Starting line traction

[93V8S10]

Hi, I'm new to this forum, and looking for some advice.

I have a 93 S10 Pu short bed, that is a street/strip truck with full street equipment. It puts out about 360HP currently with restrictive exhaust. The suspension mods so far are:

FRONT
removed sway bar
4cy springs
3 way adjustable shocks, set 90/10
polyurethane bushings

REAR
8.8 axle
overload springs removed (3 spring pack)
polyurethane busings
home made Caltrax bars
88 Buick shocks
28X10 slicks

The problem I'm having is with starting line traction. On initial launch the tires start to bite but spin like one or two revolutions, then it feels like the rear raises slightly then spins some more, approximately 4 to 6 revolutions, then it bites, transfers weight and goes.

I've had this problem for a while now, I've tried a few things but with no success. The only thing that has worked is 150# of weight. I am hoping not to go this rout.

Any ideal as to what direction I should go next?

[motocrosschris]

do you have a stock tank or a fuel cell, keeping the fuel further back would help, moving the battery to the bed will help a little too

[93V8S10]

do you have a stock tank or a fuel cell, keeping the fuel further back would help, moving the battery to the bed will help a little too

Still use stock tank, battery under bed in front of right wheel.

[Rickracer]

I'd recommend moving the battery to the very back, just ahead of the bumper for starters. Can you post any pics of it? How much air in the slicks? Gear ratio? Converter stall speed?

[RayL]

rear shocks are to loose.

[WRKTRKFROMHELL]

do you have a vid of a pasa? or pics of your bars? what 60's are you pulling?

[tyler87]

putting weight in the back, wont really solve your issue. it sounds like a setup issue. need more info. like do you have a posi, and is it working, tire psi, stall speed. and what is your pinion angle set at. there are guys out there pulling the front tires 2ft or higher off the ground, with leaf springs, and on the weight of fuel, and a battery in the back, Also do you have any pics of your homemade cal-tracs..

[WRKTRKFROMHELL]

I'm with tyler87.your home mades MAY have a design flaw causing the hop.The vid will also tell you what the trk is doing.my trk with the 380hp/3.08's would 2.0 60' on hard junk 245/60-15's & 1.80 on slicks with clamp on slapers.and 1.64 60's with the 406(I know it's lazy )

[s10ls1]

rear shocks are to loose.

I'll agree, sounds like your rear suspention is callapsing.

[93V8S10]

Thanks for all the response, I really appreciate it.

I'd recommend moving the battery to the very back, just ahead of the bumper for starters. Can you post any pics of it? How much air in the slicks? Gear ratio? Converter stall speed?

do you have a vid of a pasa? or pics of your bars? what 60's are you pulling?

I,ll check on moving the battery, but I don,t think that there is enough room unless I lose the spare.
Sorry I don't have any pictures, I don't have a digital camera. Also I don,t have any videos either, I really wish I did, I know that could answer a lot of questions. I've asked friends to take some videos, but they didn't really understand what I was looking for and the videos turned out to be useless.
I normally run between 10# and 12# in the slicks, depending on track conditions.
3.73 rear axle ratio, 2200 stall, I normally leave at 1600 RPM, 1800 pushes thorough lights, 1400 and below hits the tires too hard.
My normal 60' times are in the 2.050 and 2.080 range.

putting weight in the back, wont really solve your issue. it sounds like a setup issue. need more info. like do you have a posi, and is it working, tire psi, stall speed. and what is your pinion angle set at. there are guys out there pulling the front tires 2ft or higher off the ground, with leaf springs, and on the weight of fuel, and a battery in the back, Also do you have any pics of your homemade cal-tracs..

Rear axle is a 8.8 from a 94 Explorer, it has the factory limited slip, I replaced the clutches not long ago. I had the starting line guy watch, he said every thing looked fine. Also I can see smoke from both tires in the mirrors.
Pinion angle is 1 degree down from trans angle. I know thats very conservative, but was done for smoothness on the street.
Hears a link to the plans I used for the CalTrax bars http://www.hotrodsandhemis.com/Traction.html

I'm with tyler87.your home mades MAY have a design flaw causing the hop.The vid will also tell you what the trk is doing.my trk with the 380hp/3.08's would 2.0 60' on hard junk 245/60-15's & 1.80 on slicks with clamp on slapers.and 1.64 60's with the 406(I know it's lazy )

I can agree with that. When I first installed them I put preload on the bellcrank, but the truck road like it had no suspension, so I loosened them until they barley touch at ride hight. I thought this might be a problem, so I took measurements of everything at ride hight, full compression, and at full drop. In intend to make a full size drawing of the suspension but haven't had time yet. The CalTrax design is new for the truck, before I had just the bar from the spring plate up to a bracket welded to the frame. I know that will be hard to visualize, probably the easiest way to explain is to picture a CalTrax without the bellcrank up front. I had the same problem then.

rear shocks are to loose.

I change to the Buick shock when I installed the CalTrax bars, before I had HD S10 shocks.

I'll agree, sounds like your rear suspention is callapsing.

Shouldn't it compress for weight transfer?
It has always felt too stiff in the rear to me. I have always thought that I needed softer springs and shocks. Am I wrong?

Another thing I have been thinking about is getting taller front springs. I was hoping to raise the front about a 1'' to 1 1/2'', thinking this would raise the CG and allow for more weight transfer.

