vanillagorilla

iTrader: (1)

Here's a screen shot of a sketch I did of an ECSB truck. Everything is labeled and the dimensions were taken from my truck. All CG dimensions are estimates since I've never had actually figured out where it is. It'd proababy pretty easy though. They're educated guesses though.

Also these dimensions will be different for every truck. If you would like to pm me YOUR dimensions, then I can figure the IC location and antisquat value for your truck. I need your front leaf height, tire height, front AND rear caltrac location and how much its lowered front/rear. It's an estimate, but at least we can compare why other's trucks hook better.

So my truck has an IC behind the CG, which is probably not ideal for a nose heavy vehicle, and it's at 35" where it crosses the front wheel centerline. 35/28=1.25 or 125% anti-squat. I'm not sure if that's too much but....?

RandomHero

iTrader: (24)

So I went and bought an angle finder today and realized my angles really aren't that horrible.

Keep in mine my rear tires were on ramps so the angles may seem a bit screwy.

These are in relation to the ground

Transmission angle-180*
Front driveshaft angle-180-181*
Rear driveshaft angle-179(angling down from back to front)
Pinion angle-178(angling down from back to front)

Hopefully that makes sense. I also tightened the hell out of my long bars, but I'm worried if what the consequences of that might be for a daily driver. I don't want there to be no articulation in the rear suspension and rip off a mount.

I also picked up some v6/m5 front coil springs. I've heard they should help with weight transfer so we shall see.

silver-mod-o

iTrader: (15)

Your long bars will suffer the same fate as mine, loosen them up... Since all they are is for anti-wrap, they only need a small amount of preload. Just enough so they don't rattle so bad. Mine were so tight they actually shoved the mount forward off the frame... Just FYI.

RandomHero

iTrader: (24)

Right now they are as tight as I can get them tightening by hand. Should I back off some? This is with the truck under its own weight too.

I looked around a bit online but didn't come up with much.

silver-mod-o

iTrader: (15)

You loosened the jam-nuts on the rod ends and tightened the bars by hand and lengthened them?? If so, you'll be fine.. I tightened mine with a 24" pipe wrench

RandomHero

iTrader: (24)

LOL, ok that makes me feel better. Yes I did exactly that. Loosened then first with a wrench then twisted them by hand until they wouldn't move any more and tightened the nuts by hand again.

Thanks Ben for the help. Now I just need some drag radials to see if I can ever drop into the 1.xx 60' times.

AKlowriderZ71

iTrader: (22)

Okay, so if I'm reading this correctly, your pinion angle (relationship of the rear half of driveline to the pinion yoke) is only 1 degree. So when you accelerate hard from a stop, and the pinion gear climbs the ring gear, and you get a little bit of spring wrap, your pinion angle goes negative. Two things happen now.

1) You get a vibration(launch shudder).
2) Your leaf spring rebounds from the spring wrap, and unloads your tires. Traction is lost.

Your longbars may be helping to prevent wheelhop, but this is where Cal-tracs are superior. They work to prevent the spring wrap when launching.

I'm gonna suggest that you add shims, target 3-4 degrees of pinion angle. You want the pinion yoke pointing more towards the ground.

RandomHero

iTrader: (24)

I had a bit of a breakthrough last night....

I've been able to all but completely eliminate the vibration. I messed around with tightening the bars up last night and there is almost nothing. I'm running 4* shims right now, but I think I'm going to try and run some 6* shims and see where that puts me.

One thing I will say is that these longbars don't have the articulation that caltracs do. With them tightened up I can hear a few moans and groans when daily driving it, that are scaring me. I'll probably back them off a turn or two until I don't have to worry about them ripping the mounts off. I will say the guy who did them did a fantastic job with the welds though so I'm more worried about the frame twisting than I am tearing the mounts off.

AKlowriderZ71

iTrader: (22)

It would be smart to run those bars looser. Especially daily driving. Cranking them tight is probably adding pinion angle, which is helping your vibration. However, it is bending(loading) your springs. That stored energy is constantly being pushed through those longbars. Something will give. I would guess that it is also hurting your traction rather than helping it (too much preload).

RandomHero

iTrader: (24)

Like I said earlier they are tightened by hand with the truck on the ground so there is no preload, but there is no articulation in the rear end. I'm just hand tightening them, but as the suspension cycles there is no shackle to pivot off of so the axle is pulled forward when I hit a dip.