Help with my shocks What is my car doing on launch videos

[pdmracing]

Mr Morgan Loved your book(notice the centerline on the crosmember )

I put a camera on the fuel filter to see what was happening down there.

here is the basic info
car is a back halved H body with mild 450 hp 355 with 8 inch winters converter tci turbo 350 with Trans brake, Koni double adjustables with 12 inch hypercoil 125 lbs springs . Front is stock 4 cylinder springs, a arms and lakewood 90 10.micky thompson 26 inch et fronts (which screwed up the corner balance wildly) and 29.5 x 13.5 MT Et slicks. Car weighs 2911 with my large mass in it.


the current rear weight is 621 lr 651 RR with car at ride height & pinion angle at -2degrees. The only preload is 3 turns in the rr coil over and a spring rubber in the LF.

Shock setup is LR + 3 compression and +6 from soft on top.
RR is + 6 Compression and -4 from firm on top.

The bumpers were junk & I am replacing at this time.


here are the links 100 degree day 125 track temp 4400 da

http://youtu.be/6nupOZAyFmA


http://youtu.be/_UU_gDI0hZw


Any help, constructive comments would be appreciated and welcome.
How big a shock bumper should I run? Should I raise the right rear lower shock in mount instead of 3 turns ? Al 4 links at ride height are able to move easily.

Thanks

[supernova]

Hey, How's it going?
There is a couple things that will help that I see right off the bat.
First I would not spin the tires in the water box. It throughs water into the wheel well and than drips back on the tire. I can see wet spots on the tire after the burnout. Drive through and then do your burnout. And do a better burnout.

Second I not sure what your doing with the shock adjustment. We run the shocks even and put preload in the 4 link and or ladder bar.

Yor not spinning the tires so I'm not sure what your asking. 450 hp is not a lot to start with and with the tires your running you shouldn't have a traction problem. With that kind of power the suspension may not move much anyway. It doesn't sound like it hits very hard. Low rpm on the launch in other words.
What is it you think it should be doing?

[pdmracing]

Im launching at 3200. I bought the car 4 years ago & ran it & did well, but very inconsistant. I bought Daves book. made sure everything was square. I put it on the scales and it was the polar opposite of the current setup.( also the same as when I bought it so nothing much had changed.)

The wife bought me the camera for a gift & I would have swore the car launched in dirt, straight & true. BUT the in car showed me driving hard left on launch.

So I swapped the settings around & the I still steer left but no where as much & its become more consistent & going rounds. But you can always be better.

When viewed in slow motion it looks like the right rear lifts & almost tops out the right shock & it plants the left rear.
Just looking to see if I am going in the right direction
Thanks for the input

[John_Heard]

X2 on the water box / burnout..

Looks like you should tighten up the compression on those rear shocks a bit so when the car transfers weight it'll go to the tire instead of just compressing the springs. That might be what is wanting to steer the car too with them being so soft.

I don't see ANY hit on the tire, shocks don't extend at all that I can see? But it's not spinning either so guess that's probably not an issue. Since it's not spinning, any changes probably won't matter much, but you might be able to use a little more hit.

[supernova]

What stall is the converter? I have a few things you can try for more hit to the tire but need to know what the stall is.
I built a car 10 yrs ago that made about 485 hp with a 383 motor and have some experience with getting everything you can out of it.
What's in the rear end, A posi or spool? If it's a posi it might be worn out and causing one tire to push harder and drive the car left. I help a friend out that has a junior fuel dragster that had a posi in it that was bad and pushed the car left even though it wasn't spining the tires. Put a spool in it and fixed it.

I take it it's a 4 link set up? If so does it have a anti roll bar in it?

[pdmracing]

Spool. No anti roll bar. 4 link. 4400 stall

I'm counter steering to the left so the car is pulling right.

Thanks for the help

[supernova]

Spool, good!

Now than, stall 4400. Have you tried lowering the launch rpm to see if you get a bigger hit? Take your launch rpm down to 2400 and let it hit the converter harder thus hitting the tires harder. By doing this the motor gets a run at the converter and makes it multiply the torque better.

As far as your 4-link goes you need to learn about preloading and how it can make the car work. You said you were a heavy guy, weight on the driver side will cause the car not to leave straight. Preloading the suspension correctly will fix that. You'll also be able to set the shocks together instead if how you have them set now.

ARB is a must with a 4-link. I run a ladder bar car and isn't needed.

I also agree with John on the shocks being to stiff.

[John_Heard]

pdmracing you need to authorize earthlink to accept forum notifications from Dragstuff.com or use a different email address. I'm not filling out your spam blocker thing every day.

[pdmracing]

pdmracing you need to authorize earthlink to accept forum notifications from Dragstuff.com or use a different email address. I'm not filling out your spam blocker thing every day.

Fixed it yesterday It shouldnt be doing that

[pdmracing]

Spool, good!

Now than, stall 4400. Have you tried lowering the launch rpm to see if you get a bigger hit? Take your launch rpm down to 2400 and let it hit the converter harder thus hitting the tires harder. By doing this the motor gets a run at the converter and makes it multiply the torque better.

As far as your 4-link goes you need to learn about preloading and how it can make the car work. You said you were a heavy guy, weight on the driver side will cause the car not to leave straight. Preloading the suspension correctly will fix that. You'll also be able to set the shocks together instead if how you have them set now.

ARB is a must with a 4-link. I run a ladder bar car and isn't needed.

I also agree with John on the shocks being to stiff.

So you think the shocks are too stiff?

[supernova]

I would go up on compression and down on rebound.
My car has QA1-R double adjusts coil overs on it and I have them set with more compression and less rebound.
Less rebound allows extension to push the tire to the ground and firmer compression allows the cars weight to sit on the tire better. The more power you make the more control of the suspension you have to have. I run like 3 clicks in on rebound and 7 click in on compression out of 12 clicks total. You'll have to play with the setting to find what it likes.

[gonzo64nova]

I noticed something in the video.... you dont have any kind of filter on the overflow tube from the cell. Rubber from the burnout can be sucked in and clog the fuel pump. Jerry Bickel sells a bulkhead fitting that has a small KN style filter on it. Just drill a hole in the floor pan and connect the hose. You also might want to change to a bigger hose its supposed to be as big as the fuel outlet so it doesnt slow down the flow but I've used a -6 or -8 (depending on fuel flow) and it worked great.

[Craig W.]

Is it just me or does the car seem to squat on the hit?

Have you mapped the 4-link to know the i/c and anti-squat %?

[John_Heard]

No, I saw that too but was thinking it was weight transfer doing that?

[pdmracing]

Is it just me or does the car seem to squat on the hit?

Have you mapped the 4-link to know the i/c and anti-squat %?

Yes I have I dont have my notes at the office, But the anti squat off memory was 91%+-