Car Does Bunny Hop @ The Track

[dvw]

the video I posted should be working, yes not enough dampening for sure, gonna try it again next week as I was kicked off the track.[/QUOTE
I can't make it play.
Doug

 

[1967coronet440]

Try this Doug

 

[slimt]

Sorry my first video on you tube, haven't figured it out yet.

Alot of drop on take off. Sure looks like it needs more stability.

 

[moparcrazy]

Remind us the Specs on that new motor.

500 ci 440, 15.5 compression, Max wedge Victor Heads Fully ported, roller cam .720 & 1.6 Harland Sharps Rocks I bought from you (Bo) Indy 4500 intake, Gen 3 Dominator 1050 dynod @ 791-797 HP

 

[Lefty71]

Ah ya, 9.99 and you have to have a license

I learned that...... turned my rev limiter back down, and got right back to the big 10-0....

 

[Lefty71]

500 ci 440, 15.5 compression, Max wedge Victor Heads Fully ported, roller cam .720 & 1.6 Harland Sharps Rocks I bought from you (Bo) Indy 4500 intake, Gen 3 Dominator 1050 dynod @ 791-797 HP

Wow-wee that sounds swwweet, like maybe you shoulda got your racing license first lol. I got to the 9's with a lot less motor than that, although maybe a little lighter car, and maybe taller gear??? You know it's harder to slow them down than it is to build them up.

 

[dvw]

I saw the video. The front and rear rebound are WAY to loose. 5"-6" of travel should be plenty once the shocks get the rear housing speed under control. The shock only controls the speed of housing travel. With leafs the instant center is high and short. The car has a fair amount of power. With these parameters the reality is that it's going to throw the housing out of the car pretty hard. Tight rebound will slow the housing enough that it won't crush the tire and unload it. The front is coming up to quick as well. Hopefully the front shocks are adjustable.
Doug

 

[moparcrazy]

I saw the video. The front and rear rebound are WAY to loose. 5"-6" of travel should be plenty once the shocks get the rear housing speed under control. The shock only controls the speed of housing travel. With leafs the instant center is high and short. The car has a fair amount of power. With these parameters the reality is that it's going to throw the housing out of the car pretty hard. Tight rebound will slow the housing enough that it won't crush the tire and unload it. The front is coming up to quick as well. Hopefully the front shocks are adjustable.
Doug

Thank you Doug, the front shocks are coil overs set on the softest setting so ill start with one click and go from there, rears are set at 3 clicks and Caltracks recommended 6-7 clicks + on rebound, planning on starting at 5 clicks and adjusting from there, track is out tomorrow due to weather so maybe the weekend ill take more video and post the results, thanks again for your knowledgeable input, Jay.

 

[malex]

Seeing your problem took me back to last season, I had all the same **** and starred in videos just like you posted. Before I got things sorted out I lost a nice aluminum driveshaft, a yoke, u-joint, a bent calvert shock bracket and curled up my spring perches.
Doug has you on the right track though, he'll get you there.

For what it's worth, on my car, where I ended up to get it to hook most of the time was:
3200 RPM launch. Front double adjustable shocks set on 7, Rear double adjustable shocks set on full tight rebound and 14 compression. The extra front shock rebound helped settle things down lots.
What my car needed was the rear QA1 shocks re-valved stiffer to keep from throwing the diff out so hard. I was able to get some 1.38's with this set up, but if I turned up the launch it would go stupid right away. If your perches aren't boxed you had better check them real good with that power cause they will flatten out if not already.
Good luck!

Launch Problems


1.38 60’s - shock rebound added.

 

[moparcrazy]

Seeing your problem took me back to last season, I had all the same **** and starred in videos just like you posted. Before I got things sorted out I lost a nice aluminum driveshaft, a yoke, u-joint, a bent calvert shock bracket and curled up my spring perches.
Doug has you on the right track though, he'll get you there.

For what it's worth, on my car, where I ended up to get it to hook most of the time was:
3200 RPM launch. Front double adjustable shocks set on 7, Rear double adjustable shocks set on full tight rebound and 14 compression. The extra front shock rebound helped settle things down lots.
What my car needed was the rear QA1 shocks re-valved stiffer to keep from throwing the diff out so hard. I was able to get some 1.38's with this set up, but if I turned up the launch it would go stupid right away. If your perches aren't boxed you had better check them real good with that power cause they will flatten out if not already.
Good luck!

Launch Problems


1.38 60’s - shock rebound added.
View attachment 738694

malex thank you for the video & your input, 1.38's sure look nice compared to my 1.45 60'ft currently I'm running Calvert shocks in the rear with single adjustable QA1 coil overs in the front, launching @ 3000RPM, eventually would like to launch @ 3500rpm ? also thank you for the heads up regarding the perches, definitely going to take a look at them.

 

[malex]

malex thank you for the video & your input, 1.38's sure look nice compared to my 1.45 60'ft currently I'm running Calvert shocks in the rear with single adjustable QA1 coil overs in the front, launching @ 3000RPM, eventually would like to launch @ 3500rpm ? also thank you for the heads up regarding the perches, definitely going to take a look at them.

