No traction

[C10Blackout]

So I got my 71 c10 back up and running. We had a nice day out at the local drag strip, so I figured I would take it out for a couple passes.

The truck is a LWB lowered 4 inches in the back and 3.5 in the front with drop spindles. Nothing overly special about the motor. 355, mild can, stock heads, air gap intake. 2400 stall on a th350 trans. If my math is right it has 3.08 rear gears. Nitto NT555r's on 18psi(10.5ish inches wide)

Well I know posi is going to be my next course of action cuz my rear driver tire smoked down the track, but in the mean time I figured I would get some advice. I went a 15.9 smoking the tires all the way down the first pass. Rolled in the 2nd pass instead of launching and went a 15.6. And the final pass I launched and attempted to feather and still only could pull a 15.6 again.

What can I do to get better traction? I have an anti squat kit in the garage that I haven't had time to put on the truck(came with it), but I think that will only help so much. Just looking for some advice. Not trying to spend crazy amounts of money, but something I can build towards. I'm not looking for 9's in the quarter, but I'm not trying to be slow either.

[bhayes1]

"spinning ain't winning"

Gotta get rid of the 1-Legger if your on the track.

[C10Blackout]

Posi is definitely my next course of action. But I feel like it just keeps getting worse from this point on. Don't know to much about posi or rear ends. Still use to front wheel drive vehicles. Odds are I'm taking it to the local performance shop for the rear end work.

[custom10nut]

You have no weight in the rear. No weight, no traction. That coupled with the one wheeler, and you lay a lot of rubber on the track without low e.t.s.

[Mike C]

It needs some gear, too. Lower numeric gears put more torque to the back wheels, but they also let you modulate wheel spin MUCH better. Once those Three-Ohhs start spinning, it's all over. 3.73 posi would make the truck MUCH faster and easier to drive.

What kind of mile per hour were your passes?

[C10Blackout]

Originally Posted by Mike C

It needs some gear, too. Lower numeric gears put more torque to the back wheels, but they also let you modulate wheel spin MUCH better. Once those Three-Ohhs start spinning, it's all over. 3.73 posi would make the truck MUCH faster and easier to drive.

What kind of mile per hour were your passes?

Mid-high 80s. The truck moves once I get traction.

[Mike C]

You make enough power to get in the mid 14's if you hook it up. Posi, gears, weight on the back.

Lowering the back further or raising the front for strip work will help with weight transfer.

[C10Blackout]

Originally Posted by custom10nut

You have no weight in the rear. No weight, no traction. That coupled with the one wheeler, and you lay a lot of rubber on the track without low e.t.s.

I do have a 22 gallon fuel cell I plan to put in the bed. When the truck sits it leaks all the fuel out all over my driveway and garage.

[GASoline71]

I wouldn't do anything else until you get a limited slip or a locker in that rear end.

Gary

[special-K]

Start with posi and go from there. That is a perfect time to also swap ratio to one you chose after some research on results from others. 3.73 gives a tad less grunt (but still good) and more top end vs 4.10s. Gotta figure out what you need the most.

[James the III]

START with looking and measuring the pinion angle You lowered the truck the pinion angle most likely is way off..
Adding a posi will not help you if the pinion angle never "loads" the tires.
Seems many don't drag race or forgot how to..

[Mike C]

If you just drive around town and a tow to the strip, I'd do 4.10. Especially if you have a 28-30" tall rear tire.

Small blocks like gear.

[C10Blackout]

Originally Posted by James the III

START with looking and measuring the pinion angle You lowered the truck the pinion angle most likely is way off..
Adding a posi will not help you if the pinion angle never "loads" the tires.
Seems many don't drag race or forgot how to..

I don't know much about rear ends. That would be something I would probably have a professional do,as well as any changes I would want to make. I can do motors, but rear ends I have never learned.

[Mike C]

Originally Posted by James the III

START with looking and measuring the pinion angle You lowered the truck the pinion angle most likely is way off..
Adding a posi will not help you if the pinion angle never "loads" the tires.
Seems many don't drag race or forgot how to..

Pinion angle can certainly play a role, but for a 275-300 whp street vehicle it is just one part of the dynamic. It's never going to hook up with a single track and needs gear to ever be very good at launching. Too many of the coil spring trucks are dropped varying amounts and do hook up without altering pinion angle for this to be a cure all.

