How important is ACKERMAN

[Charley7]

How important is Ackerman. Will it make a huge difference. My car has paralel steering from what I'm understanding.outer tierod is in line with lower ball joint. It's a front steer rack. If I can add Ackerman. Should I. I do some autocross with the car.


Thanks
charley

[GEARBOXGARAGE]

It helps with the slip angle of the inside front tire and allows it to gain better traction. Ron Sutton discusses this a lot in his workshops and anything you can do to increase the effectiveness of that inside front tire is going to get you through the corner faster. Adjusting steering arm lengths (or the distance of the outer tie rod from the ball joint center line) is an effect way to tune ackerman.

[Charley7]

Ok great thanks for the reply. I'll see what's an find on Ron Sutton.

Charley

[garvir]

a stock g-body has ackermann built into it, 8 degee turn you have approx 5 degree toe out (2 1/2"), 13 degree tire angle you have approx 5 1/2 degree toe out (inches are half of degrees 1" = 2degrees. i ended up using a little reverse ackermann on my 88 monte by using a 1990 camaro center link which i had to shorten up by 1", this setup angled my pitman and idler to 6 degree out, had to shim my idler off the frame by 1 1/4" to get them both at 6 degrees out. 6 degree tire angle now has 1/2 degee toe out (1/4"), at 0 toe. at 11 degree tire angle = 1/2 degree toe out, 15 degree tire angle = 1 degree toe in (1/2"). these measurements were taken at 0 toe, i run 1/4 degree total toe out (1/8") each side. toe out incourages the initiation of a turn, toe in discourages a turn. i did a lot of math to get these numbers, i did 1 degree tire angel to 10 degree tire angle, 6 degree was the best.

[Charley7]

How did you come up with all the measurements. Did you have it on an alignment machine.

Charley

[garvir]

i used a flat plate to get my measurements, a longacre caster camber tool, really quite accurate, i made a toe adjuster checker tool that is really simple and quite accurate. use the same tape measures so they weigh the same i set my tapes both at 82", there will be a little slump in the tapes but this way the slump is the same. i had to drop it down 7" to clear headers. simple cheep and accurate. you could spend $60.00 at the front end alighment place, but this is a easy setup takes me five minutes to hook up.

[Charley7]

That's really slick. Thanks.


Charley

[Kenova]

Absolutely brilliant!!!
Who doesn't have some leftover pieces of wood laying around?

Ken

[Interceptor5588]

Ackerman is super important in autocross. Imagine the power it takes to drag a 315mm tire sideways across the pavement with 1000 lbs on it, as that is what you're trying to do in a tight turn. Not so noticeable at speed

[Rod]

read what i wrote about it hereAutocross101

[Charley7]

Thank you for the reply. My car is a dual purpose. Everyday driving and I'm getting into autocross. So I'm trying to read/learn about tuning the suspension.

Charley

[T_Raven]

What really grinds my gears is all these books on suspension leave important things out. All I've ever read about ackerman is that it's a function of tie rod vs ball joint location. My buddy and I were discussing it recently when he mounted the rack in his truck project and he pointed out something I hadn't considered, and I've never seen in a book. Tie rod angle affects ackerman, so a car can have less than ideal steering arms but still have good ackerman.

Basically on a front steer car you want the tie rods to go out and forward from the rack/center link. Then when turning they flatten out and push the steering arms further apart. If your tie rods are inline with the rack/center link, they will pull closer together as you turn.

[Charley7]

Thanks for the diagram. I was looking at my rack and its a smidge forward of the tierods. But it I sat the same level. I think I'd like to move it back. Instead of having new steering arms made.

Charley

[frojoe]

An important thing to consider when tuning Ackerman is that simply changing the steering arms will adjust Ackerman, however it will change the quickness of your steering and steering angle range, which will likely be more noticeable than change in Ackerman if you already have a pretty dialed setup that you're used to. To get the same change in tie rod end angle (viewed from above looking down) by moving your rack, I bet the change in leverage on the steering arms will affect the steering quickness negligibly, if even at all, however you'll be doing very similar Ackerman adjustment as changing the steering arm lengths.

[garvir]

on g-body cars with the old parallel steer you need a little reverse ackermann, because they have so much ackermann built into them. it would be nice to have a rack and pinion steering, how come no one has been able to develope one. hot rods from hell has a new setup for the older c trucks that might be fit in there if you cut the k member out of the way. if you ever watch street racer the farm truck just had one of the hot rod from hell k member put into there truck.