[RayL]

93v8s10
Not trying to hurt anyones feelings or be rude but there are alot of folks who REALLY don't understand how front and rear suspension work, or should work. Weight is a crutch for a improper set up. You want your rear shocks as tight as possible. The tighter the shocks the more the rear axle is pushed into the ground. If it still spins then move to the front. In slow motion the bed should rise and the tire drop when it leaves. This seperation tells you the rear end is being pushed into the ground and that whatever type of lift bar your using is lifting and getting the front up and weight to the rear. If you had a chevelle or nova then yes your rear shocks could get to tight but not with a pickup. If your soft in the rear then no weight is being put on the rear end, its being soaked up by the shocks compressing. You should move the battery to the rear. Not for the rear weight but to lighten the front up. To give you an idea and prove it can work this is a buddys truck that has 40 dollar comp. engineering shocks all the way around with slide a links. Its adjusted somewhat proper. Runs 6.0s and 60 fts 1.36-1.40 every single pass. IT don't EVEN HAVE A TAILGATE

http://videos.streetfire.net/video/8676 ... 77a7ec.htm

[sds10racer]

you might not want to hear this, but you need to go watch mopar with leaf spring leav the line. they look like they just jump up off the line and move forward at the same time. all leaf spring suspensions are the same in their design. if you want a hard leaving s10, look and ask those guys what they do.

[406shark]

you might not want to hear this, but you need to go watch mopar with leaf spring leav the line. they look like they just jump up off the line and move forward at the same time. all leaf spring suspensions are the same in their design. if you want a hard leaving s10, look and ask those guys what they do.

Mopars typically use "Super Stock" springs. They are designed for drag racing. They have a stiffer front half of the spring pack. They work great, but there are better idea's these days. A lot of the Mopar guys are using Caltracs, but Calvert Racing does not recommend using super stock springs with the Caltracs. One of the tricks of the Mopar world is a pinion snubber. It mounts to the front of the rear axle and has an adjustable rubber snubber that contacts the underside of the body upon accelerating. It stops the pinion from going up, much like traction bars do.

Jeff

[93V8S10]

93v8s10
Not trying to hurt anyones feelings or be rude but there are alot of folks who REALLY don't understand how front and rear suspension work, or should work. Weight is a crutch for a improper set up. You want your rear shocks as tight as possible. The tighter the shocks the more the rear axle is pushed into the ground. If it still spins then move to the front. In slow motion the bed should rise and the tire drop when it leaves. This seperation tells you the rear end is being pushed into the ground and that whatever type of lift bar your using is lifting and getting the front up and weight to the rear. If you had a chevelle or nova then yes your rear shocks could get to tight but not with a pickup. If your soft in the rear then no weight is being put on the rear end, its being soaked up by the shocks compressing. You should move the battery to the rear. Not for the rear weight but to lighten the front up. To give you an idea and prove it can work this is a buddys truck that has 40 dollar comp. engineering shocks all the way around with slide a links. Its adjusted somewhat proper. Runs 6.0s and 60 fts 1.36-1.40 every single pass. IT don't EVEN HAVE A TAILGATE

http://videos.streetfire.net/video/8676 ... 77a7ec.htm

No feelings hurt hear. Looks like I've been going about this rear suspension thing backa$$wards. So hears my new plan of attack:
1. Reinstall overload springs.
2. Reinstall HD S10 shocks.
3. Keep current CalTrax design lift bars. Previous bar design didn't provide lift, just prevented wheel hop.
4. Test.
5. If necessary install taller springs up front to raise CG and help counter the nose heavy weight of the street equipment.
6. As money and time allow, work to lighten front end.

Your buddy's got a nice truck, and dam$ quick too. I've known it should work, and have seen lots of other S10's work. Just haven't been able to get mine to work. Hopefully now I can. I'll get started on the work above as soon as I can and be ready in March to go back to the track. When I get some runs in I'll post back hear with some results.

Thanks for all the help!

[RayL]

leave the overload spring off...it don't do anything unless you sit on the tailgate. Loose front shocks and stiff rear ones. post some pics of your caltrac setup. raising the front is another crutch. If its loose and light enough it will have no problem getting the nose up.

[tyler87]

sorry man your right. I don't understand

[RayL]

sorry man your right. I don't understand

then hang around you might learn something.

[WRKTRKFROMHELL]

1st; if the rear is too stiff the rear will SKATE & not go anywhere.
2nd;for a trk with 28x10 stickies & a 2.0 60' its too slow(no harm ment) to need a weight transfer.
3rd;ITS A TRUCK.the rear needs to squat some.
http://media.putfile.com/slow-stangfast-trk
This is my trk 3400lbs battery in stock loc 28x10.5ET's
4th; the front needs to be able to LIFT to transfer WT.
I got sound but no vid on street-fire(?).
if this guy is running 6.0's-6.20's he has transfered wt.set up for a 8.0 trk & a 6.0 trk is like comparing a rare steak to a welldone steak.

[tyler87]

then hang around you might learn something.

u funny

[s10ls1]

Most people that say squat really don't know what is happening when they see a vehicale transfer weight correctly. Squatting is really the rear suspention callapsing or rear tires trying to come off the ground from POOR suspention setup.