Worn out bushings in the trailing arms as well as ineffective shocks are better places to spend time/energy while the housing is out getting gears.

[James the III]

Originally Posted by Mike C

Pinion angle can certainly play a role, but for a 275-300 whp street vehicle it is just one part of the dynamic. It's never going to hook up with a single track and needs gear to ever be very good at launching. Too many of the coil spring trucks are dropped varying amounts and do hook up without altering pinion angle for this to be a cure all.

Worn out bushings in the trailing arms as well as ineffective shocks are better places to spend time/energy while the housing is out getting gears.

Anytime I've changed gears.. going to a steeper set 3.73/4.11/etc
it only made a traction issue worse.. 2 tires (posi) with a pinion angle that never loads the tires. will just spin, like the peg leg.. only now it's slides sideways.. looks cool, but doesn't get you moving
In a truck with nothing over the rear tires.. the pinion angle and instant center means EVERYTHING..
Could not ask for longer ladders to leverage off of.. but you need the correct settings.. the lowering it.. did it no favors here.. the pinion angle and long arm mounting points need to change..
Posi will help.. but not where I'd go first.

[special-K]

When my shortbed is done I will have a matched set of tires on 8" wheels so I can rotate and put miles on and a pair of 10" wheels with biggest drag radials that fit for the track and local fun. I have had many of these trucks lowered 4-6" in the rear that retained a healthy driveline angle. Around 4" lined up straighter than stock. I run a 1pc driveshaft. Angle is definitely a thing to consider, but if you want to run the strip, posi rear is surely what you "need" whether your angle needs correction or not

[C10Blackout]

Okay I will get a call in to a shop today and see what I can set up.

[bhayes1]

START with looking and measuring the pinion angle You lowered the truck the pinion angle most likely is way off..
Adding a posi will not help you if the pinion angle never "loads" the tires.
Seems many don't drag race or forgot how to..

I knew everything there was to know about drag racing after I was half way through the first season of street outlaws, gas monkey, etc. :metal lol No but seriously.

[James the III]

Originally Posted by bhayes1

I knew everything there was to know about drag racing after I was half way through the first season of street outlaws, gas monkey, etc. :metal lol No but seriously.

[C10Blackout]

I'm for sure going to replace my trailing arm bushings. I'm having trouble finding a good set of shocks for a 4 inch lowered setup. Any leads?

[mikey531]

For now pump up your front tires to 45 or 50 lbs. ( don't forget to letthem back down ) Have someone look at the burnout and make sure you are using the whole tire when you launch. You may have to even add air to the tire to get it to use the total width of the tire. If you let out too much you are just using the sides of the tire. Don't shock the tire on launch do you have a line lock on the truck? That will help with staging.

[Mike C]

My truck is a leaf spring truck with a flip and re-drilled stock upper mount in the rear where I used stock length front shocks so I'm not the guy to ask! But the Bilstein 5100 (zinc bodied shock not yellow painted) is where I would spend my money.

Originally Posted by C10Blackout

I'm for sure going to replace my trailing arm bushings. I'm having trouble finding a good set of shocks for a 4 inch lowered setup. Any leads?

[C10Blackout]

I don't have a line lock just a 2400 stall. I have a set of just stock replacement shocks on the front. Would new front and rear shocks make a huge difference? Cuz if so I'll be looking for some ASAP while I have it on the lift.

[CST10]

Throw an old water bed mattress in the back filled about 1/3.

When I did that with my 70 it went from 15.1 to 14.2 in the 1/4 mile with 3.08 gears and a 1 wheel peeler. Lol.

[HO455]

Lots of good input here. Just thought I should tell you anti-squat modifications are for road handling not drag racing. You want the rear end forced down under acceleration for better traction. (This wont happen until you get a certain amount of traction, so take care of some other things first.) That is one reason those exotic sports cars do poorly at the drags, they have lots of anti-squat. You can do one or the other well, but not both. The cheapest and easiest thing is learn how to drive the truck out of the hole with the traction you have. This is something every drag racer learns, from John Force on down. John Force wins fans with burnouts not races. With the rear gears you have once the wheels are spinning they are not likely to stop, so take it easy at the start. I used to run 13.70's in my GTO with 2:75 rear gears (@ 106 MPH) on L-60 street tires. Its lots of fun to pass them on the top end.