—-
YW. Yes when I was doing leap frog it was also 1.45 60’s.
You will get a handle on it, it’s going to take shock tuning though. IMO you have crossed that line with that big power and you need to control your suspension with good good shocks now. I spent lots of time with Calvert working on my problem too, they seem reluctant to say to tighten the shocks up. Seems that on our b bodies though it needs to be done when making lots of power. Lots of anti-squat in these cars.
Hopefully your perches haven’t started to bend yet. It’s easy to reinforce them now but once they start to curl then you will have a job ahead. Imagine that pinion angle changing as it rolls back during launch..
I also run about the same engine combo as you except less compression. I’m 12.8.

The right side curled
More than the left.

 

[Cranky]

Tuning the suspension, & at launch the car literally jumps up lifting all four wheels, comes down then front wheels pop up to a wheelie.
View attachment 736557 View attachment 736558

Man, been a long time since seeing a car do that lol. And if CT is recommending you put in 6-7 in the rears, I could rather go with that and then work down if it's too much. To me, that's being on the safe side of the pie and rather not break stuff stuff because things are still too loose.

—-
YW. Yes when I was doing leap frog it was also 1.45 60’s.
You will get a handle on it, it’s going to take shock tuning though. IMO you have crossed that line with that big power and you need to control your suspension with good good shocks now. I spent lots of time with Calvert working on my problem too, they seem reluctant to say to tighten the shocks up. Seems that on our b bodies though it needs to be done when making lots of power. Lots of anti-squat in these cars.
Hopefully your perches haven’t started to bend yet. It’s easy to reinforce them now but once they start to curl then you will have a job ahead. Imagine that pinion angle changing as it rolls back during launch..
I also run about the same engine combo as you except less compression. I’m 12.8.

The right side curled
More than the left.
View attachment 738931

Yup....reinforce them before hand is the best policy!! Years ago a buddy and I chased our butts with a set of CT's on a nose heavy Challenger and CT couldn't much help but I did convince my buddy to reinforce the spring mounts before they got bent. Anyways, we ended up throwing ladder bars on the thing and it responded very well with a basic setup and then went on to running 9.30's with a small shot of the funny gas.

 

[malex]

Man, been a long time since seeing a car do that lol. And if CT is recommending you put in 6-7 in the rears, I could rather go with that and then work down if it's too much. To me, that's being on the safe side of the pie and rather not break stuff stuff because things are still too loose.



Yup....reinforce them before hand is the best policy!! Years ago a buddy and I chased our butts with a set of CT's on a nose heavy Challenger and CT couldn't much help but I did convince my buddy to reinforce the spring mounts before they got bent. Anyways, we ending up throwing ladder bars on the thing and it responded very well with a basic setup and then went on to running 9.30's with a small shot of the funny gas.

—-
One fast guy told me: Yup, we’ve all been there. He was referring to this exact problem and nope it wasn’t Cranky.
Hoping to have similar results with my new ladder bars on the 64 as Cranky did and my Calverts found a new home too.

 

[Mike Gaines]

Thank you Doug, the front shocks are coil overs set on the softest setting so ill start with one click and go from there, rears are set at 3 clicks and Caltracks recommended 6-7 clicks + on rebound, planning on starting at 5 clicks and adjusting from there, track is out tomorrow due to weather so maybe the weekend ill take more video and post the results, thanks again for your knowledgeable input, Jay.

To repeat my earlier postings:
Every thing below was with my Cal Trac 90/10 front shocks.
My typical 60' was 1.40 to 1.42 and car went consistent 10.16-10.17. Cal Trac single adj Shocks set on 1 as per cal trac recommendation for trans brake car.
I took 92lbs out of the car (from the rear axle back) with glass deck lid and other steel stuff out of the trunk.
Pulled up to the line with same setup as my 1.40 to 1.42 60' setup....3600 chip & shocks set on 1 and it just blew the tires off the car.
Talked Cal Trac, they said to put the shocks on 3.
I put the Cal Trac single adj shocks on 7.
Pulled up to the line and clicked of a 1.39 60' and went 10.06.
Next run I clicked of a 1.37 60' and went 10.04.
The suspension liked the stiffer extension and allowed the car to launch.
The better 60' and the 92 lb weight savings took the car from 10.16 to 10.04.
Made me a happy man.

 

[moparcrazy]

To repeat my earlier postings:
Every thing below was with my Cal Trac 90/10 front shocks.
My typical 60' was 1.40 to 1.42 and car went consistent 10.16-10.17. Cal Trac single adj Shocks set on 1 as per cal trac recommendation for trans brake car.
I took 92lbs out of the car (from the rear axle back) with glass deck lid and other steel stuff out of the trunk.
Pulled up to the line with same setup as my 1.40 to 1.42 60' setup....3600 chip & shocks set on 1 and it just blew the tires off the car.
Talked Cal Trac, they said to put the shocks on 3.
I put the Cal Trac single adj shocks on 7.
Pulled up to the line and clicked of a 1.39 60' and went 10.06.
Next run I clicked of a 1.37 60' and went 10.04.
The suspension liked the stiffer extension and allowed the car to launch.
The better 60' and the 92 lb weight savings took the car from 10.16 to 10.04.
Made me a happy man.

Mike as always thank you for your input, where does the car weight in now?

 

[Mike Gaines]

Mike as always thank you for your input, where does the car weight in now?

On the start line with 4 gal gas and me the car weighs 3508lbs.