

Gold Member
Joined
Feb 15, 2009
Messages
90
Reaction score
69
Location
Tiffin - IA
Hi Folks,

Finally I could test my new set of Viking DA Shocks that I installed in my car. These shocks already improve my 60ft from 1.58 to 1.54 but I'm still having tire bouncing on the start.

I'm using this setup on the Shocks:

Front: Compression = 12, Rebound 2.
Rear: Compression = 4, Rebound 12.

My car is an A Body, 3300lbs Small Block with 464WHP, Footbrake, 4500 Stall Converter, Hoosiers 28x10.5, 4.56 Gear, Leaf Springs with Assassin Traction Bars.

I'm sending two videos of the start... So if someone could see that and can support me to fix this issue will be great.





Thanks...
 
just a casual observance - you're not squatting enough on launch.. might be weight transfer - the back end seems to need to come down some.. with that much stall and that kind of HP - you should be doing wheelies!
 
i think your front shocks are still too stiff and not as ScampMike said getting enough weight transfer
 
DavidLee said:
i think your front shocks are still too stiff and not as ScampMike said getting enough weight transfer
Click to expand...

Maybe reduce rebound from 2 to 0 on the front will cause a better Weight transfer... Another thing that I'm looking is Traction Bars angle. I'm running with lower holes mounted front/rear and I understand that I'm having a very agressive rear tires hitting on the ground with this combination because front of the bar is higher them rear and when I leave the brake and car launch, loading suspension this angle change a lot hitting tires on the ground so hard as you can see on these picture that I posted below...

IMG_5420_zps0odvmuj7.jpg


IMG_5047_zpsqyvpeuxe.jpg


So, make sense or don't?
 
You should get a copy of the latest suspension manual from Mopar. I think it;s the ninth edition that's the latest. Mancini routinely has them for 10 bucks. Best 10 bucks you'll ever spend.
 
Wheel hop is caused by the loading and unloading of the tire. Most common cause is too much chassis or suspension flex. But inadequate weight transfer can also cause the problem. It's an issue of not just enough weight transfer but how quickly the weight transfers to give the suspension something to push against and keep the tires planted. Loosening up the rebound on the front shocks should help the problem.
 
bOb shingler said:
to me everything looks fine except lower the tire pressure in the slicks to 10lbs or less.
Click to expand...

I agree, no wrinkle at all........ and the other thought is that the shock is short for the height of the rear end. Unbolt that shock and see how much compression and rebound travel you have at ride height.
I think your shock is topping out which pulls/ unload the tire and cause the jack rabbit starts.

I agree also that you're not getting much weight transfer. This also could be from having to short of a shock up front. The front end tries to lift up to cause weight transfer and then the shock tops out causing the weight transfer to stop, causing the rear tire to unload at the same time.
The car set fairly high, front and back. if you ordered stock length shock, this could be your hole problem.
 
Cudafever said:
I agree, no wrinkle at all........ and the other thought is that the shock is short for the height of the rear end. Unbolt that shock and see how much compression and rebound travel you have at ride height.
I think your shock is topping out which pulls/ unload the tire and cause the jack rabbit starts.

I agree also that you're not getting much weight transfer. This also could be from having to short of a shock up front. The front end tries to lift up to cause weight transfer and then the shock tops out causing the weight transfer to stop, causing the rear tire to unload at the same time.
The car set fairly high, front and back. if you ordered stock length shock, this could be your hole problem.
Click to expand...

I agree, no wrinkle for sure! Shock lenght is fine. I did measure and I've more than 1" with suspension unbolted. probably I'll change front height because currently I've just 4" of front end travel and should be around 4.5" - 5" of front end travel... Maybe this change could help with weight transfer also.
 
???? One inch of travel(1") Is not enough.
Jack your back bumper up until your tires are off the ground and then see how much travel you have left. On inch is not enough.
Just the force of the suspension under launch, will push the suspension up(push tire down) more than the droop you create by letting the suspension droop/ hang.

In the video what i see by starting and stopping the video as you launch is....
front end comes up(weight transfer) rear start to rise,(tire loads) then you see the rear suspension stop rising, tire unloads and slip. front tire returns to the ground. Rear suspension does not move from that point on. tire goes down the track bouncing like a basket ball sort of :D
Just my thought, could be wrong.
 
Last edited:
Have u tried lowering front of car. When i ran cal tracs we had front end on lower bumps and upper bumpers off.
 
rick4106 said:
Have u tried lowering front of car. When i ran cal tracs we had front end on lower bumps and upper bumpers off.
Click to expand...

Not yet Rick... I think that will do this tonight to see if I can have more front end travel... I will check lower and upper bumpers also.

Thanks
 
rick4106 said:
Have u tried lowering front of car. When i ran cal tracs we had front end on lower bumps and upper bumpers off.
Click to expand...

Folks, I measured front end travel this weekend and had 4.2" of travel... So I reworked the upper suspension bumpers that was blocking my front end travel and lowered front of car 1/2" and now I've 5". I know that the golden rule is do not change more than one thing per time but I'm thinking in tight rear shocks extension from 12 to 18 to start.

Jully 22, 23 will have an event and I will can test my last adjustments...

Thanks Guys!
 
360tripleblack7 said:
Hi Folks,

Finally I could test my new set of Viking DA Shocks that I installed in my car. These shocks already improve my 60ft from 1.58 to 1.54 but I'm still having tire bouncing on the start.

I'm using this setup on the Shocks:

Front: Compression = 12, Rebound 2.
Rear: Compression = 4, Rebound 12.

My car is an A Body, 3300lbs Small Block with 464WHP, Footbrake, 4500 Stall Converter, Hoosiers 28x10.5, 4.56 Gear, Leaf Springs with Assassin Traction Bars.

I'm sending two videos of the start... So if someone could see that and can support me to fix this issue will be great.





Thanks...
Click to expand...

Actually looks like a pretty decent launch but some on here talk about Squat.squatting in the back means you're not transferring the all of the weight to the ground some of it was absorbed by the springs. you actually got lift the moment you left the line in the rear which indicates is pushing down on the tires and up on the body which is what you want however the more the body lifts in the rear the less it plants the tires. just my opinion don't know if that helps. What was your 60-foot time
 
investigator said:
Actually looks like a pretty decent launch but some on here talk about Squat.squatting in the back means you're not transferring the all of the weight to the ground some of it was absorbed by the springs. you actually got lift the moment you left the line in the rear which indicates is pushing down on the tires and up on the body which is what you want however the more the body lifts in the rear the less it plants the tires. just my opinion don't know if that helps. What was your 60-foot time
Click to expand...
First thing I`d do is get those "4 speed" slicks off it, and put some regular 10x 28 hoosiers, or M/T`s on it !!
 
investigator said:
Actually looks like a pretty decent launch but some on here talk about Squat.squatting in the back means you're not transferring the all of the weight to the ground some of it was absorbed by the springs. you actually got lift the moment you left the line in the rear which indicates is pushing down on the tires and up on the body which is what you want however the more the body lifts in the rear the less it plants the tires. just my opinion don't know if that helps. What was your 60-foot time
Click to expand...

Good news guys! My car has made his best ET so far. I could drop 60ft from 1.54 to 1.50 and the problem with tire boucing is almost solved but the car still boucing tires on start.
I'm sending below a video from my GoPro camera that I installed under the car. Sorry for the quality but was darken when I made the video.

 
You must log in or register to reply here.
-

Back
Top