Anti Squat and Suspension Tech

[Mnster]

Originally Posted by EeePee

The tires are spinning the wrong direction.

Tires are spining the right way, the axle case rotates back under power.

[EeePee]

You originally posted that at 3:49.

[Mnster]

Yeah I know I just had to think it through again to make sure I was right.

[hairba11]

ok, so i took a shot of my wip, and I think I can lable the lines I drew on it, and it looks like it should be fairly neutral, but I get some wicked torque twist.
Here is the shot.


Here is the link to a blank if someone wants to make suggestion
http://i137.photobucket.com/albums/q...1/P4140272.jpg

I tried to color code the lines to make it easier

[EeePee]

Your diagonal blue line represents the line of force. It needs to intersect the blue vertical line drawn through the front hub at the height of your center of gravity, the green line.

Now look where your two yellow lines are. Besides the fact they probably intersect about 5 feet in front of the truck, that point is below the line of force and that means your truck squats.

[hairba11]

so i changed the mounting point of the lower link axle side to bring the IC? in.

this should be more stable because everything intersects?
dang this head cold slowing me down.

it would also get the lower link down further to protect teh driveshaft more

[EeePee]

Here's your correct lines, based off of your guess as to where the chassis CG is located.

What is really hurting your truck is the very high CG.

[hairba11]

so would I need to try and get the cg in between the yellow link lines where they intersect the blue vertical at the front hub? like put the battery on top of the front upper links and clocking the motor out the side the requisite 90-95 degreese?
I may have to play with the chassis anyway once I get the 96t spur.

or just saying fudge it torque lean is good for you

[JohnRobHolmes]

Torque twist and squat are different items to deal with. You need to lower your chassis CG closer to the roll center (a whole nuther can of worms). Step one would be to remount your battery on the front axle or find another low spot for your battery.

[EeePee]

Originally Posted by johnrobholmes

Im gonna guess you get a bunch of squat when you peg it.

Originally Posted by raptorman57

You are correct

Check this out.

Random guess for chassis CG. 2/3A battery pack fit between frame rails in front. CG might be a little higher, maybe not...

[hairba11]

so even if I moved the shock mounting points up, it wouldn't really help because even tho the CG is lower, the links are now level and not pointing up and they still cross under the force line. and the tranny can drag.
hmmm

[Mnster]

I tried jacking with the links last night for hours on end with no change. I tired lowering the upper links no change. I tried a asmetrical setup no change in the amount of torque twist at all. The rear just has a lot of torque twist making it seem as though the rear suspension is rising but it's not best I can tell. The rear wrenchs over causing the truck to three wheel up a hill no matter what I do. There is zero torque twist in the front.

[EeePee]

Originally Posted by Mnster

The rear wrenchs over causing the truck to three wheel up a hill no matter what I do.

Time to look for stiffer springs then.

[JohnRobHolmes]

Or raise his roll center. If the rear upper link was raised on both axle and chassis it would help. I think triangulating at the chassis instead of the back would also change the twist, but I cant even start to guess how.

[carmatic]

yes, making the axis of rotation of the axles different from the axis of the center driveshaft, would cause the driveshaft to push against the links that hold the center of rotation of the axles, rather than push the wheels up and down... well you'll still get torque steer but to a lesser amount, and you'll get a kind of 'articulate steer' because your whole vehicle is moved side to side from the articulation

have you considered changing the pinion angle? like, instead of the pinion facing straight away from the center tranny, it is angled slightly upwards (i.e.facing away from the ground)...as in, remount your axle so that the driveshaft points downwards, and the joint in the shaft will be at a steeper angle
what this causes is it makes the torque from the driveshaft rotate the axle at an angle that is incompatible with how the links make your axles rotate... it would push and pull the links instead of raising and lowering your wheels

[Cole82]

Originally Posted by Mnster

I tried jacking with the links last night for hours on end with no change. I tired lowering the upper links no change. I tried a asmetrical setup no change in the amount of torque twist at all. The rear just has a lot of torque twist making it seem as though the rear suspension is rising but it's not best I can tell. The rear wrenchs over causing the truck to three wheel up a hill no matter what I do. There is zero torque twist in the front.

Don't pay attention to Mnster he had allmost zero torque twist at the comp today.
I guess the torque twist fairy payed him a visit and fixed for him.

[roddyf]

Tell me what you guys think of my link placement. I have some major torque twist. It is a 60/40 setup and seems to climb well, but the torque twist limits its ability to flex. I have a integy spring kit ordered that has 5 different set of spring rates. My rear axle is clocked and my front shocks have been shortened to 3.5 in in the front. Any ideas on how I could get rid of my torque twist? It is bad, as soon as you throttle it it lifts one front wheel and when reversing it lifts a rear wheel.

[Big Mike]

I'd say this is the root of your problem - heinously extreme angles in your front shaft. The torque applied to these joints when they're just about at the limit of their travel is going to induce lots of twist.
The hard part of it is that the exteme angle of the front driveline is caused by other discrepancies in your set up-
I can't figure out why this rig is so monster truck-like? Is it the shock placement? Those bent lower links?
Did you have to clock your rear axle that far to make your dig work?

[roddyf]

Yeah my ride height is 3.75" which i feel is a lil high. Right now it sits right at 12.5 wheelbase and if I move the links around too much I can't get the wheelbase set at 12.5. The rear axle is clocked that much just because thats how it worked out when mounting the links and it came out to 12.5 setup that way.

[carmatic]

Originally Posted by roddyf

Yeah my ride height is 3.75" which i feel is a lil high. Right now it sits right at 12.5 wheelbase and if I move the links around too much I can't get the wheelbase set at 12.5. The rear axle is clocked that much just because thats how it worked out when mounting the links and it came out to 12.5 setup that way.

are you willing to sacrifice your 12.5 number to be able to make the torque twist go away?