One-way front diff

[SilentWov]

I wanted to try a one-way front diff on race day today on my NTC3, but I wasn't expecting a bad loose condition after the change. Is this normal??????

It turns great, but was driving on egg shells to keep the back end from sliding out. I guess I can soften the rear suspension, but the change took me by surprise. Didn't think it would do that.

-Silent

 

[newnitrofan]

Hmmm that is a common problem with shaft driven cars man. My HPI RS4SS had a limited slip front diff that made that happen as well. Do you have any sort of a anti roll bar installed on the rear end??? This just might help. I actually had to stiffen my springs to have it help.

 

[SilentWov]

No roll bars front or rear. Wouldn't stiffening the rear springs only make it looser?

 

[KillerWabbit]

When is the car loose? With a front one-way, I imagine it wants to rotate during hard braking. You might want to first increase the rear toe and/or camber. You wouldn't want to put a sway bar in the rear or stiffen anything in the rear if it's loose. That'll make it worse. You'd put a sway bar up front and stiffen up the front springs if the car is oversteering.

 

[SilentWov]

Its bad loose entering the corner, especially after the 50-60' straight into a sweeper. I never use the brakes at all on this track. Before replying I double checked the brake wasn't dragging at neutral, and its not. Perhaps theres a little gear/motor backlash on the rear tires, that the fronts are no longer feeling????

Rear toe is already 2-3 degrees. I'll soften the rear springs and lighten the rear shock oil, maybe take some of the droop out. Last resort I'll add a front swaybar or blade, because I really do like the way it turns in <G>, just can't hang onto it sometimes.

Btw, I'm using a stratus touring body w/spoiler that was known to hook up pretty good prior to the change.

 

[KillerWabbit]

I wouldn't think the natural braking effect of the drivetrain to the rear wheels would be enough to cause it to be that loose.

If you're going to adjust the droop, you'd need to increase rear droop. More droop means more grip, but that also means less responsiveness and more body roll.

 

[SilentWov]

aight, here's my theory: Everyone's heard of rotating mass for acceleration. The spool-down of the differential gears, two-speed clutch, driveshaft, axles, wheels & tires (coasting), ie: the negative rotating mass of the driveline causes uneven drag and de-acceleration at the rear wheels making them slip a bit more than the front.

Who's buyin' it? :ahh:

 

[Lola GT]

That's what a one way is for, to get you into the corners like never before!

You're on the right track by softening the the rear shocks/springs.
You should have blade(adj) antiroll bars front and rear, get some if you don't.
That's what blades do, allow you to soften the suspension without getting body roll, blades do nothing until the car(chassis) tries to lean.