caltrac problems

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hotrod68

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The car will hook hard and as soon as the front end comes up about 3 inches off the ground I can feel the tires trying to break loose and by the looks of the video causing the front to come down instantly and the rear tires to bounce, any help? I've tried the shock settings every way but totally loose, and have tried the bars at so many different load settings I've lost count, I even moved the bump stops down to get more front end travel. The car is my 69 dart doing 1.44 60 foots and went 10.06 @ 132, I'm starting to wonder if I need a wider tire? Its a 9 inch slick now, Any thoughts would be great. I only have 1 weekend left to try to figure this mess out. I cant seem to figure out how to upload the video on here for you guys to watch.
 
What shocks are you running, settings? What hole are the bars in? Front shocks, settings? Try slowing the front end down, stiffen the extension on the rear shocks and the bars in the bottom hole.
 
justinp61 said:
What shocks are you running, settings? What hole are the bars in? Front shocks, settings? Try slowing the front end down, stiffen the extension on the rear shocks and the bars in the bottom hole.
Click to expand...
calvert shocks all the way around, fronts are 90/10s, rear I've tried 4 all the way to 9 and the bars are in the bottom hole, if I leave of idle it's not terrible but when I try to leave at any thing over 2 grand or on the 2 step it comes up real fast and then wants to loose traction and bounce
 
Try about 7lbs.in the slicks. If it has a snubber,leave a gap between it and the chassis,about a couple of inches. If the car still has factory leaf springs,make sure all leaves in front of the axle are clamped together. If it has the Calvert mono spring,this doesn't apply.
 
hotrod68 said:
I cant find any info on how to post a video
Click to expand...
Post your video to youtube and then put a link to it in your messages.
If you hook and then spin, your tires are rebounding (bouncing).
if back tires are bouncing you may have too much hit or too little tire pressure or both. My car does a 1.41 60' leaving off idle and I have to put 13 lbs. in the slicks to keep it from bouncing and then adjust the shocks to that tire pressure. A lot of people think lower pressure = tires will grab better, but not always the case, especially with leaf springs that raise the back end under load rather than lower it.
If you are in the 10's in a door car and you want to try 7 or 8 lbs., you'd better have some damned good steering components and chassis set up right or it will take you into the wall or worse, and it will happen at the big end.
I run 29"x12.5"x15 Hoosier slicks.
I started at 10 lbs. and went up 1/2 lb. every pass until I found where it hooked the best. Tried 9 lbs. once and it was very hard to control at the big end.
 
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You need a better shock. The last time I tried low air pressure in a smaller slick I got a good look at the wall out of the windshield at about 500' out.
 
I've been watching this video over and over and my thought is that the front end is coming up so fast in this car that it is unloading the rear tires so I think you are right justinp61, what would be a good adjustable shock for the front end to slow it down and keep the weight transferred to the rear end longer?
 
I have heard several people say the Calvert 90/10 is too loose, I've never ran them though. I have been in the high 1.30's on Competition Engineering 3 way adjustables and Rancho 9 ways. That being said I have replaced the Ranchos with Viking double adjustables and will replace the fronts with Vikings. I don't have the new engine/shock/carb/converter set up sorted out yet, but I'm hoping for some low 1.30' 60' and 6.30's in street trim on pump 93.

IMO if you are going 10.0's with 1.44 60' you have the power to go pretty deep in the 9's, I'd put a good shock on it.

Rod Ends, Shocks, and Springs | Viking Performance
 
I had trouble with the car doing the same thing
front coming up to fast
calverts on the front
took the heim joint a arms off/ went to stock rubber
to help slow, front end movement
1.56 to 1.44 60'
6.78 to a 6.64 et

edit> I posted the above about the front travel, causing my car to "leap Frog" and unload the rear
I have Rancho 9 ways,
no Caltrac,
custom leaf spring pack
069_zpsyctaiyf2.jpg
 
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............My car runs a 10.37 with a 1.451 60 doesn't spin at all.......still have a factory replacement shock on the front.....kim....
 
Finally got everything working together, took it out today and got the 60ft times down to 1.36, 1.37 and another 1.36 only got to make 3 runs, got rid of the calvert 90/10 front shocks, went with some adjustable QA 1s and raised the air pressure in the rear from 12 pounds to 16 no more bounce, with alittle more shock and cal trac tuning I should see some 1.33 or 1.34's
 
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