rear end trouble at the drags

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vkute265

vkute265

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hey all,
i recently took my valiant ute out to the track and finally got it to hook with a 1.67 60 foot but once it stood out of the hole i could feel it loading and unloading the rear tire, ill post a link for a vid if you want the start a couple of times you can see it. it didnt feel right in the car.

the rear end is leaf sprung with caltracs and competion engineering 3 way adj shocks
the rear springs are like 7 leafs (they are getting changed because the top leaf is bent) i have a 4 leaf pack which will be going back in
pretty sure both rear shocks are set at 50/50 and caltracs are set at the 1/4 turn preload they recommend you start at and in the bottom hole

will changing the springs to a softer set help?
do i need more preload on the spings

i run 275/50/15 mt e/t street/drag radials at 16psi

and thoughts or opinions would be awesome
thanks
Ash

[ame]http://s893.photobucket.com/albums/ac134/dvs265ap6/warwick%20drags%202012/?action=view&current=P5060595.mp4[/ame]
 
Hey Ash,what type of rear do you have?Sure-grip?Were you hooking,then spinning,then hooking again??Maybe your rear clutch pack is worn?
 
pettybludart said:
Hey Ash,what type of rear do you have?Sure-grip?Were you hooking,then spinning,then hooking again??Maybe your rear clutch pack is worn?
Click to expand...

It's a 8 3/4 with a factory sure grip and Richmond 4.10 gears, I had probs with traction but bigger skids and bit more tire temp helped, but it did sorta feel like that in the car, but 60 foot sorta says otherwise I think. just didn't feel right and the whole drivetrain is new to the car so still dialing it in, but I'm 19 yr old and after advice to help
 
Do you know what carrier you have(center section)the last 3 numbers on the drivers side of the center section will be either 741,742 or 489 this will help identify wether it,s a clutch type or cone type sure-grip.They can both be rebuilt(new clutches for clutch type)and machining on the cone type.Your rear might be wearing down and causing limited slip(1 wheel spinning after launch)Just a thought..Can you give us a breakdown of your setup engine,trans,torque convertor and ages of each.:thumleft:
 
pettybludart said:
Do you know what carrier you have(center section)the last 3 numbers on the drivers side of the center section will be either 741,742 or 489 this will help identify wether it,s a clutch type or cone type sure-grip.They can both be rebuilt(new clutches for clutch type)and machining on the cone type.Your rear might be wearing down and causing limited slip(1 wheel spinning after launch)Just a thought..Can you give us a breakdown of your setup engine,trans,torque convertor and ages of each.:thumleft:
Click to expand...

its a 489 case,
its a 318/392 stroker with eddy heads. solid cam, 11.6 comp forged bottom end etc, trans is a 727 full man, t/c is a bdr convertor (never again) had to be fixed by a local shop 2 weeks ago but we wont go into that, 4000stall, engine trans and t/c were all new and put in last christmas, diff chunk i bought as a unit second hand.
car ran a 7.58 at 91mph over the 1/8th

doesnt pull left or right its dead striaght out of the hole, and doesnt apear to nose over as it would if one wheel was spinning
 
Perhaps the heavy springs and cal tracs are fighting? I know they say not to run Cal Tracs with SS springs and yours sounds even heavier then that.
 
You need better shocks than those C/E 3 ways.

Porpoising is usually a shock control issue.
 
I also had the same porposing problem when I first added my CalTracs with XHD leafs.I swapped to the mono-leafs,problem solved.My 60fts are 1.44 and hoping to get lower this season.:D
Oh I,m also running 1 full turn preload with the Caltracs and QA-1 12 way adj. shocks.
 
putting the 4 leaf springs in should help out a bunch. maybe even take the smaller/shorter leaf out out too. caltracs want a leak spring to operate correctly, just enough spring to hold the hotrod up.
 
went out to our local 1/4 mile track on saturday, i changed the springs to a 4 leaf pack and it made a huge differnence alot smoother out of the hole and i ran a pb of 11.65 at @114 engine is a 318/392 stroker

post-10-1340462937612093871.jpg



couple of links

http://www.dragphotos.com.au/p109500114/efb6d381#hfb6d381

http://www.dragphotos.com.au/p109500114/e138009e5#h138009e5

heres one to compare ride height to launch
lots of suspension travel hooks well

launch.jpg
 
this is still street driven, drove it 150 odd km to a car show and back the next day.
im unsure how the mono's would be on the street
 
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